Electric-welded steel pipes. Electric-welded steel pipes GOST 10705 91 pipes specifications

. 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 longitudinal electric-welded steel pipes with a diameter of 10 to 630 mm from carbon and low-alloy steel grades used for pipelines, structures, and products for various purposes.

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

(Changed edition, Amendment No. 5,).

1. VARIETY

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

2. TECHNICAL REQUIREMENTS

2.1. Steel electric-welded 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, the pipes are made of the following groups:

A - with standardization of mechanical properties from calm, semi-calm and boiling steel grades St1, St2, St3, St4 in accordance with GOST 380;

B - with standardization chemical composition:

GOST 380;

GOST 1050;

From low-alloy steel grade 22GYu with a chemical composition according to table 1a

GOST 19281 (pipes with a diameter of 114 to 630 mm incl.);

B - with standardization of mechanical properties and chemical composition:

From calm, semi-calm and boiling steel grades St1, St2, St3, St4 in accordance with GOST 380;

From calm, semi-calm and boiling steel grades 08, 10, 15, 20 in accordance with GOST 1050;

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

D - with standardization of the test hydraulic pressure.

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

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

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

2.4. Mechanical properties the base metal of heat-treated and hot-rolled pipes must comply with the standards specified in Table 1. Mechanical properties of pipes made of steel grade 22ГЮ, 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 made of steel grades St3sp, 15, 15ps are manufactured with a yield point of 235 N / mm 2 (24 kgf / mm 2), a relative elongation of 23%; from steel grades St4sp, 20, 20ps - with a yield point of 255 N / mm 2 (26 kgf / mm 2), a relative elongation of 22%.

table 2

Note. At the request of the consumer, for pipes of all steel grades with a diameter of 10 to 60 mm, the relative elongation increases by 3% in comparison with 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 over 152 to 630 mm incl. without heat treatment and with heat treatment of 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 shall be established by agreement of the parties.

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

2.6. Cracks, captivity, sunsets, flaws and risks are not allowed on the pipe surface.

Ripples, nicks, dents, small marks, a layer of scale and traces of cleaning are allowed provided that they do not bring the wall thickness and pipe diameter beyond the maximum deviations. Displacement of edges up to 10% of the nominal wall thickness is allowed.

The surface of pipes thermally treated in a protective atmosphere must be free of scale. The presence of an oxide film is allowed.

Lack of penetration of the seams must be welded, the place of welding must be cleaned. By agreement with the consumer, on pipes with a diameter of 159 mm and more, in places where welds are repaired by welding, the displacement of the welded edges of no more than 20% of the nominal wall thickness and the height of the reinforcement bead no more than 2.5 mm are allowed.

Repair by welding the base metal of pipes is not allowed.

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

2.7. For pipes with a diameter of 57 mm and 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. Outer burrs on pipes must be removed. At the point of deburring, wall thinning is allowed by 0.1 mm above the minus tolerance.

At the request of the consumer, on pipes with an inner diameter of 33 mm and more, the inner 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 - with a wall thickness of over 3 mm.

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

2.9. The ends of the pipes should be cut at right angles and deburred. Chamfering is allowed. The slant of the cut for pipes with a diameter of up to 219 mm should not exceed 1 mm, and for pipes with a diameter of 219 mm and more - 1.5 mm. By agreement between the manufacturer and the consumer, the pipes are made cut in the mill line.

2.10. At the request of the consumer, at the ends of pipes with a wall thickness of 5 mm or more, a chamfer must be removed 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 must be left. By agreement between the manufacturer and the consumer, the bevel angle and the width of the end ring can be changed.

2.11. The pipes must be able to withstand the hydraulic test pressure. Depending on the value of the test pressure, pipes are divided into two types:

I - pipes with a diameter 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 a test hydraulic pressure calculated in accordance with GOST 3845, with an allowable stress equal to 90% of the standard yield strength for pipes of this steel grade, but not exceeding 20 MPa (200 kgf / cm 2).

(Modified 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 listed in Table 4 must withstand the impact bending tests of the base metal. Impact strength standards are indicated in table 4.

The norms for the impact strength of pipes made of steel grade 22GU are established by agreement of the parties.

Table 4

2.13. Heat-treated pipes with a diameter of up to 152 mm inclusive, pipes hot-rolled and 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 must be carried out up to the distance between 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 is 0.08;

S- nominal wall thickness, mm;

D n is the 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.

(Modified edition, Amendment No. 5).

2.14. Pipes up to 108 mm in diameter must withstand the expansion test.

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

The increase in the outer diameter of heat-treated pipes during dispensing must comply with the standards specified in table. 5.

Table 5

The increase in the outer diameter of pipes without heat treatment during expansion 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 made of steel grades 10kp, St2kp must be at least 12%.

(Changed edition, Amendments 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 up to and including 530 mm in diameter 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 in accordance with 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 of 30 to 159 mm with a ratio D / s equal to 12.5 and more must withstand the airborne test. The width of the bend to be bent, measured from the inner surface, must be at least 12% of the inner diameter of the pipe and at least 1.5 of 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 and 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 have undergone heat treatment throughout the pipe volume or heat treatment of the welded joint, must comply with the standards specified in table. 1. The ultimate tensile strength of a welded joint of pipes with a diameter of 50 to 203 mm, which have undergone heat treatment throughout the pipe volume or heat treatment of the welded joint, must be at least 0.9 of the norms specified in Table. 1.

