GOST 10706-76

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  ГОСТ 10706-76

GOST 10706−76 (ST SEV 489−77) electrically welded steel Pipes. Technical requirements (Amendments No. 1, 2, 3, 4)

GOST 10706−76

Group В62

INTERSTATE STANDARD

ELECTRICALLY WELDED STEEL PIPES

Technical requirements

Electrically welded steel line-weld tubes. Technical requirements

OKP 13 8100

Date of introduction 1978−01−01

INFORMATION DATA

1. DEVELOPED by all-Union scientific-research and design-technological Institute of the pipe industry (VNITI)

DEVELOPERS

A. O. Semenov, M. Bernstein, N. F. Kuzenko

2. APPROVED AND put INTO EFFECT by Decision of the USSR State Committee for standards from 22.04.76 N 892

Change No. 4 adopted by the Interstate Council for standardization, Metrology and certification (Protocol No. 12, 21.11.97)

Was the Technical Secretariat of MGS N 2893

The adoption of the changes voted:

3. INSTEAD, GOST 10706−63

4. The standard complies ST SEV 489−77 and sets more stringent requirements for toughness of the base metal, transverse joints, strengthen internal seam, the chamfered end of the pipe

5. Standard uniform with OBD 6120−66

6. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS

7. Limitation of actions taken by Protocol No. 5−94 of the Interstate Council for standardization, Metrology and certification (I & C N 11−12−94)

8. EDITION with Amendments No. 1, 2, 3, 4, approved in July 1980, December 1985, November 1990-April 1999 (IUS 10−80, 4−86, 2−91, 7−99)


This standard applies to longitudinal welded pipes of General purpose diameter 478−1420 mm.

(Changed edition, Rev. N 4).

1. TECHNICAL REQUIREMENTS

1.1. The pipe dimensions and limit deviations should correspond to GOST 10704.

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

And mechanical properties of carbon steel grades ST2, St3 (all degrees of oxidation) according to GOST 380, category 1 according to GOST 14637;

B — chemical composition of carbon steel grades ST2, St3 (all degrees of oxidation) with the chemical composition according to GOST 380 and GOST 14637;

The chemical composition and mechanical properties of carbon steel grades ST2 (all degrees of oxidation) according to GOST 380, category 2 according to GOST 14637, at St3kp , GOST 380, category 2 and category 3 according to GOST 14637, St3ps, st3sp according to GOST 380, categories 2, 3, 4 and 5 according to GOST 14637, and also from alloyed steel, the carbon equivalent which does not exceed 0,48%;

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

(Changed edition, Rev. N 4).

1.3. (Deleted, Rev. N 3).

1.4. The mechanical properties of the base metal pipe shall conform to the standards specified in table.2.

Table 2*

________________
* Table.1. (Deleted, Rev. N 3).

(Changed edition, Rev. N 4).

1.5. Tubes of groups A and b shall withstand mechanical testing of welded joints in tension according to GOST 6996. The tensile strength of welded joint shall not be below the interim resistance of the base metal specified for pipes made of this steel grade.

1.6. At the request of the consumer pipe group must be able to withstand the test of the toughness of the base metal. Rules of the toughness of the base metal shall be as specified in table.3.

Table 3

Note. By agreement between manufacturer and consumer impact toughness of the base metal of pipes of low-alloy steel at minus 60 °With should be not less than 2.5 kgf·m/cm(0,24 MJ/m).


For heating mains pipe is manufactured from heat-treated steel grades Ст3сп4, Ст3сп5 with the mechanical properties specified in table.3A.

Table 3A

The norms of toughness of welded joints of pipes for heat networks with temperature of minus 20 °C should be below the standards of the base metal are given in table.3A.

Standards impact resistance after mechanical aging for base metal of pipes and at minus 20 °C for weld optional until July 1, 1988

(Changed edition, Rev. N 2, 3, 4).

1.7. Pipes up to 820 mm should have no more than one longitudinal and one transverse joint. Pipe with a diameter of 820 mm and can have two longitudinal and one transverse seam. At the request of the customer can be increase in the number of transverse joints.

In the presence of transverse weld longitudinal seams shall be offset relative to one another at a distance not less than 100 mm. According to customer’s demands set the upper limit displacement of the longitudinal joints relative to each other.

(Changed edition, Rev. N 1).

