Nowadays, those who want to purchase high-quality modern binoculars have a lot of options. The choice of a wide variety of equipment from global manufacturers is unusually large, including in online stores. But it is best to choose the one that suits you in terms of technical parameters and at the same time suits you in terms of price.

This device is quite technically complex, and it is sometimes difficult for the average consumer to understand its characteristics. For example, what does “30x60 binoculars” mean? Let's try to find out.

What types of binoculars are there?

When starting to make a choice, decide what approximation is enough for you to observe, will you use the device not only in bright light, but also in the twilight, will you be satisfied with a lightweight option with which long-term observation is possible? For the same 30x60 binoculars, reviews can be very different depending on the needs of the owner.

Therefore, it is so important to decide why exactly you are buying this device and under what conditions you are going to use it.

Binoculars can be theatrical and military, naval or night vision, as well as small compact ones - for those present at the stadium during competitions. Or, on the contrary, large ones, intended for observations by astronomers. Each variety has its own characteristics. Sometimes they differ quite significantly. To do good choice, let's get acquainted with the main ones.

What is multiplicity?

This is one of the most important characteristics of such a device as binoculars. Multiplicity tells us about the ability to increase the environment. If, for example, its indicator is 8, then at the maximum approximation you will view the observed object at a distance that is 8 times less than the one at which it actually is.

Trying to buy a device with the highest possible magnification ratio is unreasonable. This indicator should be related to the circumstances and place of use of the binoculars. For observations in the field, it is customary to use equipment with magnification numbers from 6 to 8. Magnification of binoculars of 8-10 times is the maximum at which you can observe handheld. If it is higher, jitter, which is also amplified by optics, will interfere.

Binoculars with significant magnification (from 15-20x) are used in conjunction with a tripod, on which they are mounted using a special adapter or adapter. The large weight and dimensions are not suitable for long-term wearing and in most cases are not needed, especially when the view is obstructed by many obstacles.

Models with variable magnification (pancratic) are produced. The degree of magnification in them is changed manually, like photographic lenses. But due to the increased complexity of the device, they are more expensive.

What does “30x60 binoculars” mean, or Let’s talk about lens diameter

The marking of any binocular contains the size of the diameter of the front lens of its objective, which is given immediately after the magnification index. For example, what does “30x60 binoculars” mean? These numbers are deciphered as follows: 30x is the magnification factor, 60 is the size of the lens diameter in mm.

The quality of the resulting image depends on the diameter of the lens. In addition, it determines the flow of light from binoculars - the larger the diameter, the wider it is. Binoculars marked 6x30, 7x35 or, in extreme cases, 8x42 are considered universal for hiking conditions. If you plan to conduct observations in nature during the day, and you will be looking at fairly distant objects, take a device with a magnification of 8 or 10 times and a lens with a diameter of 30 to 50 mm. But at dusk they are not very effective due to less light entering the lenses.

The best binoculars for spectators at sporting events are small (pocket size) with parameters around 8x24, they are good for general shots.

If there is not enough light

In poor lighting conditions (at dusk or dawn), you should either prefer the device large diameter lenses, or sacrifice magnification. The optimal ratio may be 7x50 or 7x42.

A separate group is the so-called night binoculars - active and passive. Passive lenses are equipped with a multi-layer coating that eliminates glare. They are used in the presence of minimal lighting (for example, moonlight). Active devices also work in complete darkness, as they use infrared radiation. Their disadvantage is their dependence on the power source.

Those who like to study space objects (for example, look at the topography of the lunar surface) need binoculars that are powerful enough, with a magnification of at least 20x. For a more detailed acquaintance with the night sky, it is better for an amateur astronomer to take a telescope, which in this case cannot be replaced even by the best binoculars.

What is viewing angle?

The viewing angle (or its field) is another important characteristic. This value in degrees indicates the width of coverage. This parameter is inversely dependent on magnification - powerful binoculars have a small “angle of view”.

Binoculars with a wide viewing angle are called wide-angle (or wide-field). They are convenient to take to the mountains to better navigate in space.

Often this indicator is expressed not as a graduated angle, but as the width of a segment or space that can be viewed at a standard distance of 1000 m.

Other binocular characteristics

The exit pupil diameter is the quotient of the entrance pupil diameter divided by the magnification value. That is, for binoculars marked 6x30 this figure is 5. The optimal number in this case is about 7 mm (the size of the human pupil).

What does "30x60 binoculars" mean in this case? The fact that the exit pupil size with this marking is 2. Such binoculars are suitable for not too long observation in good lighting, then the eyes are at risk of fatigue and overstrain. If the illumination leaves much to be desired, or long-term observation is required, this indicator should be at least 5, and preferably 7 or more.

Another parameter - aperture "controls" the brightness of the image. It is directly dependent on the diameter of the exit pupil. The abstract number that characterizes it is equal to the square of its diameter. In low light conditions, it is advisable to have this indicator at least 25.

The next concept is focus. Being central, it is a universal means of quickly focusing. Its regulator is located near the hinge connecting the pipes. For glasses wearers, it is advisable to have binoculars with diopter adjustment.

What else is important

Other, not so global characteristics of binoculars, nevertheless play a significant role in their choice. Depth of field is the length of the segment to the object of observation, on which it is not necessary to change the adjusted focus. The higher the magnification of the device, the lower it is.

Binoculars have the property of stereoscopicity (binocularity) characteristic of the human eye, which makes it possible to observe objects in volume and perspective. This is its advantage over a monocular or telescope. But this quality, useful in the field, interferes in other cases. Therefore, for example, in it is reduced to a minimum.

According to the optics systems, binoculars are lens (theater, Galilean) and prism (or field). The former have good aperture, direct image, low magnification and a narrow field of view. Secondly, prisms are used that turn the inverted image obtained from the lens into a familiar one. This reduces the length of the binoculars and increases the viewing angle.

The ability of a device to transmit rays of light, expressed as a fraction, is called. For example, with a loss of 40% of light, this coefficient is 0.6. Its maximum value is one.

What type of binocular body is there?

Its main advantage is strength. Shockproof qualities are ensured by the rubber coating of the case, which also ensures reliability when held in the hands and moisture resistance in wet weather.

Modern waterproof binoculars are so sealed that they can remain under water for some time at a depth of up to 5 meters without harm. The lenses protect against fogging by filling the space between them with nitrogen. These qualities are important for tourists, hunters, and naturalists. Binoculars with a rangefinder are useful for researchers, and a device with a dim matte surface is useful for those who like to watch animals.

Certain non-standard functions of individual devices, such as image stabilizer or a built-in compass, significantly increase the cost of binoculars and are welcome only when necessary. Decide for yourself whether you really need, for example, binoculars with a rangefinder, and whether you are willing to overpay for this option.

Information on steel pipes used for sanitary installations is given in Table 4-9.

Table 4. DIMENSIONS, mm, AND WEIGHT (WITHOUT COUPLING), kg, OF WATER AND GAS STEEL PIPES ACCORDING TO GOST 3262-75

Notes: 1.
By agreement with the consumer, light pipes with rolled threads. If the thread is made by rolling, then it is allowed to reduce the internal diameter of the pipe by up to 10% along the entire length of the thread.
2. At the customer's request, pipes with a nominal bore of more than 10 mm can be manufactured with cylindrical long or short threads at both ends and couplings with the same thread at the rate of one coupling for each pipe.
3. Pipes are supplied in unmeasured, measured and multiple measured lengths:
a) unmeasured length - from 4 to 12 m;
b) measured or multiple measured length - from 4 to 8 m (by agreement
I expect the manufacturer and the consumer and from 8 to 12 m) with an allowance for each
cut at 5 mm and maximum deviation over the entire length of +10 mm.

Table 5. DIMENSIONS, mm, AND WEIGHT, kg, OF WATER AND GAS SMOOTH CUT STEEL PIPES

Nominal diameter Dy	Outside diameter	Wall thickness	Weight 1 m	Nominal diameter Dy	Outer diameter	Wall thickness	Weight 1 m
10	16	2	0,69	32	41	2,8	2,64
15	20	2,5	1,08	40	47	3	3,26
20	26	2,5	1,45	50	59	3	4,14
25	32	2,8	2,02	65	47	3,2	5,59

Notes:
1. Smooth-edged pipes, manufactured to customer order, are intended for thread rolling.
2. By agreement with the consumer, smooth-edged
pipes with a wall thickness less than that indicated in the table.
3. See note. 3 to table 4.

Table 6. DIMENSIONS, mm, AND WEIGHT, kg, OF ELECTRIC-WELDED STRAIGHT-WELMED STEEL PIPES ACCORDING TO GOST 10704-76 (INCOMPLETE RANGE)

Outer						Mass;	a 1 m at	wall thickness
diameter Dн	1		2	2,5	3	3,5	4	4,5	5	5,5	6	7	8	A-
32	0,764	1,48		1,82	2,15	2,46							—	"yam
38	0,912	1,78		2,19	2,59	2,98	-	-	-.	-			-	-
45	1,09	2,12		2,62	3,11	3,58	-	-	-i		-	-	-	-
57	-	2,71		3,96	4	4,62	5,23			-	-	-	-	-
76		3,65		4,53	5,4	6,26	7,1	7,93	8,76	9,56			-,	-
89	-	4,29		5,33	6,36	7,38	8,39	9,38	10,36	11,33
114	-	_		6,87	8,21	9,54	10,85	12,15	13,44	14,72	—		-	-
133	-				9,62	11,18	12,72	14,62	15,78	17,29		—	-	-
159		-		-	11,54	13,42	15,29	17,15	18,99	20,82	22,64	26,24	29,8	-
219	-	-		-	-	-	-	23,8	26,39	28,96	31,52	36,6	41,6	46,61
273	-	-		-		-		-		-	39,51	45,92	52,28	58,6
325	-	-		-		-	-	-	39,46	43,34	47,2	54,9	62,54	70,14
377		-		-		-		-		-		63,87	72,8	81,68
426					-			-	-	-	-	72,33	82,47	92,56

Notes:
1. Pipes are manufactured with an outer diameter from 8 to 1420 mm with a wall thickness of up to 1 to 16 mm.

a) unmeasured length:

b) measured length:

pipes with a diameter of more than 426 mm are manufactured only in unmeasured lengths

Maximum deviations along the length of measuring pipes pipe length, m up to 6 more than 6 deviations along the length, mm, for pipes of class:
I +10 +15
II +50 +70
c) a multiple of the measured length of any multiplicity not exceeding the lower limit established for measuring pipes; at
In this case, the total length of the multiple pipes should not exceed the upper limit of the measuring pipes.

Maximum deviations for the total length of multiple pipes
pipe accuracy class - I, II
length deviation, mm - +15, +100
3. The curvature of the pipes should not be more than 1.5 mm and 1 m of their length.

Table 7. DIMENSIONS, mm, AND WEIGHT, kg, OF SEAMLESS COLD-FORMED STEEL PIPES ACCORDING TO GOST 8734-75 (INCOMPLETE RANGE)

Notes:
1. Pipes are made with an outer diameter from 5 to 250 mm with a wall thickness from 0.3 to 24 mm.
2. Pipes are supplied in unmeasured, measured and multiple measured lengths:
a) unmeasured length - from 1.5 to 11.5 m;
b) measured length - from 4.5 to 9 m with maximum length deviation + 10 mm;
c) multiple measured length - from 1.5 to 9 m with an allowance for each cut of 5 mm.
3. The curvature in any section of the pipe D n more than 10 mm should not exceed 1.5 mm per 1 m of length.
4. Depending on the ratio of the outer diameter Dн to the wall thickness S, pipes are divided into extra-thin-walled (with DH/S more than 40), thin-walled (with Dн/S from 12.5 to 40), thick-walled (with Dн/S from 6 to 40). 12.5) and extra-thick-walled (with Dн/S less than 6).

