GOST 8694-75
GOST 8694−75 Pipe. The method of expansion testing (with Change No. 1)
GOST 8694−75
Group В69
INTERSTATE STANDARD
PIPE
The test method for distribution
Тubing. Hrapp testing method
Date of introduction 1977−01−01
Promulgated by decree of the State Committee of standards of Ministerial Council of the USSR from
The expiration time limit is removed by the resolution of Gosstandard dated
REPLACE GOST 8694−58
EDITION with Change No. 1, approved in April 1980 (ICS 5−80)
This standard applies to seamless and welded metal pipe of circular cross section with a wall thickness of not more than 9.0 mm and a pipe diameter not exceeding 150 mm and sets the method of expansion testing at a temperature of (20±10) °C.
Standard meets the requirements of the CMEA recommendations on standardisation RS 68−63 and ISO recommendation R 166.
The standard fully complies ST SEV 480−77 in terms of expansion testing.
(Changed edition, Rev. N 1).
1. DESIGNATION
1.1. When tested on the distribution contains the following designations:
— the initial outer diameter of sample, mm ;
— end outer diameter of sample, mm ;
— the initial wall thickness of the specimen, mm ;
— length of specimen, mm ;
the angle of taper of the mandrel, deg. ;
— value distribution, % — ;
the diameter of the cylindrical part of the mandrel, mm .
(Changed edition, Rev. N 1).
2. SAMPLING METHOD
2.1. For testing pipes for the distribution of the used samples in the form of pipe cut from the end of the pipe length 2
, if the angle of the mandrel to 30° and
a 1.5
, if the angle of the mandrel more than 30° but not less than 50 mm.
2.2. It is possible to use shorter samples, provided that the cylindrical section, the remaining after the distribution be greater than 0.5 the outer diameter of the pipe.
2.3. The cutting plane must be perpendicular to the longitudinal axis of the pipe.
The burrs on the edges of the sample should be removed.
2.4. The test can be performed directly on the pipe. The end of the pipe to be tested must be in the plane perpendicular to the axis of the pipe.
2.5. Remove inner bead on the samples taken from the welded pipe, the method does not change the properties of pipe material and weld.
2.6. The measurement of the outer diameter of the sample before and after the test is carried out with an accuracy of not more than 0.05 mm at the pipe diameter up to 20 mm and with an error of not more than 0.1 mm at the pipe diameter more than 20 mm.
3. TESTING
3.1. For tests used a mandrel with a taper angle 30; 45; 60; 90; 120°.
Notes:
1. It is possible to use mandrels with taper angles of 6 and 12°.
2. It is possible to use mandrels with a cylindrical part (Fig.1). In this case, the diameter of the cylindrical part , in millimetres, calculated in the formula
Damn.1
3.2. The working surface of the mandrel shall have a hardness of HRC50, the parameters of surface roughness not lower than
=20 µm according to GOST 2789−73 and when tested shall be covered with grease.
3.3. When testing is not permitted rotational movement of the mandrel or of the sample.
The speed of introduction of the mandrel into the sample with differences in the quality assessment test should be 20−50 mm/min.
3.4. The test is carried out to smooth the distribution of the sample end of the mandrel with a predetermined taper angle to receive the end of the sample a specified outside diameter (Fig.2).
Damn.2
4. PROCESSING OF THE RESULTS
4.1. A sign that the sample has withstood the test, is the absence of it after the distribution by the specified amount of cracks or tears with a metallic luster, assessed visually.
4.2. Size distribution in percentage is calculated by the formula
Rounding of calculated values of distribution of produce to 0.5%.
5. TEST REPORT
The test report should indicate:
— material and size of pipe;
— the results obtained.
Sec. 5. (Added, Rev. N 1).
