| Abstract Scope |
Conventionally, tool steels are repaired by welding; however, that of repairing is expensive, time consuming, and does not guarantee homogeneous quality. Hence, this study focused on developing an alternative repairing technique using direct energy deposition (DED) to minimize thermal effects. To simulate a repair using DED, AISI H13 powder was deposited onto heat-treated JIS SKD61. The deposited material was observed through scanning electron microscopy and its hardness and tensile properties were determined at 25, 200, 400, 600, and 800℃. The deposited material showed different hardness distributions in its cross section, revealing four representative features. The deposited region and dilution showed a hardness of 620 Hv with a dendrite structure. The hardness decreased to 490 Hv in the heat-affected zone, revealing a tempered martensite structure; however, it increased to 550 Hv in the substrate, and revealed a typical martensite structure. At all temperatures, the deposited material showed higher hardness than heat-treated SKD61. Moreover, it showed higher ultimate tensile strength and lower elongation in deposited region. Therefore, this study indicated that without heat treatment, a part repaired using DED can have better mechanical properties than heat-treated SKD61. |