Direct laser deposition with different types of 316L steel particle: A comparative study of final part properties

Abstract

This article investigates the role that particle size and morphology have in determining the final characteristics of a part produced by direct laser deposition. 316L stainless steel in the form of traditional gas-atomised powder and metal shavings in two size ranges were deposited into multiple-layer thin-walled parts at different process parameters. The walls were characterised, considering properties such as geometry, microstructure, composition, physical and corrosive properties and results matched to the type of build material. Results showed that using particles of >150 µm, equivalent spherical diameter offered few functional advantages, leading to a process with lower deposition efficiency and part with lower mechanical properties. Using machined shavings increases deposition efficiency and can reduce gas porosity compared with powder in the same size range, but also results in higher surface oxidation, thought to be due to higher oxidation on the original shavings. This is a barrier for some applications, but the deposition of machined shavings offers significant economic advantages.