Characterization of the HAZ in ASTM A709 HPS-100W Steel

Avidipto Biswas ^a, Zhiyong Hu ^a, Carl Hybinette ^b, Philip Nash ^a

a) Thermal Processing Technology Center, Illinois Institute of Technology,10 West 32nd Street, Chicago, IL 60616

b) Union Tank Car Company, 175West Jackson Boulevard, Chicago, IL 60604

Abstract

HPS 100W is a new grade of bridge steel. In the present work an attempt has been made to characterize the weld heat affected zone (HAZ) microstructure of this steel. The material has been subjected to thermal profiles that simulate the HAZ and the resultant microstructures have been observed and mechanical properties determined. HAZ simulation was carried out in a GLEEBLE 3500 at different peak temperatures of 850^oC, 1100^oC, 1300^oC and heat inputs of 2 kJ/mm and 3 kJ/mm followed by different stress relieving operations. Subsequently, impact toughness data have been obtained at different temperatures by means of a Charpy test. The microstructure was observed using optical, scanning and transmission electron microscopy in order to correlate the structure-property relationship of the HAZ for HPS 100W steel. Microstructures of an actual submerged arc welded (SAW) weldment were correlated with the simulated microstructures utilizing an FEM model.