GOST 8696-74

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  ГОСТ 8696-74

GOST 8696−74 electric resistance welded steel Pipes with spiral seam General purpose. Technical specifications (with Changes 1−6 N)

GOST 8696−74

Group В62

INTERSTATE STANDARD

ELECTRIC RESISTANCE WELDED STEEL PIPES WITH SPIRAL SEAM
GENERAL PURPOSE

Specifications

General-purpose electrically-welded spiral seam steel pipes.
Specifications

Date of introduction 1976−01−01

INFORMATION DATA

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

DEVELOPERS

E. A. Bliznyuki, V. P. Sokurenko, N. And. Petrenko

2. APPROVED AND promulgated by the Decree of the State Committee of standards of Ministerial Council of the USSR from 11.06.74 N 1436

3. REPLACE GOST 8696−62

4. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS

5. The expiration time limit is removed by the Resolution of Gosstandart from 21.08.91 N 1379

6. EDITION Changes N 1, 2, 3, 4, 5, 6, approved in August 1977, July 1979, December 1985, October 1988, March 1990, August 1991 (IUS 10−77, 9−79, 2−86, 1−89, 7−90, 11−91)


This standard applies to electrically welded steel pipes with spiral seam General purpose. This standard does not apply to pipes for gas pipelines and oil pipelines.

1. ASSORTMENT

1.1. The pipe dimensions shall be as specified in table.1.

Table 1

Extension table 1

Notes:

1. Theoretical weight of pipe calculated based on the reinforced seams at a relative density of steel 7.85 g/cm.

2. (Deleted, Rev. N 3).

3. On demand of the consumer is allowed to manufacture pipes with an intermediate wall thickness in the range of thicknesses stipulated in table 1.


(Changed edition, Rev. N 1, 2, 3, 4).

1.2. Pipes are manufactured in length from 10 to 12 m. the party is allowed up to 5% of a shortened pipe length less than 6 m.

(Changed edition, Rev. N 3).

1.3. Limit deviations of the outside diameter of the pipes must comply with table.2.

Table 2

mm

(Changed edition, Rev. N 3, 4, 6).

1.4. Limit deviations for wall thickness should correspond to the limit deviations on thickness of metal under GOST 19903 to the maximum width of rolled and sheet steel.

1.5. The offset edges should not exceed 25% of the nominal wall thickness but not more than 3 mm for pipes with a diameter of 530−1420 mm with a wall thickness of less than 14 mm and not more than 5 mm for pipe diameters 1420−2520 mm wall thickness of 14 mm or more.

Pipe group B allowed local offset edges to 30% of pipe wall thickness on plots of up to 10% of the length of the seam.

The displacement of the pipe manufacturing high precision should not exceed:

for pipes with a diameter of 530−1420 mm:

1,0 mm at a wall thickness of 4 mm;

1.2 mm wall thickness 5 mm;

1.4 mm with a wall thickness of 6 mm;

1.6 mm with a wall thickness of 7 mm or more;

for pipe diameters 1620−2520 mm:

15% of the nominal wall thickness.

(Changed edition, Rev. N 1, 2, 3, 5).

1.6. The ovality of pipes shall not exceed 2% of the nominal outside diameter.

The ovality of pipes manufacturing high precision should not exceed 1% of the nominal outside diameter.

(Changed edition, Rev. N 3).

1.7. The total curvature of tubes shall not exceed 0.2% of their length.

The overall curvature of the pipe manufacturing high precision should not exceed 0.1% of the length.

(Changed edition, Rev. N 3).

1.8. The pipe ends must be cut at right angle. Cut end Squareness, mm should not exceed 2 mm and for tubes with a diameter of 1420 mm and a wall thickness of 14 mm or more to 4 mm.

(Changed edition, Rev. N 2, 3).

1.9. At the ends of the pipes must be removed chamfer at an angle of 25−30° to the pipe end, must be left face ring width:

1−3 mm with a wall thickness of 4−7 mm.

1−4 mm with a wall thickness of 8−14 mm;

1−6 mm with a wall thickness of 15−25 mm.

