| 摘要 |
PURPOSE:To provide a method in which an electric or a physical characteristic value of a metallic member used under a high temperature load condition is measured in a non-destructive manner, from the measurements a creep strain damage rate is found on a basis of a relation with the characteristic value, and the member's life is estimated based on a relation between the creep strain damage rate and a creep time damage rate. CONSTITUTION:In a no-load heating test of an unused material such as Cr-Mo-V steels, a relation between hardness and a heating condition parameter P[=T (20+logt)X10<-3>, where T is heating temperature degree R(= degree F + 460), and t is heating time (h)]is shown by a single curve, and a hardness HVN in case a heating takes place for a long period of time under no-load is found by providing a working temperature and a time. In a sample varying a creep damage, a hardness HVN is measured and if a difference DELTAHVC between the hardness HVC and the hardness HVN at a like temperature and time is found, a relation between a creep damage phiCS and the difference is about linear. A hardness HVC1 of a member used at high temperature is then measured, a working condition parameter P1 is computed, from a DELTAHV1 a creep strain damage rate phiCS1 by a strain damage rule is found, from the phiCS1 a creep time damage rate phiCL1 is determined, and a residual life is found by a formula of t2=t1(1/phiCL1-1). |
