Effect of Pre- and Post-Weld Quenching and Tempering on Tempering Stability and Hot Melting Loss Resistance of Surfacing Layer of SDDVA Steel

SDDVA steel was treated by tungsten argon arc surfacing and quenching and tempering. The effect of pre- and post-weld quenching and tempering on tempering stability and hot melting loss resistance of the surfacing layer was studied. The results show that the microstructure of the surfacing layer was tempered martensite under two processes. There were more dispersed carbides precipitated from the surfacing layer under post-weld quenching and tempering process, and the microstructure was smaller; the martensite structure was more stable. The hardness reduction of the surfacing layer under post-weld quenching and tempering process after tempering at 600℃ for 48 h was only 10.2%, which was less than 30.4% of the surfacing layer under pre-weld quenching and tempering process. In the molten aluminum melting loss test at 700℃, the melting loss mass loss of the surfacing layer under pre-weld quenching and tempering process was greater than that under the post-weld quenching and tempering process, the thickness of the interface layer was larger, and the reaction between the surfacing layer and liquid aluminum was more severe. The surfacing layer under post-weld quenching and tempering process had better tempering stability and hot melting loss resistance.