The width of the face of the ring is not controlled in the seam area at a distance of 80 mm.

(Changed edition, Rev. N 2, 4).

1.10. Strengthening outer seam should be:

0.5−3.0 mm wall thickness up to 10 mm;

Of 0.5−3.5 mm with a wall thickness of 10−14 mm;

0,5−4,5 mm with a wall thickness of 15−20 mm;

0.5−5.0 mm and the wall thickness is 20 mm or more.

Pipe and tube manufacturing high precision the intensity of the seam should be:

0,5−3,2 mm with a wall thickness of 10−14 mm;

0,5−4,5 mm with a wall thickness of 15 mm or more.

Strengthen the internal weld shall not be less than 0,5 mm. On the inner seam allowed saddle, or individual recesses is not more than 2 mm, provided that the thickness of the seam in the place of indentations not less than 1 mm exceeds the allowable minimum wall thickness of the pipe.

Examples of symbols*

________________
* Examples of symbols correspond to the original. — Note the manufacturer’s database.


Pipe with an outer diameter of 630 mm, a wall thickness of 7 mm, random length, of steel grade St2kp, produced by group B GOST 8696−74:

Pipe 630х7 — St2kp GOST 8696−74

The same, of random length, of steel grade Ст3сп2 made by the group In GOST 8696−74:

Pipe 630х7 — Ст2сп2 GOST 8696−74

The same, of random length, is produced by group D GOST 8696−74:

Pipe 630х7 — D GOST 8696−74

(Changed edition, Rev. N 1, 2, 3, 6).

2. TECHNICAL REQUIREMENTS

2.1. Depending on quality pipes are made of the following groups:

And mechanical properties of carbon steel grades ST2, St3 (all degrees of oxidation) category 1 according to GOST 14637;

B — chemical composition of carbon steel grades ST2, St3 (all degrees of oxidation) according to GOST 14637;

The chemical composition and mechanical properties of carbon steel ST2 (all degrees of oxidation), category 2, St3 (all degrees of oxidation) of categories 2 and 3 St3ps st3sp and categories 4 and 5 according to GOST 14637, steel grade 20 to GOST 1050, low alloy steel according to GOST 19281 and low-alloy steel with the chemical composition given in table.3A. Brand low-alloy steel selected by manufacturer of piping with requirements for the standards of the mechanical properties required for classes of strength К45, K50, K52 and K55;

E — without the regulation of the chemical composition and mechanical properties.

Table 3A

Notes:

1. Allowed residual aluminum content of up to 0.05%, phosphorus up to 0.025% to 20% of the bottoms.

2. The accepted deviation for the upper limit of the chemical composition, %:

+0,02 — carbon;

+0,10 — manganese;

+0,005 — phosphorus,

the lower limit for all elements is unlimited.

2.2. The mechanical properties of the base metal carbon steel tubes shall be as given in table.4

Table 4

The mechanical properties of the base metal of pipes of low-alloy steels must meet are given in table.5.

Table 5

The toughness of the base metal of pipes of carbon steel st3sp St3ps category 3 and the toughness of base metal and welded joints of pipes made of steel 20 and steel grades st3sp St3ps categories 4 and 5 at a temperature of minus 20 °C must conform to the standards given in table.6.

Table 6

The toughness of welded joints of pipes made of carbon steel Ст3сп3 and Ст3пс3 at the test temperature of + 20 °C shall be not less than 49,0 j/cm(5 kgf·m/cm).

The toughness of the base metal of pipes of low alloy steel at a test temperature of minus 40 °C must be at least of 29.4 j/cm(3 kgf·m/cm), weld — least 19.6 j/cm(2 kgf·m/cm).

2.1, 2.2. (Changed edition, Rev. N 3, 4, 6).

2.3. Tubes are made with outer and inner seam. On the pipes is allowed to cross the seam of the junction of coils and a single annular weld made double-sided welding. The annular seam pipes with a diameter of 159−377 mm is performed one-sided welding.

On pipes with a diameter of 1420 mm and allowed four transverse seam from the junction of the sheets, made double-sided welding.

