Effect of high-temperature welding on fatigue life of 2.25Cr1Mo steel joint

High-temperature welding of 1.25Cr0.5Mo steel at different temperatures (550℃, 650℃, 750℃ and 850℃) was carried out. Residual stress measurement and fatigue experiments were done after welding at room and high temperatures, respectively. The maximum longitudinal and transverse residual stresses in heat-affected zone of high-temperature welded specimens were significantly reduced, comparing to those at room temperature, the reduction rate for longitudinal and transverse residual stress was 50.1%, 48.9%, 74.8%, 67.4%, 83.9%, 79.4%, 91% and 89.7%, respectively. The average fatigue life was improved 31.02%, 38.84%, 47.23% and 62.28%, respectively. The results show that high- temperature welding can significantly reduce residual stress and improve the fatigue life of the welded joint.