Manual metal arc weld modelling: Part 3 Implementation of two-layer heat-affected zone refinement technique under shop floor conditions

Abstract

The two-layer technique for refining the heat-affected zone was developed to prevent the occurrence of the coarse–grained bainitic microstructure in the HAZs of Cr–Mo–V steels. This microstructure, because of its poor creep ductility, can lead to circumferential cracking during stress relief, as well as longer–term in–service cracking. In this paper the results of an analysis of multipass manual metal arc welding (presented in an accompanying paper), in which the conditions for achieving successful two–layer refinement were defined in terms of the heat input ratio of the two layers, are incorporated into a practical welding procedure designed to produce complete refinement of the HAZ. The procedure is presented in nomographic form for use by welders and welding engineers. The scheme has been used with success in welding trials under shop floor conditions.

MST/193c