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

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

2.19. The pipes must be tight.

(Modified edition, Amendment No. 3).

3. RULES OF ACCEPTANCE

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

(Modified 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 taken for inspection.

3.3. Each pipe is subject to inspection 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.

(Modified edition, Amendment No. 3).

* Within the territory of Russian Federation GOST R 50779.71-99 ** is in effect.

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

When conducting non-destructive testing along the perimeter of the entire pipe, the hydraulic test of type I pipes is not allowed.

Instead of non-destructive testing of welded seams of pipes of type I, it is allowed to test each pipe with an increased hydraulic pressure calculated in accordance with the requirements of GOST 3845 at an allowable stress equal to 85% of the yield point for pipes with a diameter of 273 mm and more and 75% of the yield point for pipes with a diameter less than 273 mm, but not exceeding 12 MPa (120 kgf / cm 2).

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

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

** See the note of the Federal State Unitary Enterprise "STANDARTINFORM".

3.4. To check the height of the internal burr, 2% of the pipes are taken from the batch.

3.5. For flattening, expansion, beading, bending, impact strength, tendency of the base metal of pipes to mechanical aging, tension of the base metal and the weld, two pipes are taken from the batch.

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

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

(Modified edition, Amendment No. 1.).

3.6. When 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.

Retest results apply to the entire batch.

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

Places of welding seams of pipes of group D must be tested by non-destructive methods, or pipes after repair must be tested by hydraulic pressure.

(Modified 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 testing for impact strength - three samples 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 for determining the chemical composition are taken in accordance with GOST 7565.

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

where WITH, Mp, WITHr, Moe, 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 in another way.

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

(Modified edition, Amendment No. 1).

4.4. Pipes measure:

outer diameter and ovality - with an adjustable measuring bracket in accordance with GOST 2216 or a caliper in accordance with GOST 166, or a micrometer in accordance with GOST 6507;

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

curvature - with a straight edge in accordance with GOST 8026 and a probe;

wall thickness, wall thickness and height of the internal burr - with a micrometer in accordance with GOST 6507 or a wall gauge in accordance with GOST 11358;

displacement of the edges - with a template according to technical documentation or a micrometer in accordance with GOST 6507 or a vernier depth gauge in accordance with GOST 162;

oblique cut is provided by the design of the equipment for processing pipe ends, the bevel angle is provided by a goniometer in accordance with GOST 5378. In case of disagreement in assessing the quality, the oblique cut is checked with a coal miner and a probe;

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

the depth of surface defects - using a vernier depth gauge in accordance with GOST 162. The measurement of the outer diameter of the pipe is carried out at a distance of at least 15 mm from the end of the pipe for pipes with the 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 the ratio D n / S n over 35 to 75; at a distance of at least D n - for pipes with the ratio D n / S n over 75.

(Modified edition, Amendments No. 1, 3).

4.5. Impact bending test is carried out on longitudinal specimens of type 3 in accordance with GOST 9454, cut from a pipe section located at an angle of about 90 ° to weld.

Impact strength is determined as the arithmetic mean value from 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.

The manufactured tubular products must meet certain requirements. Therefore, there is GOST 10705-80 for electric-welded steel pipes, technical conditions which is governed by the characteristics of the corresponding standard products.

1 GOST 10705-80 - standard for electrowelded pipes

Technical conditions (abbreviated as TU) - a document regulating technical requirements for specific substances, materials, products, others or their group. These products, as manufactured, must meet the specified requirements, which, in addition, indicate the procedures to establish how much they have been followed.

Technical conditions GOST 10705-80 are a standard, the effect of which is extended to longitudinal steel longitudinal welded pipes with a diameter (hereinafter D) of 10-530 mm from low-alloy and carbon steel grades, widely used in the construction of structures and pipelines of various industrial and technical purpose... This standard does not apply to products intended for the manufacture of electric heaters.

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

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

By the type of heat treatment, pipes are made:

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

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

2 Requirements for mechanical indicators and properties

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

• hot-worked and heat-treated carbon steels, corresponding to the values ​​shown in Table 1;
• heat-treated steel 022ГЮ - 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 ​​shown in Table 2;
  • D more than 152 to and equal to 530 mm, corresponding to the values ​​shown in Table 3.

The surface of tubular products should not have captivity, cracks, risks, flaws and sunsets. Nicks, ripples, small risks, dents, traces of cleaning and a layer of scale are acceptable, provided that the diameter of the product and the thickness of its wall are not deduced from defects beyond the maximum deviations. The maximum allowed edge offset 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 the lack of penetration of the seams, and cleans the place of repair. Upon agreement with the consumer, on products D 159 mm and more, in places where the seams are reworked, the displacement of the edges to be welded should reach no more than 20% of the wall thickness stipulated by the norms, and the reinforcement bead is made with a maximum height of 2.5 mm. Repair of the base metal of products is not allowed. Pipes, after repair by welding, are subjected to repeated temperature treatment (respectively, along the welded 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.