Table 8. DIMENSIONS, mm, AND WEIGHT, kg, OF SEAMLESS HOT-FORMED STEEL PIPES ACCORDING TO GOST 8732-78 (INCOMPLETE RANGE)

Notes: 1, Pipes are manufactured with a diameter from 14 to 1620 mm with a wall thickness from 1.6 to 20 mm.
2. Pipes are supplied in unmeasured, measured and multiple measured lengths:
a) unmeasured length - from 4 to 12.5 m;
b) measured length - from 4 to 12.5 m;
c) multiple measured lengths - from 4 to 12.5 m with an allowance for each cut of 5 mm.
Limit deviations along the length of measured and multiple pipes:

length, m up to 6 - deviation, mm +10
more than 6, or Dн more than 152 mm - deviation, mm +15

Table 9. DIMENSIONS, mm, AND WEIGHT, kg, OF GENERAL PURPOSE STEEL PIPES WITH A SPIRAL WELD ACCORDING TO GOST 8696-74 (INCOMPLETE RANGE)

diameter Dy	3,5	4	5	6	7	8	9	10	11	12
159	13,62	15,52
219	-	21,53	26,7	-	-	-	-	-	-	-
273			33,54	-	-	-	-	-	-	-
325	_		40,5	47,91	-	-		-	-	-
377	-	-	-	55,71	-	-	-	-	-	-
426	-	-	-	-	73,41	83,7	-	-	-	-
480	-	-	-	-	82,87	94,51	-	-	-	—
530	_	52,66	65,70	78,69	91,63	104,5	117,5	-	-	-
630	-	-	78,22	93,71	109,1	124,5	139,9	155,2	-	-
720	-	-	89,48	107,2	124,9	142,6	160,2	177,7	195,2	212,6
820	-	-	102	122,3	142,4	162,6	182,7	202,7	222,7	242,7

Notes:
1. Pipes by GOST 8696-74 not used for main gas and oil pipelines.
2. Pipes are supplied in lengths from 10 to 12 m, diameters from 159 to 1420 mm, and wall thicknesses from 3.5 to 14 mm.
Water and gas pipes are made in two types: non-galvanized (black) and galvanized. Galvanized pipes are used for the installation of drinking water supply systems. They are 3% heavier than non-galvanized ones.
Before threading, welded pipes must withstand the following test hydraulic pressure: 1.5 MPa (15 kgf/cm²) - ordinary and light; 3.2 MPa (32 kgf/cm²) - reinforced. At the customer's request, pipes are tested to a pressure of 4.9 MPa (49 kgf/cm²).
For cylindrical threads, threads with torn or incomplete threads are allowed if their total length does not exceed 10% of the required thread length.

Examples of pipe designation according to GOST 3262-75

For reinforced pipes, the letter U is written after the word “pipe”;
for light pipes - the letter L.
For lightweight knurled pipes, the letter N is written after the word “pipe”.

Areas of application of pipes and symbols used for pipe products

Application areas of pipe products

1. In the oil and gas industry:

• drill pipes – for drilling exploration and production wells;
• casing pipes - to protect the walls of oil and gas wells from destruction, water ingress into the wells, to separate oil and gas formations from each other;
• tubing pipes – for the operation of boreholes during oil production.

2. For pipelines:

• water and gas pipelines;
• oil pipelines (field, for main pipelines).

3. In construction.

4. In mechanical engineering:

• boiler pipes – for boilers of various designs;
• cracking pipes - for pumping flammable petroleum products under high pressure and for the manufacture of heating elements for furnaces;
• structural pipes – for the manufacture of various machine parts.

5. For the production of vessels and cylinders.

Pipe symbols

The first number above the line indicates outside diameter pipes in mm, the second - wall thickness in mm. This is followed by the designation of the dimension or multiplicity of pipes. If the pipe is dimensional, then its length is indicated in mm; if it is unmeasured, then after the multiplicity value there are the letters “cr”. For example: a pipe multiple of 1 m 25 cm is designated 1250 kr. If the pipe is undimensional, then the multiplicity (dimension) is not indicated.

After the multiplicity, the accuracy class of the pipe is indicated. Pipe lengths are manufactured in two accuracy classes:

1 – with cutting ends and deburring outside the mill line;

2 – with cutting in the mill line.

Maximum length deviations are smaller for pipes of 1st accuracy class. If the accuracy class is not specified, then the pipe is of ordinary accuracy.

The first number under the line indicates the quality group: A, B, C, D. This is followed by the steel grade and GOST steel.

In some cases, after the word trumpet, letters are placed indicating the following:

“T” - heat-treated pipes;

“C” - pipes with zinc coating;

“P” - threaded pipes;

“Pr” - pipes of precision manufacturing;

“M” - with coupling;

“N” - pipes for thread rolling;

“D” - pipes with long threads;

“P” - pipes of increased manufacturing strength.

2 . Classification of steel pipes

There are several ways to classify pipes.

By production method:

1. Seamless:

a)rolled, hot and cold;

b)cold-deformed in cold and warm condition;

c)pressed.

2. Welded:

a) rolled, in hot and cold conditions;

b) electric resistance welding;

c) gas-electric welding.

According to the pipe cross-section profile:

1. Round;
2. Shaped – oval, rectangular, square, three-, six- and octagonal, ribbed, segmented, teardrop-shaped and other profiles.

According to the outer diameter (Dnmm):

1. Small sizes (capillary): 0.3 - 4.8;
2. Small sizes: 5 – 102;
3. Medium sizes: 102 – 426;
4. Large sizes: over 426.

Depending on the ratio of the outer diameter to the pipe wall thickness:

№	Name	Dn/ ST	ST/Dn
1	Extra thick walled	5,5	0,18
2	Thick-walled	5,5 — 9	0,18 — 0,12
3	Normal	9,1 — 20	0,12 — 0,05
4	Thin-walled	20,1 — 50	0,05 — 0,02
5	Extra-thin-walled	50	0,02

By pipe class:

1. Pipes 1-2 classes are made of carbon steels. Pipes of class 1, the so-called standard and gas, are used in cases where no special requirements are imposed. For example, when constructing scaffolding, fencing, supports, for laying cables, irrigation systems, as well as for localized distribution and supply of gaseous and liquid substances.
2. Pipes class 2 used in high and low pressure main pipelines for supplying gas, oil and water, petrochemical products, fuel and solids.
3. Class 3 pipes used in systems operating under pressure and at high temperatures, nuclear technology, oil cracking pipelines, furnaces, boilers, etc.
4. Pipes class 4 designed for exploration and exploitation of oil fields, they are used as drilling, casing and auxiliary ones.
5. Class 5 pipes– structural – used in the production of transport equipment (automotive construction, carriage building, etc.), in steel structures (overhead cranes, masts, drilling derricks, supports), as furniture elements, etc.
6. 6th class pipes used in mechanical engineering for the manufacture of cylinders and pistons of pumps, bearing rings, shafts and other machine parts, tanks operating under pressure. There are pipes of small outer diameter (up to 114 mm), medium (114-480 mm) and large (480-2500 mm and more).

According to pipe supply standards (GOST):

1. General technical specification standards establish comprehensive technical requirements for the range, quality characteristics of pipes, acceptance rules and test methods;
2. assortment standards, which include standards for general-purpose pipes used in a wide variety of sectors of the national economy, provide for maximum deviations linear dimensions pipes (diameter, wall thickness, length, etc.), curvature and mass;
3. standards of technical requirements determine the basic technical requirements for pipes for general purposes, they specify steel grades, mechanical properties (tensile strength, yield strength, elongation, in some cases - impact, toughness of the pipe material); requirements for surface quality, as well as requirements for technological tests by hydraulic pressure, flattening, expansion, bending, etc. In addition, the standards of technical requirements for pipes stipulate acceptance rules, special requirements for labeling, packaging, transportation and storage;
4. test method standards define general testing methods for hardness and impact strength, control of micro and macrostructure, determination of susceptibility to intergranular corrosion, as well as test methods specific to pipes (bending, hydraulic pressure, beading, expansion, flattening, stretching, ultrasonic flaw detection, etc.)
5. standards for labeling, packaging, transportation and storage rules stipulate requirements for these final operations of pipe production that are common to all types of cast iron and steel pipes, as well as connecting parts.

3. Characteristics of standards for pipe products

3.1. General issues of standardization of pipe products

1. What's happened state standard, where is it used, who compiles and approves it?

Answer: GOST is a state standard that applies to the entire territory Russian Federation. The compilers and developers of GOSTs can be: scientific research institutes, enterprises, organizations, control bodies and laboratories. As a result, all materials on the new GOST or on the revision of the old one converge in the State Committee for Standardization, which gives a final assessment and approves the GOST for a product, product or entire process.

1. Who can cancel GOST or make changes or additions to it?

Answer: The validity period of GOST is 5 years, however, during this period changes and additions are allowed, which are also introduced and approved by the Committee for Standardization of the Russian Federation (currently URALNITI has such powers). Reprinting GOSTs is prohibited and is prosecuted as a violation of the law; this means that no one other than the organizations listed above can make changes to the standard and no one has the right not to comply with the requirements set out in it.

1. 3. What standard sections are there in GOST standards for pipe products, and what is their content?

Answer: GOSTs containing requirements for pipes are drawn up, as a rule, according to one scheme and contain the following sections:

• assortment;
• technical requirements for this product;
• acceptance rules;
• control and testing methods;
• labeling, packaging, transportation and storage.

Section "Assortment". Provides for limiting the production of pipes in a certain range of diameters (external and internal), wall thicknesses and lengths in accordance with this GOST. All types of permissible deviations in geometric parameters are also given here: diameter, wall thickness, length, ovality, chamfer, thickness difference, curvature. This section of GOST provides examples of pipe symbols with various requirements for geometric parameters, mechanical properties, chemical composition and other technical characteristics.

Section "Technical requirements". Contains a list of steel grades from which pipes can be made, or GOST standards for the chemical composition of different steel grades. This section contains rules mechanical properties(temporary tensile strength, yield strength, elongation, hardness, impact strength, relative contraction, etc.) for different grades of steel at different test temperatures. The types of heat treatment and technological tests are specified: bending, expansion, flattening, beading, hydro- and pneumatic tests.

In this section of almost any GOST, requirements for the condition of the surface are set and unacceptable and acceptable defects are listed.

It should be noted characteristic feature GOST – lack of references to product standards.

One of the important requirements of GOST is the condition of the ends of the pipes: pipes going further for welding must be chamfered at an angle of 30 -35 ° to the end, with end blunting, and all pipes with a wall thickness of up to 20 mm. must have evenly trimmed ends.

Section "Acceptance Rules". It explains how acceptance should be carried out in quantitative and qualitative terms. Sample standards for testing and control for various parameters are specified.

Section "Methods of control and testing". General rules for sampling and methods for monitoring surfaces and geometric parameters. In addition, brief information is provided, with reference to the relevant regulatory documentation, on the conduct of technological tests and control of mechanical properties, including non-destructive methods. From this section you can find out: which GOSTs should be used if it is necessary to carry out ultrasonic testing, tests for intergranular corrosion, and hydraulic pressure tests.

Section “Labelling, packaging, transportation and storage”. Does not contain information, as it redirects to GOST 10692 - 80.

1. 4. Why do GOSTs stipulate rules for product acceptance?

Answer: For each type of pipe there are certain acceptance rules. For example, for bearing pipes, standards have been established for metallographic tests (micro- and macrostructure), the content of non-metallic inclusions (sulfides, oxides, carbides, globules, micropores); for aircraft pipes, an additional condition is to control the size of the decarbonized layer and the presence of hairs (using the Magnoflox device), for stainless steel pipes - for intercrystalline corrosion, etc.

1. 5. Show the use of GOST.

Answer: Example: a 57*4mm pipe was ordered. made of steel grade 10, length multiple of 1250 mm., increased accuracy in diameter GOST 8732-78, gr. B and clause 1.13 of GOST 8731-74.

I. Let's define permissible deviations according to geometric parameters:

A) by diameter: according to table 2 of GOST 8732-78, the diameter tolerance will be± 0.456mm;

B) according to wall thickness: according to table 3 of GOST 8732-78, the tolerance for wall thickness will be +0.5mm, -0.6mm.

D) by length: according to clause 3 of GOST 8732-78, the minimum pipe length is 5025 mm, the maximum is 11305 mm.

