Property evaluation of 304L stainless steel fabricated by selective laser melting

Abstract

PurposeAdditive manufacturing raw material cost has been recently confirmed as a significant obstacle to widespread deployment of these technologies in industry. Aiming at reducing the cost of the selective laser melting (SLM) process, the purpose of this paper is to evaluate the different properties of products fabricated by SLM using low‐cost ($10/Kg) feedstock 304L stainless steel powders. The entire process cost was also evaluated.Design/methodology/approachUsing an experimental approach, 24 samples with different shapes and sizes were fabricated with layer thickness of 30, 50 and 70 μm and laser scanning speed set at 70 and 90 mm/s. Part geometry, dimensional tolerance, surface quality, density, mechanical properties and microstructure were evaluated.FindingsResults confirmed that the SLM of low‐cost 304L powder was successful and could produce functional parts with fine details and small wall thickness. Using small layer thickness and low scanning speed improved the properties by more than 20 per cent. At a layer thickness of 30 μm and speed of 70 mm/s, density was 92 per cent and hardness was 190 HV. At layer thickness of 70 μm porosity increases and cracks started to form which decreased strength and ductility. The steel remained austenitic with no carbide films at grain boundaries due to the high melting and cooling cycles.Research limitations/implicationsThis research was limited to 304L powders. Future work should be done on different materials and should include the effect of post processing heat treatment on improving the mechanical properties and microstructure.Practical implicationsThe cost of the SLM process using feedstock powders was less than 10per cent of the cost of using the special powders from a machine manufacturer with almost no effect on product quality.Originality/valueThe paper describes how cost reduction in the SLM process was achieved by using 304L powder.