Structure and hardness of O.5Cr– Mo–V and 2Cr–Mo simulated heat–affected zones

Abstract

A heat-affected zone (HAZ) thermal simulation technique has been used to produce coarse-grained bainite and fine-grained ferrite-bainite microstructures similar to those obtained in the heat-affected zones of single and multipass commercial welds in 0.5Cr-Mo-V and 2Cr-Mo materials. The effects on the HAZ grain size, hardness, and carbide distribution of various single and double weld thermal cycle combinations relevant to welding practice have been examined. The metallurgical phenomena which occur during a weld thermal cycle are described and related to the as-welded HAZ hardness to provide a detailed picture of the component microstructures in 0.5Cr-Mo-V and 2Cr-Mo heat-affected zones.