Heated Band Width Criterion Based on Stress Relief in Local Post Weld Heat Treatment of Concurrent Tubular Joint(Mechanics, Strength & Structure Design)

概要

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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 3-D 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 conditions are quite similar. The different welding sequences have little influence on the location of the peak value of stress. The degree of welding stress relief in hot spots of tubular joints under different conditions of local PWHT has been analyzed. The residual stress is greatly reduced with increase of the heated band width in local PWHT. The relations between heated band width and stress of circumferential and axial components are quite different. The optimum heated band widths for circumferential and axial components are 3.46√<Rt> and 4.8√<Rt>. Based on the computed results for serial computations with varying the parameters in local PWHT, a criterion of heated band width is recommended for the local PWHT of concurrent tubular joint in.