PREDICTION METHOD OF LARGEST INCLUSION DIAMETER IN STEEL PRODUCT, AND ESTIMATION METHOD OF ROLLING FATIGUE LIFE OF STEEL PRODUCT

摘要

PROBLEM TO BE SOLVED: To provide a method for predicting the largest diameter of an inclusion highly accurately in a short time, which is useful for estimating a rolling fatigue life of a steel product.;SOLUTION: A plurality of ultrasonic fatigue test pieces are collected from a steel product which is a prediction object, and an ultrasonic fatigue test is performed by using the ultrasonic fatigue test pieces, to thereby cause fatigue fracture, and a fracture surface after being fractured is observed, and 8-13 fatigue fracture samples wherein an inclusion works as a starting point of fracture respectively are obtained. As for the obtained 8-13 fatigue fracture samples, the diameter of each inclusion working as a starting point of fracture is measured, and diameters of each inclusion is subjected to extreme value statistics, to thereby predict the largest inclusion diameter equivalent to a risk volume in a thrust rolling fatigue test of the steel product.;COPYRIGHT: (C)2010,JPO&INPIT