Outer burrs on the pipes must be removed. In the place of its removal, a thinning of the wall is allowed in excess of the tolerance (minus) of 0.1 mm. At the request of the customer, for pipe products with an inner D of 33 mm and more, the inner burr is partially removed or flattened, while its height or the height of the traces from it should 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 inner diameter of up to 33 mm, the height of the burr and its traces is set by agreement between the customer and the manufacturer. Tubular products must have ends that are strictly cut at right angles and deburred. Chamfering allowed. For products D up to 219 mm, the slant of the cut 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 with a wall thickness of 5 mm or more, chamfer is made 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 value 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 the customer's requirements with a hydraulic test pressure regulated by GOST 3845-75, with a permitted stress of 90% of the standard yield point 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 and more, the base metal is tested for impact bending (the required impact strength is given in Table 4). Heat-treated products made of 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-rolled, D of which is more than 20 up to and equal to 152 mm and with walls with a thickness of 0.06 Dн or less, as well as pipe products with heat treatment of the welded seam must withstand test loads for flattening ...

For products D up to 108 mm, dispensing tests are carried out. Tubular products without heat treatment, D up to 20 mm, and D 20–60 mm with walls with a thickness of more than 0.06 DH, are not subjected to the expansion test. The outer diameter of the heat-treated pipes should increase during expansion in accordance with the established norms reflected in Table 5.

For products without heat treatment, the increase in diameter during dispensing should be at least 6%. In the case of the customer's requirements, the outer diameter of heat-treated products made of steel 10kp, St2kp with walls up to 4 mm thick should increase by at least 12% when dispensing. At the request of the consumer, products are tested for bending, beading, stretching. After all the checks carried out, longitudinal electric-welded steel pipes GOST 10705-80 must remain tight.

Appendix 1. Chemical composition of steel grade 22GYu.

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;
• chrome - 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 made with a yield point of 235 N / mm 2 (24 kgf / mm 2), a relative elongation of 23%; from steel grades St4sp, 20, 20ps - with a yield point of 255 N / mm 2 (26 kgf / mm 2), a relative elongation of 22%.

table 2

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

Table 3

Table 4

GOST 10705-80

INTERSTATE STANDARD

ELECTRIC WELDED STEEL PIPES

TECHNICAL CONDITIONS

Date of introduction 01.01.82

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

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

1. VARIETY

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

2. TECHNICAL REQUIREMENTS

2.1. Steel electric-welded 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, the pipes are made of the following groups:

A - with standardization of mechanical properties from calm, semi-calm and boiling steel grades St1, St2, St3, St4 in accordance with GOST 380;

B - with the standardization of the chemical composition:

GOST 380;

GOST 1050;

From steel grade 08Yu in accordance with GOST 9045;

GOST 19281

B - with standardization of mechanical properties and chemical composition:

From calm, semi-calm and boiling steel grades St1, St2, St3, St4 in accordance with GOST 380;

From calm, semi-calm and boiling steel grades 08, 10, 15, 20 in accordance with GOST 1050;

From steel grade 08Yu in accordance with GOST 9045;

From low-alloy steel grade 22GYu with a chemical composition according to table 1a (pipes with a diameter from 114 to 630 mm inclusive);

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 of 114 to 630 mm incl.);

D - with standardization of the test hydraulic pressure.

Pipes are made of 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.

(Modified edition, Amendment No. 7)

Table 1a

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

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

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

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

2.4. The mechanical properties of the base metal of heat-treated and hot-rolled pipes of groups A and B made of carbon and low-alloy steels must comply with the standards specified in Art. The mechanical properties of the base metal of heat-treated pipes of groups A and B made of steel grade 22ГЮ are established by agreement between the manufacturer and the consumer.

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

(Changed edition, Amendment No. 6,).

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

(Modified edition, Amendment No. 7)

2.5. The mechanical properties of the base metal of pipes of groups A and B without heat treatment and with heat treatment of a welded joint with a diameter of 10 to 152 mm, inclusive, must comply with the standards specified in, with a diameter over 152 to 630 mm inclusive - the standards specified in.

2.6. Cracks, captivity, sunsets, flaws and risks are not allowed on the pipe surface.

Ripples, nicks, dents, small marks, a layer of scale and traces of cleaning are allowed provided that they do not bring the wall thickness and pipe diameter beyond the maximum deviations. Displacement of edges up to 10% of the nominal wall thickness is allowed.

The surface of pipes thermally treated in a protective atmosphere must be free of scale. The presence of an oxide film is allowed.

Lack of penetration of the seams must be welded, the place of welding must be cleaned. By agreement with the customer, on pipes with a diameter of 159 mm and more, in places where welds are repaired by welding, the displacement of the welded edges of no more than 20% of the nominal wall thickness and the height of the reinforcement bead no more than 2.5 mm are allowed.

Repair by welding the base metal of pipes is not allowed.

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

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

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

2.6, 2.7.

2.8. Outer burrs on pipes must be removed. At the point of deburring, wall thinning is allowed by 0.1 mm above the minus tolerance.

At the request of the customer, on pipes with an inner diameter of 33 mm and more, the inner 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 - with a wall thickness of over 3 mm.

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

(Changed edition, Amendment No. 1,).

2.9. The ends of the pipes should be cut at right angles and deburred. Chamfering is allowed. The slant of the cut for pipes with a diameter of up to 219 mm should not exceed 1.0 mm, with a diameter of 219 to 426 mm inclusive - 1.5 mm, with a diameter of more than 426 mm - 2.0 mm. By agreement between the manufacturer and the customer, the pipes are made cut in the mill line.

