Date of introduction 01.01.93

1. This standard specifies a range of longitudinal electric welded steel pipes. 2. The dimensions of the pipes must correspond to the table. 1 . 3. The length of the pipe is made: of unmeasured length: with a diameter of up to 30 mm - not less than 2 m; pr and d diameter with v. 30 to 70 mm - not less than 3 m; with a diameter of St. 70 to 152 mm - not less than 4 m; with a diameter of St. 152 mm - not less than 5 m. At the request of the consumer, pipes of groups A and B in accordance with GOST 10705 with a diameter of over 152 mm are manufactured with a length of not less than 10 m; pipes of all groups up to 70 mm in diameter - at least 4 m long; measured length: with a diameter of up to 70 mm - from 5 to 9 m; with a diameter of St. 70 to 219 mm - 6 to 9 m; with a diameter of St. 219 to 426 mm - from 10 to 12 m. Pipes over 426 mm in diameter are made only of unmeasured length. By agreement between the manufacturer and the consumer, pipes with a diameter over 70 to 219 mm are allowed to be made from 6 to 12 m; multiple of length with a multiplicity of at least 250 mm and not exceeding its lower limit established for measuring pipes. The allowance for each cut is set at 5 mm (if no other allowance is specified) and is included in each multiplicity.

Table 1

Outer diameter, mm
Outer diameter, mm

Continuation of table. 1

Outside diameter, mm	Theoretical mass of 1 m of pipes, kg, with wall thickness, mm
Outside diameter, mm

Continuation of table. 1

Outside diameter, mm	Theoretical mass of 1 m of pipes, kg, with wall thickness, mm
Outside diameter, mm

Continuation of table. 1

Outside diameter, mm	Theoretical mass of 1 m of pipes, kg, with wall thickness, mm
Outside diameter, mm

Continuation of table. 1

Outside diameter, mm

Theoretical mass of 1 m of pipes, kg, with wall thickness, mm

Continuation of table. 1

Outside diameter, mm	Theoretical mass of 1 m of pipes, kg, with wall thickness, mm
Outside diameter, mm

Continuation of table. 1

Outside diameter, mm	Theoretical mass of 1 m of pipes, kg, with wall thickness, mm
Outside diameter, mm

Continuation of table. 1

Outside diameter, mm

Theoretical mass of 1 m of pipes, kg, with wall thickness, mm

Notes: 1. In the manufacture of pipes in accordance with GOST 10706, the theoretical weight increases by 1% due to the reinforcement of the seam. 2. By agreement between the manufacturer and the consumer, pipes with dimensions 41.5 ґ1.5-3.0 are manufactured; 43 ґ1.0; 1.53.0; 43.5 ґ1.5-3.0; 52 ґ2.5; 69.6 ґ1.8; 111.8 ґ2.3; 146.1 ґ5.3; 6.5; 7.0; 7.7; 8.5; 9.5; 10.7; 152.4 ґ1.9; 2.65; 168 ґ2.65; 177.3 ґ1.9; 198 ґ2.8; 203 ґ 2.65; 299 ґ4.0; 530 ґ7.5; 720 ґ7.5; 820 ґ8.5; 1020 ґ9.5; 15.5; 1220 ґ13.5; 14.6; 15.2 mm, as well as with an intermediate wall thickness and diameters within the table. 1.3. Pipe dimensions in brackets are not recommended for new design. 3.1. Pipes of measured and multiple lengths are manufactured in two accuracy classes: I - from the trimmed ends and removal of the aushers; II - without trimming and deburring (with cutting in the line of the mill). 3.2. Limit deviations along the length of the measuring pipes are given in table. 2.

table 2

3.3. Maximum deviations in total for multiple pipes should not exceed: + 15 mm - for pipes of I class of accuracy; + 100 mm - for pipes of accuracy class II. 3.4. At the request of the consumer, pipes of measured and multiple lengths of II class of accuracy must be with cut ends and on one or two sides. 4. Limit deviations for the outer diameter of the pipe are given in table. 3.

Table 3

Note. For diameters monitored and perimeter measurement, the highest and lowest perimeter limits are rounded to the nearest 1 mm. 5. At the request of the consumer, pipes in accordance with GOST 10705 are manufactured with a one-sided or offset tolerance for the outer diameter. One-sided or offset tolerance should not exceed the sum of the maximum deviations given in table. 3. 6. Limit deviations in the thickness of the wall should correspond to: ± 10% - with a pipe diameter of up to 152 mm; GOST 19903 - for pipe diameters over 152 mm for the maximum sheet width of normal accuracy. By agreement between the consumer and the manufacturer, it is allowed to manufacture pipes with a one-sided tolerance in the wall thickness, while the one-sided tolerance should not exceed the sum of the maximum deviations in the wall thickness. 7. For pipes with a diameter of more than 76 mm, the wall thickening at the burr by 0.15 mm is allowed. 8. Pipes for pipelines with a diameter of 478 mm and more, manufactured in accordance with GOST 10706, are supplied with maximum deviations for the outer diameter of the ends, given in table. 4.

Table 4

9. Out-of-roundness and uniformity of pipes with a diameter of up to 530 mm inclusive, made in accordance with GOST 10705, should be no more than the maximum deviations, respectively, in the outer diameter and wall thickness. Pipes with a diameter of 478 mm and more, manufactured in accordance with GOST 10706, must be of three classes in accuracy in terms of ovality. The ovality of the end in pipes should not exceed: 1% of the outer diameter of pipes for the 1st class of accuracy; 1.5% of the outer diameter of pipes for the 2nd accuracy class; 2% of the outer diameter of pipes for the 3rd accuracy class. The ovality of the ends of pipes with a wall thickness of 0.0 to 1 of the outer diameter is established by agreement between the manufacturer and the consumer. 10. The curvature of pipes manufactured in accordance with GOST 10705 should not exceed 1.5 mm per 1 m of length. At the request of the consumer, the rims from pipes with a diameter of up to 152 mm should be no more than 1 mm per 1 m of length. The total curvature of pipes manufactured in accordance with GOST 10706 should not exceed 0.2% of the pipe length. The wear curve for 1 m of the length of such pipes is not determined. 11. Technical requirements must comply with GOST 10705 and GOST 10706. Examples of symbols: A pipe with an outer diameter of 76 mm, a wall thickness of 3 mm, gauge length, accuracy class II and in other words, from steel grade St3sp, manufactured according to group B GOST 10705-80:

The same, with increased accuracy along the outer diameter, length divisible by 2000 mm, accuracy class 1 to length, from steel and grade 20, manufactured according to group B GOST 10705-80:

A pipe with an outer diameter of 25 mm, a wall thickness of 2 mm, a length multiple of 2000 mm, II class of accuracy to length, manufactured according to group D of GOST 10705-80;

A pipe with an outer diameter of 1020 mm, increased manufacturing accuracy, wall thickness 12 mm, increased accuracy in the outer diameter of the ends, 2nd class of accuracy in ovality, unmeasured length, made of steel mark and St3sp, manufactured according to group e B GOST 10706 -76 Note. In the symbols of pipes that have undergone heat treatment throughout their entire volume, the letter T is added after the words "pipe"; pipes that have undergone local heat treatment of the weld, add the letter L.

