Study on microstructure, mechanical properties and machinability of efficiently additive manufactured AISI 316L stainless steel by high-power direct laser deposition

High-power direct laser deposition (HP DLD) was utilized to fast generate AISI 316L stainless steel parts with large size and excellent mechanical properties. In order to efficiently manufacture the stainless steel parts with high surface quality and dimensional accuracy, a dry milling finish was applied. During the DLD process, heat retaining powder was employed to prevent buckling deformation. The effect of building direction on the microstructure, mechanical properties and machinability of the stainless steel was investigated. It was found that the microstructure was homogeneous, at the building direction of 0 degrees, while a number of larger dendritic grains were present in the microstructure, at the building direction of 90 degrees. The tensile properties and hardness values at the building direction of 0 degrees were higher than those at the building direction of 90 degrees. For both building directions, the decrement in surface roughness and the increment in cutting force and tool wear, were observed with the increase in cutting speed. The cutting force, tool wear and surface roughness of the additive manufactured stainless steel at the building direction of 0 degrees were relatively higher, which implies that the anisotropy in the machinability could be utilized to increase efficiency and reduce production cost. (C) 2016 Elsevier B.V. All rights reserved.