Manufactured pipe products must meet certain requirements. Therefore, there is GOST 10705-80 for electric-welded steel pipes, technical specifications which regulates the characteristics of the corresponding standard products.

1 GOST 10705-80 – standard for electric welded pipes

Technical specifications (abbreviated as TU) are a document regulating technical requirements for specific substances, materials, products, other things or their groups. These products, when manufactured, must satisfy specifications, which also include procedures to determine whether they have been met.

Technical specifications GOST 10705-80 are a standard that applies to straight-seam electric-welded steel pipes with a diameter (hereinafter D) of 10–530 mm made of low-alloy and carbon steel grades, widely used in the construction of structures and pipelines for various industrial and technical purposes. This standard does not apply to products intended for the manufacture of thermal electric heaters.

According to GOST 10705-80, straight-seam electric-welded steel pipes, the range of which in terms of size and permitted maximum deviations are regulated by GOST 10704-91, must comply with the following technical requirements. Depending on the required quality indicators of pipe products, they are manufactured into the following groups:

• A – with mechanical properties of established standards from calm, boiling, semi-quiet steel grades St1, St2, St3, St4 according to GOST 380-94;
• B – with the chemical composition of the established steel standards:
  • calm, boiling, semi-calm brands:
    • St1–St4 according to GOST 14637-89 and GOST 380-94;
  • 08Yu according to GOST 9045-93;
  • low-alloy 22GYu (pipes with a diameter of 140–426 mm) with the chemical composition specified in Appendix 1;
• B – with the chemical composition, as well as the mechanical properties of the established steel standards:
  • semi-calm, boiling, calm brands:
    • St1–St4 according to GOST 380-94;
    • 20, 15, 10, 08 according to GOST 1050-88;
  • 08Yu according to GOST 9045-93;
  • low-alloy 22GYu (pipes with a diameter of 140–426 mm) with the chemical composition specified in Appendix 1;
• D - with hydraulic test pressure of established standards.

According to the type of heat treatment, pipes are made:

• heat-treated (along the welded joint or the entire volume);
• hot-reduced;
• without processing.

Heat treatment of pipe products throughout the entire volume is chosen by the manufacturer. The specified temperature exposure can be carried out in a protective atmosphere (by agreement between the consumer and the manufacturer). Products made from steel 22ГУ are produced processed according to weld seam or the entire volume, and from St1 - without processing.

2 Requirements for mechanical properties and properties

According to GOST 10705-80, technical conditions regulate the following mechanical parameters of the base metal of products:

• hot-reduced and heat-treated carbon steels, corresponding to the values ​​​​reflected in Table 1;
• heat-treated from steel 022ГУ - by agreement of the parties;
• without heat treatment and with weld seam treatment:
  • D from 10 to and equal to 152 mm, corresponding to the values ​​​​reflected in Table 2;
  • D more than 152 to and equal to 530 mm, corresponding to the values ​​​​reflected in Table 3.

The surface of pipe products should not have stains, cracks, risks, flaws and sunsets. Nicks, ripples, small marks, dents, traces of stripping and a layer of scale are acceptable, provided that the diameter of the product and the thickness of its wall are not taken beyond the maximum deviations by defects. The maximum permitted displacement of edges from the nominal thickness is 10%.

The surface of pipes thermally treated in a protective atmosphere may have an oxide film, but must be free of scale.

The manufacturer welds any gaps in the seams and cleans the repair area. When agreed with the consumer, on products D 159 mm and more, in places where seams are being finalized, the displacement of the welded edges should reach no more than 20% of the wall thickness specified by the standards, and the reinforcement bead should be made with a maximum height of 2.5 mm. Repairs to the base metal of products are not allowed. Pipes, after repair by welding, are subjected to repeated temperature treatment (respectively for the welding joint or the entire volume).

1 transverse seam is allowed on products D (in mm):

• 57 and more;
• less than 57 – by mutual agreement between the manufacturer and the customer.

Any external bead on the pipes must be removed. At the point where it is removed, the wall may be thinned beyond a tolerance (minus) of 0.1 mm. At the customer’s request, for pipe products with an internal diameter of 33 mm or more, the internal burr is partially removed or flattened, and its height or the height of traces from it must be (in mm):

• 0.35 or less - for walls less than 2 mm thick;
• 0.4 – 2–3 mm;
• 0.5 – over 3 mm.

For products with an internal diameter of up to 33 mm, the height of the burr and its traces are established by agreement between the customer and the manufacturer. Tubular products must have ends cut strictly at right angles and cleared of burrs. Chamfering is allowed. For products D up to 219 mm, the cut bevel should be a maximum of 1 mm, and for D 219 mm and more - 1.5 mm.

According to the customer's request, at the ends of products whose wall thickness is 5 mm or more, they are chamfered at a bevel angle of 25–30° to the end surface of the pipe, leaving an end ring 1.8 mm ±0.8 mm wide (by agreement between the customer and the manufacturer, the width of the ring , the bevel angle may be different).

3 Requirements for hydraulic and mechanical testing of pipes

Products must withstand hydraulic test pressure, according to the magnitude of which pipes are divided into types:

• I – D up to 102 mm (pressure value 6.0 MPa), D 102 mm and more (pressure value 3.0 MPa);
• II - products of groups A, B, which are manufactured according to customer requirements with a hydraulic test pressure regulated by GOST 3845-75, with an allowed stress of 90% of the standard yield threshold for pipe products made of this steel, but not exceeding 20 MPa.

For heat-treated products made of steel St3ps, St3sp, 10, 15 and 20 with walls 6 mm thick or more, the base metal is tested for impact bending (the required impact strength is given in Table 4). Heat-treated products made from 22GYu steel are tested for impact bending if required by the customer; viscosity standards are established by mutual agreement of the parties.

Heat-treated pipes D up to and equal to 152 mm, products without heat treatment and hot-reduced, D of which is more than 20 up to and equal to 152 mm and with walls with a thickness of 0.06 Dn or less, as well as pipe products with heat treatment of the weld must withstand test flattening loads .

For products D up to 108 mm, expansion tests are carried out. Tubular products without heat treatment D up to 20 mm, and D 20–60 mm with walls thicker than 0.06 DN are not subjected to expansion testing. The outer diameter of heat-treated pipes must increase during distribution in accordance with the established standards reflected in Table 5.

For products without heat treatment, the increase in diameter during dispensing should reach a minimum of 6%. In case of customer requirements, the outer diameter of heat-treated products made of steel 10kp, St2kp with walls up to 4 mm thick should increase during distribution by at least 12%. At the request of the consumer, products are tested for bending, beading, and stretching. After all inspections, straight-seam electric-welded steel pipes according to GOST 10705-80 must remain sealed.

Appendix 1. Chemical composition of steel grade 22ГУ.

Mass fraction of elements in% (no more):

• carbon – 0.15–0.22;
• silicon – 0.15–0.30;
• manganese – 1.20–1.40;
• aluminum – 0.02–0.05;
• titanium – 0.03;
• chromium – 0.4;
• nitrogen – 0.012;
• calcium – 0.02;
• sulfur – 0.01;
• phosphorus – 0.02.

