Fatigue life optimization for 17-4Ph steel produced by selective laser melting

Abstract

Purpose The mechanical characterization of selective laser melting (SLM) parts is an industrial challenge. This paper aims to propose a methodology to control the fatigue life of 17-4Ph stainless steel by selecting the most relevant manufacturing parameters: i.e. laser power, laser travel speed, hatch spacing and laser defocusing. Design/methodology/approach A rough and refined design of experiment (DOE) is carried out to target the best combination of process parameters. A response surface model is then constructed to predict the parameter combination that optimizes the fatigue performance. Findings This study results show that the fatigue limit of the specimens manufactured by SLM (471.7 MPa at 107 cycles) has reached near 90% of the value found in samples machined from a bar. This demonstrates the applicability of the method proposed to optimize the SLM process and control the fatigue life of 17-4Ph stainless steel. The study results are compared with other research works and provide an increase of 18% to the fatigue limit. Originality/value This study showcases a DOE methodology to optimize the SLM parameters to achieve fatigue performance as great as that of solid 17-4Ph stainless steel.