D) pipe ovality: diameter tolerance* 2;

E) pipe wall thickness;

G) pipe curvature.

The symbol for the pipe in our example is: pipe 57p*4.0*1250kr GOST8732-78.

B 10 GOST 8732-74

II. Since the pipes were ordered according to group B of GOST 8731-74, it is necessary to check the compliance of their actual mechanical properties with the properties indicated in Table 2 of the said GOST:

A) tensile strength;

B) test for metal fluidity;

C) specimen elongation test.

1. Inspection of surfaces: unacceptable and acceptable defects.

IV. Trimming pipe ends and methods for determining the depth of a defect.

1. Since the order contains clause 1.13, it is necessary to carry out technological tests, in this case, check two samples for flattening.
2. The steel grade is determined by the sparking method.

VII. Labeling, packaging and storage (see GOST 10692-80).

1. 6. What are technical specifications and who writes them?

Answer: Technical specifications are a regulatory agreement concluded between the manufacturer of pipes (cylinders) and the consumer of the specified products.

The preparation of technical specifications is preceded by technical specifications, project development, numerous analyzes and examinations.

Specifications are approved by the technical managers of the manufacturing enterprise and the consumer enterprise, and then registered with UralNITI.

1. 7. How do technical conditions differ from GOST?

Answer: A feature of specifications is the use of non-standard requirements and characteristics (dimensions, permissible deviations, defects, etc.). One should not think that specifications are “weaker” than GOST and the technology for manufacturing products according to specifications can be simplified. On the contrary, a number of specifications contain more stringent requirements for manufacturing accuracy, surface cleanliness, etc., for which the buyer pays extra to the manufacturer.

A distinctive point is the flexibility of technical conditions, the ability to make some change or addition “on the fly” that does not require a long time for its approval. When working with specifications, a standardization system, one-time products, and individual orders are widely used.

1. 8. Scope of technical conditions.

Answer: There are technical conditions on a republican scale, for example. Specifications for all types of food products, as well as intradepartmental ones, for example, specifications for the supply of pipe blanks between the Pervouralsk New Pipe Plant and the Oskol EMC. Within our enterprise, there are 30 specifications for the supply of billets from pipe rolling shops to pipe drawing shops, and we apply up to 500 different specifications for all pipe products.

3.2. Characteristics of products manufactured in accordance with the main GOSTs

1. GOST – 10705 – 80 – electric-welded steel pipes

This standard applies to straight-seam steel pipes with a diameter of 8 to 520 mm with a wall thickness of up to 10 mm inclusive, made of carbon steel. It is used for pipelines and structures for various purposes.

A)irregular length (pipes not of the same length):

• with a diameter of up to 30 mm. – at least 2 m;
• with a diameter from 30 to 70 mm. – at least 3 m;
• with a diameter from 70 to 152 mm. – at least 4 m;
• with a diameter of more than 152 mm. – at least 5 m.

In a batch of pipes of unmeasured length, up to 3% (by weight) of shortened pipes is allowed:

• not less than 1.5 m – for pipes with a diameter of up to 70 mm;
• not less than 2 m – for pipes with a diameter of up to 152 mm;
• at least 4 m - for pipes with a diameter of up to 426 mm.

Pipes with a diameter over 426 mm are manufactured only in unmeasured lengths.

b)measured length(same length)

• with a diameter of up to 70 mm - from 5 to 9 m;
• with a diameter from 70 to 219 mm - from 6 to 9 m;
• with a diameter from 219 to 426 mm - from 10 to 12 m.

V)multiple length any multiplicity (2,4,6,8,10-fold 2), not exceeding the lower limit established for measuring pipes. In this case, the total length of the multiple pipes should not exceed the upper limit of the measuring pipes. The allowance for each multiple is set to 5 mm (GOST 10704-91).

Pipe lengths are manufactured in two accuracy classes:

1. with cutting edges and deburring outside the mill line;

2. with cutting in the mill line.

The maximum deviation for the total length of multiple pipes does not exceed:

• +15 mm – for pipes of 1st accuracy class;
• +100 mm – for pipes of accuracy class 2 (according to GOST 10704-91).

The curvature of the pipes should not exceed 1.5 mm per 1 meter of length.

Depending on the quality indicators, pipes of the following groups are manufactured:

A– with standardization of mechanical properties of calm, semi-quiet and boiling steel grades St2, St3, St4 according to GOST 380-88;

B– with standardization of the chemical composition of calm, semi-quiet and boiling steel grades 08, 10, 15 and 20 according to GOST 1050-88. And steel grade 08Yu according to GOST 9045-93.

IN– with standardization of mechanical properties and chemical composition of calm, semi-quiet and boiling steel grades VSt2, VSt3, VSt4 (categories 1, 23-6), as well as calm, semi-quiet and boiling steel grades 08, 10, 15, 20 according to GOST 1050- 88 and steel grades 08Yu according to GOST 90-45-93 for diameters up to 50 mm.

D– with test standardization hydraulic pressure.

They produce heat-treated pipes (throughout the entire volume of the pipe or welded joint) and pipes without heat treatment.

2. GOST 3262 – 75 – steel water and gas pipes

This standard applies to non-galvanized and galvanized welded steel pipes with cut or rolled cylindrical threads and without threads. They are used for water and gas pipelines, heating systems, as well as for parts of water and gas pipeline structures. Pipe lengths range from 4 to 12 meters.

When determining the mass of non-galvanized pipes relative density steel was taken equal to 7.85 g/cm. Galvanized pipes are 3% heavier than non-galvanized pipes.

The following pipe lengths are produced:

A)of unmeasured lengthfrom 4 to 12 m.

According to GOST 3262-75, up to 5% of pipes with a length of 1.5 to 4 m are allowed in a batch.

b)measured or multiple length from 4 to 8 m (by order of the consumer), and from 8 to 12 m (by agreement between the manufacturer and the consumer) with an allowance for each cut of 5 mm and a maximum deviation for the entire length plus 10 mm.

According to GOST 3262-75, maximum deviations in pipe mass should not exceed +8%.

The curvature of pipes per 2 m length should not exceed:

• 2 mm – with nominal bore up to 20 mm;
• 1.5 mm – with a nominal bore over 20 mm.

The ends of the pipes must be cut at right angles.

Galvanized pipes must have a continuous zinc coating of the entire outer and inner surface with a thickness of at least 30 microns. The absence of the specified coating is allowed on the ends and threads of pipes and couplings.

3. GOST 8734 – 75 – cold-deformed seamless steel pipes

Manufactured:

A)of unmeasured lengthfrom 1.5 to 11.5 m;

b)measured lengthfrom 4.5 to 9 m with an allowance for each cut of 5 mm.

In each batch of pipes of standard length, no more than 5% of pipes of unmeasured length are allowed, not shorter than 2.5 m.

According to GOST 8734-75, the curvature of any pipe section per 1 m of length should not exceed:

• 3 mm – for pipes with a diameter of 5 to 8 mm;
• 2 mm – for pipes with a diameter of 8 to 10 mm;
• 1.5 mm – for pipes with a diameter over 10 mm.

4. GOST 8731 – 81 – hot-deformed seamless steel pipes

This standard applies to hot-formed seamless pipes made of carbon, low-alloy, alloy steel for pipeline structures, machine parts and chemical purposes.

Pipes made from ingots are not allowed to be used for transporting hazardous substances (classes 1, 2, 3), explosive and fire hazardous substances, as well as steam and hot water.

The technical level indicators established by this standard are provided for the highest quality category.

Technical requirements

Pipe dimensions and maximum deviations must comply with those given in GOST 8732-78 and GOST 9567-75.

Depending on the standardized indicators, pipes should be manufactured in the following groups:

A– with standardization of mechanical properties of steel grades St2sp, St4sp, St5sp, St6sp according to GOST 380-88;

B– with standardization of the chemical composition of mild steel grades according to GOST 380-88, 1st category, group B, with normal mass fraction manganese according to GOST 1050-88, as well as steel grades according to GOST 4543-71 and GOST 19281-89;

IN– with standardization of mechanical properties and chemical composition of steel grades according to GOST 1050-88, GOST 4543-71, GOST 19281-89 and GOST 380-88;

G– with standardization of the chemical composition of steel grades according to GOST 1050-88, GOST 4543-71 and GOST 19281-89 with control of mechanical properties on heat-treated samples. The standards of mechanical properties must correspond to those specified in the steel standards;

D– with standardization of test hydraulic pressure, but without standardization of mechanical properties and chemical composition.

Pipes are manufactured without heat treatment. At the request of the consumer, pipes must be manufactured heat-treated.

5. GOST – 20295 – 85 – welded steel pipes

Used in main gas and oil pipelines.

This standard applies to straight-seam and spiral-welded steel pipes with a diameter of 159-820 mm used for the construction of main gas and oil pipelines, oil product pipelines, process and field pipelines.

Main parameters and dimensions .

Pipes are made of three types:

1. longitudinal welded with a diameter of 159-426 mm, manufactured by resistance welding with high frequency currents;

2. spiral welded - with a diameter of 159-820 mm, made by electric arc welding;

3. straight-seam - with a diameter of 530-820 mm, made by electric arc welding.

4.3. Questions about the steel grades used

1. 1. By what criteria are steels classified?

Answer: Steels are classified:

• by chemical composition: carbon, alloyed (low-, medium-, high-alloyed);
• by structure: hypoeutectoid, hypereutectoid, ledeburite (carbide), ferritic, austenitic, pearlitic, martensitic;
• by quality: ordinary quality, high quality, high quality, especially high quality;
• by application: structural, instrumental, with special operational properties (heat-resistant, magnetic, corrosion-resistant), with special physical properties.

1. 2. What does the designation of steel grades consist of? (examples).

Answer: All steels have their own markings, which primarily reflect their chemical composition. In steel markings, the first digit indicates the content in hundredths of a percent. Then follow the letters of the Russian alphabet, indicating the presence of an alloying element. If there is no number after the letter, this means that the content of the alloying element is no more than one percent, and the numbers following the letter mean its content in percent. Example: 12ХН3А – carbon content – ​​0.12%; chromium – 1.0%; nickel – 3.0%; High Quality.

1. 3. Decipher the following designations of steel grades:

20A, 50G, 10G2, 12Kh1MF, 38Kh2MYuA, 12Kh18N12T, 12Kh2MFSR, 06Kh16N15M2G2TFR – ID, 12Kh12M1BFR – Sh.

Answer:

• 20A – carbon content 0.2%, high quality;
• 50G – carbon content – ​​0.5%, manganese – 1%;
• 10G2 - carbon content - 0.1%, manganese - 2%;
• 12Х1МФ - carbon content - 0.12%, chromium - 1%, molybdenum, tungsten - up to 1%;
• 38Х2МУА - carbon content - 0.38%, chromium - 2%, molybdenum, aluminum - up to 1%, high quality;
• 12Х18Н12Т – carbon content – ​​0.12%, chromium – 18%, nickel – 12%, titanium – up to 1%;
• 12X2MFSR - carbon content - 0.12%, chromium - 2%, molybdenum, tungsten, silicon, boron - up to 1%;
• 06Х16Н15М2Г2ТФР - ID - carbon content - 0.06%, chromium - 16%, nickel - 15%, molybdenum - 2%, manganese - 2%, titanium, tungsten, boron - up to 1%, vacuum - induction plus arc remelting;
• 12Х12М1БФР – Ш – carbon content – ​​0.12%, chromium – 12%, molybdenum – 1%, niobium, tungsten, boron – up to 1%, slag remelting.

1. 4. How is the method of steel production reflected in the designations of steel grades?

Answer: In recent years, to improve the quality of steel, new methods of smelting have been used, which are reflected in the designations of steel grades:

• VD – vacuum-arc;
• VI – vacuum – induction;
• Ш – slag;
• PV – direct reduction;
• ESR – electron slag remelting;
• SD – vacuum-arc after slag remelting;
• EBL – electron beam remelting;
• PAP – plasma-arc remelting;
• IS – vacuum-induction plus electroslag remelting;
• IP - vacuum-induction plus plasma-arc remelting.

