Fatigue Crack Propagation Properties of Welded Joints at 300°C

Fatigue crack propagation properties of welded joints were investigated on steel plate for boilers and other pressure vessels. The fatigue crack propagation properties at 300°C became similar to those at room temperature when the thermal stress could be reduced down to -1 MPa by using center cracked type specimen with longitudinal slits and a specially designed furnace. The tensile residual stress was +152 MPa in the as-welded joint, and +12 MPa after PWHT. The fatigue threshold was about 2.7, 5.1 and 7.3 MN/m 3/2 for weld metal in the as-welded condition, after PWHT and the base metal, respectively.