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Numerical Simulation of the Laser Welding of 2205 Duplex Stainless Steel
A. Ghosh, D. Misra and S.K. Acharyya

Laser beam welding has become one of the promising welding techniques in diverse industries, such as aerospace, automotive, microelectronics, shipbuilding, etc., due to its superior features; namely, ease of automation, thin and small weld seams, minimum distortion and high welding speed. In this work the laser welding process is investigated considering phase change for butt joint welding of 2205 Duplex stainless steel plates via process modelling by finite element method (FEM) and statistical techniques. The objective of the present research is to investigate the effects of process parameters such as laser power, scanning speed and beam diameter on evolution of thermal field and formation of weld bead geometry. A three-dimensional (3-D) FEM numerical model with moving heat source is developed using COMSOL MULTIPHYSICS 4.2a. Statistical techniques are used to develop a mathematical model based on simulation results to predict maximum temperature and weld bead dimensions, namely, depth of penetration and bead width. Second order equations are developed by response surface methodology (RSM) to predict the responses, with significant accuracy. Effects of parameters and their interactions on the responses are studied, using the developed RSM models. Simulated results show that the maximum temperature at weld zone, bead width and depth of penetration increases with laser power and decreases with scanning speed. It is also seen that with increase of beam diameter, maximum temperature at weld zone and depth of penetration decreases while bead width increases. A multi-objective optimization on depth of penetration and bead width is conducted according to the desired optimisation criteria.

Keywords: 2205 Duplex stainless steel, laser welding, butt joint, bead width, depth of penetration, finite element method (FEM), response surface methodology (RSM)

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