The microhardness and internal stresses allocation in superheating pipes welded node made of dissimilar steels

Abstract

The object of research is the welded knot made of dissimilar steels 12Cr1MoV and Di-59. Research methods are spectral analysis, microhardness measurements and X-ray analysis. It is established that the structural-phase nonuniformity, significant concentration fluctuations of alloying elements, the spread in values of microhardness and mechanical characteristics along the length of the pipe can cause significant value of internal macrostress that leads to the formation of the “flaw” defect type in the welding process. It is shown how to distinguish between flaws that have appeared on the stage of production from operating flaws.