Theoretical Thermal Model of MIG Welding of FSS (AISI 430) Using ANSYS and its Experimental Verification

Metallurgical and mechanical properties of a weldment depend on its cooling rate and temperature distribution during welding. Temperature distribution and cooling rate are responsible for formation of different microstructures and different size of grain in different zones. If cooling rate and temperature distribution can be predicted in advance it will help the design engineer at the design stage itself to design a good welded joint. Determination of cooling rate and temperature distribution in welding experimentally is very costly and time taking. In this work the cooling rate and temperature distribution was theoretically predicted using ANSYS14 and experimentally verified. For the theoretical thermal analysis, 3D modeling of thermal simulation of arc welding (MIG) process was done by using ANSYS14. The special feature of the analysis is the use of a fast iterative procedure during a single pass welding. Temperature dependent metal properties of AISI 430 were taken from standard data source and were utilized till to the liquid phase. Element shape '3-D 10-Node tetrahedral' (solid 87) was used in 3-D analysis. Conduction and convection are considered as heat transfer mode. The experimental values of welding speed, welding current, and arc voltage were used for theoretical analysis. Thermocouples were used to record welding temperature using data tracker and computer. Five thermocouples were fixed at the middle line of the plate to measure temperature distribution and cooling rate practically. Two plates of FSS were welded by MIG welding in butt joint position in single pass.