INFORMATION DATA

1. DEVELOPED AND INTRODUCED by the Ministry of Metallurgy of the USSR DESIGNERS VP Sokurenko, Cand. tech. sciences; V. M. Vorona, Cand. tech. Sciences; P. N. Ivshin, Cand. tech. Sciences; NF Kuzenko, VF Ganzina 2. APPROVED AND INTRODUCED BY Decree of the Committee for Standardization and Metrology of the USSR No. 1743 dated 15.11.91 3. REPLACE GOST 10704-76 4. REFERENCE REFERENCE STANDARD AND TECHNICAL DOCUMENTS 5. REDISSION. December 1996

Applications of pipes and symbols used for pipe products

Applications of tubular 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 reservoirs from each other;
tubing - for the operation of boreholes in oil production.

2. For pipelines:

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

3. In construction.

4. In mechanical engineering:

boiler pipes - for boilers of various designs;
cracking pipes - for pumping flammable oil 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 the outer diameter of the pipe in mm, the second - the wall thickness in mm. This is followed by the designation of the dimension or frequency of pipes. If the pipe is measured, then its length is indicated in mm, if it is not measured, then after the magnitude of the multiplicity there are the letters "cr". For example: a pipe multiple of 1 m 25 cm is designated 1250 cr. If the pipe is unmeasured, then the multiplicity (dimension) is not indicated.

After the multiplicity, the accuracy class of the pipe is set. Two accuracy classes are manufactured along the length of the pipe:

1 - with ends trimming and deburring outside the mill line;

2 - with cutting in the mill line.

Limit deviations in length are less for pipes of 1 class of accuracy. If the accuracy class is not specified, then the pipe is of normal accuracy.

The first number under the line denotes the quality group: A, B, C, D. Then follows the steel grade and GOST steel.

After the word pipe, in some cases, letters are placed indicating the following:

“T” - heat-treated pipes;

"C" - pipes with zinc coating;

“R” - threaded pipes;

"Pr" - tubes of precision manufacturing;

“M” - with a clutch;

“N” - pipes for thread rolling;

"D" - pipes with a long thread;

"P" - pipes of increased production strength.

2 ... Steel pipe classification

There are several ways to classify pipes.

By production method:

1. Seamless:

a)rolled, hot and cold;

b)cold-deformed in a cold and warm state;

c)pressed.

2. Welded:

a) rolled, hot and cold;

b) electric resistance welding;

c) gas electric welding.

Along the profile of the pipe section:

Round;
Shaped - oval rectangular, square, three-, six and octahedral, ribbed, segmental, drop-shaped and other profiles.

By the size of the outer diameter (Dnmm):

Small sizes (capillary): 0.3 - 4.8;
Small sizes: 5 - 102;
Medium sizes: 102 - 426;
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:

Pipes 1-2 classes are made of carbon steel. Class 1 pipes, the so-called standard and gas pipes, are used in cases where there are no special requirements. For example, in the construction of scaffolding, fences, supports, for laying cables, irrigation systems, as well as for the localized distribution and supply of gaseous and liquid substances.
Class 2 pipes used in high and low pressure main pipelines for supplying gas, oil and water, petrochemical products, fuel and solids.
Class 3 pipes They are used in systems operating under pressure and at high temperatures, in nuclear technology, in oil cracking pipelines, in furnaces, boilers, etc.
Class 4 pipes intended for exploration and exploitation of oil fields, they are used as drilling, casing and auxiliary.
Class 5 pipes- structural - used in the production of transport equipment (auto building, car building, etc.), in steel structures(overhead cranes, masts, oil derricks, supports), as pieces of furniture, etc.
Class 6 pipes are 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 the standards for the supply of pipes (GOST):

General specification standards establish comprehensive product specifications, quality characteristics pipes, acceptance rules and test methods;
assortment standards, which include standards for general-purpose pipes used in various sectors of the national economy, provide for maximum deviations of linear dimensions of pipes (diameter, wall thickness, length, etc.), curvature and mass;
technical requirements standards define the main technical requirements for pipes of general purpose, they specify steel grades, mechanical properties (tensile strength, yield strength, relative elongation, in some cases - impact, ductility of the pipe material); requirements for surface quality, as well as requirements for technological tests by hydraulic pressure, flattening, spreading, bending, etc. In addition, the standards for technical requirements for pipes stipulate the rules of acceptance, special requirements for labeling, packaging, transportation and storage;
test method standards define general test methods for hardness and impact strength, micro and macro structure control, determination of intergranular corrosion tendency, as well as test methods specific to pipes (bending, hydraulic pressure, beading, expansion, flattening, stretching, ultrasonic flaw detection, etc.) etc.)
standards for the rules of marking, packaging, transportation and storage stipulate the requirements for these final operations of pipe production, common for all types of cast iron and steel pipes, as well as fittings.

3. Characteristics of standards for pipe products

3.1. General issues of standardization of tubular products

What is a state standard, where is it applied, who draws up and approves it?

Answer: GOST is a state standard, which applies to the entire territory. Russian Federation... Compilers - developers of GOSTs can be: 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 the final assessment and approves the GOST for a product, product or a whole process.

Who can cancel GOST or make a change or addition to it?

Answer: The GOST is valid for 5 years, however, during this period, changes and additions are permissible, which are also introduced and approved by the Committee for Standardization of the Russian Federation (currently, URALNITI has such powers). Reprinting of GOSTs is prohibited and prosecuted as a violation of the law; this means that no one other than the above organizations can make changes to the standard and no one has the right to disregard the requirements set out in it.

3. What are the typical sections in GOSTs for pipe products, what is their content?

Answer: GOSTs containing requirements for pipes are drawn up, as a rule, according to the same 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 given here: in diameter, wall thickness, length, ovality, chamfer, difference in wall thickness, curvature. This section of GOST provides examples of pipe symbols with different requirements for geometric parameters, mechanical properties, chemical composition and other technical characteristics.

Chapter " Technical requirements". Contains a list of steel grades from which pipes can be made, or GOSTs for chemical composition different brands become. In this section, there are standards for mechanical properties (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 discussed: bending, distribution, flattening, beading, hydro and pneumatic tests.

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

It should be noted that a characteristic feature of GOSTs is the absence of references to product standards.

One of the important requirements of GOSTs is the condition of the pipe ends: pipes that go 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 straight cut ends.

Section "Acceptance rules". Explains how acceptance should be done in quantitative and qualitative terms. The norms of samples for testing and control on various parameters are being negotiated.

