微小分布き裂の極値統計解析によるSUS316L鋼のクリープ寿命推定

抄録

The purpose of this study is to develop the creep life prediction method based on the extreme value analysis of maximum surface lengths of multiple-site small surface cracks found in high-temperature creep of an austenitic stainless steel SUS316L. Creep interruption tests of the steel were conducted at 873K and 948K in air in order to measure the positions and the surface lengths of multiple-site cracks by using scanning laser microscope. The optimum area for the determination of the density and the surface length distributions of the cracks observed. The area is the smallest area that can draw the inference for the statistical distributions of all the cracks found on the surfaces of the specimens. The maximum surface crack length distributions were inferred and the return periods were obtained for the prediction of creep lives. The result showed that the predicted creep lives agreed well with the experimental creep lives for all the tests performed.