Assessment and Test of the Creep-Fatigue Crack Behavior for a High Temperature Component

Abstract

Creep-fatigue crack behavior has been investigated for a welded component with 316L stainless steel and Mod. 9Cr–1Mo steel through assessment and test. The evaluation of creep-fatigue crack initiation and propagation was carried out for 316L stainless steel according to the French RCC-MR A16 guide, and the evaluation of creep-fatigue crack initiation for a Mod.9Cr–1Mo steel specimen was carried out with an extended A16 method. A test for a structural specimen with a diameter of 500 mm, height of 440 mm, and thickness of 6.3 mm was performed to compare its results with that by an assessment according to the A16 guide. The specimen was subjected to creep-fatigue loads with 2 h of dwell time at 600°C and various primary loads. The creep-fatigue crack behaviors for the two materials were assessed, observed, and compared. The results showed that the A16 guide for the austenitic stainless steel was fairly conservative for the assessment of creep-fatigue crack initiation while it was reasonably conservative for creep-fatigue crack growth for the present specimen.