Influence of particle size and powder morphology on the process efficiency of laser cladding of 316L stainless steel

Abstract

The atomization process (gas vs. water) largely influences the shape and particle size distribution of the produced 316L powder. The goal of this study is to investigate how the atomization process, particle size distribution, and powder morphology affect the efficiency of the laser cladding of 316L. For this purpose, 316L laser cladding experiments were performed using three different commercial 316L powder feedstocks: (i) gas-atomized in the range 20–53 µm, (ii) gas-atomized in the range of 45–125 µm, and (iii) water-atomized with a maximum size of 250 µm. This paper presents the analysis of the chemical composition, morphology, and particle size distribution of the three feedstocks produced by both atomization methods. To assess the process efficiency of the laser cladding process, rectangular prisms of approximate size 50 mm x 40 mm x 10 mm were manufactured with the three powder feedstock. The efficiency was measured by weighing the substrate before and after manufacturing the prism, obtaining efficiency averages above 90% in all cases. Cross sections of the manufactured prisms were extracted to analyze their geometry, metallographic quality, and microstructure, showing compositional differences depending on the atomization process used (gas and water). Analyses measure a higher content of oxides in the prisms made from the water atomized powder. The results of the experiments demonstrate that (i) both water- and gas-atomized powders result in the efficient production of high-quality 316L parts using laser cladding, and (ii) the oxide content and composition are strongly influenced by the oxides inherited from the powder manufacturing method.