Modeling and Numerical Simulation of Thermal Cycles During GTAW Welding
7 Pages Posted: 20 May 2019 Last revised: 31 May 2019
Date Written: April 1, 2019
During the welding operations, the heat flux transferred to the welded parts by the electric arc leads to significant increases in temperatures. At each point in the part, the maximum temperatures reached, vary according to the position of this point relative to the heat source. Knowledge of the exact distribution of temperatures is essential in order to predict the extent and thus the mechanical behavior of heat affected zone. The present work concerns the numerical simulation of the heat transfer phenomenon during Gas Tungsten Arc Welding process (GTAW). Two cases were taken into consideration, the autogenous welding of 304L stainless steel and the heterogeneous welding of the same grade with plain carbon steel. The heat source of the GTAW is modeled by a Gaussian surface source of bi-elliptic form (source of Goldak). The model is implemented under Matlab software. The results obtained with the model were compared and compared, both with numerical simulations with the Comsol computational code and the experiment. For this purpose, an experimental bench has been designed and realized. The experimental device makes ensure to measure the temperatures at eight points located on the welding line and at different distances from this line. The results showed that the implemented model gave a distribution in good agreement with that obtained with Comsol simulation. Nevertheless, the experimental measurements show considerable variations and variations with those of the model. This is probably due to errors related to the positioning of thermocouples. However, the simplifying hypotheses considered in modeling and simulation does not accurately represent phenomena that are always complex and difficult to reproduce numerically.
Keywords: Thermal Cycles, Gas Tungsten Arc Welding (GTAW), Austenitic Stainless Steel
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