Effect of the laser power on the geometrical features of SS316L additively manufactured by direct laser metal deposition

Abstract

Additive manufacturing is one of the most important and, of course, the most attractive technologies that has attracted the attention of industries and researchers in the last few decades. The direct laser metal deposition (DLMD) method is one of the additive manufacturing methods that can be used to produce metal parts with good dimensional accuracy and quality. In this research, the effect of laser power (i.e. 200, 230, and 260 watts) on the geometrical dimensions and microhardness of 316L single-track layers additively manufactured by the DLMD method was studied. In addition, the microstructure of the deposited layers was investigated. The height (H) and the maximum width of the deposited layer (Wmax), the width of the interface (Wint), penetration depth (D), and microhardness characteristics of the single-track layers were considered as output responses. The results showed that by increasing the laser power, the height, Wmax, Wint, and penetration depth of the single-track layers increased. At the maximum laser power (260 W), the maximum height and Wmax and Wint of the deposited layers were obtained at 830, 970, and 615 µm, respectively. The microhardness of the samples varied from 281 to 314 HV. Examination of the microstructure of the deposited layers showed solidification in columnar and equiaxed dendritic structures in all parts of the single-track layers, with the formation of secondary phases in the interdendritic regions.