2.10. At the request of the customer, 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 customer, the bevel angle and the width of the end ring can be changed.

2.11. The pipes must be able to withstand the hydraulic test pressure. Depending on the value of 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 customer's request with a test hydraulic pressure calculated in accordance with GOST 3845, with an allowable stress equal to 90% of the standard yield strength for pipes of this steel grade, but not exceeding 20 MPa (200 kgf / cm 2).

(Modified edition, Amendment No. 5).

2.12. Pipes heat-treated throughout the entire volume, groups A and B, with a wall thickness of at least 6 mm, made of steels of grades St3sp, St3ps (categories 3-5), 10, 15, 20 and low-alloy steels must withstand impact bending tests of the base metal ... In this case, the norms of impact strength must correspond to those indicated in table. ... The impact bending test of the base metal of thermally treated pipes of groups A and B made of steel grade 22GYu is carried out at the request of the customer, the impact strength standards are set by agreement between the manufacturer and the customer.

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

Flattening of heat-treated pipes must be carried out up to the distance between 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 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 H ... Flattening of pipes with heat treatment of the welded joint and hot-rolled pipes should be carried out to a distance of 1/2D H.

At the request of the customer, 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 up to 108 mm in diameter must withstand the expansion test.

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

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

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

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

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

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

2.17. Heat-treated throughout the entire volume of carbon steel pipes with a diameter of 30 to 159 mm with a wall thickness of no more than 0.08Dmust withstand the airborne test. The size of the flanging must be at least 24%, while the width of the folded bead, measured from the inner surface of the pipe, must be at least 1.5 times the wall thickness of the pipe.

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.

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,,,).

2.19. The pipes must be tight.

(Modified edition, Amendment No. 3).

3. RULES OF ACCEPTANCE

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

(Modified 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 taken for inspection.

3.3. Each pipe is subject to inspection 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 customer.

(Modified edition, Amendment No. 3).

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

3.6. When 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.

Retest results apply to the entire batch.

3.7. Places of welding seams 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 of welding seams of pipes of group D must be tested by non-destructive methods, or pipes after repair must be tested by hydraulic pressure.

(Modified 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 testing for impact strength - three samples 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 for determining the chemical composition are taken in accordance with GOST 7565.

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

where WITH, Mp, WITH r, Moe, V,Si, Ni- mass fraction of carbon, manganese, chromium, molybdenum, vanadium, copper, nickel in steel,%.

(Modified edition, Amendment No. 6).

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

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

(Modified edition, Amendment No. 1).

4.4. Pipes measure:

outer diameter and ovality - with an adjustable measuring bracket in accordance with GOST 2216 or a caliper in accordance with GOST 166, or a micrometer in accordance with GOST 6507;

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

curvature - with a straight edge in accordance with GOST 8026 and a probe;

wall thickness, wall thickness and height of the internal burr - with a micrometer in accordance with GOST 6507 or a wall gauge in accordance with GOST 11358;

displacement of the edges - with a template according to technical documentation or a micrometer in accordance with GOST 6507 or a vernier depth gauge in accordance with GOST 162;

oblique cut is provided by the design of the equipment for processing pipe ends, the bevel angle is provided by a goniometer in accordance with GOST 5378. In case of disagreement in assessing the quality, the oblique cut is checked with a coal miner and a probe;

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

the depth of surface defects - using a vernier depth gauge in accordance with GOST 162. The measurement of the outer diameter of the pipe is carried out at a distance of at least 15 mm from the end of the pipe for pipes with the 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 the ratioD n / S n over 35 to 75; at a distance of at leastD n - for pipes with the ratioD n / S n over 75.

(Changed edition, Amendment No. 1,).

4.5. The impact bending test is carried out on longitudinal specimens of type 3 in accordance with 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 from 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 impact test temperature is specified by the customer in the pipe purchase order.

(Changed edition, Amendment No. 1,).

4.6. The tendency of the base metal of pipes to mechanical aging is determined according to GOST 7268. Straightening of samples by static load is allowed.

4.7. The tensile test is carried out in accordance with GOST 10006 on a longitudinal proportional short sample.

When tested on specimens of a segmented section, the latter is cut from a section located at an angle of about 90 ° to the weld, and is not straightened in the calculated part.

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

If disagreements arise, the pipes are tested in accordance with GOST 10006.

(Changed edition, Amendment No. 1,).

4.8. Flattening test is carried out according to GOST 8695.

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

(Modified edition, Amendment No. 3).

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

4.11. The test for boarding is carried out in accordance with GOST 8693. Burr removal is allowed on the flanging section.

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

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

(Modified edition, Amendment No. 7).

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

4.14. The control of the welded seam is carried out by non-destructive methods (ultrasonic, eddy current, magnetic or X-ray equivalent method) according to the technical documentation.

