Investigation of CMT Welding AISI H13 Hot Work Tool Steel on Weld Bead Geometry, Microstructure, and Mechanical Performance.

The focus of this paper was on welding AISI H13 tool steel by the cold metal transfer method to investigate the effects of welding variables on weld bead geometry, microstructure, and mechanical performance. The variable sets consisted of welding voltages of 16–24 V and speeds of 0.25–1.25 mm/s. The weldments were smooth without weld seam defects due to low-voltage welding. The weld bead height was variably influenced by the welding process factors as the welding voltage increased and the welding speed remained constant. The bead height decreased with increasing voltage. Conversely, the dilution percentage increased as the voltage increased. While maintaining a low voltage, a higher bead width was formed. The optimized conditions were achieved at 18 V and 0.25 mm/s, with a bead height of 8.8 ± 0.1 mm, bead width of 17.5 ± 1.0 mm, and penetration depth of 3.59 ± 1.1 mm. However, the influences of the welding speed on microstructural changes were less significant than those of the welding voltage. The voltage had a minimal influence on the ferrite phase formation of the weld metal and heat-affected zones. The mechanical properties, such as the impact toughness of the welded seam, imparted the material with higher absorbed impact energy than the parent material. The impact toughness decreased with an increase in welding voltage. Moreover, the fusion zones of the weldments had lower hardness values than the heat-affected zones and base material. The chromium contents in the microstructure significantly affected the microstructure and microhardness characteristics of the weld metal and heat-affected zones. [ABSTRACT FROM AUTHOR]