Section "Methods of control and testing". Are given general rules sampling and methods of surface control and geometric parameters. In addition, given short info, 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: what GOSTs should be used if it is necessary to carry out ultrasonic testing, tests for intergranular corrosion, and hydraulic pressure tests.

Section "Marking, packaging, transportation and storage". It does not contain information, as it redirects to GOST 10692 - 80.

4. Why are the rules for product acceptance stipulated in GOSTs?

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

5. Show the use of GOST.

Answer: Example: ordered pipe 57 * 4mm. 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 us determine the permissible deviations in terms of geometric parameters:

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

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

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

D) pipe ovality: diameter tolerance* 2;

E) the wall thickness of the pipe;

G) curvature of the pipe.

Conventional designation of the pipe in our example: pipe 57p * 4.0 * 1250kr GOST 8732-78.

В 10 GOST 8732-74

II. Since the pipes are 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 named GOST:

A) tear resistance;

B) metal flow test;

C) test for elongation of the sample.

Surface inspection: unacceptable and acceptable defects.

IV. Trimming the ends of pipes and a method for determining the depth of the defect.

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

Vii. Labeling, packaging and storage (see GOST 10692–80).

6. What are the technical specifications, who makes them?

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

The drafting of technical specifications is preceded by technical assignments, project development, numerous analyzes and expertise.

TU is approved by technical managers of the manufacturer and consumer, and then registered with UralNITI.

7. What is the difference between technical conditions and GOST?

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

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

8. Scope of technical conditions.

Answer: There are technical conditions on a republican scale, for example. TU for all types of food products, as well as intradepartmental, for example, TU for the supply pipe billet between Pervouralsk Novotrubny Plant and Oskolsk EMK. Inside our enterprise, there are 30 TUs for the supply of billets from pipe rolling shops to pipe-drawing shops, and we use up to 500 different TUs 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 longitudinal steel pipes with a diameter of 8 to 520 mm with a wall thickness of up to 10 mm inclusive, of carbon steel. It is used for pipelines and structures for various purposes.

a)off-gauge length (pipes not of the same length):

with a diameter of up to 30 mm. - not less than 2 m;
with a diameter of 30 to 70 mm. - not less than 3 m;
with a diameter of 70 to 152 mm. - not less than 4 m;
with a diameter of more than 152 mm. - not less than 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;
not less than 4 m - for pipes up to 426 mm in diameter.

Pipes over 426 mm in diameter 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 of 70 to 219 mm - from 6 to 9 m;
with a diameter of 219 to 426 mm - from 10 to 12 m.

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

Two accuracy classes are manufactured along the length of the pipe:

1. with trimming and deburring outside the mill line;

2. with cutting in the mill line.

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

+15 mm - for pipes of the 1st class of accuracy;
+100 mm - for pipes of the 2nd class of accuracy (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 the standardization of mechanical properties of calm, semi-calm and boiling steel grades St2, St3, St4 in accordance with GOST 380-88;

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

V- with standardization of mechanical properties and chemical composition from calm, semi-calm and boiling steel grades ВСт2, ВСт3, ВСт4 (categories 1, 23-6), as well as calm, semi-calm and boiling steel grades 08, 10, 15, 20 according to GOST 1050- 88 and steel grades 08Yu in accordance with GOST 90-45-93 for diameters up to 50 mm.

D- with standardization of the test hydraulic pressure.

Heat-treated pipes (throughout the entire volume of the pipe or welded joint) and pipes without heat treatment are produced.

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

This standard applies to non-galvanized and galvanized steel welded pipes with threaded 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 pipelines. The length of the pipes is from 4 to 12 meters.

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

The following are manufactured along the length of the pipe:

a)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 customer's order), and from 8 to 12 m (by agreement between the manufacturer and the customer) with a 5 mm allowance for each cut and a maximum deviation for the entire length plus 10 mm.

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

The curvature of pipes for 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 not less than 30 microns thick. The absence of the specified coating is allowed on the ends and threads of pipes and couplings.

3.GOST 8734 - 75 - seamless cold-worked steel pipes

Manufactured:

a)unmeasured lengthfrom 1.5 to 11.5 m;

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

In each batch of pipes of measured 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 - seamless hot-deformed steel pipes

This standard applies to hot-worked seamless pipes 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 the transportation of hazardous substances (1, 2, 3 classes), explosion and flammable substances, as well as a pair and hot water.

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

Technical requirements

Pipe sizes and maximum deviations must correspond to those given in GOST 8732-78 and GOST 9567-75.

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

A- with standardization of mechanical properties of steel grades St2sp, St4sp, St5sp, St6sp in accordance with GOST 380-88;

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

V- 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 norms of mechanical properties must correspond to those specified in the standards for steel;

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

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

5.GOST - 20295 - 85 - welded steel pipes

They are used in main gas and oil pipelines.

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

Basic parameters and dimensions .

Pipes are made of three types:

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

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

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

4.3. Questions about the steel grades used

1. What are the criteria for classifying steel?

Answer: Steel is classified:

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

2. What is made up of symbol steel grades? (examples).

Answer: All steels have their own markings, which primarily reflect their chemical composition. In the marking, the first digit indicates the content in hundredths of a percent. Then follow the letters of the Russian alphabet, indicating the presence of the alloying element. If there is no number behind the letter, this means that the content of the alloying element is not more than one percent, and the numbers following the letter indicate its content in percent. Example: 12ХН3А - carbon content - 0.12%; chromium - 1.0%; nickel - 3.0%; High Quality.

3. Decipher the following designations of steel grades:

20A, 50G, 10G2, 12X1MF, 38X2MYUA, 12X18N12T, 12X2MFSR, 06X16N15M2G2TFR - ID, 12X12M1BFR - 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%;
38Х2МЮА - 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%;
12Х2МФСР - 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.

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

Answer: B last years to improve the quality of steel, new methods of its smelting are used, which are reflected in the designations of steel grades:

VD - vacuum - arc;
VI - vacuum - induction;
W - slag;
PV - direct recovery;
EPSh - electron slag remelting;
ШД - vacuum-arc after slag remelting;
ELP - electron beam remelting;
PDP - plasma-arc remelting;
ISh - 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 - electrostalskaya search engine;
EI - electrostalskaya 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.

5. Tell about carbon steel grades.

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

In terms of quality, structural carbon steel is divided into two groups: ordinary quality and high quality.

Common grade steel is used for irresponsible building structures, fasteners, sheet metal, rivets, welded pipes. For structural carbon steel of ordinary quality, GOST 380–88 is set. 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 C supplied by mechanical properties and chemical composition.

High-quality carbon structural steel is supplied in terms of chemical composition and mechanical properties, GOST 1050-88. It is used for parts operating under increased loads and requiring resistance to impact and friction: gear wheels, axles, spindles, ball bearings, connecting rods, crankshafts, for the manufacture of welded and seamless pipes. Automatic machine also belongs to structural carbon steels. To improve the processing by cutting, sulfur, lead, 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% or more of carbon. Differs in hardness and strength and is divided into high quality and high quality.