In addition to those listed, pipes are manufactured from experimental steel grades with the following designations:

• EP – Elektrostal search;
• EI – Elektrostal Research;
• ChS – Chelyabinsk steel;
• ZI – Zlatoust research;
• VNS – VIEM stainless steel.

According to the degree of deoxidation, steels are marked as follows: boiling - KP, semi-calm - PS, calm - SP.

1. 5. Talk about carbon steel grades.

Answer: Carbon steel is divided into structural and tool by purpose. Structural carbon steel is steel containing up to 0.6% carbon (as an exception, 0.85% is allowed).

Based on quality, structural carbon steel is divided into two groups: ordinary quality and high-quality.

Ordinary quality steel is used for non-critical building structures, fasteners, sheet metal, rivets, welded pipes. GOST 380–88 is established for structural carbon steel of ordinary quality. This steel is smelted in oxygen converters and open-hearth furnaces and is divided into three groups: group A, supplied according to mechanical properties; group B, supplied by chemical composition and group B, supplied by mechanical properties and chemical composition.

High-quality carbon structural steel is supplied according to its chemical composition and mechanical properties, GOST 1050-88. It is used for parts operating under high loads and requiring resistance to impact and friction: gears, axles, spindles, ball bearings, connecting rods, crankshafts, for the manufacture of welded and seamless pipes. Automatic steel also belongs to structural carbon steels. To improve cutting processing, sulfur, lead, and selenium are introduced into its composition. This steel is used to make pipes for the automotive industry.

Tool carbon steel is steel containing 0.7% carbon or more. It is characterized by hardness and strength and is divided into high-quality and high-quality.

Quality steel grades according to GOST 1435-90: U7, U8, U9, U10A, U11A, U12A, U13A. The letter "U" stands for carbon tool steel. The numbers behind the letter “Y” indicate the average carbon content in tenths of a percent. The letter "A" at the end of the brand indicates high-quality steel. The letter "G" means high manganese content. Chisels, hammers, stamps, drills, stamps, and various measuring instruments are made from tool carbon steel.

1. 6. Tell us about alloy steel grades.

Answer: In alloy steel, along with the usual impurities (sulfur, silicon, phosphorus), there are alloying ones, i.e. binding elements: chromium, tungsten, molybdenum, nickel, as well as silicon and manganese in increased quantities. Alloy steel has highly valuable properties that carbon steel does not have. The use of alloy steel saves metal and increases the durability of products.

The influence of alloying elements on the properties of steel:

• chromium – increases hardness,corrosion resistance;
• nickel – increases strength, ductility, corrosion resistance;
• tungsten – increases hardness and red resistance, i.e. ability to maintain high temperatures wear resistance;
• vanadium – increases density, strength, impact and abrasion resistance;
• cobalt – increases heat resistance, magnetic permeability;
• molybdenum – increases red resistance, strength, corrosion resistance at high temperatures;
• manganese – with a content of more than 1.0% increases hardness, wear resistance, and resistance to shock loads;
• titanium – increases strength and corrosion resistance;
• aluminum – increases scale resistance;
• niobium – increases acid resistance;
• copper – reduces corrosion.

In steel special purpose Rare earth elements are also introduced; alloyed steels can contain several alloying elements simultaneously. According to their purpose, alloy steels are divided into structural, tool and steels with special physical and chemical properties.

Structural alloy steel according to GOST 4543-71 is divided into three groups: high-quality, high-quality, especially high-quality. In high-quality steel, a sulfur content of up to 0.025% is allowed, and in high-quality steel - up to 0.015%. The scope of application of structural alloy steel is very wide. The most common steels are:

• chromium, with good hardness and strength: 15X, 15XA, 20X, 30X, 30XRA, 35X, 40X, 45X
• manganese, characterized by wear resistance: 20G, 50G, 10G2, 09G2S (ts. 5,8,9);
• chromomanganese: 19ХГН, 20ХГТ, 18ХГТ, 30ХГА;
• silicon and chromium-silicon, with high hardness and elasticity: 35ХС, 38ХС;
• chrome-molybdenum and chrome-molybdenum-vanadium, especially durable, resistant to abrasion: 30ХМА, 15ХМ, 15Х5М, 15Х1МФ;
• chromium-manganese-silicon steels (chromansil): 14KhGSA, 30KhGSA, 35KhGSA;
• chromium-nickel, very durable and ductile: 12Х2Н4А, 20ХН3А, 12ХН3А;
• chromium-nickel-tungsten, chromium-nickel-vanadium steels: 12Kh2NVFA, 20Kh2N4FA, 30KhN2VA.

Tool alloy steel is used for the manufacture of cutting, measuring and impact stamping tools. The most important elements Such steels are chromium, tungsten, molybdenum, manganese. Measuring tools are made from this steel - thread gauges, staples (7ХФ, 9ХФ, 11ХФ); cutting – cutters, drills, taps (9ХС, 9Х5ВФ, 85Х6НФТ); stamps, press molds (5ХНМ, 4Х8В2). The most important tool alloy steel is high-speed. Used in the manufacture of drills, cutters, taps. The main properties of this steel are hardness and red resistance. The alloying elements are tungsten, chromium, cobalt, vanadium, molybdenum - R6M3, R14F14, R10K5F5, etc.

1. 7. Tell us about stainless steel grades.

Answer:

• Corrosion-resistant – high-chromium steels alloyed with nickel, titanium, chromium, niobium and other elements. Designed to work in environments of varying aggressiveness. For weak aggressive environments steels 08Х13, 12Х13, 20Х13, 25Х13Н2 are used. Parts made from these steels work on outdoors, in fresh water, in wet steam and salt solutions at room temperature.

For environments of medium aggressiveness, steels 07Х16Н6, 09Х16Н4Б, 08Х17Т, 08Х22Н6Т, 12Х21Н5Т, 15Х25Т are used.

For environments of increased aggressiveness, steels 08Х18Н10Т, 08Х18Н12Т, 03Х18Н12 are used, which have high resistance to intergranular corrosion and heat resistance. The structure of corrosion-resistant steels, depending on the chemical composition, can be martensitic, martensitic-ferritic, ferritic, austenitic-martensitic, austenitic-ferritic, austenitic.

• Cold-resistant steels must retain their properties at -40° С –80° C. The most widely used steels are: 20Х2Н4ВА, 12ХН3А, 15ХМ, 38Х2МУА, 30ХГСН2А, 40ХН2МА, etc.
• Heat-resistant steels are able to withstand mechanical loads at high temperatures (400 – 850° WITH). Steels 15Х11МФ, 13Х14Н3В2ФР, 09Х16Н15М3Б, and others are used for the manufacture of steam superheating devices and blades steam turbines, high pressure pipelines. For products operating at higher temperatures, steels 15Х5М, 16Х11Н2В2МФ, 12Х18Н12Т, 37Х12Н8Г8МБФ, etc. are used.
• Heat-resistant steels are able to resist oxidation and scaling at temperatures of 1150 - 1250° For the manufacture of steam boilers, heat exchangers, thermal furnaces, equipment operating at high temperatures in aggressive environments, steel grades 12Х13, 08Х18Н10Т, 15Х25Т, 10Х23Н18, 08Х20Н14С2, etc. are used.
• Heat-resistant steels are intended for the manufacture of parts operating under load at a temperature of 600 ° C for a long period of time. These include: 12Х1МФ, 20Х3МВФ, 15Х5ВФ, etc.

1. 8. The influence of harmful impurities on the quality of steel.

Answer: Most alloying elements are aimed at improving the quality of steels.

At the same time, there are steel components that negatively affect its quality.

• Sulfur gets into steel from cast iron, and into cast iron from coke and ore. Sulfur and iron form a compound located along the grain boundaries of steel. When heated to 1000 -1200 ° C (for example, when rolling), it melts, the bond between the grains is weakened, and the steel is destroyed. This phenomenon is called red brittleness.
• Phosphorus, like sulfur, enters steel from ores. It greatly reduces the ductility of steel; steel becomes brittle at normal temperatures. This phenomenon is called cold brittleness.
• Oxygen is partially dissolved in steel and is present in the form of non-metallic inclusions - oxides. Oxides are brittle; during hot processing they do not deform, but crumble and loosen the metal. As the oxygen content increases, tensile strength and impact strength decrease significantly.
• Nitrogen is absorbed from the atmosphere by the liquid metal during melting and is present in the steel in the form of nitrides. Nitrogen reduces the toughness of carbon steels.
• Hydrogen can be present in steel in the atomic state or in the form of compounds with iron - hydrides. Its presence in large quantities leads to the occurrence of internal stresses in the metal, which can be accompanied by cracks and ruptures (flocks). Titanium alloys are very sensitive to hydrogen saturation, where special measures are taken to prevent hydrogenation of the metal.
• Copper - in high content (over 0.18%) in low-carbon steels significantly increases the steel’s susceptibility to aging and cold brittleness.

4.4. Raw material for pipe production

The starting material for the production of seamless pipes is usually mild steel; for welded pipes, mild steel, semi-mild steel, and boiling steel are equally used.

Advantages of boiling steel: smaller size of the primary shrinkage cavity; complete absence of secondary shrinkage cavity; less non-metallic inclusions; better surface quality; higher metal ductility; the strength of the metal is lower and the toughness is higher; lower production cost.

Disadvantages of boiling steel: higher concentration of impurities; there are more subcortical bubbles and it is more difficult to control the process of their formation; more intensive aging of the metal and less resistance to corrosion.

Advantages of mild steel: less concentration of harmful impurities; absence of subcortical bubbles.

Disadvantages of quiet steel: larger dimensions of the primary shrinkage cavity; secondary shrinkage cavity is significant; worse surface quality; less metal viscosity; production is more expensive.

For the production of seamless pipes, boiling and semi-quiet steel is used only for pipes of less critical purposes precisely because of the high concentration of impurities and a significant number of subcortical bubbles. In recent years, to improve the quality of pipe steel, blowing liquid metal with argon, vacuuming, treating steel with synthetic slags, and additives have been used powder reagents. Steels with a high carbon content are used to make large-diameter pipes, which are used in the oil industry as casing and drill pipes, as well as other critical pipes. Steels with lower carbon content are used for the production of steam boiler pipes and other pipes.

Depending on the production method, the blank for the manufacture of pipes enters the workshop either in the form of a faceted cast ingot or an ingot in the shape of a truncated cone, a solid rolled rod of round or square section, a hollow cylindrical blank made by centrifugal casting, or in the form of strips and sheets.

Welded pipes and blanks for all other products are obtained from strip and sheet billets. listed types designed for the production of seamless pipes.

To produce pipes from high-alloy, low-plasticity steels, hollow cylindrical blanks have recently been used as blanks. At the same time, the labor-intensive and sometimes impossible operation of piercing the workpiece (obtaining a hollow workpiece from a solid-section workpiece) from these steels is eliminated.

Some pipe rolling plants use square or polyhedral ingots.

Solid cylindrical ingots are used to produce finished pipes by pressing.

Round rolled billets are usually used in the production of pipes with a diameter of less than 140 mm . Some installations produce pipes with a diameter of over 140 mm from a round rolled billet, maximum diameter which reaches 320-350 mm.

For the production of welded pipes with a diameter of up to 520 mm In various installations, hot-rolled (strip), hot-rolled pickled and cold-rolled strips are used.

On modern mill designs, the strip is fed in the form of rolls of varying weights depending on the length of the strip in the roll and the size of the produced pipes. In some installations, strips with beveled edges are used to obtain a high-quality weld.

Pipes with a diameter of over 520 mm are welded from individual sheets of hot-rolled steel.

In the metal supplied for the manufacture of pipes, various defects are sometimes observed, often associated with the technology of its production: non-metallic inclusions in various types of workpieces, shrinkage cavities, bubbles, cracks in ingots; films and burrs on rolled workpieces; tears, delaminations and distorted dimensions of sheets, etc.

These defects can affect the quality of the resulting pipes. Therefore, careful preliminary inspection, repair and metal rejection greatly contribute to the production of high-quality steel pipes.