Table 1

Note. At the request of the consumer, pipes with a wall thickness of 4 mm or more from steel grades St3sp, 15, 15ps are manufactured with a yield strength of 235 N/mm 2 (24 kgf/mm 2), a relative elongation of 23%; from steel grades St4sp, 20, 20ps - with a yield strength of 255 N/mm 2 (26 kgf/mm 2), relative elongation of 22%.

Table 2

Note. At the consumer’s request, for pipes of all steel grades with a diameter from 10 to 60 mm, the relative elongation increases by 3% compared to the standards given in Table 2.

Table 3

Table 4

With a diameter from 10 to 530 mm made of carbon and low-alloy steel, used for pipelines and structures for various purposes, except for pipes used for the manufacture of thermal electric heaters, they are manufactured in accordance with GOST 10705-80.

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

• A - with standardization of mechanical properties of calm, semi-quiet and boiling steel grades St1, St2, St3, St4 according to GOST 380 (category 4 according to GOST 16523, category 1 according to GOST 14637);
• B - with rationing chemical composition from calm semi-quiet and boiling steel grades St1, St2, St3, St4 according to GOST 380 and GOST 14637, from calm, semi-quiet and boiling steel grades 0.8, 10, 15 and 20 according to GOST 1050, from steel grade 08Yu according to GOST 9045, from low-alloy steel grade 22ГУ with the chemical composition given in the table (pipes with a diameter of 140 to 426 mm);
• B - standardization of mechanical properties and chemical composition of calm, semi-quiet and boiling steel grades St1, St2, St3, St4 according to GOST 380 (category 4 according to GOST 16523 and categories 2-5 according to GOST 14637), heat treated in a protective atmosphere. Pipes made from steel grade 22GYU are produced by heat treatment along the welded joint or throughout the entire volume, pipes made from steel grade St1 - without heat treatment.

Table 1. Chemical composition of steel grade 22ГУ (GOST 10705-80).

Mechanical properties of the base metal of pipes with a diameter of 10 to 152 mm inclusive without heat treatment and with heat treatment welded joint must comply with the standards specified in table 2.

Table 2. Mechanical properties of the base metal of heat-treated and hot-reduced carbon steel pipes (GOST 10705-80)

Note.

Table 3. Mechanical properties of the base metal of pipes with a diameter of 10 to 152 mm inclusive without heat treatment and with heat treatment of the welded joint (GOST 10705-80)

Note.

At the consumer's request, pipes with a wall thickness of 4 mm or more are manufactured:

• from steel grades St3sp, 15, 15ps - with a yield strength of 235 N/mm2 (24 kgf/mm2), relative elongation of 23%;
• from steel grades St4sp, 20, 20ps - with a yield strength of 255 N/mm2 (26 kgf/mm2), relative elongation of 22%;

Table 4. Mechanical properties of the base metal of pipes with a diameter of 10 to 152 mm inclusive without heat treatment and with heat treatment of the welded joint (GOST 10705-80)

Note. At the request of the consumer, for pipes of all grades of steel with a diameter from 10 to 60 mm, the relative elongation increases by 3% compared to the standards given in the table.

Table 4. Mechanical properties of the base metal of pipes with a diameter of over 152 to 530 mm inclusive without heat treatment of the welded joint (GOST 10705-80)

. Replaced by GOST 10692-2015.

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INTERSTATE STANDARD

ELECTRIC WELDED STEEL PIPES

TECHNICAL CONDITIONS

Date of introduction 01/01/82

This standard applies to straight-seam electric-welded steel pipes with a diameter of 10 to 630 mm made of carbon and low-alloy steel grades used for pipelines, structures, as well as products for various purposes.

The standard does not apply to steel pipes used for the manufacture of thermal electric heaters.

(Changed edition, Amendment No. 5,).

1. ASSORTMENT

1.1. The dimensions and maximum deviations of pipes must comply with GOST 10704.

2. TECHNICAL REQUIREMENTS

2.1. Electric-welded steel pipes are manufactured in accordance with the requirements of this standard and according to technical regulations approved in the prescribed manner.

2.2. Depending on the quality indicators, pipes are manufactured into the following groups:

A - with standardization of mechanical properties of calm, semi-quiet and boiling steel grades St1, St2, St3, St4 according to GOST 380;

B - with standardization of the chemical composition:

GOST 380;

GOST 1050;

Made from low-alloy steel grade 22ГУ with a chemical composition according to table 1a

GOST 19281 (pipes with a diameter from 114 to 630 mm inclusive);

B - with standardization of mechanical properties and chemical composition:

From calm, semi-quiet and boiling steel grades St1, St2, St3, St4 according to GOST 380;

From calm, semi-quiet and boiling steel grades 08, 10, 15, 20 according to GOST 1050;

Made from low-alloy steel grades according to GOST 19281 and others regulatory documents with a standardized carbon equivalent of no more than 0.46% (pipes with a diameter from 114 to 630 mm inclusive);

D - with normalization of test hydraulic pressure.

Pipes are made from rolled products in accordance with GOST 14637 (categories 1 - 5), GOST 16523 (category 4), GOST 9045, GOST 19281 and other regulatory documents approved in the prescribed manner.

Table 1a

2.3. Pipes made of carbon steel grades are manufactured by heat treatment (throughout the entire volume of the pipe or along the welded joint), hot-reduced or without heat treatment. Pipes made from steel grade St1 are manufactured without heat treatment.

Pipes made from low-alloy steel grades are manufactured heat-treated (throughout the entire volume of the pipe or along the welded joint) or without heat treatment.

The type of heat treatment is chosen by the manufacturer. By agreement between the manufacturer and the consumer, the pipes are thermally treated in a protective atmosphere.

2.4. The mechanical properties of the base metal of heat-treated and hot-reduced pipes must comply with the standards specified in Table 1. The mechanical properties of pipes made of steel grade 22ГУ, as well as pipes made of low-alloy steel grades not listed in Table 1, are established by agreement of the parties.

Table 1

Note. At the request of the consumer, pipes with a wall thickness of 4 mm or more from steel grades St3sp, 15, 15ps are manufactured with a yield strength of 235 N/mm 2 (24 kgf/mm 2), a relative elongation of 23%; from steel grades St4sp, 20, 20ps - with a yield strength - 255 N/mm 2 (26 kgf/mm 2), relative elongation 22%.

Table 2

Note. At the request of the consumer, for pipes of all grades of steel with a diameter from 10 to 60 mm, the relative elongation increases by 3% compared to the standards given in table. 2.

Table 3

2.5. The mechanical properties of the base metal of pipes with a diameter of 10 to 152 mm inclusive without heat treatment and with heat treatment of the welded joint must comply with the standards specified in Table. 2. Mechanical properties of the base metal of pipes with a diameter of over 152 to 630 mm inclusive. without heat treatment and with heat treatment, the welded joint must comply with the standards specified in table. 3. The mechanical properties of pipes made of low-alloy steel grades not listed in tables 2 and 3 are established by agreement of the parties.

(Changed edition, Amendment No. 5, , ).

2.6. Cracks, spots, dents, flaws and risks are not allowed on the surface of the pipes.

Ripples, nicks, dents, small scratches, a layer of scale and traces of stripping are allowed provided that they do not take the wall thickness and diameter of the pipe beyond the maximum deviations. Edge displacement up to 10% of the nominal wall thickness is allowed.

The surface of pipes heat-treated in a protective atmosphere should be free of scale. The presence of an oxide film is allowed.