Quality steel grades in accordance with GOST 1435 -90: U7, U8, U9, U10A, U11A, U12A, U13A. The letter "U" stands for carbon tool steel. The numbers behind the letter "Y" show the average carbon content in tenths of a percent. The letter "A" at the end of the mark indicates high quality steel... The letter "G" means a high content of manganese. Chisels, hammers, stamps, drills, stamps, various measuring tools are made of tool carbon steel.

6. Tell about alloyed steel grades.

Answer: Along with the usual impurities (sulfur, silicon, phosphorus) in alloy steel, there are alloying ones, i.e. binding elements: chromium, tungsten, molybdenum, nickel, as well as silicon and manganese in an increased amount. Alloy steel has high value 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:

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

Rare-earth elements are also introduced into special-purpose steels; several alloying elements can be simultaneously present in alloyed steels. According to their purpose, alloyed 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 field of application of structural alloy steel is very large. Most widespread received the following steels:

chromium, with good hardness, strength: 15X, 15XA, 20X, 30X, 30XPA, 35X, 40X, 45X
manganese, characterized by wear resistance: 20G, 50G, 10G2, 09G2S (c. 5,8,9);
chromium manganese: 19HGN, 20HGT, 18HGT, 30HGA;
siliceous and chrome-siliceous, with high hardness and elasticity: 35ХС, 38ХС;
chromium-molybdenum and chromium-molybdenum-vanadium, extra strong, resistant to abrasion: 30XMA, 15XM, 15X5M, 15X1MF;
chromium-manganese-silicon steels (chromansil): 14HGSA, 30HGSA, 35HGSA;
chromium-nickel, very strong and plastic: 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 of such steel are chromium, tungsten, molybdenum, manganese. Measuring tools are made of this steel - thread gauges, staples (7HF, 9HF, 11HF); cutting - cutters, drills, taps (9XC, 9X5VF, 85X6NFT); stamps, molds (5ХНМ, 4Х8В2). The most important tool alloy steel is high speed steel. It is used in the manufacture of drills, cutters, taps. The main properties of this steel are hardness and redness. Alloying elements are tungsten, chromium, cobalt, vanadium, molybdenum - R6M3, R14F14, R10K5F5, etc.

7. Tell 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 different aggressiveness. For slightly aggressive environments, steels 08X13, 12X13, 20X13, 25X13H2 are used. Parts made of these steels work outdoors, in fresh water, in wet steam and salt solutions at room temperature.

For mediums of medium aggressiveness, steels 07X16H6, 09X16H4B, 08X17T, 08X22H6T, 12X21H5T, 15X25T are used.

For environments with increased aggressiveness, steels 08X18H10T, 08X18H12T, 03X18H12 are used, which are highly resistant 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 should retain their properties at - 40° From -80° C. The following steels are most widely used: 20X2N4VA, 12XN3A, 15XM, 38X2MYUA, 30XGSN2A, 40XH2MA, etc.
Heat-resistant steels are able to withstand mechanical stress at high temperatures (400 - 850° WITH). Steel 15Х11МФ, 13Х14Н3В2ФР, 09Х16Н15М3Б, and others are used for the manufacture of superheating devices, blades of 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 scale formation at temperatures of 1150 - 1250° Steel grades 12Х13, 08Х18Н10Т, 15Х25Т, 10Х23Н18, 08Х20Н14С2, etc. are used for the manufacture of steam boilers, heat exchangers, thermal furnaces, equipment operating at high temperatures in corrosive environments.
Heat-resistant steels are intended for the manufacture of parts operating in a loaded state at a temperature of 600 ° C for a long period of time. These include: 12X1MF, 20X3MVF, 15X5VF, etc.

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

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

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

Sulfur - gets into steel from cast iron, and cast iron - from coke and ore. Sulfur with iron forms a compound located along the grain boundaries of the steel. When heated to 1000 -1200 ° With (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, gets into steel from ores. It greatly reduces the ductility of steel; steel becomes brittle at ordinary temperatures. This phenomenon is called cold brittleness.
Oxygen - partially dissolved in steel and present in the form of non-metallic inclusions - oxides. Oxides are brittle, do not deform during hot processing, but crumble and loosen the metal. As the oxygen content increases, the tensile strength and toughness are significantly reduced.
Nitrogen is absorbed from the atmosphere by liquid metal during smelting and is present in steel as nitrides. Nitrogen lowers the toughness of carbon steels.
Hydrogen - can be in the atomic state in steel 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 (flocs). Titanium alloys are very sensitive to hydrogen saturation, where special measures are taken against the hydrogenation of the metal.
Copper - in a high content (over 0.18%) in low-carbon steels significantly increases the tendency of steel to aging and cold brittleness.

4.4. Raw material for pipe production

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

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

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

Benefits of Quiet Steel: less concentration of harmful impurities; lack of subcortical blisters.

Disadvantages of Quiet Steel: larger size of the primary shrinkage cavity; significant secondary shrinkage cavity; worse surface quality; less toughness of the metal; more expensive production.

For the manufacture of seamless pipes, boiling and semi-calm steel is used only for pipes of a less critical purpose precisely because of the high concentration of impurities and a significant amount of subcrustal bubbles; in recent years, to improve the quality of pipe steel, blowing of liquid metal with argon, evacuation, processing of steel with synthetic slags, additives powder reagents. Steels with a high carbon content are used for the manufacture of large-diameter pipes, which are used in the oil industry as casing and drill pipes, as well as other critical pipes. Steels with a lower carbon content are used for the production of steam boiler rooms and other pipes.

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

Welded pipes are obtained from strip and sheet billets, billets of all others the listed types designed for the manufacture of seamless pipes.

For the production of pipes from high-alloy low-plastic steels in recent times hollow cylindrical blanks are used as a workpiece. This eliminates the laborious and sometimes unfeasible operation of piercing the workpiece (obtaining a hollow workpiece from a workpiece with a solid section) from these steels.

Some pipe mills use square or multi-faceted ingots.

Solid ingots of cylindrical shape are used in the production of 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, the maximum diameter of which reaches 320-350 mm.

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

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

Pipes with a diameter of over 520 mm are welded from separate 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 billets, shrinkage cavities, bubbles, cracks on ingots; captivity and burrs on rolled blanks; tears, delamination and distorted sheet sizes, etc.

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

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

obtaining high quality steel pipes.

4.5. Production technology of pipes, bends and cylinders

The technology for the production of pipe products is considered on the example of the organization of production at OJSC "Pervouralsk Novotrubny 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 users and are also used as blanks for cold processing (manufacturing of cold-worked pipes).

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

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

Rice. 1. Production process of hot rolled pipes

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

preparation of billets for rolling;
heating the workpiece;
stitching the workpiece into the sleeves;
rolling of sleeves into pipes on a continuous mill;
heating pipes before calibration or reduction;
rolling pipes on a sizing or reduction mill;
pipe cutting;
cooling pipes and their 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 tubes of the same constant size are rolled, which are then brought to the size specified by orders on a sizing or reduction mill.

