High-temperature damage evaluation method for austenitic heat-resistant steel

摘要

PURPOSE:To evaluate the amount of defect of an austenite heat-resistance steel more quickly than and with an equal accuracy as with a breakdown test method. CONSTITUTION:The surface of machine parts is polished and etched for exposing the metal texture of an austenite heat-resistance steel and the exposed metal texture is observed by a replica method or by fitting a portable microscope to the position concerned directly. Then, the length in crystal grain boundary direction of a minute cavity generated at the crystal grain boundary in a constant area of the observed metal texture is measured, each measured value is added and then the sum of the length of the minute cavity generated in the constant area is divided by the constant area or the sum of the length of the crystal grain boundary in the constant area, thus obtaining a minute cavity line density and a minute cavity grain boundary rate. The measured value is fitted to the relation chart between the minute cavity line density or the minute cavity grain boundary rate which is previously obtained according to a laboratory test and a life consumption rate to obtain the life consumption rate of the heat-resistance steel.