TEST METHOD OF METALS FOR UNCONVERTIBLE DAMAGE Russian patent published in 2013 - IPC G01N19/08 

FIELD: test equipment.

SUBSTANCE: specimen is cut out of the tested metal and heat treated; a series of basic specimens is cut out of the heat treated specimen; the above specimens are tested for impact strength; the obtained values of impact strength are processed by means of a least squares method so that an average value of impact strength, which is accepted as a basic one, is obtained. Another series of specimens is cut out of the tested metal sheet for performance of fatigue tests; with that, the first specimen from that series is tested till destruction; the second specimen is loaded during the number of cycles, which are equal to the half of the number of cycles till destruction of the first specimen; the first specimen and the following specimens from the same series are loaded, thus changing the number of loading cycles from specimen to specimen. Each specimen, except the first one, are heat treated after loading in the modes, which were used when obtaining basic value of impact strength; after that, out of each of them along the direction of the applied load there cut are series of specimens with the sizes similar to the sizes of basis specimens for impact strength test. Impact strength tests of the obtained specimens are performed; obtained values of impact strength are processed using the least squares method so that an average value of impact strength is obtained for each of the series. The obtained average values of impact strength are analysed by comparing them to the basic one, and the range of the number of metal loading cycles is determined, in which fall of impact strength values of heat treated specimens is started, which characterises the moment of formation of microcracks in metal.

EFFECT: possibility of receiving the data not only on total durability of metal at certain loading parameters, but also on the moment of formation of unconvertible damages in metal.

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