Thermal cycles and its effect on HAZ microstructure and mechanical properties of 10CrNi3MoV steel in double-sided double arc welding

Abstract

Thermal cycles of heat-affected zones (HAZs) in double-sided double arc welding (DSDAW) were measured in this study. The microstructure and impact toughness of specimens imposing typical thermal cycles of coarse-grained heat-affected zone (CGHAZ) were analysed by using thermal simulation. The results show that the two arcs influenced each other even during the deposition of the fourth layer in each side. Both of the two arcs could reduce the cooling rate of HAZs. Besides, the heating of the rear arc may make HAZ sustain in bainite transformation interval for a long time and lead to the formation of granular bainite which could deteriorate welding joint. To obtain good toughness of joint by DSDAW, the arc distance during filling pass depositing should be properly enlarged to eliminate granular baintie under the premise that the trough temperature (T t) is higher than 200 °C.