IMPROVED METHOD FOR CYCLIC TESTING OF FULL-THICKNESS SAMPLES OF MAIN PIPELINES FOR STRESS CORROSION CRACKING Russian patent published in 2024 - IPC G01N17/00 

FIELD: corrosion tests.

SUBSTANCE: methods for testing pipe steels for susceptibility to stress corrosion cracking (SCC). The method of cyclic testing of full-thickness samples of pipes of main gas pipelines for stress corrosion cracking (SCC) includes taking samples from pipes in the annular direction from the base metal and weld with and without corrosion cracks. An artificial defect in the form of a notch is applied to some samples without defects and a crack is grown from it before testing begins. Samples are tested in air, in a background corrosive environment, with the addition of activators, without SCC inhibitors and in their presence. Testing of samples is carried out according to a four-point bending scheme, applying a cyclic force from the concave side of the sample. Cyclic loading of samples is carried out in successive blocks of cycles, the number of cycles in which increases as the value of the voltage asymmetry coefficient increases.

EFFECT: increasing the accuracy and reliability of predicting the resistance of low-carbon, low-alloy pipe steels to stress corrosion cracking.

6 cl, 1 dwg, 1 tbl