Improvement of build speed and quality of h13 tool steel processed by laser-beam powder bed fusion with a high-power laser

Abstract

Laser-Beam Powder Bed Fusion (PBF-LB), which is a type of AM technology, offers the advantage of fabricating complex shapes such as dies with conformal cooling channels. Recently, due to the optimization of process parameters, it has become possible to manufacture H13 tool steel products without cracks. On the other hand, in light of the fact that PBF-LB is time-consuming, there is a demand to improve building speed in order to increase productivity. In this research, to achieve high-speed PBF-LB process of alloy tool steel, the microstructures of specimens via PBF-LB using high power laser were evaluated and the possibility of achieving PBF-LB with high speed and high quality was studied. As a result, the optimum fabrication condition of high-speed PBF-LB using 1 kW multi-mode fiber laser was elucidated by studying a process map between laser power and scan speed on relative density. In addition, tempered specimens processed by the high-speed PBF-LB have achieved microstructures and mechanical properties equivalent to those processed by conventional PBF-LB.