Finite Element Simulation for Thermo-Mechanical Transient Behavior of Mild Steel Plate Agglutinated by Gas Tungsten Arc Welding (GTAW) Technique

Abstract

Finite element approach was employed in this study to simulate the thermo-mechanical transient behavior of mild steel plate agglutinated by gas tungsten arc welding (GTAW) technique. This was achieved through computational modelling and experimental technique. It was observed that most of the heat transfer occurred around the fusion zone via conduction. However, not all of the 100% heat was transferred to the weld pool due to heat losses taking place during heat transfer. The strength of the weld deposit increased with lower heat inputs, although this also varied greatly as a result of the variable welding inputs employed in the welding sequence. Therefore, applying lower heat input can improve the tensile yielding effect of the material. It was observed that each finite element profile model had a region characterized by minimum and maximum welding temperature and yield strength which revealed that maximum temperature and maximum yield strength (tensile) value both occurred around the welded region or fusion zone, indicating that the fusion zone is stronger than the parent metal. Yield strength of the AISI 1018 mild steel plate before welding operation was obtained as 370MPa, which is quite lower than that obtained after welding. The study also revealed the correlation between FEM modelled and experimentally determined output parameters, as maximum FEM and experimental yield strength values of 478.724 and 470.713MPa were produced by welding temperature of 1391 and 1406oC. The findings revealed that FEM is an effective tool that can adequately model and simulate the thermo-mechanically related material thermal cycle and yield strength.