METHOD FOR ESTIMATING CREEP LIFE OF GAS TURBINE HIGH-TEMPERATURE PART

摘要

PROBLEM TO BE SOLVED: To estimate the creep life of gas turbine high-temperature parts whose operating temperature is unknown, with the average particle diameter of a deposit that can be measured after using for a certain period as an index. SOLUTION: An unused material of an alloy used for an actual machine is used, a creep test at various kinds of temperatures and stresses selected from a stress range applied to a turbine part is performed, and the average particle diameter of a deposit on creep rupture is measured, thus obtaining a constant. Then, a test is interrupted at various kinds of times, the average particle diameter and the deposit area rate of a test material and a creep distortion are measured at each interruption, and a constant is obtained. On the other hand, a deposit average diameter and an area rate are measured for a gas turbine high-temperature part that is used for a certain period and a deposit coarseness speed under usage conditions is calculated from an operation time, thus measuring the relationship between the operation time and the speed. Then, the change of a creep damage rate with time is estimated. The change of the creep distortion with time is estimated from the area rate and the average particle diameter of the part for a certain period. Time for reaching the creep damage rate is compared with time for reaching the creep distortion and the shorter time is used as a life.