Remaining-Life Estimation for High-Temperature Materials Under Creep Load by Replicas

Abstract

The remaining-life estimation of components is acquired in three steps:

1. Calculation of the life consumption indicates where tests on exposed material should be carried out.

2. Tests on exposed material are carried out on most exposed parts to evaluate the real creep degradation of the exposed material.

3. Continued operation is based on the results of the precalculation and the creep degradation of the material. At the next inspection the material tests will indicate whether a prolonged safe operation is possible.

Material tests for remaining-life estimation are based mainly on replicas by which the creep life can be evaluated more quickly, more easily, and at lower cost than by any other method, presuming that the creep degradation starts from the outer surface of the parts. Replicas are then most effective in the time-to-failure estimation of parts, although they allow a high life exhaustion. After 6 yr of experience, not even unscheduled repair has been necessary for inspected parts.