Microstructure and Hardness of CMT Wire-Arc Additive Manufactured H13 Steel Formed Parts in Different Deposition Paths

H13 steel formed part was prepared by cold metal transfer wire-arc additive manufacturing in different deposition paths. Based on the thermo-elastic-plastic finite element method, the thermal history of the formed part was studied. The microstructure and hardness evolution of formed part was studied by tests. The results show that the thermal history of the 5-layer single-pass and single-layer 5-pass formed part deposited in the codirection and bidirection path was basically the same. The peak temperature of the middle point of the third layer of bidirection deposited 5-layer single-pass formed part was much higher than that of the middle point of the third pass of bidirection deposited single-layer 5-pass formed part, and the heat accumulation effect of the 5-layer single-pass formed part was more obvious. The lath martensite structure of 5-layer single-pass formed part was coarsened than that of single-layer 5-pass formed part. The hardness of the codirection deposited 5-layer single-pass formed part at the same height was slightly higher than that of bidirection deposited formed part, and the hardness of the codirection deposited and bidirection deposited 5-layer single-pass formed part was basically the same. The average hardness of the 5-layer single-pass formed part was slightly smaller than that of single-layer 5-pass formed part.