5. MARKING, PACKAGING, TRANSPORTATION AND STORAGE

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

INFORMATION DATA

1. DEVELOPED AND INTRODUCED by the Ministry of Ferrous Metallurgy of the USSR

2. APPROVED AND PUT INTO EFFECT by the Decree of the USSR State Committee for Standards dated 25.12.80 No. 5970

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

Registered by the IGU Technical Secretariat No. 3166

INTERSTATE STANDARD

ELECTRIC WELDED STEEL PIPES

TECHNICAL CONDITIONS

Official edition

Standardinform

UDC 669.14-462.2: 621.791.7: 006.354

Group B62

INTERSTATE STANDARD

ELECTRIC WELDED STEEL PIPES

Technical conditions

Electrically welded steel tubes. Specifications

ISS 23.040.10 OKP 13 7300 13 8100 13 8300

Date of introduction 01.01.82

This standard applies to steel longitudinal electric-welded pipes with a diameter of 10 to 530 mm from 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 heating electric heaters.

1. VARIETY

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

2. TECHNICAL REQUIREMENTS

2.1. Steel electric-welded 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, the pipes are made of the following groups:

А - with standardization of mechanical properties made of calm, semi-calm and boiling steel grades St1, St2, StZ, St4 in accordance with GOST 380 (category 4 in accordance with GOST 16523, category 1 in accordance with GOST 14637);

B - with standardization of the chemical composition from calm, semi-calm and boiling steel grades St1, St2, StZ, St4 according to GOST 380 and GOST 14637, from calm, semi-calm and boiling steel grades 08, 10, 15 and 20 according to GOST 1050, from steel grade 08Yu in accordance with GOST 9045, from low-alloy steel grade 22GYu with the chemical composition given in table. 1a (pipes with a diameter of 140 to 426 mm);

B - with standardization of mechanical properties and chemical composition from calm, semi-calm and boiling steel grades St1, St2, StZ, St4 according to GOST 380 (category 4 according to GOST 16523 and categories 2-5 according to GOST 14637), from calm, semi-calm and boiling steel grades 08, 10, 15, 20 in accordance with GOST 1050, from steel 08Yu in accordance with GOST 9045, from low-alloy steel grade 22GYu with the chemical composition given in table. 1a (pipes with a diameter of 140 to 426 mm);

D - with standardization of the test hydraulic pressure.

2.3. Pipes are manufactured thermally treated (over the entire volume of the pipe or along a welded joint), hot-rolled and without heat treatment.

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

Pipes made of steel grade 22GYu are made heat-treated along the welded joint or throughout the entire volume, pipes made of steel grade St1 - without heat treatment.

Official edition

Reprinting prohibited

Standards Publishing House, 1981 5) STANDARDINFORM, 2005 5) STANDARDINFORM, 2008

Table 1a

2.4. The mechanical properties of the base metal of heat-treated and hot-rolled carbon steel pipes must comply with the standards specified in table. 1. The mechanical properties of heat-treated pipes made of steel grade 22ГЮ 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 StZps, 15, 15ps are manufactured with a yield point of 235 N / mm 2 (24 kgf / mm 2), a relative elongation of 23%; from steel grades St4sp, 20, 20ps - with a yield point of 255 N / mm 2 (26 kgf / mm 2), a relative elongation of 22%.

table 2

Note. At the request of the consumer, for pipes of all steel grades with a diameter of 10 to 60 mm, the relative elongation increases by 3% in comparison with 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. The mechanical properties of the base metal of pipes with a diameter over 152 to 530 mm inclusive without heat treatment and with heat treatment of the welded joint must comply with the standards specified in table. 3.

2.6. Cracks, captivity, sunsets, flaws and risks are not allowed on the pipe surface.

Rowing, nicks, dents, small marks, a layer of scale and traces of stripping are allowed when

provided that they do not bring the wall thickness and pipe diameter beyond the maximum deviations. Displacement of edges up to 10% of the nominal wall thickness is allowed.

The surface of pipes thermally treated in a protective atmosphere must be free of scale. The presence of an oxide film is allowed.

Lack of penetration of the seams must be welded, the place of welding must be cleaned. By agreement with the consumer, on pipes with a diameter of 159 mm and more, in places where welds are repaired by welding, the displacement of the welded edges of no more than 20% of the nominal wall thickness and the height of the reinforcement bead no more than 2.5 mm are allowed.

Repair by welding the base metal of pipes is not allowed.

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

2.7. On pipes with a diameter of 57 mm and 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.

2.2-2.7. (Modified edition, Amendment No. 5).

2.8. Outer burrs on pipes must be removed. At the point of deburring, wall thinning is allowed by 0.1 mm above the minus tolerance.

At the request of the consumer, on pipes with an inner diameter of 33 mm and more, the inner 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 - with a wall thickness of over 3 mm.

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

2.9. The ends of the pipes should be cut at right angles and deburred. Tolerance

Remedy for chamfering. The slant of the cut for pipes with a diameter of up to 219 mm should not exceed 1 mm, and for pipes with a diameter of 219 mm and more - 1.5 mm. By agreement between the manufacturer and the consumer, the 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 must 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 the width of the end ring can be changed.

2.11. The pipes must be able to withstand the hydraulic test pressure. Depending on the value of the test pressure, pipes are divided into two types:

I - pipes with a diameter 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 a test hydraulic pressure calculated in accordance with GOST 3845, with an allowable stress equal to 90% of the standard yield strength for pipes of this steel grade, but not exceeding 20 MPa (200 kgf / cm 2).

2.12. Heat-treated pipes made of steels of grades StZsp, StZps (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 norms of impact strength must correspond to those indicated in table. 4.

