DETERMINATION OF CRITICAL BRITTLENESS TEMPERATURE OF METALS AND ALLOYS Russian patent published in 2014 - IPC G01N3/18 

FIELD: metallurgy.

SUBSTANCE: specimens are selected from macro sample of one of elements of the set of oil-and-gas equipment. Every specimen is subjected to blistering by stretching to one of residual strain of 0, 10, 20, 30 and 40%. Then, test specimens are cut from every specimen of macro samples to measure their hardness at every test temperature -60, -40, -20, 0, 10, 20°C. Now, for every residual strain and every test temperature, specimens are subjected to percussive bending. Dependence of resilience on hardness for every test temperature. Critical brittleness temperature is defined as the point the curve of resilience dependence on temperature with standard resilience for metal of said group of single-type of oil-and-gas equipment. Dependence of resilience on hardness is described by the formula KCV=A e^B*H, where A and B are experimental factors for every metal and test temperature, H is Brinell hardness.

EFFECT: higher accuracy and reliability of results, lower labour input at determination.

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