(Changed edition, Rev. N 2).

2.4. Allowed output of a transverse seam on the end of the pipe and crossing it with girth. The intersection of the helical seam and the transverse seam of the junction of the coils should be not less than 300 mm from the pipe end or the ring weld.

2.5. Cracks, slivers, shell, bundles and sunsets on the pipe surface are not permitted.

Minor nicks, dings, small risks, a thin layer of oxides and traces of Stripping defects are allowed if they do not take the thickness of the wall beyond the set limit tolerances.

On the surface of the tubes of groups B and D allowed the individual defects of the base metal, if the minimum wall thickness in places of their occurrence is at least 70% of the nominal thickness.

Allowed welding defects of pipes with the subsequent sweep of the place of welding and hydraulic re-test.

(Changed edition, Rev. N 4).

2.6. Metal seams should be without pores, cavities, cracks and other defects.

Lack of fusion weld the pipe groups A, B and C are not allowed. The transition from the weld reinforcement to the base metal of the pipes should be smooth, without undercuts. Allowed separate undercuts to a depth of 0.5 mm, a length of not more than 0.3 m with a total length of not more than 10% of the length of the seam. The coincidence of undercuts in a single cross-section with inside and outside seam is not allowed.

Norms of permissible defects of seams, determined by the physical non-destructive methods, established by the normative documentation.

(Changed edition, Rev. N 1, 5).

2.7. Transverse and spiral pipes group must withstand the mechanical tensile tests.

The value of the temporary tear resistance of the welds should be not below the value of the temporary resistance of the base metal.

2.8. The value of the hydraulic test pressure without considering the axial pressure is determined according to GOST 3845 when the permitted voltage equal to 180 MPa (18 kgf/cm) for tubes of groups B and D and 0.85 of the yield strength specified in table.4 and 5 for tubes of groups A and B. thus for tubes of groups B and D the test pressure must not exceed 3.5 MPa (35 kgf/cm). At the request of the consumer for pipe bands In allowable stress is taken equal to 0, 90 from the standard yield.

When tested on presses of various designs with axial support the value of hydraulic pressure determined in accordance with GOST 3845.

(Changed edition, Rev. N 3).

2.9. Welded joint of pipes of the group must withstand the test of static bending. The angle of bend should be not less than 100°.

(Changed edition, Rev. N 5).

3. ACCEPTANCE RULES

3.1. Pipes take by the parties. The party should consist of pipes of the same size, of the same steel grade, same group and be accompanied by one document on quality according to GOST 10692 add: chemical composition of steel in accordance with the document on the quality of the manufacturer of the workpiece.

(Changed edition, Rev. N 3).

3.2. Inspection and measurement is subjected to each pipe.

Testing of welded joints of pipe bands In non-destructive methods is carried out at the request of the consumer.

(Changed edition, Rev. N 5).

3.3. Test the hydraulic pressure is subjected to each pipe.

3.4. To control the mechanical properties of the party pick up two tubes.

3.5. To check the chemical composition of the enterprise-the consumer select three tubes from the party.

3.6. Lack of fusion in welds of tubes of groups A, B, and C control on every fifth tube in the party.

(Changed edition, Rev. N 3, 4).

3.7. Test the impact strength of the base metal and welded joints of pipe bands In held at the request of the consumer on the pipes with wall thickness of 6 mm or more.

(Changed edition, Rev. N 3).

3.8. If unsatisfactory test results of at least one of the indicators it is carried out re-testing at twice the sample taken from the same batch.

The results of repeated tests are final and apply to the entire party.

3.9. Testing of welded joints in static bending is carried out at the request of the consumer.

(Added, Rev. N 3).

4. TEST METHODS

4.1. Chemical composition of steel test according to GOST 22536.0 to GOST 22536.6. Samples for determining the chemical composition of the steel are selected according to GOST 7565.

(Changed edition, Rev. N 5).

4.2. Outer diameter (mm), pipes check measurement of perimeter and calculated by the formula

,

where perimeter of the cross section, mm;

 — thickness of tape, mm.