Table 4

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

2.13. Heat-treated pipes with a diameter of up to 152 mm inclusive, pipes hot-rolled and without heat treatment with a diameter of more than 20 to 152 mm inclusive and a wall thickness of 0.06 Z) H and 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 up to the distance between flattening planes H, mm, calculated by the formula

(1 + a) ■ s s

where a is the coefficient for pipes made of steel grades 08Yu, 08kp, 8ps, 08, Yukp, St2kp is 0.09, and for pipes from other steel grades it is 0.08; s - nominal wall thickness, mm;

Z) H - 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 H. Flattening of pipes with heat treatment of the welded joint should be carried out to a distance equal to 1/2 Z) H.

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 Z) H.

2.11-2.13. (Modified edition, Amendment No. 5).

2.14. Pipes up to 108 mm in diameter must withstand the expansion test.

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

The increase in the outer diameter of heat-treated pipes during dispensing must comply with the standards specified in table. 5.

Table 5

The increase in the outer diameter of pipes without heat treatment during expansion 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 Yukp, St2kp should be at least 12%.

(Modified edition, Amendments 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 up to and including 530 mm in diameter must withstand the bend test. The bend radius for pipes with a diameter of up to 60 mm must be at least 2.5 A "for the base metal of pipes with a diameter 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 with a diameter of 30 to 159 mm with a D / s ratio equal to

12.5 or more must withstand the airborne test. The width of the bend to be bent, measured from the inner surface, must be at least 12% of the inner diameter of the pipe and at least

1.5 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, StZ, St4.

2.18. Pipes with a diameter of 50 mm and more, 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 have undergone heat treatment throughout the pipe volume or heat treatment of the welded joint, must comply with the standards specified in table. 1. The ultimate tensile strength of a welded joint of pipes with a diameter of 50 to 203 mm, which have undergone heat treatment throughout the pipe volume or heat treatment of the welded joint, must be at least 0.9 of the norms specified in Table. 1.

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

(Modified edition, Amendment 1.3).

2.19. The pipes must be tight.

(Modified edition, Amendment No. 3).

3. RULES OF ACCEPTANCE

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

(Modified 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 taken for inspection.

3.3. Each pipe is subject to inspection of the dimensions and quality of the pipe surface. It is allowed to control sizes and surfaces selectively on each batch with a single-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.

(Modified edition, Amendment No. 3).

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

When carrying out non-destructive testing along the perimeter of the entire pipe, it is allowed not to carry out a hydraulic test of type I pipes.

Instead of non-destructive testing of welded seams of pipes of type I, it is allowed to test each pipe with an increased hydraulic pressure calculated in accordance with the requirements of GOST 3845 at an allowable stress equal to 85% of the yield point for pipes with a diameter of 273 mm and more and 75% of the yield point for pipes with a diameter less than 273 mm, but not exceeding 12 MPa (120 kgf / cm 2).

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

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

When inspecting the quality of the seam by non-destructive methods, additional control is carried out by hydraulic pressure on 15% of the pipes from the batch.

By agreement between the manufacturer and the consumer, testing of pipes by hydraulic pressure is not carried out.

(Introduced additionally, Amendment No. 3).

3.4. To check the height of the internal burr, 2% of the pipes are taken from the batch.

3.5. For flattening, expansion, beading, bending, impact strength, tendency of the base metal of pipes to mechanical aging, tension of the base metal and the weld, two pipes are taken from the batch.

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

At the request of the consumer, the determination of the impact strength is not carried out.

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

(Modified edition, Amendment No. 1).

3.6. When 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.

Retest results apply to the entire batch.

3.7. Places of welding seams 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 and. 3.3a ​​of this standard.

Places of welding seams of pipes of group D must be tested by non-destructive methods, or pipes after repair must be tested by hydraulic pressure.

(Modified 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 testing for impact strength - three samples for each test temperature.

4.2. The chemical composition of steel is determined in accordance with GOST 22536.0 - GOST 22536.6, GOST 12344 - GOST 12354. Samples for determining the chemical composition are taken in accordance with GOST 7565.

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

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

(Modified edition, Amendment No. 1).

4.4. Pipes measure:

length - with a tape measure in accordance with GOST 7502;

outer diameter and ovality - with an adjustable measuring bracket in accordance with GOST 2216 or a caliper in accordance with GOST 166, or a micrometer in accordance with GOST 6507;

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

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

curvature - with a straight edge in accordance with GOST 8026 and a probe;

wall thickness, wall thickness and height of the internal burr - with a micrometer in accordance with GOST 6507 or a wall gauge in accordance with GOST 11358;

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

oblique cut - the parameter is provided by the design of the equipment for processing the ends

the bevel angle of the chamfer - with a goniometer in accordance with GOST 5378. In case of disagreement in assessing the quality, the miter of the cut is checked with a square and a probe;

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

the depth of surface defects - with a depth gauge according to GOST 162. Measurement of the outer diameter of the pipe is carried out at a distance of at least 15 mm from the end of the pipe for pipes with the ratio of the outer diameter to the wall thickness Z) H / s H equal to 35 or less; at a distance of at least 2/3 Ai - for pipes with a ratio D u / s u over 35 to 75; at a distance of at least D, - for pipes with a D H / s H ratio over 75.

(Modified edition, Amendments No. 1, 3).

4.5. The impact bending test is carried out on longitudinal specimens 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 from 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.

