Multi-criteria optimization of weld bead in pulsed Nd:YAG laser welding of stainless steel 316

Abstract

Laser welding is widely used for its advantages like deeper weld penetration, narrow heat affected zone, higher welding speeds and better weld quality with less damage to the workpiece compared to arc welding processes. The purpose of this paper is to determine the influence of major laser welding process parameters of beam pulse energy, travel speed and focal position on weld fusion zone geometry in stainless steel and optimizing these parameters to obtain maximum penetration and minimum weld width simultaneously. The experiments were planned according to Taguchi’s L16 orthogonal array. The grey-based Taguchi method was then employed to convert the multiple quality criteria into one single relational grade. Based on the calculated relational grade, Taguchi tools such as analysis of variance and signal-to-noise ratio were used to analyze and obtain the significant parameters and evaluate the optimum combination levels of the mentioned process parameters. Moreover, the effect of optimization procedure was studied on the microstructure and micro-hardness of the weldments. It was concluded that this optimization method can lead to elimination of chain ferrite precipitation and more uniform micro-hardness across the weld bead. The confirmation experiments verified that this method can effectively improve multiple performance characteristics and the results are reproducible in laser welding.

Characterization of Porous Scaffolds Fabricated by Joining Stacking Based Laser Micro-Spot Welding (JS-LMSW) for Tissue Engineering Applications

“…However, due to the recrystallization of the material and due to the melting at the spot weld, softening occurred in the HAZ and fusion zones presenting lower values of hardness than the base material. Solati et al [ 41 ] reported a reduction in the hardness results from the BM forward to the center of the FZ due to changes in microstructure in laser seam welds of AISI316L sheet of 0.6 mm of thickness. The microstructure observed in this study has also been observed in other stainless steels (i.e., AISI304, AISI316) seam welded by an Nd-YAG laser [ 42 ].…”

FEM-Based Simulative Study for Multi-Response Optimization of Powder Bed Fusion Process

“…The generic methodology adopted in Taguchi-based GRA is depicted in Figure 1. The detail of the process can be found elsewhere in the literature [28][29][30][31][32][33][34][35]. The selection of a suitable design matrix depends upon the number of factors, their levels, and the interaction of interest.…”

Applied Laser Forming: Shaping the Future of Rapid Prototyping

“…Therefore, the manufacturing system of the INTERLASE project covers a number of scientific domains, starting with, but not limited to, computer aided process planning (CAPP), process control, laser processing (cutting, welding, forming, and other laser processes), sequencing, and process monitoring. Looking at the core processes, both laser cutting and laser welding are established manufacturing processes with extensive research being conducted in process-related phenomena [29] [30], process optimization [31], scheduling, and integration [32] [28]. In contrast, laser forming is primarily receiving academic interest and is yet to be utilized in manufacturing.…”