Lack of penetration in seams must be welded, and the welding area must be cleaned. By agreement with the consumer, on pipes with a diameter of 159 mm or more, in places where seams are repaired by welding, a displacement of the welded edges is allowed by no more than 20% of the nominal wall thickness and the height of the reinforcement bead is not more than 2.5 mm.

Repairs by welding the base metal of pipes are not allowed.

In the case of repair by welding of pipes that have undergone heat treatment, they are subjected to repeated heat treatment (respectively throughout the entire volume or along the welded joint).

2.7. On pipes with a diameter of 57 mm or more, one transverse seam is allowed.

By agreement between the manufacturer and the consumer, one transverse seam is allowed on pipes with a diameter of less than 57 mm.

2.6, 2.7.

2.8. External beads on pipes must be removed. At the deburring site, the wall may be thinned by 0.1 mm above the minus tolerance.

At the request of the consumer, on pipes with an internal diameter of 33 mm or more, the internal burr must be partially removed or flattened, while the height of the burr or its traces should not exceed 0.35 mm - with a wall thickness of less than 2 mm; 0.4 mm - with a wall thickness of 2 to 3 mm; 0.5 mm - for wall thickness over 3 mm.

The height of the internal flash or its traces for pipes with an internal diameter of less than 33 mm is established by agreement between the manufacturer and the consumer.

2.9. The ends of the pipes must be cut at right angles and cleared of burrs. The formation of a chamfer is allowed. The cutting angle for pipes with a diameter of up to 219 mm should not exceed 1 mm, and for pipes with a diameter of 219 mm or more - 1.5 mm. By agreement between the manufacturer and the consumer, pipes are made cut in the mill line.

2.10. At the consumer's request, the ends of pipes with a wall thickness of 5 mm or more should be chamfered at an angle of 25 - 30 ° to the end of the pipe and an end ring with a width of (1.8 ± 0.8) mm should be left. By agreement between the manufacturer and the consumer, the bevel angle and width of the end ring can be changed.

2.11. The pipes must withstand the test hydraulic pressure. Depending on the test pressure, pipes are divided into two types:

I – pipes with a diameter of up to 102 mm – test pressure 6.0 MPa (60 kgf/cm 2) and pipes with a diameter of 102 mm and more – test pressure 3.0 MPa (30 kgf/cm 2);

II – pipes of groups A and B, supplied at the request of the consumer with test hydraulic pressure calculated according to GOST 3845, with a permissible stress equal to 90% of the standard yield strength for pipes made of this steel grade, but not exceeding 20 MPa (200 kgf/cm 2).

(Changed edition, Amendment No. 5).

2.12. At the request of the consumer, heat-treated throughout the entire volume of pipes made of carbon steel with a wall thickness of at least 6 mm and low-alloy steel with an outer diameter of at least 219 mm and a wall thickness of at least 6 mm of the grades given in Table 4 must withstand impact bending tests of the base metal. Impact strength standards are shown in Table 4.

Standards for the impact strength of pipes made of steel grade 22ГУ are established by agreement of the parties.

Table 4

2.13. Heat-treated pipes with a diameter of up to 152 mm inclusive, hot-reduced pipes without heat treatment with a diameter of more than 20 to 152 mm inclusive and a wall thickness of 0.06 D n or less, as well as pipes with heat treatment of the welded joint must withstand the flattening test.

Flattening of heat-treated pipes should be carried out to the distance between the flattening planes N, mm, calculated by the formula

Where A– the coefficient for pipes made of steel grades 08Yu, 08kp, 8ps, 08, 10kp, St2kp is 0.09, and for pipes made of other steel grades it is 0.08;

S– nominal wall thickness, mm;

D n – nominal outer diameter of the pipe, mm.

Flattening of pipes without heat treatment should be carried out to a distance equal to 2/3 D n. Flattening of pipes with heat treatment of the welded joint should be carried out to a distance equal to 1/2 D n.

At the request of the consumer, flattening of heat-treated pipes with a diameter of over 152 to 530 mm should be carried out to a distance equal to 2/3 D n.

(Changed edition, Amendment No. 5).

2.14. Pipes with a diameter of up to 108 mm must withstand the expansion test.

Pipes with a diameter of up to 108 mm made of carbon steel grades listed in Table 5 must withstand the expansion test.

The increase in the outer diameter of heat-treated pipes during distribution must correspond to the standards specified in table. 5.

Table 5

The increase in the outer diameter of pipes without heat treatment during distribution should be at least 6%.

At the request of the consumer, the increase in the outer diameter when distributing heat-treated pipes with a wall thickness of up to 4 mm from steel grades 10kp, St2kp should be at least 12%.

(Changed edition, Amendment No. 1, 3, 4,).

2.15. At the request of the consumer, pipes must withstand the tests provided for in paragraphs. 2.16 - 2.18.

2.16. Heat-treated pipes with a diameter of up to 530 mm inclusive must withstand the bend test. The bend radius for pipes with a diameter of up to 60 mm must be at least 2.5 D n, for the base metal of pipes with a diameter of over 60 to 530 mm according to GOST 3728. By agreement between the manufacturer and the consumer, the bend radius can be reduced.

2.17. Heat-treated pipes made of carbon steel grades with a diameter from 30 to 159 mm with a ratio D/s, equal to 12.5 or more, must withstand the onboard test. The width of the bent side, measured from the inner surface, must be at least 12% of the internal diameter of the pipe and at least 1.5 times the wall thickness.

The flange angle should be:

90° - for pipes made of steel grades 08, 10, 15, St2;

60° - for pipes made of steel grades 20, St3, St4.

2.18. Pipes with a diameter of 50 mm or more of groups A and B must withstand the tensile test of the welded joint.

The tensile strength of a welded joint of pipes with a diameter of 219 to 530 mm, which has undergone heat treatment throughout the entire volume of the pipe or heat treatment of the welded joint, must comply with the standards specified in Table. 1. The tensile strength of a welded joint of pipes with a diameter of 50 to 203 mm, which has undergone heat treatment throughout the entire volume of the pipe or heat treatment of the welded joint, must be at least 0.9 of the standards specified in table. 1.

The tensile strength of a welded joint of pipes without heat treatment with a diameter of 50 mm or more must comply with the standards specified in table. 2 and 3.

(Changed edition, Amendment No. 1, 3,).

2.19. Pipes must be sealed.

(Changed edition, Amendment No. 3).

3. ACCEPTANCE RULES

3.1. Pipes are accepted in batches. The batch must consist of pipes of the same size, one steel grade, one type of heat treatment and one manufacturing group, accompanied by one quality document, in accordance with GOST 10692 with the addition of the chemical composition of the steel in accordance with the quality document of the manufacturer of the workpiece.

The number of pipes in a batch should be no more than, pcs.:

1000 - with a diameter of up to 30 mm;

600 - with a diameter of St. 30 to 76 mm;

400 - with a diameter of St. 76 to 152 mm;

200 - with a diameter of St. 152 mm.

(Changed edition, Amendment No. 1).

3.2. In case of disagreement in assessing the quality of the chemical composition, at least one pipe from the batch is selected for testing.

3.3. Each pipe is subjected to control of the dimensions and quality of the pipe surface. It is allowed to control dimensions and surfaces selectively on each batch with a one-stage normal level of control in accordance with the requirements of GOST 18242 *. Control plans are established by agreement between the manufacturer and the consumer.

