文献类型：会议论文

英文题名：Study on creep-fatigue damage evaluation for advanced 9%-12% chromium steels under stress controlled cycling

作者：Zhao, Peng[1];Xuan, Fuzhen[1]

机构：[1]E China Univ Sci & Technol, Key Lab Safety Sci Pressurized Syst, Minist Educ, Sch Mech & Power Engn, Shanghai 200237, Peoples R China

会议论文集：7th China-Japan Bilateral Symposium on High Temperature Strength of Materials

会议日期：AUG 23-27, 2010

会议地点：Dalian, PEOPLES R CHINA

语种：英文

外文关键词：Creep-fatigue; Creep damage; 9%-12%Cr steels; Stress control; Time fraction rule

摘要：Creep-fatigue interaction is one of the main damage mechanisms in high temperature plants and their components. Assessment of creep-fatigue properties is of practical importance for design and operation of high temperature components. However, the standard evaluation techniques, i.e. time fraction rule and ductility exhaustion one have limitations in accounting for the effects of control mode on the cyclic deformations. It was found that conventional linear cumulative damage rule failed in accurately evaluating the creep-fatigue life under stress controlled condition. The calculated creep damages by time fraction rule were excessively high, which led to overly conservative prediction of failure lives. In the present study, it was suggested that such over estimation of creep damage was mainly caused by anelastic strain upon stress loading. For precise assessment under conditions of stress control, a modified creep damage model accounting for the effect of anelastic creep was proposed. The assessments of creep fatigue data under stress controlled condition were performed with the new approach developed in this paper for a rotor material and a boiler material used in ultra supercritical power plants. It was shown that a more moderate amount of creep damage was obtained by the new model, which gave better predictions of failure life.