Effect of Residual Stresses on Fatigue Crack Growth Behavior of HT80 Steel Weldments Under Low Temperatures

Abstract

The influence of residual stresses on the fatigue crack growth behavior and fatigue fracture toughness of welded joints at temperatures ranging from room temperature down to 93 K was evaluated by fracture mechanics approach. At temperatures above 123K, the crack growth rates of the welds were dominated by residual stresses rather than temperatures. At temperatures below 123 K, the crack growth rates increased markedly because of the occurrence of cleavage. The crack growth rates of the welds were correlated with the effective stress intensity factor range estimated by superposition approach, when the mechanism of crack growth was dominated by striation formation The fatigue fracture toughness of the welds was also correlated with the Kmax which is taken into the residual stresses.