(Changed edition, Amendment No. 3).

* GOST R 50779.71-99 is in force on the territory of the Russian Federation **.

** 3.3a. Welded seams of pipes of groups A, B and C must be subjected to 100% testing using non-destructive methods.

When carrying out non-destructive testing along the perimeter of the entire pipe, hydraulic testing of Type I pipes is permitted not to be carried out.

It is allowed, instead of non-destructive testing of type I pipe welds, to test each pipe with increased hydraulic pressure, calculated in accordance with the requirements of GOST 3845 at an allowable stress equal to 85% of the yield strength for pipes with a diameter of 273 mm or more and 75% of the yield strength for pipes with a diameter of less than 273 mm, but not exceeding 12 MPa (120 kgf/cm2).

Group D pipes must be subjected to hydraulic pressure testing or weld inspection using non-destructive methods.

(Changed edition, Amendment No. 5, Amendment).

** See note from FSUE STANDARTINFORM.

3.4. To check the height of the internal flash, 2% of the pipes from the batch are selected.

3.5. To test for flattening, expansion, beading, bending, impact strength, the tendency of the base metal of pipes to mechanical aging, tensile strength of the base metal and weld, two pipes are selected from the batch.

The yield strength of the base metal of pipes is determined at the request of the consumer.

Pipes subjected to the flattening test are not subjected to the expansion test.

(Changed edition, Amendment No. 1.).

3.6. If unsatisfactory test results are obtained for at least one of the indicators, repeated tests are carried out on a double number of pipes selected from the same batch.

The results of repeated tests apply to the entire batch.

3.7. The welding places of pipes of groups A, B, C must be checked by non-destructive methods, and the repaired pipes must be tested with hydraulic pressure in accordance with the requirements of clause 3.3a of this standard.

Places where seams are welded in pipes of group D must be tested using non-destructive methods, or pipes after repair must be tested with hydraulic pressure.

(Changed edition, Amendment No. 5).

4. TEST METHODS

4.1. For quality control, one sample is cut from each selected pipe for each type of test, and for impact strength testing, three samples are cut for each test temperature.

4.2. The chemical composition of steel is determined according to GOST 22536.0 - GOST 22536.6, GOST 12344 - GOST 12354. Samples to determine the chemical composition are taken according to GOST 7565.

Metal carbon equivalent ( WITH e) low alloy steel grades are calculated using the formula

Where WITH, MP, WITHr, Mo, V,Si,Ni- mass fraction of carbon, manganese, chromium, molybdenum, vanadium, copper, nickel in steel, %.

4.3. Inspection of the pipe surface is carried out visually. The depth of defects is checked by filing or another method.

It is allowed to control the surface and dimensions of pipes using non-destructive methods according to technical documentation.

(Changed edition, Amendment No. 1).

4.4. Pipes measure:

outer diameter and ovality - with an adjustable measuring clamp according to GOST 2216 or a caliper according to GOST 166, or a micrometer according to GOST 6507;

internal diameter - with a plug in accordance with GOST 14810 or with a caliber in accordance with GOST 2015, or by subtracting two wall thicknesses from the outer diameter;

curvature - with a straight edge according to GOST 8026 and a feeler gauge;

wall thickness, thickness difference and height of the internal burr - with a micrometer according to GOST 6507 or a wall gauge according to GOST 11358;

displacement of the edges - using a template according to technical documentation or a micrometer according to GOST 6507 or a depth gauge according to GOST 162;

The cutting angle is ensured by the design of the equipment for processing pipe ends, the chamfer angle is ensured by a goniometer in accordance with GOST 5378. In case of disagreement in quality assessment, the cut angle is checked with a charcoal cutter and a probe;

the end ring at the ends of the pipes - with a ruler in accordance with GOST 427;

depth of surface defects - using a depth gauge according to GOST 162. The outer diameter of the pipe is measured at a distance of at least 15 mm from the end of the pipe for pipes with a ratio of the outer diameter to the wall thickness D n/ S n equal to 35 or less; at a distance of at least 2/3 D n - for pipes with ratio D n/ S n over 35 to 75; at a distance of at least D n - for pipes with ratio D n/ S n over 75.

(Changed edition, Amendment No. 1, 3).

4.5. The impact bending test is carried out on longitudinal samples of type 3 according to GOST 9454, cut from a section of the pipe located at an angle of about 90° to the weld.

Impact strength is determined as the arithmetic mean value based on the test results of three samples. On one of the samples, a decrease in impact strength by 9.8 × 10 4 J/m 2 (1 kgf × m/cm 2) is allowed.

GOST 10705-80

INTERSTATE STANDARD

ELECTRIC WELDED STEEL PIPES

TECHNICAL CONDITIONS

Date of introduction 01.01.82

This standard applies to straight-seam electric-welded steel pipes with a diameter of 10 to 630 mm made of carbon and low-alloy steel grades used for pipelines, structures, as well as products for various purposes.

The standard does not apply to steel pipes used for the manufacture of thermal electric heaters.

(Changed edition, Amendment No. 5,).

1. ASSORTMENT

1.1. The dimensions and maximum deviations of pipes must comply with GOST 10704.

2. TECHNICAL REQUIREMENTS

2.1. Electric-welded steel pipes are manufactured in accordance with the requirements of this standard and according to technical regulations approved in the prescribed manner.

2.2. Depending on the quality indicators, pipes are manufactured into the following groups:

A - with standardization of mechanical properties of calm, semi-quiet and boiling steel grades St1, St2, St3, St4 according to GOST 380;

B - with standardization of the chemical composition:

GOST 380;

GOST 1050;

Made from steel grade 08Yu according to GOST 9045;

Made from low-alloy steel grade 22ГУ with a chemical composition according to table 1a

GOST 19281 (pipes with a diameter from 114 to 630 mm inclusive);

B - with standardization of mechanical properties and chemical composition:

From calm, semi-quiet and boiling steel grades St1, St2, St3, St4 according to GOST 380;

From calm, semi-quiet and boiling steel grades 08, 10, 15, 20 according to GOST 1050;

Made from steel grade 08Yu according to GOST 9045;

From low-alloy steel grades in accordance with GOST 19281 and other regulatory documents with a standardized carbon equivalent of no more than 0.46% (pipes with a diameter from 114 to 630 mm inclusive);

D - with normalization of test hydraulic pressure.

Pipes are made from rolled products in accordance with GOST 14637 (categories 1 - 5), GOST 16523 (category 4), GOST 9045, GOST 19281 and other regulatory documents approved in the prescribed manner.

(Changed edition, Amendment No. 7)

Table 1a

2.3. Pipes made of carbon steel grades are manufactured by heat treatment (throughout the entire volume of the pipe or along the welded joint), hot-reduced or without heat treatment. Pipes made from steel grade St1 are manufactured without heat treatment.

Pipes made from low-alloy steel grades are manufactured heat-treated (throughout the entire volume of the pipe or along the welded joint) or without heat treatment.

The type of heat treatment is chosen by the manufacturer. By agreement between the manufacturer and the consumer, the pipes are thermally treated in a protective atmosphere.

2.2, 2.3 (New edition, Amendment No. 6).

2.4. The mechanical properties of the base metal of heat-treated and hot-reduced pipes must comply with the standards specified in Table 1. The mechanical properties of pipes made of steel grade 22ГУ, as well as pipes made of low-alloy steel grades not listed in Table 1, are established by agreement of the parties.

