Effect of prior heat treatment of base metal on the deformation behavior of heat affected zones

Abstract

Instrumented hardness tests on the different heat-affected zones (HAZs) present in weldments of modified 9Cr-1Mo steel, exhibit lower curvature of the loading line for the inter-critical HAZ (ICHAZ) compared to that for the other HAZs irrespective of the initial heat treatment given to the base metal. The curvature of the loading line for the ICHAZ for the weldment made from this material subjected to higher solutionising treatment temperature (1150°C/1h and 760°C/3h) is higher than that for the ICHAZ for the weldment made from material subjected to the conventional higher solutionising treatment temperature (1050-1070°C). The increase in the curvature of the loading line could be correlated to the increase in resistance against indentation of the material with increase in solutionising treatment temperature.