A comprehensive study on laser welding of stainless steel 301LN in lap joint configuration

Abstract

Laser welding offers distinct advantages over traditional methods: less heat impact, no filler metal needed, and strong weld penetration. It is efficient and cost-effective, perfect for joining materials like the stainless steel 301LN, and ideal for industries addressing climate change. This study delves into the impact of various operating parameters on weld quality, specifically focusing on microstructure and microhardness. Using the Taguchi method, it is designed an experimental setup to systematically analyze these factors. The microstructure analysis shows a unique grain structure in the weld bead and a small heat-affected zone (HAZ), indicating precise welding control. Weld penetration measurements correlated with specific operating parameters using microstructure imaging. The microhardness analysis further underlined the control over HAZ thickness, crucial for ensuring the integrity of the welded joint. Through analysis of variance (ANOVA), it is identified significant factors affecting physical properties, help to construct a mathematical model to quantify parameter influences accurately. Findings suggest that minimizing the focal spot diameter is key to optimizing weld penetration, albeit in a delicate balance with welding speed and laser power settings. Adjusting these parameters can also influence the chemical composition match between the weld bead and base material, crucial for structural integrity. For achieving the desired hardness close to the base material, specific parameter ranges are recommended: a beam oscillation amplitude of 1.45 mm, a beam oscillation amplitude between 2.82 and 2.97 kW, and a focal spot diameter above 0.34 mm. Findings offer practical insights for improving weld quality and efficiency in industrial applications.