Note: At the request of the consumer, pipes with a wall thickness of 4 mm or more from steel grades St3sp, 15, 15ps are manufactured with a yield strength of 235 N/mm 2 (24 kgf/mm 2), a relative elongation of 23%; from steel grades St4sp, 20, 20ps - with a yield strength - 255 N/mm 2 (26 kgf/mm 2), relative elongation 22%.

(Changed edition, Amendment No. 6).

Note: At the request of the consumer, for pipes of all grades of steel with a diameter from 10 to 60 mm, the relative elongation increases by 3% compared to the standards given in.

(Changed edition, Amendment No. 7)

2.5. The mechanical properties of the base metal of pipes with a diameter of 10 to 152 mm inclusive without heat treatment and with heat treatment of the welded joint must comply with the standards specified in Table. 2. Mechanical properties of the base metal of pipes with a diameter of over 152 to 630 mm inclusive. without heat treatment and with heat treatment, the welded joint must comply with the standards specified in. The mechanical properties of pipes made of low-alloy steel grades not listed in tables and are established by agreement of the parties.

(Changed edition, Amendment No. 5, , ).

2.6. Cracks, spots, dents, flaws and risks are not allowed on the surface of the pipes.

Ripples, nicks, dents, small scratches, a layer of scale and traces of stripping are allowed provided that they do not take the wall thickness and diameter of the pipe beyond the maximum deviations. Edge displacement up to 10% of the nominal wall thickness is allowed.

The surface of pipes heat-treated in a protective atmosphere should be free of scale. The presence of an oxide film is allowed.

Lack of penetration in seams must be welded, and the welding area must be cleaned. By agreement with the consumer, on pipes with a diameter of 159 mm or more, in places where seams are repaired by welding, a displacement of the welded edges is allowed by no more than 20% of the nominal wall thickness and the height of the reinforcement bead is not more than 2.5 mm.

Repairs by welding the base metal of pipes are not allowed.

In the case of repair by welding of pipes that have undergone heat treatment, they are subjected to repeated heat treatment (respectively throughout the entire volume or along the welded joint).

2.7. On pipes with a diameter of 57 mm or more, one transverse seam is allowed.

By agreement between the manufacturer and the consumer, one transverse seam is allowed on pipes with a diameter of less than 57 mm.

2.6, 2.7.

2.8. External beads on pipes must be removed. At the deburring site, the wall may be thinned by 0.1 mm above the minus tolerance.

At the request of the consumer, on pipes with an internal diameter of 33 mm or more, the internal burr must be partially removed or flattened, while the height of the burr or its traces should not exceed 0.35 mm - with a wall thickness of less than 2 mm; 0.4 mm - with a wall thickness of 2 to 3 mm; 0.5 mm - for wall thickness over 3 mm.

The height of the internal flash or its traces for pipes with an internal diameter of less than 33 mm is established by agreement between the manufacturer and the consumer.

2.9. The ends of the pipes must be cut at right angles and cleared of burrs. The formation of a chamfer is allowed. The cutting angle for pipes with a diameter of up to 219 mm should not exceed 1 mm, and for pipes with a diameter of 219 mm or more - 1.5 mm. By agreement between the manufacturer and the consumer, pipes are made cut in the mill line.

2.10. At the consumer's request, the ends of pipes with a wall thickness of 5 mm or more should be chamfered at an angle of 25 - 30 ° to the end of the pipe and an end ring with a width of (1.8 ± 0.8) mm should be left. By agreement between the manufacturer and the consumer, the bevel angle and width of the end ring can be changed.

2.11. The pipes must withstand the test hydraulic pressure. Depending on the test pressure, pipes are divided into two types:

I – pipes with a diameter of up to 102 mm – test pressure 6.0 MPa (60 kgf/cm 2) and pipes with a diameter of 102 mm and more – test pressure 3.0 MPa (30 kgf/cm 2);

II – pipes of groups A and B, supplied at the request of the consumer with test hydraulic pressure calculated according to GOST 3845, with a permissible stress equal to 90% of the standard yield strength for pipes made of this steel grade, but not exceeding 20 MPa (200 kgf/cm 2).

(Changed edition, Amendment No. 5).

2.12. At the request of the consumer, heat-treated throughout the entire volume of pipes made of carbon steel with a wall thickness of at least 6 mm and low-alloy steel with an outer diameter of at least 219 mm and a wall thickness of at least 6 mm of the grades given in the table must withstand impact bending tests of the base metal. Impact strength standards are indicated in the table.

Standards for the impact strength of pipes made of steel grade 22ГУ are established by agreement of the parties.

2.13. Heat-treated pipes with a diameter of up to 152 mm inclusive, hot-reduced pipes without heat treatment with a diameter of more than 20 to 152 mm inclusive and a wall thickness of 0.06D n or less, as well as pipes with heat treatment of the welded joint must withstand the flattening test.

Flattening of heat-treated pipes should be carried out to the distance between the flattening planes N, mm, calculated by the formula

Where A– the coefficient for pipes made of steel grades 08Yu, 08kp, 8ps, 08, 10kp, St2kp is 0.09, and for pipes made of other steel grades it is 0.08;

S– nominal wall thickness, mm;

D n – nominal outer diameter of the pipe, mm.

Flattening of pipes without heat treatment should be carried out to a distance equal to 2/3D n . Flattening of pipes with heat treatment of the welded joint should be carried out to a distance equal to 1/2D n.

At the request of the consumer, flattening of heat-treated pipes with a diameter of over 152 to 530 mm should be carried out to a distance equal to 2/3D n.

(Changed edition, Amendment No. 5).

2.14. Pipes with a diameter of up to 108 mm must withstand the expansion test.

Pipes with a diameter of up to 108 mm made of carbon steel grades listed in Table 5 must withstand the expansion test.

The increase in the outer diameter of heat-treated pipes during distribution must comply with the standards specified in.

The increase in the outer diameter of pipes without heat treatment during distribution should be at least 6%.

At the request of the consumer, the increase in the outer diameter when distributing heat-treated pipes with a wall thickness of up to 4 mm from steel grades 10kp, St2kp should be at least 12%.

(Changed edition, Amendment No. 1, 3, 4,).

2.15. At the request of the consumer, pipes must withstand the tests provided for in paragraphs. - .

The tensile strength of a welded joint of pipes without heat treatment with a diameter of 50 mm or more must comply with the standards specified in and.

(Changed edition, Amendment No. 1, 3,).

2.19. Pipes must be sealed.

(Changed edition, Amendment No. 3).

3. ACCEPTANCE RULES

3.1. Pipes are accepted in batches. The batch must consist of pipes of the same size, one steel grade, one type of heat treatment and one manufacturing group, accompanied by one quality document, in accordance with GOST 10692 with the addition of the chemical composition of the steel in accordance with the quality document of the manufacturer of the workpiece.

The number of pipes in a batch should be no more than, pcs.:

1000 - with a diameter of up to 30 mm;

600 - with a diameter of St. 30 to 76 mm;

400 - with a diameter of St. 76 to 152 mm;

200 - with a diameter of St. 152 mm.

3.2. In case of disagreement in assessing the quality of the chemical composition, at least one pipe from the batch is selected for testing.