The methods used to detect internal defects in the workpiece (non-metallic inclusions, shrinkage cavities, bubbles, etc.) are provided for in the technical conditions for the delivery of the workpiece.

obtaining high-quality steel pipes.

4.5. Technology for the production of pipes, bends and cylinders

The technology for the production of pipe products is considered using the example of organizing production at OJSC Pervouralsk New Pipe Plant.

Hot rolled pipe production technology

Raw materials for the production of hot-rolled pipes in the form of round rods come from metallurgical plants.

Hot-rolled pipes are shipped to end consumers and are also used as blanks for cold processing (production of cold-deformed pipes).

For the production of seamless hot-rolled pipes, the plant uses two installations with pipe rolling on a short mandrel (Stifel type), one installation with pipe rolling on a long mandrel in a three-roll stand (Assel type), and one installation with a continuous mill with pipe rolling on a long movable mandrel .

In Fig. Figure 1 shows the technological process of mill 30-102, which produces pipes with a diameter of 32-108 mm and a wall thickness of 2.9 to 8 mm. The unit's capacity is 715 thousand tons of pipes per year.

Rice. 1. Hot rolled pipe production process

The technological process for manufacturing pipes on a unit with a continuous mill consists of the following operations:

• preparing the workpiece for rolling;
• heating the workpiece;
• stitching the workpiece into the sleeves;
• rolling sleeves into pipes on a continuous mill;
• heating pipes before calibration or reduction;
• rolling pipes on a sizing or reduction mill;
• pipe cutting;
• pipe cooling and finishing.

The main advantage of the unit is its high productivity and high quality pipes. The presence of a modern reduction mill operating with tension in the 30-102 mill significantly expands the range of rolled pipes, both in diameter and in wall thickness.

On a continuous mill, rough pipes of one constant size are rolled, which are then brought to the sizes specified by orders in a sizing or reduction mill.

The workpiece is heated in two 3-strand sectional furnaces, each about 88 meters long. The heating part of the sectional furnace is divided into 50 sections; they, in turn, are divided into 8 zones. Temperature in each zone is supported automatically.

The correct heating of the metal is controlled by a photoelectric pyrometer, which measures the temperature of the sleeve emerging from the rolls of the piercing mill. The workpiece heated in the oven is cut using cantilever-type scissors with a bottom cut. The piercing of the heated and centered workpiece is carried out on a 2-roll piercing mill with barrel-shaped rolls and axial delivery.

Rolling of pipes in a continuous mill. The name of the mill means the continuity of the process and the simultaneous presence of the processed metal in several stands. A long cylindrical mandrel is inserted into the sleeve obtained after rolling on a piercing mill, after which it, together with the mandrel, is directed into the rolls of a continuous mill. The mill consists of 9 stands of the same design, located at an angle of 45 degrees to the floor plane and 90 degrees to each other. Each stand has two rolls with round grooves.

After removing the long mandrel from the pipe, they are sent to a 12-stand calibration mill to obtain a diameter within the specified limits, or to a 24-stand reduction mill to roll pipes to lower diameters.

Before calibration or reduction, the pipes are heated in heating induction furnaces. From the calibration table, pipes with a diameter of 76 to 108 mm are obtained, after the reduction table - from 32 to 76 mm.

Each stand of both mills has three rolls located at an angle of 120 degrees

in relation to each other.

Pipes rolled on a sizing mill and having a length of over 24 meters are cut in half on a stationary circular saw. After rolling on a reduction mill, the pipes are cut with flying shears into lengths from 12.5 to 24.0 meters. In order to eliminate curvature and reduce ovality cross section After cooling, the pipes are straightened on a straightening mill.

After straightening, the pipes are cut into lengths.

Pipe finishing is carried out on production lines, which include: pipe trimming machines, pipe trimming machines, a purge chamber for removing chips and scale, and a quality control inspection table.

Technology for the production of cold-formed pipes

Cold-deformed pipes are made from hot-rolled billets (hot-rolled pipes of our own production), subjected, if necessary, to mechanical boring and turning. Rolling is carried out in warm or cold mode using technological lubricants.

For the production of cold-deformed pipes with a diameter from 0.2 to 180 mm with a wall thickness from 0.05 to 12 mm from carbon, alloy and high-alloy steels and alloys, the plant uses 76 cold rolling mills, 33 pipe drawing mills and 41 cold pipe rolling mills, coil and long-mandrel mills drawing There are production lines for coil drawing of especially thick-walled pipes for fuel lines of diesel engines, fin pipes for boilers of steam superheaters of thermal power plants, profile seamless and electric-welded cold-deformed pipes are manufactured. various shapes.

The high quality of pipes is ensured by the use of heat treatment in a protective atmosphere, as well as grinding and electropolishing of internal and external surfaces.

In Fig. 2 are given technological processes, used in the manufacture of cold-deformed pipes.

Fig.2. Cold-formed pipe production process

The technology of pipe manufacturing in pipe drawing shops has the following general sections:

• preparation of workpieces for production;
• cold rolling of pipes;
• cold drawing of pipes;
• combined method (rolling and drawing);
• heat treatment of finished and intermediate pipes;
• chemical treatment of finished and intermediate pipes;
• finishing;
• control of finished products.

All workpieces submitted for inspection are first subjected to pickling to remove scale remaining on the pipes after hot rolling. Pickling is carried out in the baths of the pickling department. After pickling, the pipes are sent for washing and drying.

Cold rolling mills for pipes are designed for cold and warm rolling of pipes made of carbon, alloy, stainless steels and alloys. Characteristic feature and the advantage of CPT mills is the ability to achieve a 30-88% reduction in the cross-sectional area of ​​pipes and an elongation factor from 2 to 8 or more in one rolling cycle.

The designs of CHP mills installed in the plant's workshops are varied and differ from each other in standard sizes, the number of simultaneously rolled pipes and modifications.

The drawing process (at the plant only cold drawing of pipes is used) consists of passing (pulling) the billet pipe through a drawing ring, the diameter of which is smaller than the diameter of the workpiece.

Technological lubricant (its composition varies depending on the drawing method) is applied to the pipes to reduce the coefficient of friction during drawing.

The plant also uses pipe drawing on drums.

All pipes after drawing (drawn to the finished size or intermediate), as a rule, are subjected to heat treatment in continuous muffle or roller furnaces. The exception is some types of pipes, which are delivered without heat treatment.

Heat-treated pipes undergo straightening: preliminary straightening on cam straightening presses and roller straightening machines and final straightening on roller straightening mills.

Cutting the ends of pipes with deburring and cutting measures is carried out using pipe cutters or with abrasive wheels machines. To completely remove burrs, a number of workshops use steel brushes.

Pipes that have passed all finishing operations are presented for inspection at the inspection tables of the quality control department.

Electric welded pipe production technology

To produce straight-seam electric-welded pipes with diameters from 4 to 114.3, the plant has 5 electric welding mills. In the production of pipes from carbon steels, the method of high-frequency welding is used, and from high-alloy steels - arc welding in an inert gas environment. These technologies combined with by physical methods control and hydraulic tests ensure the reliability of pipes when used in mechanical engineering and building structures.

Removal of internal burr and high cleanliness of the inner surface of the pipes make it possible to obtain high quality products. Additionally, welded pipes can be subjected to mandrel and non-mandrel drawing and rolling on roller mills. Heat treatment in an oven with a protective atmosphere ensures a light-colored surface of the pipes.

The factory uses the most modern technology welding - high frequency currents (radio frequency). The main advantages of this pipe welding method:

• possibility of achieving high welding speed;
• obtaining pipes with high-quality seams from hot-rolled unetched billets;
• relatively low energy consumption per 1 ton of finished pipes;
• the possibility of using the same welding equipment when welding various low-alloy steel grades.

The principle of the method is as follows: a high-frequency current, passing near the edges of the tape, intensively heats them up, and when they come into contact in the welding unit, they are welded due to the formation of a crystal lattice. An important advantage of the high-frequency welding method is that the microhardness of the weld and transition zone differs by only 10 - 15% from the microhardness of the base metal. Such a structure and properties of a welded joint cannot be obtained by any of the existing pipe welding methods.

In Fig. Figure 3 shows the technological process for the production of electric-welded pipes for household refrigerators.

Fig.3. Electric welded pipe production process

The raw material for the production of electric-welded pipes is strip (rolled sheet metal) coming from metallurgical plants. The workpiece comes in rolls with a width of 500 to 1250 mm, and for the production of pipes a strip with a width of 34.5 - 358 mm is required, i.e. The roll must be cut into narrow strips. A slitting unit is used for this purpose.

The joined strip is fed by pulling rollers into the strip drum storage to ensure a continuous technological process due to the created reserve of strip. From the storage, the tape enters the forming mill, which consists of 7 stands of two rolls each. Between each stand there is a pair of vertical (edger) rolls to stabilize the movement of the belt. The forming machine is designed for cold profiling of the strip into an endless billet.

The formed pipe (but with an open gap between the edges) enters the welding unit of the mill, where the edges are welded using high-frequency currents. Due to the pressure of the welding unit, part of the metal protrudes both inside the pipe and outside in the form of a burr.

After welding and removal of the outer flash, the pipe is directed along a roller conveyor located in a closed chute to the calibration and profiling unit, while it is generously watered with cooling emulsion. The cooling process continues both in the calibrating and profiling mill and when cutting the pipe with a flying circular saw.

Calibration of round pipes is carried out in a 4-stand calibration mill. Each stand has two horizontal rolls, and between the stands there are vertical rolls, also two each.

Profiling of square and rectangular pipes is carried out in four 4-roll stands of the profiling section.

Electric-welded pipes for household refrigerators, after profiling, additionally undergo high-frequency annealing, cooling and then enter a galvanizing bath to be coated with an anti-corrosion coating.

The finishing equipment for electric welded pipes includes: a facing machine with two end heads for processing pipe ends; hydraulic press for testing pipes, if prescribed by regulatory documentation; baths for pneumatic testing of pipes for refrigerators.

Technology for the production of polyethylene-lined pipes

Polyethylene-lined steel pipes and connecting parts of pipelines (bends, tees, transitions) are designed to move aggressive media, water and oil under pressure up to 2.5 MPa and are used in the chemical and oil refining industries.

Maximum operating temperature of lined pipes + (plus) 70° C, minimum temperature installation for pipes with flanges 0°C, for wafer connections - (minus) 40°C.

The plant produces complete steel, polyethylene-lined pipelines with flanged connections ready for installation, which include: lined pipes, equal-bore and transition tees, concentric transitions and bends.

Lined pipes can be with internal, external or double (inside and outside) lining. Lined pipes are distinguished by the strength of steel and the high corrosion resistance of plastics, which allows them to effectively replace pipes made of high-alloy steel or non-ferrous metals.

Low-pressure polyethylene (high density) of pipe grades is used as a lining layer, which protects the metal both from internal corrosion due to the influence of transported products, and from external corrosion - soil or air.

In Fig. 4 shows the technological processes used in the manufacture of polyethylene-lined pipes.

Polyethylene pipes are produced by continuous screw extrusion on lines with worm drives.

Steel pipes Before lining, they are cut to cut lengths corresponding to pipeline specifications. Threads are cut at the ends of the pipes, thrust threaded rings are screwed in, and loose flanges are put on.

Pipes intended for connection into pipelines without flanges (oil and gas field, water supply) are cut to measured lengths, the ends of the pipes are processed, and chamfered.

The lining of steel pipes occurs using the joint drawing method or the tightening method. The tees are lined with injection molding.

Pipes with flanges are lined from the inside, without flanges - from the inside, outside or on both sides.

After lining at the ends of the flange connection pipes, the lining layer is flanged onto the ends of the threaded rings.

Tees and concentric transitions are lined using plastic injection molding on injection molding machines. Bent bends are made from short lined pipes on pipe bending machines. The housings of sector bends are lined polyethylene pipes followed by flanging the ends onto flanges.