The billet is heated in two 3-strand sectional furnaces with a length of about 88 meters each. The heating part of the sectional furnace is divided into 50 sections; they, in turn, are divided into 8 zones. The temperature regime in each zone is maintained automatically.

The correctness of metal heating is controlled by a photoelectric pyrometer, which measures the temperature of the sleeve leaving the rolls of the piercing mill. The billet heated in the furnace is cut using cantilever scissors with a lower cut. The heated and centered billet is pierced on a 2-roll piercing mill with barrel rolls and axial delivery.

Rolling 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 guided 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 plane of the floor and 90 degrees to each other. Each stand has two round groove rolls.

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

Before calibration or reduction, the pipes are heated in induction heating furnaces. From the calibration table, pipes with a diameter of 76 to 108 mm are obtained, after a 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 to lengths from 12.5 to 24.0 meters. In order to eliminate the curvature and reduce the ovality of the cross-section, the pipes after cooling are straightened on a skew-roll straightening mill.

After straightening, the pipes are cut to length.

Pipe finishing is carried out on production lines, which include: pipe cutting machines, pipe cutting machines, a blow chamber for removing chips and scale, an inspection table of the Quality Control Department.

Cold-formed pipes production technology

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

For the manufacture of cold-deformed pipes with a diameter of 0.2 to 180 mm with a wall thickness of 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 rolling mills, coiled and long straightening mills. dragging. There are production lines for coiled drawing of especially thick-walled pipes for fuel lines of diesel engines, fin pipes for boilers of superheaters of thermal power plants, profiled seamless and electric-welded cold-deformed pipes of various shapes are manufactured.

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

In fig. 2 shows the technological processes used in the manufacture of cold-worked pipes.

Fig. 2. Cold formed pipe production process

The technology for manufacturing pipes in pipe-drawing shops has the following general sections:

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

The entire billet going for inspection is preliminarily subjected to pickling to remove the scale left on the pipes after hot rolling. The pickling is carried out in the baths of the pickling department. After etching, the pipes are sent for washing and drying.

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

The designs of the KhPT mills installed in the workshops of the plant are diverse and differ from each other in standard sizes, the number of simultaneously rolled pipes and modification.

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

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

The plant also uses drum drawing.

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

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

Cutting the ends of pipes with deburring and cutting out the measure is carried out on pipe-cutting cutting tools or with abrasive wheels. For complete deburring, steel brushes are used in a number of workshops.

Pipes that have passed all finishing operations are presented for control to the inspection tables of the Quality Control Department.

Technology for the production of electrowelded pipes

For the production of longitudinal electric-welded pipes with a diameter from 4 to 114.3, the plant has 5 electric welding mills. In the manufacture of pipes from carbon steels, the method of high-frequency welding is used, from high-alloy steels - arc welding in inert gases. These technologies, combined with physical control methods and hydraulic testing, ensure the reliability of pipes when used in mechanical engineering and building structures.

Removing the inner burr, high cleanliness of the inner surface of the pipes allow us to obtain high quality products. In addition, welded pipes can be subjected to mandrel and crimp-free drawing and rolling on roller mills. Heat treatment in a protective atmosphere furnace provides a light-colored pipe surface.

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

the ability to achieve a high welding speed;
production of pipes with a high-quality seam from a hot-rolled un-etched billet;
relatively low power 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, intensely heats them up, and when they touch 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 the transition zone differs only by 10 - 15% from the microhardness of the base metal. Such structure and properties of a welded joint cannot be obtained by any of the existing pipe welding methods.

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

Fig. 3. Welded pipe manufacturing process

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

The stuck tape is fed by the pulling rollers to the strip drum accumulator to ensure a continuous technological process due to the created tape reserve. From the storage, the tape enters the forming mill, which consists of 7 stands with two rolls in each. Between each stand there is a pair of vertical (edged) rolls to stabilize the belt movement. The forming mill is designed to shape the strip into an endless blank in the cold state.

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

After welding and removing the outer burr, the pipe is directed along a roller table located in a closed chute to the calibration and profiling unit, while it is abundantly watered with a cooling emulsion. The cooling process continues both in the sizing mill and when cutting the pipe with a flying circular saw.

Sizing of round tubes is carried out in a 4-stand sizing mill. Each stand has two horizontal rolls, and vertical rolls are installed between the stands, also two pieces each.

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

After profiling, electric-welded pipes for household refrigerators undergo high-frequency annealing, cooling and then go to the galvanizing bath to be coated with an anti-corrosion coating.

The finishing equipment for electric-welded pipes includes: a facing machine with two socket heads for processing pipe ends; hydraulic press for testing pipes, if it is prescribed by the normative documentation; tubs for pneumatic testing of pipes for refrigerators.

Production technology of pipes lined with polyethylene

Polyethylene lined steel pipes and pipe fittings (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.

The maximum operating temperature of lined pipes is + (plus) 70 ° С, the minimum installation temperature for pipes with flanges is 0 ° С, for wafer joints - (minus) 40 ° С.

The plant produces a set of steel, polyethylene lined pipelines with flanged connections in a ready-to-install form, which include: lined pipes, equal and transition tees, concentric transitions and bends.

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

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

In fig. 4 shows the technological processes used in the manufacture of pipes lined with polyethylene.

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

Before lining, steel pipes are cut to length according to pipeline specifications. Threads are cut at the ends of the pipes, threaded thrust 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 length, pipe ends are processed, chamfers are removed.

Lining of steel pipes is carried out by the joint drawing method or by the tightening method. 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 pipes of the flange connection, the lining layer is flanged onto the ends of the threaded rings.

Tees and concentric reductions are lined with plastic injection molding on injection molding machines. Bent bends are made of short lined pipes on pipe bending machines... The bodies of the sector bends are lined with polyethylene pipes with subsequent flanging of the ends onto flanges.

Fig. 3. Production process of pipes lined with polyethylene

Elbow production technology

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

Outside diameter: 45 - 219 mm, wall thickness: 2.5 - 8 mm, bending angle: 30 °, 45 °, 60 °, 90 °, 180 °, steel grades: 20, 09G2S, 12X18H10T.

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

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

According to the general quality strategy of Novotrubny Zavod, elbows are made only from section pipes using full cycle control of properties of finished products. The conformity of products to the accepted normative and technical documentation is confirmed by 100% verification of dimensional characteristics and laboratory tests. For the production of parts, permits and certificates of supervisory authorities have been obtained, confirming the suitability of our products for use in environments of high aggressiveness, including at facilities supervised by the Gosgortekhnadzor of Russia.

