Extreme High-Speed DED of AISI M2 Steel for Coating Application and Additive Manufacturing

This work focuses on the development of the 3D Extreme High-Speed DED process (EHLA3D), a variant of the laser-based Directed Energy Deposition (DED-LB), for the processing of the material HSS M2. Characteristics for the EHLA3D process are feed rates of >20 m/min, high cooling rates, and layer thicknesses in the range of 100 µm. This work covers the three subsequent stages: (1) a process parameter study on single-track deposition, (2) development of coating parameters, and (3) development of parameters for AM. In scope of stage 2, a coating parameter with a powder mass flow of ṁ = 1.9 kg/h was achieved. A variation in the deposition angles indicates that the coating process is feasible within a tilted deviation of up to 20°. In stage 3, a process parameter with a deposition rate of ṁ = 0.4 kg/h was developed. The hardness results of the as-built specimen with 67 HRC exceeds the hardness of conventionally manufactured and heat-treated M2 steel. The results of this work indicate that the EHLA3D process can be potentially utilized for the additive manufacturing with the material M2 as well as for the productive deposition of anti-wear coatings on free-form surfaces.