Effect of the Laser Power on the Geometrical Features of 316L Stainless Steel Additively Manufactured by Direct Laser Metal Deposition (DLMD)
O. Mehrabi, S.M.H. Seyedkashi and M. Moradi
Additive manufacturing (AM) 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 AM methods that can be used to produce metal parts with good dimensional accuracy and quality. In this research the effect of laser power on the geometrical dimensions and microhardness of 316L stainless teel single-track layers additively manufactured by the DLMD method onto a 4130 steel substrate was studied. In addition, the microstructure of the 316L stainless steel DLMD layers was investigated. The height and the maximum width of the 316L stainless steel DLMD layer, the width of the interface, penetration depth, and microhardness characteristics of the 316L stainless DLMD single-track layers were considered as output responses. The results showed that by increasing the laser power, the height, maximum width of the 316L stainless steel DLMD layer, width of the interface, and penetration depth of the 316L stainless DLMD single-track layers increased. At the maximum laser power of 260 W the maximum height and maximum width of the 316L stainless steel DLMD layer and width of the interface of the 316L stainless steel DLMD 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 316L stainless steel DLMD 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.
Keywords: Fibre laser, 316L stainless steel, 4130 steel, powder, additive manufacturing (AM), direct laser metal deposition (DLMD), laser power, geometrical features, microstructure, microhardness