Enhanced red hardness through fine carbides in M2 high-speed steel fabricated via electron beam powder bed fusion

M2 high-speed steel (HSS) is a crucial raw material for the manufacturing of high-performance precision cutting tools. Additive manufacturing technology, such as electron beam powder bed fusion (EB-PBF), enables the short-flow and high-efficiency fabrication of tools with complex structures, presenting promising development prospects. This study investigated the microstructural evolution and hardness variation of EB-PBF fabricated M2 HSS under simulated tool service conditions (500–600 °C, 1–3 cycles, 1 h per cycle). After service, the grain structure of the samples was further refined from 2.67 μm to 1.27–1.49 μm, accompanied by intensified precipitation of intracrystalline fine carbides, while the hardness remained between 61 and 66.1 HRC. Compared to the wrought bulk counterpart (quenched and tempered), the material exhibits a maximum improvement of 14 % in red hardness and 10.5 % in wear resistance.