INCLUSION RATING BY STATISTICS OF EXTREME VALUES AND ITS APPLICATION TO FATIGUE-STRENGTH PREDICTION AND QUALITY-CONTROL OF MATERIALS

The inclusion rating method by statistics of extreme values (IRMSE) using square-root area of inclusions as the size parameter enables one to discriminate between current super-clean steels. Moreover, IRMSE enables one to predict the size (square-root area(max)) of maximum inclusions contained in domains larger than the inspection domain. The statistical distribution of square-root area(max) can be used for the quality control of materials and for the prediction of a scatter band of fatigue strength. Practical procedures of inclusion rating and prediction of a scatter band of fatigue strength are shown.