Fig.3. The production process of polyethylene-lined pipes

Bend production technology

Steeply curved seamless welded bends in accordance with GOST 17375-83 and TU 14-159-283-2001 are intended for transporting non-aggressive and moderately aggressive media, steam and hot water at a nominal pressure of up to 10 MPa (100 kgf/cm 2) and a temperature range from minus 70° C to plus 450° C.

Outer diameter: 45 – 219 mm, wall thickness: 2.5 – 8 mm, bending angle: 30°, 45°, 60°, 90°, 180°, steel grades: 20, 09G2S, 12Х18Н10Т.

For the production of bends, modern energy-saving and environmentally friendly technology was chosen, which gives the best quality indicators of the finished product, both in terms of dimensional characteristics and mechanical properties.

The main equipment is a press for hot drawing of a pipe billet along a horn-shaped core using induction heating.

According to overall strategy quality of Novotrubny Plant, bends are made only from high-quality pipes using a full cycle of control of the properties of the finished product. Compliance of products with accepted regulatory and technical documentation is confirmed by 100% verification of dimensional characteristics and laboratory tests. For the production of parts, permits and certificates from supervisory authorities have been obtained, confirming the suitability of our products for use in highly aggressive environments, including at facilities supervised by the State Technical Supervision Authority of Russia.

In Fig. 4 shows the technological processes used in the manufacture of bends.

Rice. 5. Bend production process

The production technology of bends includes the following stages:

• cutting pipes obtained from the pipe shops of the plant into dimensional blanks (nozzles) and having passed the appropriate final quality control;
• hot drawing of pipes along a horn-shaped core. Broaching is carried out on special hydraulic presses using graphite-based lubricants;
• hot volumetric straightening of bends in vertical hydraulic presses(calibration). In this case, geometric dimensions, primarily diameters, are corrected;
• preliminary gas-flame or plasma trimming of the allowance of uneven ends of bends;
• mechanical restoration ends of bends and chamfering (trimming);
• QC acceptance:

—control of geometric dimensions,

—hydrotesting,

—laboratory tests of the mechanical properties of a batch of bends,

—marking.

5. Quality issues for pipe products

1. 1. What types of control are provided for by regulatory documentation?

Answer: Any regulatory documentation (GOST, TU, specification) necessarily provides for the following types of pipe inspection:

• external surface quality control;
• quality control of the internal surface;
• control of geometric parameters: outer and 9 or) inner diameter, wall thickness, curvature, perpendicularity of the ends to the pipe axis, length, chamfer width (where measured according to regulatory and technical documentation), thread sizes (for threaded pipes).

1. 2. What are the requirements for pipes before starting inspection?

Answer:

• pipes must have a working label;
• pipe surfaces must be dry and clean;
• pipes should lie on the inspection table in the inspection area in one row with an interval depending on the diameter, allowing them to move freely (turning around their axis) to inspect the entire surface, and not just in a certain area.
• The pipes must be straight, i.e. roll freely on the rack, have evenly cut ends and burrs removed.

Note: in some cases, customers allow uncut ends, and permission is given to not straighten the pipes.

1. 3. How is visual inspection of the outer surface of pipes performed?

Answer: It is carried out directly on inspection tables (racks) by inspectors with normal vision without the use of magnifying means. The surface is inspected in sections, followed by re-edging each pipe so that the entire surface is inspected. Simultaneous monitoring of several pipes is allowed; It should be remembered that the total inspection surface does not exceed the visual angle. In doubtful cases, i.e. when the defect is not clearly defined. The inspector is allowed to use a file or sandpaper, with which he cleans the surface of the pipe.

1. 4. How to assess the depth of an external defect if it is located in the middle of the pipe length?

Answer: If it is necessary to determine the depth of a defect, a control filing is made, followed by a comparison of the pipe diameter before and after removal of the defect:

1. 1. The diameter is measuredDnear the defect;
2. 2. The minimum diameter at the defect site is measured, i.e. maximum defect depth;
3. 3. Wall thickness is measuredSalong the generatrix of the defect;
4. 4. Defect depth:D— dis compared (taking into account permissible deviations) with the actual wall thickness.

To determine the nature of the defect, it is compared with samples of defects (standards) approved in the proper manner.

1. 5. Why and how is instrument monitoring of the outer surface of pipes used?

Answer: Instrument testing is used to assess the quality of the outer surface of pipes for critical purposes: boiler houses, for aviation equipment, nuclear energy, ball bearing factories, etc.

Devices for such control are ultrasonic, magnetic or eddy current testing installations.

1. 6. How to visually inspect the inner surface of pipes?

Answer: The essence of this control method is that a light bulb on a long holder is inserted into each pipe, which has a sufficiently large internal channel, on the side opposite from the controller, with the help of which it can move along the pipe and illuminate dubious places. For smaller sizes (in pipe drawing shops), so-called backlight screens are used, consisting of a number of “daylight” lamps that provide an even light.

1. 7. Why and how is instrument monitoring of the internal surface of pipes used?

Answer: Used for critical pipes. It is divided into instrument control and control using periscopes using a special technique, with a 4-fold increase in the area of ​​the controlled surface. To determine the nature and depth of the defect on the inner surface, a dubious section of the pipe can be cut out for additional control (for example, on a microscope) and conclusion.

Inspection of pipes with a small internal cross-section is carried out with the naked eye or using magnification on samples cut along the generatrix of the pipe (“boat”).

8. How is pipe wall thickness measured manually?

Answer: The wall thickness is checked at both ends of the pipe. The measurement is carried out with a pipe micrometer type MT 0-25 of the second accuracy class, at least at two diametrically opposite points. If a wall difference or maximum permissible values ​​is detected, the number of measurements increases.

1. 8. How is manual inspection of the outer diameter of pipes performed?

Answer: The outer diameter of the pipes is manually controlled using a smooth micrometer type MK of the second class, or with calibrated staples in at least two sections. In each section, at least two measurements are taken at an angle of 90 ° one to another, i.e. in mutually perpendicular planes. If defects or maximum permissible values ​​are detected, the number of sections and measurements increases.

1. 9. Why and how is instrument monitoring of the outer diameter of pipes used? Examples.

Answer: It is used for critical purpose pipes and is carried out simultaneously with monitoring the continuity of surfaces and wall thickness using UKK-2 instruments, R RA. On cold roller mills (CRRM) for technological control pipe diameter, a CED device (compact electromagnetic diameter meter) is used.

10. How is manual inspection of the internal diameter of pipes carried out? Examples.

Answer: It is produced in accordance with orders using a certified gauge (for sizes from 40 mm and more commonly called “rolling pin”) of the “pass-no-pass” type for the length specified by the regulatory documentation at both ends of the pipe. For example, for pump and compressor pipes according to GOST 633-80, straightness control at each end of 1250 mm is required; At the same time, the internal diameter is controlled. To control the internal diameter of pipes used for the manufacture of shock absorbers, where required high accuracy sizes, special devices are used - bore gauges.

11. When is instrument monitoring of the internal diameter of pipes necessary? Examples.

Answer: It is used only for pipes for critical purposes and is produced on devicesRPAand UKK - 2, for example, in the production of stainless pipes.

12. How is the curvature (straightness) of pipes controlled? Examples.

Answer: The straightness of pipes, as a rule, is ensured by production technology and, practically, is checked “by eye”. In doubtful cases, or as required by regulatory documentation, the actual curvature is measured. It is performed on any one measuring section or along the entire length of the pipe, depending on the requirements of regulatory documentation. To measure curvature, you need a flat horizontal surface (ideally a surface plate). A measuring section with the maximum “by eye” curvature is selected; if the curvature is in the same plane as the slab, a 1 meter long straight edge, type ShchD, second accuracy class, is placed on the side and using a set of feeler gauges No. 4, the gap between the pipe and the straight edge is checked.

13. In what cases and how is chamfer dullness controlled?

Answer: performed as required by regulatory documentation using a measuring ruler or template. The chamfer angle is monitored as required by regulatory documentation using a protractor.

14. When and how is the perpendicularity of the pipe end to its axis checked?

Answer: A metal square is used. The short side of the square is placed along the generatrix of the pipe. The long side of the square is pressed against the end of the pipe in 2 - 3 sections. The presence of a gap and its size is checked with a feeler gauge.

15. How to measure pipe length manually?

Answer: it is carried out by two workers by applying a measuring tape of a metal RS-10 or plastic tape measure along the generatrix of the pipe being measured.

16. Methods for determining steel grades.

Answer: control of steel grades is carried out using the following methods:

• sparking;
• steeloscoping;
• chemical or spectral analysis.

6. Questions: classification of types of defects in the manufacture of pipes and methods for correcting them

1. 1. What are the main categories of defects identified during the production and control of finished products?

Answer: The accepted quality accounting system divides defects identified during the control of finished products into two categories: defects due to the fault of steelmaking and steel rolling production and defects in pipe rolling production (this includes defects in cold-deformed and welded pipes).

1. 2. Types and causes of defects in steelmaking that affect the quality of pipes.

Answer:

• The shrinkage cavity, open and closed, is a cavity formed during the solidification of the metal after it is cast into molds. The cause of this defect may be a violation of steel casting technology, the shape of the mold, or the composition of the steel. The most advanced method of combating shrinkage cavities is continuous casting of steel.
• Liquation in steel. Liquation is the heterogeneity of steel and alloys in composition, formed during their solidification. An example of segregation is a segregation square, which is revealed in transverse macrosections of metal and represents structural heterogeneity in the form of differently etched zones, the contours of which repeat the shape of the ingot. The reasons for the segregation square may be an increased content of impurities (phosphorus, oxygen, sulfur), a violation of the casting technology or solidification of the ingot, or the chemical composition of the steel (for example, with a wide solidification temperature limit). Reducing the segregation square is achieved by reducing impurities, lowering the steel casting temperature and reducing the mass of the ingots.
• Internal bubbles. They are cavities formed as a result of the release of gases during crystallization of the ingot. The most common cause of bubbles is a high concentration of oxygen in the liquid metal. Measures to prevent bubbles: complete deoxidation of the metal, use of well-dried materials for alloying and slag formation, drying of casting devices, cleaning of molds from scale.
• Honeycomb. These are gas bubbles located in the form of a honeycomb at a very short distance from the surface of an ingot of boiling or semi-calm steel. Lead to steel delamination. Possible reasons for their appearance may be high steel casting rates, increased gas saturation, and overoxidation of the melt.
• Axial porosity. The presence of small pores of shrinkage origin in the axial zone of the ingot. Occurs when the last portions of liquid metal solidify under conditions of insufficient supply of liquid metal. Reducing axial porosity is achieved by casting steel into molds with a large taper, as well as insulating or heating the profitable part.
• Crust twists. The defect consists of curled metal crusts and spatter located near the surface of the ingot, affecting part or all of the ingot. On microsections in the defect zone there are large accumulations of non-metallic inclusions, and decarburization and scale are often observed. Crust curls, floods, and splashes can occur in metal of all grades of steel using any casting method. Reasons: cold metal casting, slow speed casting, as well as casting of metal characterized by high viscosity. An effective means of preventing defects is casting under liquid synthetic slag.
• Hairs. The defect is expressed in the form of thin, sharp scratches of varying depths, caused by contamination of the surface of the ingot or pipe blank with non-metallic inclusions (slag, refractories, insulating mixtures). Surface defects are clearly visible on turned or pickled pipe blanks, as well as when descaling finished pipes. Preventive measures: use of high-quality refractories, aging of metal in ladles, casting under liquid slag, various refining melts.

1. 3. Types and causes of defects in steel rolling production that affect the quality of pipe production?

