Study on Local Thermal Stress Distribution in Welded Pipe Joint of Dissimilar Materials

Abstract

This paper deals with thermal stress distribution analysed by the finite element method, in welded pipe joints of fcrritic steel and austenitic stainless steel, taking into consideration of the effect of difference in the expansion coefficicnts (500℃). The results are summarized as follows. (1) Stress distribution of the weld interface depends upon the bevel angle of the joint. For example, σ_0=35 kg/mm^2 is found in the ferritic side of I-butt joint, but σ_0 (outer surface)=23.8kg/mm^2, σ_0 (inner surface)=47.1 kg/mm^2 in the case of 45° レ joint. On the while, in any case, the normal and shear stress to the weld interface are comparatively small. (2) Distribution of the axial stress σ_z on the outer surface close to the fusion line is quite different from that calculated by Mather's method. And considerably high maximum value of σ_z is induced in this region,