3.3. Each pipe is subjected to control of the dimensions and quality of the pipe surface. It is allowed to control dimensions and surfaces selectively on each batch with a one-stage normal level of control in accordance with the requirements of GOST 18242 *. Control plans are established by agreement between the manufacturer and the consumer.

(Changed edition, Amendment No. 3).

* GOST R 50779.71-99 is in force on the territory of the Russian Federation **.

3.6. If unsatisfactory test results are obtained for at least one of the indicators, repeated tests are carried out on a double number of pipes selected from the same batch.

The results of repeated tests apply to the entire batch.

3.7. The welding areas of pipes of groups A, B, C must be checked by non-destructive methods, and the repaired pipes must be tested with hydraulic pressure in accordance with the requirements of this standard.

Places where seams are welded in pipes of group D must be tested using non-destructive methods, or pipes after repair must be tested with hydraulic pressure.

(Changed edition, Amendment No. 5).

4. TEST METHODS

4.1. For quality control, one sample is cut from each selected pipe for each type of test, and for impact strength testing, three samples are cut for each test temperature.

4.2. The chemical composition of steel is determined according to GOST 22536.0 - GOST 22536.6, GOST 12344 - GOST 12354. Samples to determine the chemical composition are taken according to GOST 7565.

Metal carbon equivalent ( WITH e) low alloy steel grades are calculated using the formula

Where WITH, MP, WITH r, Mo, V,Si, Ni- mass fraction of carbon, manganese, chromium, molybdenum, vanadium, copper, nickel in steel, %.

(Changed edition, Amendment No. 6).

4.3. Inspection of the pipe surface is carried out visually. The depth of defects is checked by filing or another method.

It is allowed to control the surface and dimensions of pipes using non-destructive methods according to technical documentation.

(Changed edition, Amendment No. 1).

4.4. Pipes measure:

outer diameter and ovality - with an adjustable measuring clamp according to GOST 2216 or a caliper according to GOST 166, or a micrometer according to GOST 6507;

internal diameter - with a plug in accordance with GOST 14810 or with a caliber in accordance with GOST 2015, or by subtracting two wall thicknesses from the outer diameter;

curvature - with a straight edge according to GOST 8026 and a feeler gauge;

wall thickness, thickness difference and height of the internal burr - with a micrometer according to GOST 6507 or a wall gauge according to GOST 11358;

displacement of the edges - using a template according to technical documentation or a micrometer according to GOST 6507 or a depth gauge according to GOST 162;

The cutting angle is ensured by the design of the equipment for processing pipe ends, the chamfer angle is ensured by a goniometer in accordance with GOST 5378. In case of disagreement in quality assessment, the cut angle is checked with a charcoal cutter and a probe;

the end ring at the ends of the pipes - with a ruler in accordance with GOST 427;

depth of surface defects - using a depth gauge according to GOST 162. The outer diameter of the pipe is measured at a distance of at least 15 mm from the end of the pipe for pipes with a ratio of the outer diameter to the wall thicknessD n/ S n equal to 35 or less; at a distance of at least 2/3D n - for pipes with ratioD n/ S n over 35 to 75; at a distance of at leastD n - for pipes with ratioD n/ S n over 75.

(Changed edition, Amendment No. 1, 3).

4.5. The impact bending test is carried out on longitudinal samples of type 3 according to GOST 9454, cut from a section of the pipe located at an angle of about 90° to the weld.

Impact strength is determined as the arithmetic mean value based on the test results of three samples. On one of the samples, a decrease in impact strength by 9.8 is allowed× 10 4 J/m 2 (1 kgf × m/cm 2).

The temperature of the impact bending test is specified by the customer in the order for the supply of pipes.

4.6. The tendency of the base metal of pipes to mechanical aging is determined according to GOST 7268. It is allowed to edit samples with a static load.

4.7. The tensile test is carried out according to GOST 10006 on a longitudinal proportional short sample.

When testing on segment-section samples, the latter is cut out from a section located at an angle of about 90° to the weld and is not straightened in the calculation part.

Instead of tensile testing, it is allowed to monitor the tensile strength, yield strength and relative elongation of pipes using non-destructive methods.

If disagreements arise, pipe testing is carried out in accordance with GOST 10006.

(Changed edition, Amendment No. 1,).

4.8. The flattening test is carried out according to GOST 8695.

4.9. The expansion test is carried out according to GOST 8694 on a mandrel with a taper of 30°. It is allowed to use mandrels with a taper of 1:10 and remove burrs in the distribution area.

(Changed edition, Amendment No. 3).

4.10. The bend test is carried out according to GOST 3728. Pipes with a diameter of 114 mm are tested on cut longitudinal strips 12 mm wide.

4.11. The boarding test is carried out according to GOST 8693. In the flanging area, deburring is allowed.

4.12. Determination of the temporary resistance of a welded joint is carried out on ring samples according to technical documentation.

On pipes with a diameter of 219 mm or more, it is allowed to carry out testing in accordance with GOST 6996 on type XII samples with the welded joint reinforcement removed, cut perpendicular to the pipe axis, using a static load when straightening the samples.

(Changed edition, Amendment No. 7).

4.13. Hydraulic testing of pipes is carried out in accordance with GOST 3845 with a pressure exposure of 5 s.

4.14. Inspection of the weld is carried out using non-destructive methods (ultrasonic, eddy current, magnetic or x-ray equivalent methods) according to technical documentation.

5. LABELING, PACKAGING, TRANSPORTATION AND STORAGE

5.1. Labeling, packaging, transportation and storage - in accordance with GOST 10692.

INFORMATION DATA

1. DESIGNED AND INTRODUCED by the Ministry ferrous metallurgy of the USSR

2. APPROVED AND ENTERED INTO EFFECT by Resolution of the USSR State Committee on Standards dated December 25, 1980 No. 5970

Change No. 5 was adopted by the Interstate Council for Standardization, Metrology and Certification (Minutes No. 13 of May 28, 1998)

Registered by the Technical Secretariat of the IGU No. 3166

STATE STANDARD OF THE USSR UNION

ELECTRIC WELDED STEEL PIPES

TECHNICAL CONDITIONS

GOST 10705-80

Publishing house of standards

Moscow

STATE STANDARD OF THE USSR UNION

Date of introduction 01.01.82

This standard applies to straight-seam electric-welded steel pipes with a diameter from 10 to 530 mm made of carbon and low-alloy steel, used for pipelines and structures for various purposes.

The standard does not apply to steel pipes used for the manufacture of thermal electric heaters.

1. ASSORTMENT

1.1. The dimensions and maximum deviations of pipes must comply with GOST 10704 -91

2. TECHNICAL REQUIREMENTS

2.1. Electric-welded steel pipes are manufactured in accordance with the requirements of this standard and according to technical regulations approved in the prescribed manner.