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

(Modified edition, Amendment No. 1).

4.6. The tendency of the base metal of pipes to mechanical aging is determined in accordance with GOST 7268. It is allowed to straighten samples by static load.

4.7. The tensile test is carried out in accordance with GOST 10006 on a longitudinal (in the form of a strip or a pipe segment) proportional to a short sample.

When tested on specimens of a segmented section, the latter is cut from a section located at an angle of about 90 ° to the weld, and is not straightened in the calculated part.

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

If disagreements arise, the pipes are tested in accordance with GOST 10006.

(Modified edition, Amendment No. 1).

4.8. Flattening test is carried out according to GOST 8695.

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

(Modified edition, Amendment No. 3).

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

4.11. Flanging test is carried out in accordance with GOST 8693. Burr removal is allowed in the flanging section.

4.12. The determination of the temporary resistance of the welded joint of pipes with a diameter of 50-530 mm is carried out on ring samples according to technical documentation.

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

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

4.14. The control of the welded seam is carried out by non-destructive methods (ultrasonic, eddy current, magnetic or X-ray equivalent method) according to the technical documentation.

5. MARKING, PACKAGING, TRANSPORTATION AND STORAGE

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

INFORMATION DATA

1. DEVELOPED AND INTRODUCED by the Ministry of Ferrous Metallurgy of the USSR

2. APPROVED AND PUT INTO EFFECT by the Decree of the USSR State Committee for Standards dated 25.12.80 No. 5970

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

Registered by the IGU Technical Secretariat No. 3166

3. REPLACE GOST 10705-63

4. REFERENCE REGULATORY AND TECHNICAL DOCUMENTS

5. The limitation of the validity period was lifted by the Resolution of the State Standard of 12.07.91 No. 1247

6. EDITION (November 2005) with Amendments No. 1, 2, 3, 4, 5, approved in December 1986, December 1987, June 1989, July 1991, April 1999 (IUS 2-87, 3-88, 10-89, 10-91, 7-99); Amendment (NUS 5-2005)

Reprinted (as of March 2008).

See notes of FGUP "STANDARTINFORM" (p. 9).

NOTES FGUP "STANDARTINFORM"

1 Specified in the section "Information data" to GOST 10705-80:

GOST 380-94 was replaced by GOST 380-2005;

GOST 18242-72 was replaced by GOST R ISO 2859-1-2007.

2 In the information index “ National standards»No. 5-2005 amendment published

to GOST 10705-80 Electric-welded steel pipes. Specifications [see. Edition (June 2001) with Amendments No. 1, 2, 3, 4, 5 and the collection “Metal pipes and fittings to them. Part 3. Welded pipes. Profile pipes "(Edition 2001)]

Editor R.G. Goverdovskaya Technical editor V.N. Prusakova Proofreader V.I. Barentseva Computer layout I.А. Naleykina

Signed for printing on April 29, 2008. Format 60 x 84 1 / s. Offset paper. Times headset. Offset printing. Uel. print sheet 1.40. Academic and Publishing House 1.10. Circulation 97 copies. Zach. 428.

FSUE "STANDARTINFORM", 123995 Moscow, Granatny per., 4.

Typed in FSUE "STANDARTINFORM" on a PC

Printed at the branch of the Federal State Unitary Enterprise "STANDARTINFORM" - type. "Moscow printer", 105062 Moscow, Lyalin per., 6.

STATE STANDARD OF THE UNION OF SSR

ELECTRIC WELDED STEEL PIPES

TECHNICAL CONDITIONS

GOST 10705-80

Publishing house of standards

Moscow

STATE STANDARD OF THE UNION OF SSR

Date of introduction 01.01.82

This standard applies to steel longitudinal electric-welded pipes with a diameter of 10 to 530 mm from 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 electric heaters.

(Modified edition, Amendment No. 5).

1. VARIETY

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

2. TECHNICAL REQUIREMENTS

2.1. Steel electric-welded 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, the pipes are made of the following groups:

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

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

В - with standardization of mechanical properties and chemical composition from calm, semi-calm and boiling steel grades St1, St2, St3, St4 in accordance with GOST 380-94 (category 4 in accordance with GOST 16523-89 and category 2-5 in accordance with GOST 14637 -89), from calm, semi-calm 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 standardization of the test hydraulic pressure.

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

2.3. Pipes are manufactured thermally treated (over the entire volume of the pipe or along a welded joint), hot-rolled and without heat treatment.

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

Pipes made of steel grade 22GYu are manufactured thermally treated along the welded joint or throughout the entire volume, pipes made of steel grade St1 - without heat treatment.

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

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 over 152 to 530 mm inclusive without heat treatment and with heat treatment of the welded joint must comply with the standards specified in Art.

2.6. ... Cracks, captivity, sunsets, flaws and risks are not allowed on the pipe surface.

Ripples, nicks, dents, small marks, a layer of scale and traces of cleaning are allowed provided that they do not bring the wall thickness and pipe diameter beyond the maximum deviations. Displacement of edges up to 10% of the nominal wall thickness is allowed.

The surface of pipes thermally treated in a protective atmosphere must be free of scale. The presence of an oxide film is allowed.

Lack of penetration of the seams must be welded, the place of welding must be cleaned. By agreement with the consumer, on pipes with a diameter of 159 mm and more, in places where seams are repaired by welding, the displacement of the welded edges of no more than 20% of the nominal wall thickness and the height of the reinforcement bead no more than 2.5 mm are allowed.

