METHOD FOR DEFINITION OF THRESHOLD OF STRESSES OF CORROSION TORQUE TREATMENT OF STEEL OR ALLOY UNDER CONSTANT DEFORMATION Russian patent published in 2017 - IPC G01N17/04 

FIELD: metallurgy.

SUBSTANCE: invention relates to resistance studies against Stress corrosion cracking (SCC) of steels and alloys in corrosive environments under laboratory and industrial conditions and can be used to determine the stress thresholds of stresses of stress-corrosion cracking of steels and alloys in various corrosive environments. The creation of fixed stresses in steel or alloy samples before testing is carried out by the method of constant deformation. Essence: the stress threshold of corrosion cracking of steel or alloy is determined under constant deformation, including smooth loading of the samples, their reliable centring, ensuring a constant deformation during the entire test period, followed by an evaluation of corrosion resistance by visual inspection of samples. The stress threshold is estimated in laboratory and industrial conditions. In each of the samples, a predetermined constant deformation is created in the region of the stresses under study. In each test device, samples are placed that are loaded in equal parts from the yield point (0÷1,2)×σ_0,2. The duration of the test is up to cracking, with a total duration of at least 1000 hours. The stress threshold value of the stress corrosion cracking of the test material under laboratory or industrial conditions will correspond to the value of the stress in the first sample, which has no cracks and is located next to the samples undergone stress corrosion cracking.

EFFECT: obtaining a specific value of the stress corrosion cracking threshold for steels or alloys in equipment that will allow designing, manufacturing and operating equipment or pipelines in such a way that the actual stress values do not exceed the threshold stresses, thereby eliminating corrosion cracking of equipment and pipelines.

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