Optimization of Selective Laser Melting Process Parameters Via Taguchi's Methods and Gray Relational Analysis for 3D Printing of 18Ni-300 Maraging Steel

Taguchi methods and gray relational analysis are used to determine optimal processing conditions for the selective laser melting (SLM) of 18Ni-300 maraging steel. The following SLM process parameters are selected for optimization: laser power (P), scanning speed (v), and hatch spacing (h). Statistical analysis indicates that SLM parameter configuration no. 5 (275 W, 700 mm s(-1), 0.08 mm) as most suitable for the simultaneous improvement of tensile strength, elongation (or ductility), hardness, and impact toughness. The order of influence of SLM parameters is identified as follows: P approximate to v>h. Samples with improved mechanical properties can be produced using configurations with higher linear energy density (EL). This is because the increased laser energy input facilitates complete melting of metal powder, as well as better interlayer bonding between melt pools. Higher EL can be achieved by either increasing P or decreasing v. Digital image correlation analysis indicates that tensile test samples with higher porosity exhibit lower ductility due to its inability to accommodate plastic strain accumulation for prolonged durations. Fractography analysis indicates that during tensile loading, cracks will nucleate around the pore perimeter and propagate via microvoid coalescence. Fracture will occur at regions with higher porosity due to it having multiple crack initiation sites.

Automated summary

Taguchi methods and gray relational analysis were used to optimize the selective laser melting (SLM) process parameters for 18Ni-300 maraging steel. The optimal configuration (275 W, 700 mm/s, 0.08 mm) was identified, which resulted in improved tensile strength, elongation, hardness, and impact toughness. Increasing the linear energy density (EL) was found to be beneficial for producing samples with better mechanical properties.