Repair by welding the base metal of pipes is not allowed.

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

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

2.7. For pipes with a diameter of 57 mm and 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. Outer burrs on pipes must be removed. In the place of deburring, the wall thinning is allowed by 0.1 mm in excess of the minus tolerance.

At the request of the consumer, on pipes with an inner diameter of 33 mm and more, the inner 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 - with a wall thickness of over 3 mm.

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

(Modified edition, Amendments No. 1, 3).

2.9. The ends of the pipes should be cut at right angles and deburred. Chamfering is allowed. The slant of the cut for pipes with a diameter of up to 219 mm should not exceed 1 mm, and for pipes with a diameter of 219 mm and more - 1.5 mm. By agreement between the manufacturer and the consumer, the pipes are made cut in the mill line.

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

2.11. The pipes must be able to withstand the hydraulic test pressure. Depending on the value of the test pressure, pipes are divided into two types:

I - pipes up to 102 mm in diameter - 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 a test hydraulic pressure calculated in accordance with GOST 3845-75, with an allowable stress equal to 90% of the standard yield strength for pipes of this steel grade, but not exceeding 20 MPa (200 kgf / cm 2).

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

2.12. Heat-treated pipes made of steels of 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 norms of impact strength must correspond to those specified in Art.

2.13. Heat-treated pipes with a diameter of up to 152 mm inclusive, pipes hot-rolled and without heat treatment with a diameter of more than 20 to 152 mm inclusive and a wall thickness of 0.06 Dн and 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 up to the distance between flattening planes H, mm, calculated by the formula

,(1)

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 is 0.08;

S is the nominal wall thickness, mm;

Dн is the nominal outer diameter of the pipe, mm.

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

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

2.14. Pipes up to 108 mm in diameter 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 DH are not tested for expansion.

Increased 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 expansion 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 made of steel grades 10kp, St2kp must be at least 12%.

(Modified edition, Amendments No. 1, 3, 4).

2.15. At the request of the consumer, the 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 that have undergone heat treatment throughout the pipe volume 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 that have undergone heat treatment but 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 ultimate 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. The pipes must be tight.

(Modified edition, Amendment No. 3).

3. RULES OF ACCEPTANCE

3.1. Pipes are accepted in batches. A batch should 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 10692-80

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 taken for inspection.

3.3. Each pipe is subject to inspection 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.

(Modified edition, Amendment No. 3).

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

When carrying out non-destructive testing along the perimeter of the entire pipe, hydraulic testing of pipes of the type I allowed not to conduct.

Allowed instead of non-destructive testing of welded seams of pipes of the type I 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 point for pipes with a diameter of 273 mm and more and 75% of the yield point for pipes with a diameter of less than 273 mm, but not exceeding 12 MPa (120 kgf / cm 2).

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

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

3.4. To check the height of the internal burr, 2% of the pipes are taken from the batch.

3.5. For flattening, expansion, beading, bending, impact strength, tendency of the base metal of pipes to mechanical aging, tension of the base metal and the weld, two pipes are taken from the batch.

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

At the request of the consumer, the determination of the impact strength is not carried out.

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

(Modified edition, Amendment No. 1).

3.6. When 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.

Retest results apply to the entire batch.

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

Places of welding seams of pipes of group D must be tested by non-destructive methods, or pipes after repair must be tested by 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 testing for impact strength, 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 for determining the chemical composition are taken in accordance with GOST 7565-81.

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

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

(Modified edition, Amendment No. 1).

4.4. Pipes measure:

length - with a tape measure but GOST 7502-89.

outer diameter and ovality - with an adjustable measuring bracket in accordance with GOST 2216-84 or a caliper in accordance with GOST 166-89 or a micrometer in accordance with GOST 6507-89 ;;

or a caliper in accordance with GOST 166-89, or a micrometer in accordance with GOST 6507-89;

inner 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 in accordance with GOST 8026-92 and a probe;

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

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

oblique cut is provided by the design of the equipment for processing pipe ends, the bevel angle is provided by a goniometer in accordance with GOST 5378-88. In case of disagreement in assessing the quality, the oblique cut is checked with a coal miner and a probe;

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

the depth of surface defects - using a barbell depth gauge in accordance with GOST 162-90. The measurement of the outer diameter of the pipe is carried out at a distance of at least 15 mm from the end of the pipe for pipes with the ratio of the outer diameter to the wall thicknessD H / S H equal to 35 or less; at a distance of at least 2/3 D H -for pipes with an attitudeD H / S H over 35 to 75; at a distance of at least D H - for pipes with ratioD H / S H over 75.

(Modified edition, Amendments No. 1, 3).

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

Impact strength is determined as the arithmetic mean value from the test results of three samples. On one of the samples, a decrease in impact strength by 9.8 is allowed· 10 4 J / m2 (1 kgf · m / cm 2).

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

(Modified edition, Amendment No. 1).

4.6. The tendency of the base metal of pipes to mechanical aging is determined according to GOST 7268-82. Straightening of samples by static load is allowed.

4.7. The tensile test is carried out in accordance with GOST 10006-80 on a longitudinal (in the form of a strip or a pipe segment) proportional to a short sample.

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

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