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

Rice. 5. Manufacturing process of elbows

The technology for the production of bends includes the following stages:

cutting into measured billets (nozzles) of pipes obtained from the pipe shops of the plant and having passed the appropriate final quality control;
hot broaching of branch pipes along the 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, the geometrical dimensions are edited, primarily diameters;
preliminary flame or plasma cutting of the allowance for the uneven ends of the bends;
mechanical restoration ends of bends and chamfering (trimming);
OTK acceptance:

—control of geometric dimensions,

—hydrotesting,

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

—marking.

5. Quality issues of tubular products

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

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

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

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

Answer:

pipes must have a working label;
pipe surfaces must be dry and clean;
the pipes must lie on the inspection table in the inspection zone in one row with an interval depending on the diameter, allowing their free movement (tilting around their axis) to inspect the entire surface, and not only in a certain zone.
The pipes must be straight, i.e. roll freely on the rack, have exactly cut ends and removed burrs.

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

3. How is it produced visual control the outer surface of the pipes?

Answer: It is made directly on inspection tables (racks) by inspectors with normal vision without the use of magnifying devices. Inspection of the surface is carried out in sections with the subsequent reordering of each pipe so that the entire surface is inspected. It is allowed to simultaneously control several pipes at once; it should be remembered that the total surface of the examination does not exceed the angle of view. In doubtful cases, i.e. when the defect is not clearly pronounced. The inspector is allowed to use a file or emery paper, with the help of which he removes the surface of the pipe.

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

Answer: If it is necessary to determine the depth of the defect, a control filing is done with a subsequent comparison of the pipe diameter before and after the removal of the defect:

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

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

5. For what and how is the instrument control of the outer surface of pipes used?

Answer: Instrumental control is used to assess the quality of the outer surface of pipes for critical purposes: boiler rooms, for aviation equipment, nuclear power, ball bearing factories, etc.

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

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, from the side opposite to the controller, with which it can move along the pipe and illuminate dubious places. For smaller sizes (in pipe-drawing shops), so-called screens are used - backlights, consisting of a number of lamps " daylight»And giving an even light.

7. Why and how is the instrumental inspection of the inner surface of pipes used?

Answer: It is used for critical pipes. It is subdivided into instrumental control and control using periscopes according to a special technique, with an increase in the area of the controlled surface by 4 times. 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 the manual measurement of pipe wall thickness performed?

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

8. How is the manual control of the outside diameter of pipes carried out?

Answer: Manually, the outer diameter of the pipes is controlled using a smooth micrometer of the MK type of the second class, or with calibrated clamps in at least two sections. In each section, at least two measurements are made at an angle of 90 ° one to the other, i.e. in mutually perpendicular planes. In case of detection of defects or maximum permissible values, the number of sections and measurements increases.

9. For what and how is the instrument control of the outer diameter of pipes used? Examples.

Answer: It is used for critical pipes and is carried out simultaneously with the control of the continuity of surfaces, wall thickness on UKK-2 devices, R RA. On roller cold rolling mills (CPTR) for technological control of the pipe diameter, the KED device (compact electromagnetic diameter) is used.

10. How is the manual control of the inner diameter of pipes carried out? Examples.

Answer: It is produced in accordance with orders using a certified caliber (for sizes from 40 mm. And the more common name "rolling pin") of the "pass - no pass" type for the length specified in the regulatory documentation from both ends of the pipe. For example, for tubing in accordance with GOST 633-80, straightness control is required at each end by 1250mm; the inner diameter is monitored at the same time. To control the inner diameter of pipes going to the manufacture of shock absorbers, where required high accuracy sizes, special devices are used - internal gauges.

11. When is instrumental control of the inner diameter of pipes necessary? Examples.

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

12. How is the control of the curvature (straightness) of pipes carried out? Examples.

Answer: Straightness of pipes, as a rule, is ensured by production technology and, in practice, is checked "by eye". In doubtful cases, or at the request of regulatory documents, the actual curvature is measured. It is performed on any one measured section or along the entire length of the pipe, depending on the requirements of regulatory documents. To measure curvature, a flat horizontal surface is required (ideally a surface plate). A measured section with the maximum "by-eye" curvature is selected; if the curvature is in the same plane with the plate, a straight edge 1 meter long, type SCHD, second accuracy class, is applied from the side and using a set of probes No. 4, the gap between the pipe and the ruler is checked.

13. In what cases and how is the control of chamfer blunting performed?

Answer: produced at the request of regulatory documents using a measuring ruler or template. The control of the implementation of the chamfer angle is carried out at the request of regulatory documents 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 elbow is applied along the generatrix of the pipe surface. 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 is pipe length measured manually?

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

16. Methods for determining steel grades.

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

sparking;
steeloscopy;
chemical or spectral analysis.

6. Questions of classification of types of defects in the manufacture of pipes and ways to correct them

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

Answer: The adopted quality accounting system divides defects detected 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-worked and welded pipes).

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

Answer:

The open and closed shrinkage cavity is a cavity formed during the solidification of the metal after it is poured into molds. The cause of this defect may be a violation of the steel casting technology, the shape of the mold, the composition of the steel. The most advanced method for dealing with shrinkage cavities is continuous casting of steel.
Liquidation in steel. Liquidation is the compositional heterogeneity of steel and alloys that forms during their solidification. An example of segregation is the segregation square, which is revealed in the transverse macrosections of the metal and is a structural heterogeneity in the form of differently etched zones, the contours of which repeat the shape of the ingot. The reasons for the liquation square can be an increased content of impurities (phosphorus, oxygen, sulfur), a violation of the technology of casting or solidification of the ingot, the chemical composition of steel (for example, with a wide temperature limit solidification). A decrease in the liquation square is achieved by a decrease in impurities, a decrease in the casting temperature of steel and a decrease in the mass of ingots.
Internal bubbles. They are cavities formed as a result of the release of gases during the crystallization of the ingot. The most common cause of bubbles is the high concentration of oxygen in the liquid metal. Bubble prevention measures: complete metal deoxidation, use of well-dried materials for alloying and slagging, drying of pouring devices, cleaning of molds from scale.
Honeycomb. These are gas bubbles located in the form of honeycombs at a very small distance from the surface of an ingot of boiling or semi-calm steel. Leads to steel delamination. Possible reasons their appearance can be high rates of steel casting, increased gas saturation, over-oxidation of the melt.
Axial porosity. Presence of fine pores of shrinkage origin in the axial zone of the ingot. It occurs when the last portions of liquid metal solidify under conditions of insufficient liquid metal supply. A decrease in axial porosity is achieved by pouring steel into molds with a large taper, as well as by warming or heating the bottom part.
Inversions of the crusts. A defect consists of rolled metal crusts and splashes located at the surface of the ingots, affecting part or all of the ingot. On the microsection in the defect zone, there are large accumulations of non-metallic inclusions; decarburization and scale are often observed. Turns of crusts, floods, splashes can be found in metal of all steel grades with any casting method. Reasons: cold metal casting, slow casting speed, and high toughness metal casting. An effective means of preventing a defect is casting under liquid synthetic slag.
Hairline. The defect is expressed in the form of thin, sharp notches of different depths caused by contamination of the surface of the ingot or pipe billet with non-metallic inclusions (slags, refractories, insulating mixtures). Surface defects are well detected on a turned or etched pipe billet, as well as during descaling of finished pipes. Preventive measures: use of high-quality refractories, holding metal in ladles, casting under liquid slag, various refining remelting.

