Microstructure and Mechanical Properties of Cold Metal Transfer Wire-Arc Additive Manufactured H13 Steel Block

H13 steel blocks with a 5-layer and 15-pass structure were prepared by robotic cold metal transfer wire-arc additive manufacturing technique. The surface quality, microstructure and mechanical properties of the deposited block were investigated. The results show that there was no macro-crack on the surface of H13 steel block. The structure of the body-zone of the block was acicular martensite with uniform grain orientation, and the structure of the lap-zone was composed of acicular martensite with irregular grain orientation and irregular ferrite. The average micro-hardness of the body-zone of the block was 479 HV, which was much higher than that of annealed H13 steel (254 HV), while the hardness of the lap-zone significantly decreased due to the presence of ferrite, with the average value of 381 HV. The overall tensile properties of the cold metal transfer wire-arc additive manufactured H13 steel block were better than those of annealed H13 steel.