2.2. Depending on the quality indicators, pipes are manufactured into the following groups:

A - with standardization of mechanical properties of calm, semi-quiet and boiling steel grades St1, St2, St3, St4 according to GOST 380-94 (category 4 according to GOST 16523-89, category 4 according to GOST 14637-89);

B - with standardization of the chemical composition of calm, semi-quiet and boiling steel grades St1 St2, St3, St4 according to GOST 380 -94 and GOST 14637 -89, from calm, semi-quiet and boiling steel grades 08, 10, 15 and 20 according to GOST 1050- 88, made of steel grade 08Yu according to GOST 9045

B - with standardization of mechanical properties and chemical composition of calm, semi-quiet and boiling steel grades St1, St2, St3, St4 according to GOST 380-94 (category 4 according to GOST 16523-89 and categories 2-5 according to GOST 14637-89), from calm, semi-quiet and boiling steel grades 08, 10, 15 and 20 according to GOST 1050-88, from steel grade 08YU according to GOST 9045-93, from low-alloy steel grade 22GYu with the chemical composition given in (pipes with a diameter of 140 to 426 mm) ;

D - with normalization of test hydraulic pressure.

(Changed edition, Amendment No. 4, Amendment No. 5).

2.3. Pipes are manufactured by heat treatment (throughout the entire volume of the pipe or along the welded joint), hot-reduced and without heat treatment.

The type of heat treatment throughout the entire volume of the pipe is chosen by the manufacturer. By agreement between the manufacturer and the consumer, the pipes are thermally treated in a protective atmosphere.

Pipes made from steel grade 22GYu are produced by heat treatment along the welded joint or throughout the entire volume, pipes made from steel grade St1 are made without heat treatment.

(Changed edition, Amendment No. 1, Amendment No. 5).

2.4. The mechanical properties of the base metal of heat-treated and hot-reduced carbon steel pipes must comply with the standards specified in. The mechanical properties of heat-treated pipes made of steel grade 22ГУ are established by agreement of the parties.

Note. At the request of the consumer, pipes with a wall thickness of 4 mm or more from steel grades St3sp, 15, 15ps are manufactured with a yield strength of 235 N/mm2 (24 kgf/mm2), relative elongation of 23%; from steel grades St4sp, 20, 20ps - with a yield strength - 255 N/mm2 (26 kgf/mm2), relative elongation 22%.

(Changed edition, Amendment No. 2, Amendment No. 3, Amendment No. 4 Amendment No. 5).

2.5. The mechanical properties of the base metal of pipes with a diameter of 10 to 152 mm inclusive without heat treatment and with heat treatment of the welded joint must comply with the standards specified in Table. . The mechanical properties of the base metal of pipes with a diameter of over 152 to 530 mm inclusive without heat treatment and with heat treatment of the welded joint must comply with the standards specified in.

Note. At the request of the consumer, for pipes of all grades of steel with a diameter from 10 to 60 mm, the relative elongation increases by 3% compared to the standards given in table. .

(Changed edition, Amendment No. 1, Amendment No. 3, Amendment No. 4, Amendment No. 5).

2.6. . Cracks, spots, dents, flaws and risks are not allowed on the surface of the pipes.

Ripples, nicks, dents, small scratches, a layer of scale and traces of stripping are allowed provided that they do not take the wall thickness and diameter of the pipe beyond the maximum deviations. Edge displacement up to 10% of the nominal wall thickness is allowed.

The surface of pipes heat-treated in a protective atmosphere should be free of scale. The presence of an oxide film is allowed.

Lack of penetration in seams must be welded, and the welding area must be cleaned. By agreement with the consumer, on pipes with a diameter of 159 mm or more, in places where seams are repaired by welding, a displacement of the welded edges is allowed by no more than 20% of the nominal wall thickness and the height of the reinforcement bead is not more than 2.5 mm.

Repairs by welding the base metal of pipes are not allowed.

In the case of repair by welding of pipes that have undergone heat treatment, they are subjected to repeated heat treatment (respectively throughout the entire volume or along the welded joint).

(Changed edition, Amendment No. 1, Amendment No. 4, Amendment No. 5).

2.7. On pipes with a diameter of 57 mm or more, one transverse seam is allowed.

By agreement between the manufacturer and the consumer, one transverse seam is allowed on pipes with a diameter of less than 57 mm.

2.8. External beads on pipes must be removed. At the deburring site, the wall may be thinned by 0.1 mm above the minus tolerance.

At the request of the consumer, on pipes with an internal diameter of 33 mm or more, the internal burr must be partially removed or flattened, while the height of the burr or its traces should not exceed 0.35 mm - with a wall thickness of less than 2 mm; 0.4 mm - with a wall thickness of 2 to 3 mm; 0.5 mm - for wall thickness over 3 mm.

The height of the internal flash or its traces for pipes with an internal diameter of less than 33 mm is established by agreement between the manufacturer and the consumer.

(Changed edition, Amendment No. 1, 3).

2.9. The ends of the pipes must be cut at right angles and cleared of burrs. The formation of a chamfer is allowed. The cutting angle for pipes with a diameter of up to 219 mm should not exceed 1 mm, and for pipes with a diameter of 219 mm or more - 1.5 mm. By agreement between the manufacturer and the consumer, pipes are made cut in the mill line.

2.10. At the request of the consumer, the ends of pipes with a wall thickness of 5 mm or more should be chamfered at an angle of 25-30° to the end of the pipe and an end ring with a width of 1.8 mm ± 0.8 mm should be left. By agreement between the manufacturer and the consumer, the bevel angle and width of the end ring can be changed.

2.11. The pipes must withstand the test hydraulic pressure. Depending on the test pressure, pipes are divided into two types:

I - pipes with a diameter of up to 102 mm - test pressure 6.0 MPa (60 kgf/cm2) and pipes with a diameter of 102 mm and more - test pressure 3.0 MPa (30 kgf/cm2);

II - pipes of groups A and B, supplied at the request of the consumer with test hydraulic pressure calculated according to GOST 3845-75, with an allowable stress equal to 90% of the standard yield strength for pipes made of this steel grade, but not exceeding 20 MPa (200 kgf /cm2).

(Changed edition, Amendment No. 3, Amendment No. 5).

2.12. Heat-treated pipes made of steel grades St3sp, St3ps (categories 3-5), 10, 15 and 20 with a wall thickness of at least 6 mm must withstand the impact bending test of the base metal. In this case, the standards of impact strength must correspond to those specified in.

The impact bending test of the base metal of heat-treated pipes made of steel grade 22ГУ is carried out at the request of the consumer, the standards of impact strength are established by agreement of the parties.

(Changed edition, Amendment No. 1, Amendment No. 4, Amendment No. 5).

2.13. Heat-treated pipes with a diameter of up to 152 mm inclusive, hot-reduced pipes without heat treatment with a diameter of more than 20 to 152 mm inclusive and a wall thickness of 0.06 Dn or less, as well as pipes with heat treatment of the welded joint must withstand the flattening test.

Flattening of heat-treated pipes should be carried out to the distance between the flattening planes H, mm, calculated by the formula

Where A- the coefficient for pipes made of steel grades 08Yu, 08kp, 8ps, 08, 10kp, St2kp is 0.09, and for pipes made of other steel grades it is 0.08;

S - nominal wall thickness, mm;

Dn - nominal outer diameter of the pipe, mm.

Flattening of pipes without heat treatment should be carried out to a distance equal to 2/3 Dn. Flattening of pipes with heat treatment of the welded joint should be carried out to a distance equal to 1/2 Dn.

At the request of the consumer, flattening of heat-treated pipes with a diameter of over 152 to 530 mm should be carried out to a distance equal to 2/3 Dn.

(Changed version of Amendment No. 1, Amendment No. 3, Amendment No. 4, Amendment No. 5).