1.8. The height of the reinforcement bead of the outer longitudinal and transverse joints should conform to the standards specified in table.4.

Table 4

mm

Allowed in the field repair of welds and tacks of the increase in the height of the reinforcement bead of 1 mm in excess of the limits specified in table.4.

The height of the reinforcement bead at the center of the inner weld shall be not less than 0.5 mm. is allowed at the ends of the pipe length not less than 150 mm flush internal weld to a height of 0−0,5 mm.

(Changed edition, Rev. N 4).

1.9. The pipe ends must be cut at right angle. Deviation from the right angle (slant cut) shall not exceed the specified in table.5.

Table 5

mm

1.10. The pipe ends must be chamfered at an angle of 25−30° to the pipe end. This should be left to the socket ring (blunting) with a width of 1,0−3,0 mm for tubes with diameter up to 1020 mm inclusive and a width of 1.0−5.0 mm for pipes with a diameter of more than 1020 mm.

At the request of the consumer, the chamfer angle of the chamfer should be 30−35°, and for pipes with a wall thickness of 17 mm and more cutting edges must be performed in accordance with the devil.1.

Allowed cutting edges in accordance with the devil.1, to carry out on pipes with a wall thickness of 15 mm.

Damn.1

1.9, 1.10. (Changed edition, Rev. N 4).

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

Minor nicks, rabiza, dents, small risks, a thin layer of oxides, traces of grinding and welding defects are allowed if they do not take wall thickness for maximum deviations. In addition, you risk a longitudinal depth of less than 0.2 mm, applied in automatic welding for the seam areas.

Permitted welding of pipe defects with subsequent Stripping of the place of welding and re-test hydraulic pressure.

1.12. Surface defects of the weld metal in the form of pores, cavities, cracks, blowholes and other defects, reducing the density and strength of the weld metal below the level of the base metal are not permitted.

Allowed traces of shrinkage of the metal along the longitudinal axis of the weld (utiny). The value of shrinkage should take the elevation gain beyond the permitted minimum height of the seam.

The transition from the weld reinforcement to the base metal should be smooth (without undercutting).

Permitted without repair undercuts to a depth of 0.5 mm. At the coincidence of undercuts on the outer and inner seams that one of them must be fixed.

Allowed repair of welded pipes with the subsequent test them by hydraulic pressure or control the repair site by physical methods.

1.13. Each tube shall withstand a test hydraulic pressure.

Pipe group A shall be tested by hydraulic pressure, calculated by the formula given in GOST 3845 (), while the allowable stress is taken equal to 0.5 of the minimum value of the time resistance set for this grade of steel.

According to customer requirements allowable stress must be equal to 0.85 times the minimum yield strength.

Pipe groups shall be tested by hydraulic pressure, calculated by the formula given in GOST 3845 (), when permitted by the voltage equal to 0.9 of the minimum yield strength specified for the steel grade.

Tubes of groups B and D shall withstand a test hydraulic pressure of not less than 25 kgf/cm(2,5 MPa). Pipe sizes 920x7, 1020x8, 1120x8, 1120x9, 1220x9, 1220x10, 1320x9, 1320x10, 1320x11, 1420x10 and 1420x11 mm experience under the pressure of 20 kgf/cm(2.0 MPa).

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

The hydrotesting is not exposed pipe length of 10 m, obtained by docking, or more than two pipes that have passed the hydrostatic testing. At the request of the consumer transverse weld should be controlled by non-destructive physical methods.

(Changed edition, Rev. N 2, 4).

1.14. Welded pipes for heat networks should be controlled by non-destructive methods for its entire length.

At customer’s request, weld pipe groups should be monitored by nondestructive methods.

(Changed edition, Rev. N 2, 3).

1.15. Welded joints of pipes for heating mains shall be tested for static bending.

The minimum allowed bend angle for welded joints of pipes made of carbon steel not less than 100°.

The rate of testing of welded joints in static bending optional until July 1, 1988

(Added, Rev. N 2).

2. ACCEPTANCE RULES

2.1. The pipe presented to the receiving parties. The party should consist of pipes of the same size, one grade of steel and one group of manufacturing and be accompanied by one document on quality according to GOST 10692.

The number of tubes in a batch must not exceed 100 pieces

(Changed edition, Rev. N 2).

2.2. Inspection and measurement is subjected to each pipe.

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

2.4. To control the mechanical properties and toughness from the party taken:

for single-joint pipes — two pipes;

for double seam pipe — one pipe.

