Achieving high hardness and wear resistance in phase transition reinforced DC53 die steel by laser additive manufacturing

Additive manufacturing (AM) becomes a potential way to prepare molds, since it provides an effective option to produce parts with complex geometries in fewer steps. Among the mold steel materials, DC53 is considered as a superior steel grade by die and mold making industries due to its high hardness and wear resistance. However, the fabrication of spherical DC53 powder and its AM processing feasibility has not yet been reported. In the present work, spherical DC53 powder and its AMed parts were prepared by plasma rotating electrode process (PREP) and laser-directed energy deposition (LDED), respectively. The feasibility of DC53 powder for LDED preparation and the mechanical properties of laser directed energy deposited (LDEDed) parts were investigated. It is found that the spherical DC53 powder prepared by PREP is well suited for LDED. The kinetic effects during PREP change the phase composition of DC53 powder (transformation from pearlite to austenite). Compared to commercially available DC53 (cast DC53 after heat treatment), the LDEDed part exhibits comparable relative density. Normally, the main phase in commercially available DC53 is pearlite. Since the LDED process is still a rapid prototyping process, the main phase in LDED parts is the same as that in the powder, which is gamma-Fe. Interestingly, the phase transformation induced by kinetic effects could increase the hardness and wear resis-tance of DC53 effectively (the hardness has increased by 28.2 % and the wear rate has reduced by 47 %.), which is of great significance for the fast and efficient preparation of high performance molds.