Answer:

• Internal ruptures due to deformation. They are formed during hot deformation (rolling) in the axial zone of blooms or a pipe blank due to its overheating. Axial overheating ruptures are most common in high-carbon and high-alloy steels. The formation of a defect can be prevented by reducing the heating temperature of the metal before deformation or reducing the degree of deformation in one pass.
• Birdhouse. It is an internal transverse thermal crack in an ingot or workpiece that opens during rolling. The cause of the defect is sudden heating of a cold ingot or workpiece, during which the outer layers of the metal heat up faster than the inner ones, and stresses arise, leading to rupture of the metal. The most prone to the formation of birdhouses are high-carbon steels U7 - U12 and some alloy steels (ShKh - 15, 30KhGSA, 37KhNZA, etc.). Measures to prevent defects - compliance with the technology of heating ingots and workpieces before rolling.
• Fractures. These are open breaks, located at an angle or perpendicular to the direction of greatest elongation of the metal, formed during hot deformation of the metal due to its reduced ductility. Rolling a pipe billet from blooms with flaws leads to the appearance of rolled films on the surface of the rods. The reasons for the appearance of flaws can also be violations of metal heating technology and large degrees of compression. Workpieces with flaws are thoroughly cleaned.
• Steelmaking captivity. This term refers to defects in the form of delamination of metal of various shapes, connected to the base metal. The lower surface of the film is oxidized, and the metal underneath is covered with scale. The causes of steel-smelting caps can be the rolling out of defects in the ingot of steel-smelting origin: crust twists, accumulations of subcrustal and surface gas bubbles, longitudinal and transverse cracks, sagging, etc. Measures to prevent steel melting captivity: compliance with steel smelting and casting technology.

1. 4. Methods for detecting surface and internal metal defects.

Answer: In modern practice, the following main methods are used for detecting and studying surface and internal defects in metal:

• external inspection of the product;
• ultrasonic testing to identify internal defects;
• electromagnetic testing methods to detect surface defects;
• local surface cleaning;
• sedimentation of samples cut from rods to more clearly identify surface defects;
• stepwise turning of rods to identify hairs;
• studies of the macrostructure on transverse and longitudinal templates after etching;
• study of longitudinal and transverse fractures;
• electron microscopic research methods;
• examination of unetched microsections (to assess contamination with non-metallic inclusions);
• study of the microstructure after etching to identify structural components;
• X-ray diffraction analysis.

1. 5. Types and causes of defects in the production of pipes by hot rolling. Measures to correct defects.

Answer:

• Rolling captivity. Longitudinal orientation defect. The reason is the rolling out of surface defects of the pipe blank or bloom in the pipe: trimming, seaming, mustache, forging, wrinkles. External films cannot be repaired and are a final defect.
• Flockens. They are thin metal tears that form due to structural stresses in steel saturated with hydrogen. They usually appear in rolled metal and are detected by ultrasonic testing. Flocks appear during metal cooling at a temperature of 250 ° From and below. They are found mainly in structural, tool and bearing steels. Measures to prevent flakes: vacuum-arc remelting.
• Cracks. During the formation of an ingot and its subsequent deformation, a number of defects in the form of cracks are encountered in practice: hot cracks, stress cracks, etching cracks, etc. Let's look at the most typical ones - hot cracks.

A hot crystallization crack is an oxidized rupture of metal formed during the period of crystallization of the ingot due to tensile stresses exceeding the strength of the outer layers of the ingot. Rolled hot cracks can be oriented along the rolling axis, at an angle to it, or perpendicular, depending on the location and shape of the initial defect in the ingot. Factors that cause cracking include: overheating of the liquid metal, increased casting speed, increased sulfur content as the ductility of steel decreases, violation of steel casting technology, and the influence of the steel grade itself. Cracks cannot be repaired and are a final defect.

• Delamination. This is a violation of the continuity of the metal caused by the presence in the original ingot of a deep shrinkage cavity, shrinkage looseness or accumulation of bubbles, which, with subsequent deformation, comes out to the surface or end edges of the product. Preventive measures: reduction of harmful impurities in the metal, reduction of gas saturation, use of additives, compliance with steel smelting and casting technology. Delaminations cannot be repaired and are a final defect.
• Sunset. This is a violation of the continuity of the metal in the direction of rolling on one or both sides of the product (pipe) along its entire length or along its part as a result of rolling up a whisker, undercutting or rolling out from a previous gauge. The reason for sunsetting is usually the overflow of metal into the working caliber, when it (the metal) is “squeezed out” into the space between the calibers in the form of a mustache, and then rolls up. Preventive measures: correct calibration of the tool, compliance with rolling technology. It cannot be repaired and is a final defect.
• Sinks. A surface defect, which is local depressions without breaking the continuity of the metal of the pipe, which were formed from the loss of local films, non-metallic inclusions, and rolled-in objects. Preventive measures: use high-quality pipe blanks, adherence to rolling technology.
• Selling A surface defect that is a through hole with thinned edges, elongated in the direction of deformation. The causes of the defect are the ingress of foreign bodies between the deforming tool and the pipe.
• Cracks of pipe origin. A surface defect of longitudinal orientation, which is a violation of the continuity of the metal in the form of a narrow gap, usually going deep into the wall at a right angle to the surface. Reasons: reduction of frozen pipes, excessive deformation during rolling or straightening, presence of residual stresses in the metal that were not relieved by heat treatment. Preventive measures: compliance with pipe production technology. The final marriage.
• Internal captivity. The cause of internal caps is premature opening of the cavity in the core of the workpiece before piercing. The appearance of internal films is greatly influenced by the ductility and toughness of the metal being pierced. To prevent capping on cold-deformed pipes, the pipe blank is subjected to boring on pipe boring machines.
• Dents. A surface defect that represents local depressions without disturbing the continuity of the metal. A type of dents are tool marks.
• Screw track A surface defect consisting of periodically repeating sharp protrusions and ring-shaped depressions located along a helical line. Reason: incorrect setting of the piercing mill rulers or rolling machines. Preventive measures: compliance with pipe production and finishing technology.

1. 6. Types and causes of defects in the manufacture of cold-deformed pipes. Ways to fix a marriage.

Answer:

• Birdhouse. A surface defect that is oblique, often at an angle of 45° , metal tears of varying depths up to through. More often found on high-carbon and alloy cold-formed pipes. Causes: excessive deformation causing excessive additional stress; insufficient ductility of the metal due to poor-quality intermediate heat treatment of the pipes. Preventive measures: correct calibration of the working tool, compliance with pipe production technology. They cannot be repaired and are a final defect.
• Scale. Formed when heat treatment pipes, degrades the quality of pipe surfaces and impedes inspection. When straightening pipes that have undergone heat treatment, part of the scale is mechanically removed, while part remains, turning it into scrap. Precautionary measures: Heat treatment in ovens with a protective atmosphere, pickling or machining of pipes.
• Squeeze. Most often occurs during mandrelless drawing of cold-deformed pipes. Reason: loss of stability of the cross-section of the pipe during rolling, excessive deformations, overfilling of the drawing ring with metal due to improper calibration.
• Risks and challenges. Risks are depressions on the outer or inner surfaces of the pipe, without changing the continuity of the metal. Scuffing - differs from a risk in that part of the metal of the pipe is mechanically torn off and collected along the axis of the pipe into chips, which can then fall off. Reason: poor preparation of the drawing tool, foreign particles getting between the tool and the pipe, low mechanical characteristics of the pipe metal. Preventive measures: compliance with pipe production technology.
• Internal ring marks and omissions (pipe shaking). Reason: poor-quality coating before drawing, low ductility of the metal, high drawing speed. Preventive measures: compliance with pipe production technology.
• Rowanberry. Minor irregularities of various shapes located over the entire surface of the pipe or part of it. Reasons: poor surface preparation for rolling and drawing, increased wear of rolling tools, poor quality lubrication, dirty pickling baths, poor processing at intermediate stages of manufacturing. Preventive measures: compliance with pipe production technology.
• Over-traffic. A surface defect in the form of point or contour depressions located in individual areas or over the entire surface of pipes, representing local or general damage to the metal surface during etching. Cannot be repaired.
• Penetration. A surface defect characteristic only of the contact method of electrochemical polishing. Reasons for penetration on the outer surface: high current density and poor contact of the current-carrying brush with the surface of the pipe. Melting on the inner surface is a consequence of poor insulation of the cathode rod, wear of insulators on the cathode, small interelectrode distance, and large curvature of the cathode rod. Preventive measures: compliance with the technology of electrochemical polishing of pipes. Cannot be repaired.

1. 7. Types and causes of defects in the manufacture of welded pipes. Measures to prevent marriage.

Answer:

• Displacement of tape edges during welding. It is the most typical type of defect in the production of electric-welded pipes. The causes of this defect are: misalignment of the axis of the rollers of the forming mill in the vertical plane; incorrect roll adjustment; asymmetrical position of the tape relative to the axis of forming and welding; welding unit malfunction.
• Lack of penetration. This type of defect is when the seam of a welded pipe is either extremely weak or remains completely open, i.e. the edges of the tape do not meet and are not welded. The reasons for lack of penetration may be: narrow tape; discrepancy between the welding speed and the heating mode (high speed, low current); offset of the tape edges; insufficient compression in welding rolls; failure of the ferrite assembly.
• Burns. Defects under this name are located on the surface of the pipe near the weld line, both on one side of the weld and on both sides. The causes of arson are: high arc power, resulting in overheating of the belt edges; damage to the inductor insulation; poor quality tape preparation.
• External and internal burrs. Burr is metal squeezed out of a seam when the edges of the tape are compressed; its appearance is technologically inevitable. Technical specifications There is a complete absence of burrs. Its presence indicates incorrect installation of the deburring cutter and its dullness.

1. 8. What types of defects cannot be repaired and why?

Answer: Rolled caps, cracks of pipe origin, cracks, delamination, sunsets, birdhouses, over-etching, penetrations cannot be repaired and are a final defect.

Metallurgical enterprises of Russia

7.1. Metallurgical plants

1. 1. JSC "West Siberian Metallurgical Plant" - Novokuznetsk: circle made of carbon steel grades, circle made of alloy steel grades, circle made of stainless steel grades.
2. 2. JSC "Zlatoust Metallurgical Plant" - Zlatoust: circle made of carbon steel grades, circle made of alloy steel grades, circle made of stainless steel grades.
3. 3. OJSC "Izhstal" - Izhevsk: circle made of stainless steel grades.
4. 4. OJSC "Kuznetsk Metallurgical Plant" - Novokuznetsk: circle made of carbon steel grades.
5. 5. OJSC "Magnitogorsk Iron and Steel Works" - Magnitogorsk: strip, circle made of carbon steel grades.
6. 6. JSC "Metallurgical Plant "Red October" - Volgograd: circle made of carbon steel grades, circle of alloy steel grades, circle of ball bearing steel grades, circle of stainless steel grades.
7. 7. JSC Metallurgical Plant Elektrostal - Elektrostal: strip, circle made of stainless steel grades.
8. 8. OJSC "Nizhny Tagil Metallurgical Plant" - Nizhny Tagil: circle made of carbon steel grades.
9. 9. JSC "Novolipetsk Metallurgical Plant" - Lipetsk: strip.

10. OJSC "Orsko-Khalilovsky Metallurgical Plant" - Novotroitsk: strip, circle made of carbon steel grades, circle made of low-alloy steel grades.

11. OJSC "Oskol Electro-Metallurgical Plant" - Stary Oskol: circle made of carbon steel grades.

12. OJSC "Severstal" (Cherepovets Metallurgical Plant) - Cherepovets: strip, circle made of carbon steel grades.

13. JSC "Serov Metallurgical Plant" - Serov: a circle made of carbon steel grades, a circle made of alloy steel grades, a circle made of ball-bearing steel grades.

14. OJSC "Chelyabinsk Metallurgical Plant" - Chelyabinsk: stainless steel strip, circle of carbon steel grades, circle of alloy steel grades, circle of ball bearing steel grades, circle of stainless steel grades.

7.2. Pipe factories and their brief characteristics

OJSC Pervouralsk New Pipe Plant (PNTZ)

Located in Pervouralsk, Sverdlovsk region.

Produced assortment:

— water and gas pipes in accordance with GOST 3262-75 with a diameter of 10 to 100 mm;

— seamless pipes in accordance with GOST 8731-80 with a diameter from 42 to 219 mm;

— seamless cold-deformed pipes in accordance with GOST 8734 and TU 14-3-474 with diameters from 6 to 76 mm.

— electric welded pipes according to GOST 10704 with a diameter from 12 to 114 mm.

PNTZ also produces pipes according to special orders (thin-walled, capillary, stainless steel).

