Experimental Study of Laser Beam Welding Process Parameters on AISI 4130-309 Joint Strength

Abstract

Abstract Laser Beam Welding (LBW) is extensively being utilized in manufacturing processes to join dissimilar metals and alloy steels because its special advantages of controlled heating, Low Heat Affected Zone (HAZ) and smaller weld bead formation. However, it is viewed as a strange strategy with applications normally and constrained to welding of thick plates of metals. With a new generation of high power lasers, there has been a renewed interest in thick section LBW (also known as Keyhole Laser Welding (KLW)). KLW makes the process a possibility for industrial applications dealing with thick metals for welding in power plants, pipelines, offshore structures, shipbuilding. The advantages provided by such LBW, is suitable for joining at high process speed, low heat input, and to achieve high productivity, leading to significantly reduction in process costs. LBW of dissimilar metals such as alloy steel and stainless steel is still a challenging task, particularly due to the formation of martensitic formation in HAZ, brittle phases in the weld and solidification cracking in the fusion zone. Such issues can significantly deteriorate strength of the welded joint. Therefore, the aim of the present work is to examine the basic phenomena that happen inside the different weld zones and their impact on weld quality in the wake of LBW joints. Taguchi L25 is chosen and experiments are conducted with LBW considering 2 mm thick dissimilar metals, i.e. AISI 4130 and AISI 309 stainless steel by varying Laser Power, Welding Speed, Beam Angle, Focal Point Position and Focal Length. The experimental output results that are measured for the mechanical properties like Ultimate Tensile Strength and Impact Strength. The Analysis of Variance (ANOVA) is carried out to obtain the influence of the process parameters and statistical evolution of the results. Firefly optimization algorithm is used to determine the optimal combination of the process parameters of the LBW