4.3. Hydraulic test of pipes shall be carried out according to GOST 3845 with time under pressure of not less than 30 C.

4.4. To conduct the tensile tests of base metal and welds from each selected pipe cut out one sample.

Tensile test on base metal pipe with a diameter of 159−377 mm spend on a longitudinal axis of the pipe five times in the samples according to GOST 10006, taken from the plot perimeter, angled 90° to the weld seam.

Tensile test on base metal pipe with a diameter of 530 mm and more is carried out according to GOST 10006 five times on the flat samples cut perpendicular to the pipe axis. Sampling — according to GOST 7564.

Instead of the allowed tensile tests to monitor the pipes using non-destructive methods ensure that the mechanical properties of standards specified in this standard.

The differences in the assessment of the level of mechanical properties testing is carried out according to GOST 10006.

The pipe bands allowed In the test on samples cut perpendicular to the axis of the rolled sheet.

Tensile test on welded joints of pipes shall be carried out according to GOST 6996на transverse plane the samples of a type XII with the removed reinforcement.

(Changed edition, Rev. N 3, 4).

4.5. To test the impact of each selected pipe cut out 3 of the sample.

Test the impact strength of the base metal is carried out according to GOST 9454 on samples cut perpendicular to the pipe axis. Tests carried out on samples of type 1, with wall thickness over 10 mm and the samples of type 3 with a wall thickness of 10 mm or less.

Test on toughness of the base metal is carried out according to GOST 9454.

Test on the impact strength of the welded connection is carried out on the samples according to GOST 6996типов VI, VII, VIII notched in the center seam. Samples of the welded joints cut perpendicular to the seam.

In the manufacture of specimens for mechanical tests allowed to edit the workpiece with application of a static load.

Allowed testing of the impact strength is not carried out, and control the impact strength of pipes is to be done by nondestructive methods. Nondestructive testing methods carried out according to the technical documentation.

The differences in the assessment of the level of impact toughness test performed according to GOST 9454.

(Changed edition, Rev. N 3, 5).

4.6. Lack of fusion in welds check for microtemplate or x-ray control according to normative documentation.

(Changed edition, Rev. N 3, 4).

4.7. On the tube measure:

perimeter — measuring tape according to GOST 7502;

the diameter of the shackle — according to GOST 18360, 18365 GOST, GOST 2216 or a caliper according to GOST 166;

ovality — bracket according to GOST 18360, 18365 GOST, GOST 2216 or caliper churchyard, 166 or measuring tape according to GOST 7502;

the length — measuring tape according to GOST 7502 or automated means of measurement according to normative documentation;

the wall thickness of a micrometer according to GOST 6507 or thickness gauge according to GOST 11358;

total curvature — normative documentation;

the offset edges device according to the normative documentation or gauges churchyard 162;

cosine Reza parameter is ensured by design of equipment for processing of pipe ends;

the mechanical ring on the pipe ends (blunting) — a ruler according to GOST 427;

the angle of the bevel of the bevel — protractor according to GOST 5378;

the amount of strengthening of welded joints — a device according to the normative documentation.

The perimeter and ovality measured at the ends of the pipes.

(Changed edition, Rev. N 3, 4, 5, 6).

4.8. Test of susceptibility to mechanical aging shall be carried out according to GOST 7268 without prior 10% deformation.

4.9. Testing of welded joints in static bending is carried out according to GOST 6996 the samples of a type XXVII, cut perpendicular to the pipe axis.

4.8, 4.9. (Added, Rev. N 3).

5. MARKING, PACKAGING, TRANSPORTATION AND STORAGE

5.1. Marking, packaging, transportation and storage welded steel pipes with spiral seam according to GOST 10692. The marking on each pipe additionally indicate:

room tubes;

batch number — for pipes with a diameter of 426 mm or more;

year of manufacture;

the mark in TCI;

pipe size (diameter, wall thickness and length).

Allowed for the labeling of pipes instead of steel grades to apply it the symbol that point in the document about quality. Allowed to apply the trademark method of marking or applying paint.

(Changed edition, Rev. N 1).

5.2. (Deleted, Rev. N 3).