(Changed edition, Rev. N 4).

2.5. The chemical composition of the steel take on the document about the quality of the manufacturer of the workpiece. If necessary, check the chemical composition of the finished pipes are produced in one tube from the party.

2.6. 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 or heat.

The results of repeated tests apply to the entire party.

(Changed edition, Rev. N 2).

3. TEST METHODS

3.1. Chemical composition of steel check, if necessary, according to GOST 22536.0 — GOST 22536.6. Samples for determining the chemical composition of the steel selected according to GOST 7565.

3.2. The outer diameter of the pipe () are in millimeters checked by measuring the perimeter and is calculated by the formula

,

where is the perimeter of the cross section of the pipe, mm;

 — thickness of tape, mm;

0,2 — accuracy when measuring the perimeter due to the bias of the roulette when combining divisions.

(Changed edition, Rev. N 1).

3.3. Hydraulic test of pipes shall be carried out according to GOST 3845 with time under pressure of not less than 10 s.

3.4. To conduct the tensile tests of base metal and welded joints of each selected pipe is cut the same way. Samples selected in accordance withGOST 7564.

The tensile test on parent metal is carried out five times for the transverse specimens according to GOST 10006.

Is allowed tensile tests to inspect 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.

Allowed tensile test on parent metal of pipes of low-alloy steels to produce normative documentation approved in the established order.

(Changed edition, Rev. N 4).

3.5. Tensile test on welded joint shall be carried out according to GOST 6996 the samples of a type XII with the removed reinforcement. Samples for testing welded joints in tension are taken perpendicular to the seam.

3.6. For testing the impact strength of each selected pipe is cut on three samples of base metal and three specimens of welded joints. For testing the base metal, the impact strength after mechanical aging additionally selected based on three samples in accordance with GOST 9454.

Inspection of base metal of pipes for impact strength is carried out on samples cut perpendicular to the pipe axis. The test is performed according to GOST 9454 on samples of type I if wall thickness is over 10 mm, and type 3 with a wall thickness of 10 mm or less.

Control of the welded joint impact strength carried out on samples of type VII with a wall thickness of 10 mm or less, and type VI with a wall thickness of 11 mm according to GOST 6996. The incision on percussion samples performed by the line of fusion seam welded the latter, perpendicular to the rolling surface of the metal.

The toughness of the base metal and the welded joint is defined as the arithmetic average of the results of tests of three samples. On one of the samples permitted a decrease in toughness of 4.9 j/cm(0.5 kgf·m/cm), except for pipes intended for heating systems.

(Changed edition, Rev. N 2).

3.7. In the manufacture of specimens for mechanical tests allowed to edit samples with the application of static loads.

3.8. Method and methodology of quality control of the weld by physical methods established by the manufacturer.

Norms of permissible defects identified by NDT methods, established by the normative documents approved in the prescribed manner.

3.9. The carbon equivalent value for the individual melting low alloy steel () in percent is calculated by the formula

,

where , , is the mass fraction of carbon, manganese and vanadium %.

(Added, Rev. N 1).

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

(Added, Rev. N 2).

3.11. On the tube measure:

perimeter — 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 6507with a thickness gauge according to GOST 11358;

curvature — straightedge and feeler according to the normative document;

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

the depth of the defect at the place of Stripping the gauges according to GOST 162;

the mechanical ring on the pipe ends (blunting) line according to GOST 427;

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

(Changed edition, Rev. N 2, 4).

3.12. Test pipes on static bending is carried out in the normative documentation.

3.12. (Added, Rev. N 2).

4. MARKING, PACKAGING, TRANSPORTATION AND STORAGE

4.1. Marking, packaging, transportation and storage of pipes according to GOST 10692.

Mechanized marking signs may be placed at a distance of 500 mm from the pipe end. The area of the marking note the black paint in the form of a directional arrow or a straight line.

The marking on each pipe additionally indicate:

room tubes;

batch number;

year of manufacture;

stamp of technical control;

pipe size (diameter and wall thickness);

the designation of this standard.

Allowed for the labeling of pipes instead of steel grades to apply it the symbol that is specified in the instrument of quality.

Pipe, the last heat treatment, stigmatized with the sign «T».

(Changed edition, Rev. N 2).

APP. (Deleted, Rev. N 3).