Effect of chemical micro-heterogeneity on the susceptibility to local failure of the metal of the heat-affected zone of welded joints

Abstract

The mechanism of the effect of chemical and structural micro-heterogeneity on the susceptibility to local failure of the metal of the heat-affected zone of welded joints in 12Cr18Ni12Ti steel in the conditions of high-temperature low-frequency low cycle loading is substantiated theoretically and by experiments. The method is proposed for the evaluation of the probability of fluctuation formation of the regions of chemical micro-heterogeneity, taking into account the growth of austenite grains in welding and the effect of heat input.

Keywords:

• welded joints
• heat affected zone HAZ
• chemical micro-heterogeneity
• optical and electron microscopy
• low-frequency low-cycle load
• local destruction