Creep Stress Relaxation and Crack Incubation in the Presence of Structural Elastic Follow-Up

This paper explores the behavior of steel components operating at high temperature subjected to combinations of applied and residual stresses. Two series of experiments are summarized that used Type 316H stainless steel samples tested at 550 °C. First, creep stress relaxation under displacement control with elastic follow-up is explored. Experimental results are compared with theoretical predictions and show that accounting for stress history during relaxation is necessary. A second set of experiments explores how combinations of applied and residual stress influence creep crack incubation, again with elastic follow-up. Incubation times with elastic follow-up close to conventional displacement control are longer than constant load.