2.14. Pipes with a diameter of up to 108 mm must withstand the expansion test.

Pipes without heat treatment with a diameter of up to 20 mm, as well as with a diameter of 20-60 mm with a wall thickness of more than 0.06 DN, are not tested for expansion.

Increasing the outer diameter of heat-treated ones. pipes during distribution must comply with the standards specified in.

The increase in the outer diameter of pipes without heat treatment during distribution should be at least 6%.

At the request of the consumer, the increase in the outer diameter when distributing heat-treated pipes with a wall thickness of up to 4 mm from steel grades 10kp, St2kp should be at least 12%.

(Changed edition, Amendment No. 1, 3, 4).

2.15. At the request of the consumer, pipes must withstand the tests provided for in paragraphs. -

The tensile strength of a welded joint of pipes with a diameter of 219 to 530 mm, which has undergone heat treatment throughout the entire volume of the pipe or heat treatment of the welded joint, must comply with the standards specified in. The tensile strength of a welded joint of pipes with a diameter of 50 to 203 mm, which has undergone heat treatment throughout the entire volume of the pipe or heat treatment of the welded joint, must be at least 0.9 of the standards specified in.

The tensile strength of a welded joint of pipes without heat treatment with a diameter of 50 mm or more must comply with the standards specified in table. And .

2.19. Pipes must be sealed.

(Changed edition, Amendment No. 3).

3. ACCEPTANCE RULES

3.1. Pipes are accepted in batches. The batch must consist of pipes of the same size, one steel grade, one type of heat treatment and one manufacturing group, accompanied by one quality document, according to GOST 10692-80

with the addition of the chemical composition of the steel in accordance with the document on the quality of the manufacturer of the workpiece.

The number of pipes in a batch should be no more than, pcs.:

1000 - with a diameter of up to 30 mm;

600 - with a diameter of St. 30 to 76 mm;

400 - with a diameter of St. 76 to 152 mm;

200 - with a diameter of St. 152 mm.

3.2. In case of disagreement in assessing the quality of the chemical composition, at least one pipe from the batch is selected for testing.

3.3. Each pipe is subjected to control of the dimensions and quality of the pipe surface. It is allowed to control dimensions and surfaces selectively on each batch with a one-stage normal level of control in accordance with the requirements of GOST 18242-72. Control plans are established by agreement between the manufacturer and the consumer.

(Changed edition, Amendment No. 3).

3.3a. Welded seams of pipes of groups A, B and C must be subjected to 100% testing using non-destructive methods.

When carrying out non-destructive testing along the perimeter of the entire pipe, hydraulic testing of Type I pipes is permitted not to be carried out.

It is allowed, instead of non-destructive testing of Type I pipe welds, to test each pipe with increased hydraulic pressure, calculated in accordance with the requirements of GOST 3845-75 at an allowable stress equal to 85% of the yield strength for pipes with a diameter of 273 mm or more and 75% of the yield strength for pipes with a diameter of less than 273 mm, but not exceeding 12 MPa (120 kgf/cm2).

Group D pipes must be subjected to hydraulic pressure testing or weld inspection using non-destructive methods.

(Introduced additionally, Amendment No. 3). (Changed edition, Amendment No. 5). (Amendment,).

3.4. To check the height of the internal flash, 2% of the pipes from the batch are selected.

3.5. To test for flattening, expansion, beading, bending, impact strength, the tendency of the base metal of pipes to mechanical aging, tensile strength of the base metal and weld, two pipes are selected from the batch.

The yield strength of the base metal of pipes is determined at the request of the consumer.

At the request of the consumer, impact strength is not determined.

Pipes subjected to the flattening test are not subjected to the expansion test.

(Changed edition, Amendment No. 1).

3.6. If unsatisfactory test results are obtained for at least one of the indicators, repeated tests are carried out on a double number of pipes selected from the same batch.

The results of repeated tests apply to the entire batch.

3.7. The welding places of pipes of groups A, B, C must be checked by non-destructive methods, and the repaired pipes must be tested with hydraulic pressure in accordance with the requirements of clause 3.3a of this standard.

Places where seams are welded in pipes of group D must be tested using non-destructive methods, or pipes after repair must be tested with hydraulic pressure.

(Introduced additionally, Amendment No. 1, Amended edition, Amendment No. 5).

4. TEST METHODS

4.1. For quality control, one sample is cut from each selected pipe for each type of test, and for impact strength testing, three samples are cut for each test temperature.

4.2. The chemical composition of steel is determined according to GOST 22536.0 -87; GOST 22536.1 -88; GOST 22536.2 -87; GOST 22536.3 -88; GOST 22536.4 -88; GOST 22536.5 -87; GOST 22536.6 -88 GOST 12344-88; GOST 12345-88; GOST 12346-78; GOST 12347-77, GOST 12348-78; GOST 12349-83; GOST 12350-78; GOST 12351 -81; GOST 12352-81; GOST 12353-78; GOST 12354-81. Samples to determine the chemical composition are taken according to GOST 7565-81.

4.3. Inspection of the pipe surface is carried out visually. The depth of defects is checked by filing or another method.

It is allowed to control the surface and dimensions of pipes using non-destructive methods according to technical documentation.

(Changed edition, Amendment No. 1).

4.4. Pipes measure:

length - tape measure according to GOST 7502-89.

outer diameter and ovality - with an adjustable measuring clamp according to GOST 2216-84 or a caliper according to GOST 166-89 or a micrometer according to GOST 6507-89;;

internal diameter - with a plug in accordance with GOST 14810-69, or with a caliber in accordance with GOST 2015-84, or by subtracting two wall thicknesses from the outer diameter;

curvature - with a straight edge according to GOST 8026-92 and a feeler gauge;

wall thickness, wall thickness and height of the internal burr - with a micrometer according to GOST 6507-90 or a wall gauge according to GOST 11358-89;

displacement of the edges - using a template according to technical documentation or a micrometer according to GOST 6507-90 or a depth gauge according to GOST 162-90;

The cutting angle is ensured by the design of the equipment for processing pipe ends, the chamfer angle is ensured by a goniometer in accordance with GOST 5378-88. If there is a disagreement in assessing the quality, the cut angle is checked with a charcoal cutter and a feeler gauge;

end ring at the ends of the pipes - a ruler in accordance with GOST 427 -75;

depth of surface defects - using a depth gauge according to GOST 162-90. The outer diameter of the pipe is measured at a distance of at least 15 mm from the end of the pipe for pipes with a ratio of the outer diameter to the wall thickness D H/ S H equal to 35 or less; at a distance of at least 2/3 DH - for pipes with a ratio D H/ S H over 35 to 75; at a distance of at least DH - for pipes with ratio D H/ S H over 75.

(Changed edition, Amendment No. 1, 3).

4.5. The impact bending test is carried out on longitudinal samples of type 3 according to GOST 9454-78, cut from a section of pipe located at an angle of about 90° to the weld.

Impact strength is determined as the arithmetic mean value based on the test results of three samples. On one of the samples, a decrease in impact strength by 9.8·104 J/m2 (1 kgf·m/cm2) is allowed.

The temperature for impact bending testing of pipes made of steel grades 08, 10, 15 and 20 is selected by the consumer.

(Changed edition, Amendment No. 1).

4.6. The tendency of the base metal of pipes to mechanical aging is determined according to GOST 7268-82. It is allowed to edit samples with a static load.