Effect of SiC Addition on Microhardness and Relative Density during Selective Laser Melting of 316L Stainless Steel

Abstract

The utilization of 316L stainless steel has been very common in marine, automotive, architectural, and biomedical applications due to its adequate corrosion resistance to cracks after the completion of welding process. However, there has been ongoing attempts to investigate the potential enhancement in the strength and durability of 316L stainless steel by reinforcing it with silicon carbide (SiC). The present work adopts the selective laser melting (SLM) technique to fabricate SiC-reinforced 316L steel to boost its microhardness and strength properties. The methodology involved the addition of 1% wt. silicon carbide with particle sizes <40 μm to reinforce the stainless steel matrix. An SLM metal printing machine equipped with a continuous wave of 300 W fiber laser is employed to form the specimens. To measure the properties of the final product, EDX, XRD, FESEM, and universal tensile test machines have been used. The maximum value of 296 HV was obtained for a 1% volume of SiC compared to the 285 HV microhardness of pure stainless steel 316L. FESEM examination showed that the SiC microparticles were dissolved completely and they were randomly distributed in the melting basin. The samples were dissolved entirely, and the best porosity was obtained at 0.4% with influential parameters of 200 W laser power, 70 µm hatching distance, 30 µm layer thickness, and 700 mm/s velocities. The results also revealed that the microhardness at these parameters is the best compared to the samples produced with different values. The volumetric energy density was also considered. The findings can be informative to the researchers and manufacturers interested in 316L steel industry.