Heated Band Width Criterion in Local Post Weld Heat Treatment of Three Dimensional Tubular Joint

A direct quantitative method has been proposed to assess the effectiveness of stress relief for tubular joint in local post weld heat treatment (PWHT).The three-dimensional welding residual stress and temperature fields in local PWHT are constructed. The characteristics of stress distribution in local PWHT for tubular joints have been studied using visco-elastic-plastic FEM. The welding stress distributions in single pass welding of different welding condition are quite similar.The different welding sequences don't have much influence on the location of the peak value stress. The degree of welding stress relief in hot spots of tubular joint under different condition of local PWHT has been analyzed. The residual stress is greatly lessened with increase of the heated band width in local PWHT.The relations between the heated band width and the stress of circumferential and axial components are quite different, the optimum heated band widths for circumferential and axial component are 3.46√Rt and 4.8√Rt. With computation of main processing parameters in local PWHT, a criterion of heated band width has been recommended for the concurrent tubular joint in lcoal PWHT.