Effect of Heat Input on HAZ Properties and Microstructure of SMA490BW Corrosion Resistance Steel

Abstract

Welding thermal cycle of SMA490BW corrosion resistance steel with different heat inputs were simulated by using Gleeble-3500 thermo-mechanical simulator to investigate the microstructure and impact toughness of the heat-affected zone (HAZ). The results shows that the microstructure of the coarse-grain heat affected zone(CGHAZ) is mainly composed of lath bainites and the surpass critical coarse-grain heat affected zone(SCCGHAZ) consists mainly of granular bainites with a small content of ferrites. The grain size increased with the heat input increasing, Besides, the impact energy of the surpass critical coarse-grain heat affected zone(SCCGHAZ) is higher than that of the coarse-grain heat affected zone(CGHAZ), when the heat input energy is 15kJ/cm after twice thermal cycle, the impact energy is highest.