Failure behavior of heat-affected zones within HSLA-100 and HY-100 steel weldments

The deformation and fracture behavior of simulated heat-affected zones (HAZ ) within HSLA-100 and HY-100 steel weldments has been studied as a function of stress state using notched and unnotched axisymmetric tensile specimens . For the case of the HSLA-100 steel, the results for fine-grained, as well as coarse-grain HAZ (CGHAZ) material, show that, despite large differences in the deformation behavior when compared to base plate or weld metal, the failure strains are only weakly dependent on the thermal history or micros tructure. Ductile microvoid fracture dominates the failure of the HSLA-100 steel with small losses of ductility occurring in the HAZ conditions only a t high stress triaxialities. In contrast, the HY-100 steel is susceptible t o a large loss of ductility over all of the stress states when subjected to a severe, single-pass simulation of a CGHAZ The ductility loss is greatest at the high stress triaxiality ratio in which case failure initiation occu rs by a combination of localized cleavage and ductile microvoid fracture.