Hydraulic test and flattening test for steel pipe

- Feb 28, 2018-

Hydraulic test and flattening test

GB / T13296-2002 standards for hydraulic test and flattening test of the relevant provisions
1, hydraulic test
Steel should be carried out by hydraulic test, the test pressure by type
(2) calculation. The maximum test pressure of 20 MPa, the test pressure, the stabilization time should not be less than 5 s, the pipe should not leak phenomenon.
P = 2SR / D
(2) Where: P-experimental pressure, in megapascals (MPa);
S-pipe nominal wall thickness, in millimeters (mm);
D-pipe nominal diameter, in millimeters (mm);
R - Allowable stress, in megapascals (MPa)
1). Ferritic steel pipe, as specified in Table 3, the non-proportional extension strength of 60% of the minimum, austenitic steel pipe, according to Table 3, the minimum non-proportional extension strength of 50%.

Eddy current testing can replace the hydraulic test.
Eddy current testing with artificial tube defects should be consistent with GB / T 773 acceptance level B requirements.
2, flattening test
Steel pipes with a wall thickness of not more than 10 mm shall be flattened, and cracks and rips shall not be allowed after the flattened sample.
The sample wall thickness H after crushing is calculated according to formula (3): H = (1 α) S / (α S / D)
(3) H-flattened outer wall distance, in millimeters (mm);
α-unit length deformation coefficient.
Austenitic steel pipe 0.09, ferritic steel pipe 0.08;
 S-pipe nominal wall thickness, in millimeters (mm);
D-pipe nominal diameter, in millimeters (mm) glenflange