PREDICTION OF MICROSTRUCTURE AND PROPERTIES IN THE HEAT-AFFECTED ZONEOF HSLA-100 WELDMENTS

The objective of this study was to model the evolution of the microstr ucture and the resultant hardness in the heat affected zone (HAZ) of H SLA-100 steel weldments. The experimental HAZ results of Spanos et al. , where four different weld thermal cycles, with two peak temperatures (1400 and 900 degrees C) and two cooling rates (5 and 60 K s(-1)), we re emulated in a heating/quenching dilatometer, are compared with the results of three weld simulation models for the decomposition of auste nite. The three models are those of Kirkaldy and co-workers, Ion, East erling, and Ashby, and Bhadeshia and co-workers. All of the models req uire the chemical composition, a thermal profile, and an austenite gra in size measurement. All of the models gave excellent results for the fast cooling rates. Bhadeshia's model gave good results for one of the slower cooling rates, but not the other. Neither Kirkaldy's model nor that of Ion et al. was satisfactory for the slower cooling rate cases .