ANALYSIS OF THERMAL STRESSES AT DISSIMILAR METAL PIPE WELDS

Due to the differences in the coefficients of thermal expansion between stainless steel and carbon steel, under the same change in temperature, stainless steel will expand 25-32% more than carbon steel. When these dissimilar metals are welded together and used in high temperature environments, both the interface between the pipes and the pipes themselves experience thermal stresses. A piping system analysis based on beam-type elements does not calculate all these additional thermal stresses. In this paper, an elastic, linear, finiteelement analysis, using isoparametric quadrilateral elements, attempts to quantify these thermal stresses at buttwelded joints of dissimilar metals by considering an example of a stainless steel pipe welded to a carbon steel pipe.