3. What are the types and causes of defects in steel rolling production that affect the quality in the manufacture of pipes?

Answer:

Internal tears during deformation. Formed during hot deformation (rolling) in the axial zone of blooms or pipe billet 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 lowering the heating temperature of the metal before deformation or by reducing the degree of deformation in one pass.
Birdhouse. It is an internal transverse thermal crack opened during rolling in an ingot or billet. The cause of the defect is the sharp heating of a cold ingot or billet, in which the outer layers of the metal heats up faster than the inner ones, and stresses arise that lead to the rupture of the metal. The most prone to the formation of birdhouses are high-carbon steels U7 - U12 and some alloyed steels (ShKh - 15, 30KhGSA, 37KhNZA, etc.). Defect prevention measures - adherence to the technology of heating ingots and billets before rolling.
Flaws. These are open discontinuities, located at an angle or perpendicular to the direction of the greatest drawing of the metal, are formed during hot deformation of the metal due to its reduced plasticity. Rolling a tubular billet from blooms with flaws leads to the appearance of rolled caps on the surface of the rods. The reasons for the appearance of flaws can also be violations of the technology of heating the metal and large degrees of reduction. Blanks with flaws are thoroughly cleaned.
Steel-making captivity. This term refers to defects in the form of delamination of metal of various shapes, combined with the base metal. The bottom surface of the captivity is oxidized, and the metal under it is covered with scale. The reasons for the occurrence of steelmaking traps can be rolling out defects of an ingot of steelmaking origin: crusts twisting, accumulations of subcrustal and surface gas bubbles, longitudinal and transverse cracks, sagging, etc. Measures to prevent steelmaking captivity: compliance with the technology of steelmaking and casting.

4. Methods for detecting surface and internal metal defects.

Answer: B modern practice the following basic methods of detecting and studying surface and internal metal defects are used:

external inspection of the product;
ultrasonic testing to detect internal defects;
electromagnetic control methods for detecting surface defects;
local cleaning of the surface;
upsetting of samples cut from rods for a clearer identification of surface defects;
stepped turning of bars to identify hair strands;
studies of the macrostructure on transverse and longitudinal templates after etching;
investigation of longitudinal and transverse fractures;
electron microscopic research methods;
study of non-etched microsections (to assess contamination with non-metallic inclusions);
study of the microstructure after etching to identify structural components;
X-ray structural analysis.

5. Types and causes of defects in the manufacture of pipes by hot rolling. Corrective measures for marriage.

Answer:

Rolling captivity. Longitudinal orientation defect. The reason is the rolling out of defects in the surface of a pipe billet or bloom in the pipe: trimming, rolling, mustache, zakova, wrinkles. External caps cannot be repaired and are permanent defects.
Flockens. These are thin metal breaks resulting from structural stresses in hydrogen-saturated steel. They usually appear in rolled metal and are detected by ultrasonic testing. Flockens appear in the process of metal cooling at a temperature of 250 ° C and below. They are found mainly in structural, tool and bearing steels. Flock prevention measures: 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 consider the most typical hot cracks.

Hot crystallization crack is an oxidized metal fracture formed during the 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 perpendicularly, depending on the location and shape of the original ingot defect. Factors causing cracking include: overheating of liquid metal, increased speed casting, increased sulfur content, as the ductility of steel decreases, violation of the technology of casting steel, the influence of the steel grade itself. Cracks cannot be repaired and are permanent defects.

Layering. This is a violation of the continuity of the metal caused by the presence of a deep shrinkage cavity in the original ingot, shrinkage looseness, or an accumulation of bubbles, which, upon subsequent deformation, emerges on 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 the technology of steel smelting and casting. Bundles cannot be repaired and are permanent defects.
Sunset. This is a violation of the continuity of the metal in the direction of rolling from one or both sides of the product (pipe) along its entire length or along its part as a result of rolling a mustache, undercutting or rolling from the previous caliber. The reason for the decline is usually the overflow of the metal of the working gauge, when it (the metal) is “squeezed” into the space between the calibers in the form of a mustache, and then rolled up. Preventive measures: correct tool calibration, adherence to rolling technology. It cannot be repaired and is a final defect.
Sinks. A surface defect, which is local depressions without disrupting the continuity of the pipe metal, which were formed from the fallout of local captives, non-metallic inclusions, rolled objects. Preventive measures: use of high-quality pipe billets, adherence to rolling technology.
Selling. A surface defect that is a through hole with thinned edges, elongated in the direction of deformation. The defect is caused by the ingress of foreign bodies between the deforming tool and the pipe.
Cracks of pipe-rolling origin. A defect in the surface of a longitudinal orientation, which is a violation of the continuity of the metal in the form of a narrow rupture, usually going deep into the wall at a right angle to the surface. Reasons: reduction of cooled pipes, excessive deformation during rolling or straightening, the presence of residual stresses in the metal that were not removed by heat treatment. Preventive measures: compliance with pipe production technology. Final marriage.
Internal captives. The cause of internal captivity is the premature opening of the cavity in the core of the workpiece before piercing. The appearance of internal captives is greatly influenced by the plasticity and toughness of the metal being pierced. To prevent captivity on cold-deformed pipes, the pipe billet is subjected to boring on pipe-boring machines.
Dents. A surface defect, which is local grooves without breaking the continuity of the metal. A kind of dents are tool prints.
Screw trace. A surface defect in the form of periodically repeating sharp protrusions and annular depressions located along a helical line. Cause: Incorrect setting of the lines of the piercing mill or break-in machines. Preventive measures: compliance with production technology and pipe finishing.

