METHOD OF INSPECTING STRESS CORROSION CRACKING RESISTANCE OF PIPE STEEL Russian patent published in 2014 - IPC G01N17/00 

FIELD: chemistry.

SUBSTANCE: method of inspecting stress corrosion cracking resistance of pipe steel comprises preparing cylindrically shaped samples, applying voltage and exposing said samples to the testing medium; wherein the samples are subjected to preliminary tensile deformation with stretch ratio of 1-10%; applying a load, the value of which is 50-80% of the yield point, and placing the samples into the testing medium with pH 2.5-5 for 180-360 hours; breaking down the samples on air by stretching on a breaking machine, and judging stress corrosion cracking resistance from the difference in mechanical properties of steel in the initial state and after testing; wherein stress corrosion cracking resistance is judged from the degree of change in plasticity, which is calculated using the formula: $$\xi =\frac{{\delta }_5^0-{\delta }_5^H}{{\delta }_5^0}\cdot 100\%,$$ where $${\delta }_5^0$$ is relative elongation in the initial state; $${\delta }_5^H$$ is relative elongation after testing, wherein steel for which the value ξ ranges from 0 to +10% is assigned class 1 resistance, steel for which the value ξ is greater than +10% or ranges from minus 10% to 0% is assigned class 2 resistance and steel for which the value ξ is minus 10% is assigned class 3 resistance.

EFFECT: high information value and reliability while shortening the duration of testing for stress corrosion cracking resistance, taking into account the susceptibility of steel to nonuniform plastic deformation, and enabling the classification of steel according to stress corrosion cracking resistance.

2 cl, 2 tbl