OJSC Volzhsky Pipe Plant (VTZ)

Located in the city of Volzhsky, Volgograd region.

Produced assortment:

— large diameter spiral welded pipes from 325 to 2520 mm.

The good quality of products produced by VTZ determines a stable sales market, and for pipes with a diameter of 1420 to 2520 VTZ is a monopolist in Russia.

OJSC Volgograd Pipe Plant VEST-MD (VEST-MD)

Located in Volgograd.

Produced assortment:

—water and gas pipes in accordance with GOST 3262-77 with a diameter of 8 to 50 mm;

—electric welded pipes in accordance with GOST 10705-80 with a diameter from 57 to 76 mm.

WEST-MD is simultaneously engaged in the production of capillary and thin-walled pipes of small diameters.

OJSC Vyksa Metallurgical Plant (VMZ)

Located in Vyksa, Nizhny Novgorod region. The Vyksa Metallurgical Plant specializes in the production of electric welded pipes.

— 3262 with a diameter from 15 to 80mm.

— 10705 with a diameter from 57 to 108 mm.

— 10706 with a diameter from 530 to 1020 mm.

— 20295 with a diameter from 114 to 1020 mm.

According to GOST 20295-85 and TU 14-3-1399, they come with heat treatment and meet the highest quality requirements.

OJSC "Izhora Plants"

Located in Kolpino, Leningrad region.

Produced assortment:

— seamless pipes in accordance with GOST 8731-75 with a diameter from 89 to 146 mm.

OJSC Izhora Plants also carries out special orders for the production of seamless thick-walled pipes.

OJSC Seversky Pipe Plant (STZ)

Located in the Sverdlovsk region at Polevskoy station.

Produced assortment:

— water and gas pipes in accordance with GOST 3262-75 with a diameter of 15 to 100 mm;

— electric welded pipes in accordance with GOST 10705-80 with a diameter from 57 to 108 mm;

— seamless pipes in accordance with GOST 8731-74 with a diameter from 219 to 325 mm.

— electric welded pipes in accordance with GOST 20295-85 with a diameter from 114 to 219 mm.

High quality pipes made from mild steel of group “B”.

OJSC Taganrog Metallurgical Plant (TagMet)

Located in Taganrog.

— 3262 with a diameter from 15 to 100mm.

— 10705 with a diameter from 76 to 114 mm.

Seamless pipes with a diameter of 108-245 mm.

JSC Trubostal

Located in St. Petersburg and focused on the North-West region.

— water and gas pipes in accordance with GOST 3262-75 with a diameter of 8 to 100 mm;

— electric welded pipes in accordance with GOST 10704-80 with a diameter from 57 to 114 mm;

OJSC Chelyabinsk Pipe Rolling Plant (ChTPZ)

Located in Chelyabinsk.

Produced assortment:

— seamless pipes in accordance with GOST 8731-78 with diameters from 102 to 426 mm;

— electric welded pipes in accordance with GOST 10706, 20295 and TU 14-3-1698-90 with diameters from 530 to 1220 mm.

— electric welded pipes in accordance with GOST 10705 with diameters from 10 to 51 mm.

— water and gas pipes in accordance with GOST 3262 with diameters from 15 to 80 mm.

In addition to the main diameters, ChelPipe produces galvanized water and gas pipes.

Agrisovgaz LLC (Agrisovgaz)

Located in the Kaluga region, Maloyaroslavets

OJSC Almetyevsk Pipe Plant (ATP)

Located in Almetyevsk.

OJSC Bor Pipe Plant (BTZ)

Located in the Nizhny Novgorod region, Bor.

OJSC Volgorechensk Pipe Plant (VrTZ)

Located in the Kostroma region, Volgorechensk.

OJSC Magnitogorsk Iron and Steel Works (MMK)

Located in Magnitogorsk.

OJSC Moscow Pipe Plant FILIT (FILIT)

Located in Moscow.

OJSC Novosibirsk Metallurgical Plant named after. Kuzmina" (NMZ)

Located in Novosibirsk.

PKAOOT "Profile-Akras" (Profile-Akras)

Located in the Volgograd region, Volzhsky

OAO Severstal (Severstal)

Located in Cherepovets.

JSC Sinarsky Pipe Plant (Sinarsky Pipe Plant)

Located in the Sverdlovsk region, Kamenets-Uralsky.

OJSC "Ural Pipe Plant" (Uraltrubprom)

Located in the Sverdlovsk region, Pervouralsk.

JSC "Engels Pipe Plant" (ETZ) Located in the Saratov region, Engels

8. Basic norms for loading pipe products

8.1. Basic standards for loading rolled pipes into railway cars

Water and gas pipe according to GOST 3262-78

Diameter from 15 to 32 mm, with walls no more than 3.5 mm.

Water and gas pipe according to GOST 3262-78

Diameter from 32 to 50 mm, with walls no more than 4 mm.

The loading rate is from 45 to 55 tons per gondola car.

Water and gas pipe according to GOST 3262-78

Diameter from 50 to 100 mm with walls no more than 5 mm.

The loading rate is from 40 to 45 tons per gondola car.

Electric welded pipe according to GOST 10704, 10705-80

Diameter from 57 to 108 mm with walls no more than 5 mm.

The loading rate is from 40 to 50 tons per gondola car.

Electric welded pipe according to GOST 10704, 10705-80

Diameter from 108 to 133 mm with walls no more than 6 mm.

The loading rate is from 35 to 45 tons per gondola car.

Electric welded pipe according to GOST 10704-80, 10705-80, 20295-80

Diameter from 133 to 168 mm with walls no more than 7 mm.

Electric welded pipe according to GOST 10704-80, 20295-80

Diameter from 168 to 219 mm with walls no more than 8 mm.

The loading rate is from 30 to 40 tons per gondola car.

Electric welded pipe according to GOST 10704-80, 20295-80

Diameter from 219 to 325 mm with walls no more than 8 mm.

Electric welded pipe according to GOST 10704-80, 20295-80

Diameter from 325 to 530 mm with walls no more than 9 mm.

The loading rate is from 25 to 35 tons per gondola car.

Electric welded pipe according to GOST 10704-80, 20295-80

Diameter from 530 to 820 mm with walls no more than 10-12 mm.

The loading rate is from 20 to 35 tons per gondola car.

Electric welded pipe according to GOST 10704-80, 20295-80

Diameter from 820 mm with walls from 10 mm or more.

The loading rate is from 15 to 25 tons per gondola car.

Spiral welded pipe

Loading norms are similar to the loading norms for electric welded pipe.

Seamless pipeaccording to GOST 8731, 8732, 8734-80

Diameter from 8 to 40 mm with walls no more than 3.5 mm.

The loading rate is from 55 to 65 tons per gondola car.

The remaining loading norms are similar to the loading norms for electric-welded pipes.

All loading standards for railway cars depend on tubular packaging (bags, bulk, boxes, etc.). The issue of packaging must be approached with clear calculations in order to reduce costs during rail transportation.

8.2. Basic standards for loading rolled pipes into trucks

Loading standards for MAZ, KAMAZ, URAL, KRAZ vehicles with a scow (body) length of no more than 9 meters range from 10 to 15 tons, depending on the diameter of the pipe and the length of the scow (body) struts.

Loading standards for MAZ, KAMAZ, URAL, KRAZ vehicles with a scow (body) length of no more than 12 meters range from 20 to 25 tons, depending on the diameter of the pipe and the length of the scow (body) struts.

Special attention must be paid to the length of the pipe: it is not allowed to transport a pipe whose length exceeds the length of the scow (body) by more than 1 meter.

During intercity transportation, it is not allowed to load vehicles of all brands with more than 20 tons per vehicle. Otherwise, a large fine will be charged for overloading the axle. The fine is collected at weight control points installed on highways by the Russian Transport Inspectorate.

The main materials for manufacturing are various grades of carbon and alloy steel, aluminum and its alloys, brass and copper. Depending on the main component, there are several types of metal circles. These varieties and percentage components in their composition are given in Table 1.

Technical documentation

• GOST 2590–2006 “High-rolled hot-rolled round steel products. Assortment"
• GOST 7417–75 “Calibrated round steel. Assortment"
• GOST 535–2005 “Rolled section and shaped products made of carbon steel of ordinary quality. General technical conditions"
• GOST 5632–72 “High-alloy steels and corrosion-resistant, heat-resistant and heat-resistant alloys. Stamps"
• GOST 21488–97 “Extruded rods from aluminum and aluminum alloys. Technical specifications"
• GOST 4784–97 “Aluminium and wrought aluminum alloys. Stamps"
• GOST 1131-76 “Deformable aluminum alloys in ingots. Technical specifications"
• GOST 2060–2006 “Brass rods. Technical specifications"
• GOST 15527–2004 “Copper-zinc (brass) alloys processed by pressure. Stamps"
• GOST 1535–2006 “Copper rods. Technical specifications"

One of the types of products of the metal rolling industry is pipes of a wide range. Modern construction Russia cannot do without the use of this unique material. Steel products They have high strength characteristics, they are durable and reliable.

The most significant use of steel pipes is the construction of transportation systems: oil, water and gas. In addition to the actual pipeline work, metal pipes are used to insulate communications.

You should purchase metal pipes only on the basis of data on the temperature and humidity conditions under which it will be used.

As for the cross-sectional shape, the most common one is round. When fulfilling your order, we work with specific parameters and can produce rolled pipes with the required diameter. We are also ready to supply pipes of square, rectangular and other sections. It all depends on the specific production needs.

Steel pipes are made from various steel grades: 10, 20, 35, 45, 09G2S, 10G2, 20Х, 40Х, 30ХГСА, 20Х2Н4А, etc.

Steel pipes are divided by type into:

• Electric-welded steel pipes - Non-galvanized and galvanized welded steel pipes used for water pipelines, gas pipelines, heating systems and structural parts.
• Seamless steel pipes - Steel pipes that do not have a weld or other connection. They are made by rolling, forging, pressing or drawing.

Steel pipes are divided by class into:

• Water-gas pipes (WGP): GOST 3262 and Galvanized water-gas pipes - GOST 3262
• Electric-welded pipes: GOST 10705, 10704 and Galvanized electric-welded pipes GOST 10705, 10704
• Large diameter pipes: Main pipes GOST 20295 and Electrical pipes GOST 10706
• Seamless pipes: Hot-deformed GOST 8731, 8732 and Cold-deformed GOST 8731, 8734

STEEL WATER AND GAS PIPES

The length of the pipe is made from 4 to 12 m:

a) measured or multiple measured length with an allowance for each cut of 5 mm and a longitudinal deviation over the entire length plus 10 mm;

b) of unmeasured length.

By agreement between the manufacturer and the consumer, up to 5% of pipes with a length of 1.5 to 4 m are allowed in a batch of unmeasured pipes.

The length of the pipe is made from 4 to 12 m

Dimensions, mm

Conditional bore, mm	Outer diameter, mm	Pipe wall thickness
	ordinary	reinforced
				According to the length of the pipe they are made: unmeasured length: with a diameter of up to 30 mm - at least 2 m; with a diameter of St. 30 to 70 mm - at least 3 m; with a diameter of St. 70 to 152 mm - at least 4 m; with a diameter of three St. 152 mm - not less than 5 m. measured length: Pipes are made of three types: 1 - straight-seam welded with a diameter of 159-426 mm, manufactured by resistance welding with high-frequency currents; 2 - spiral welded with a diameter of 159-820 mm, made by electric arc welding; 3 - straight-seam with a diameter of 530-820 mm, made by electric arc welding. Depending on the mechanical properties, pipes are manufactured in strength classes: K 34, K 38, K 42, K 50, K 52, K 55, K 60. Pipes are manufactured in lengths from 10.6 to 11.6 m. Dimensions, mm Outer diameter, mm Wall thickness, mm According to the length of the pipe, the following should be made: unmeasured length - ranging from 4 to 12.5 m; measured length - within unmeasured; length, a multiple of the measured length - within the unmeasured length with an allowance for each cut of 5 mm; approximate length - within unmeasured length. Dimensions, mm