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

Answer:

Birdhouse. A surface defect that is oblique, often at an angle of 45° , metal breaks of various depths up to through. More commonly found on high carbon and alloy cold worked pipes. Causes: excessive deformation, which caused excessive additional stresses; insufficient ductility of the metal due to poor quality intermediate heat treatment of pipes. Preventive measures: correct calibration of the working tool, adherence to pipe production technology. They cannot be repaired, they are the final marriage.
Scale. Formed during heat treatment of pipes, degrades the quality of pipe surfaces and interferes with inspection. When straightening pipes that have undergone heat treatment, part of the scale is mechanically removed, and part remains, transforming it into scrap. Precautionary measures: Heat treatment in ovens with protective atmosphere, pickling or machining of pipes.
Snack. It is most often found in the case of non-dragging of cold-deformed pipes. Cause: loss of stability of the pipe cross-section during rolling, excessive deformation, metal overflow of the drawing ring due to incorrect calibration.
Risks and bullies. Risks - grooves on the outer or inner surfaces of the pipe, without changing the continuity of the metal. Seizure - differs from risks in that part of the pipe metal is mechanically stripped off and collected along the pipe axis into chips, which can then fall off. Reason: poor preparation of the drawing tool, ingress of foreign particles between the tool and the pipe, low mechanical characteristics of the pipe metal. Preventive measures: compliance with pipe production technology.
Inner rings and gaps (pipe jitter). Reason: poor quality coating before drawing, low ductility of the metal, high drawing speed. Preventive measures: compliance with pipe production technology.
Rowan. Minor irregularities of various shapes, located over the entire surface of the pipe or part of it. Reasons: poor-quality surface preparation for rolling and drawing, increased wear of the rolling tool, poor-quality lubrication, dirty pickling baths, poor processing at intermediate stages of manufacturing. Preventive measures: compliance with pipe production technology.
Rubbed. A surface defect in the form of point or contour depressions located in individual sections or over the entire surface of the pipes, representing local or general damage to the metal surface during etching. It cannot be repaired.
Melting. 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 pipe surface. Fusion 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 pipe polishing. It cannot be repaired.

7. Types and causes of defects in the manufacture of welded pipes. Marriage prevention measures.

Answer:

Offset of tape edges during welding. It is the most typical type of defect in the production of electric-welded pipes.The reasons for this defect are: misalignment of the axis of the rolls of the forming mill in vertical plane; incorrect roll setting; asymmetrical position of the tape relative to the axis of forming and welding; malfunction of the welding unit.
Lack of fusion. This type of marriage, when the seam of a welded pipe is either extremely fragile, or remains completely open, i.e. the edges of the tape do not converge or weld. The reasons for lack of penetration can be: narrow tape; inconsistency of the welding speed with the heating mode (the speed is high, the current is low); displacement of the edges of the tape; insufficient reduction in the welding rolls; failure of the ferrite set.
Burns. Defects under this name are located on the surface of the pipe near the welding line, both on one side of the weld, and on both sides. The reasons for arson are: high power of the arc, resulting in overheating of the edges of the tape; damage to the insulation of the inductor; poor-quality preparation of the tape.
Outer and inner burr. Burr is a metal squeezed out of the seam when the edges of the tape are squeezed, its appearance is technologically inevitable. The technical conditions provide for the complete absence of burrs. Its presence speaks of improper installation of the cutter of the deburring tool, its bluntness.

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

Answer: Rolled captivity, cracks of pipe-rolling origin, cracks, delamination, sunsets, birdhouses, rubbing, penetration cannot be repaired and are a final marriage.

Metallurgical enterprises of Russia

7.1. Metallurgical plants

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

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

11. JSC "Oskol Electro-Metallurgical Plant" - Stary Oskol: a circle of carbon steel grades.

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

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

14. JSC "Chelyabinsk Metallurgical Plant" - Chelyabinsk: stainless steel strip, a circle of carbon steel grades, a circle of alloyed steel grades, a circle of ball bearing steel grades, a circle of stainless steel grades.

7.2. Pipe plants and their brief description

OJSC "Pervouralsk Novotrubny Plant" (PNTZ)

Located in the city of 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 of 42 to 219 mm;

— seamless cold-worked 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 of 12 to 114 mm.

PNTZ also manufactures pipes for special orders (thin-walled, capillary, stainless).

Volzhsky Pipe Plant OJSC (VTZ)

Located in the city of Volzhsky, Volgograd region.

Produced assortment:

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

The good quality of products manufactured by VTZ determines a stable sales market, and for pipes with a diameter of 1420 to 2520 VTZ is a monopoly 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 of 57 to 76 mm.

In parallel, VEST-MD is engaged in the production of capillary and thin-walled pipes of small diameters.

OJSC "Vyksa Metallurgical Plant" (VMZ)

Located in the city of Vyksa, Nizhny Novgorod region. Vyksa Steel Works specializes in the production of electric-welded pipes.

— 3262 with a diameter from 15 to 80mm.

— 10705 with a diameter from 57 to 108mm.

— 10706 with a diameter from 530 to 1020mm.

— 20295 with a diameter from 114 to 1020mm.

According to GOST 20295-85 and TU 14-3-1399 they are heat treated and meet the highest quality requirements.

Izhorskiye Zavody OJSC

Located in Kolpino, Leningrad Region.

Produced assortment:

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

Also, Izhorskiye Zavody OJSC carries out special orders for the production of seamless thick-walled pipes.

OJSC "Seversky Pipe Plant" (STZ)

Located in the Sverdlovsk region at the 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 of 57 to 108 mm;

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

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

Pipes of high quality from group “B” calm steel.

JSC "Taganrog Metallurgical Plant" (TagMet)

Located in Taganrog.

— 3262 with a diameter from 15 to 100mm.

— 10705 with a diameter from 76 to 114mm.

Seamless pipes with a diameter of 108-245 mm.

JSC "Trubostal"

Located in St. Petersburg and is 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 of 57 to 114 mm;

OJSC "Chelyabinsk Pipe-Rolling Plant" (ChTPZ)

Located in the city of 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, ChTPZ is engaged in the production of galvanized water and gas pipes.

Agrisovgaz LLC (Agrisovgaz)

Is in Kaluga region, Maloyaroslavets

OJSC "Almetyevsk Pipe Plant" (ATZ)

Located in the city of Almetyevsk.

JSC "Borsky Pipe Plant" (BTZ)

Located in the Nizhny Novgorod region, Bor.

Volgorechensky Pipe Plant OJSC (VRTZ)

Is in Kostroma region, Volgorechensk.

OJSC "Magnitogorsk Iron and Steel Works" (MMK)

Located in the city of Magnitogorsk.

JSC "Moscow Pipe Plant" FILIT "(FILIT)

Located in Moscow.

JSC Novosibirsk Metallurgical Plant named after Kuzmina "(NMZ)

Located in Novosibirsk.

PKAOOT "Profile-Akras" (Profile-Akras)

Located in the Volgograd region, Volzhsky

JSC "Severstal" (Severstal)

Located in the city of Cherepovets.

OJSC "Sinarsky Pipe Plant" (Sinarsky Pipe Plant)

Located in the Sverdlovsk region, Kamenetsk-Uralsky.

OJSC "Ural Pipe Plant" (Uraltrubprom)

Located in the Sverdlovsk region, Pervouralsk.

OJSC "Engels pipe plant" (ETZ) Located in the Saratov region, Engels

8. Basic rates of loading of rolled pipes

8.1. Basic norms for loading pipe-rolling into railway wagons

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.

Loading rate from 45 to 55 tons per 1 gondola car.

Water and gas pipe according to GOST 3262-78

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

Loading rate from 40 to 45 tons per 1 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 1 gondola car.

Electric welded pipe according to GOST 10704, 10705-80

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

Loading rate from 35 to 45 tons per 1 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.