Finite Element Simulation of Weld Bead Geometry and Temperature Distribution during GTA Welding of Modified 9Cr-1Mo Steel and Experimental Validation

摘要

The thermal analysis of Modified 9Cr-1Mo steel plate during GTA welding is carried out using finite element method employing SYSWELD software. First, the simulation of bead on plate welds for 16 varying process parameter conditions by employing a double ellipsoidal heat source was carried out. Simulated bead on plate weld bead dimensions for the 16 welds were compared with the actual bead dimensions obtained experimentally. Then the simulation of GTA welding of square butt joint on 3 mm thick plates of dimensions 300 × 125 × 3 mm was carried out. The simulated thermal profiles were validated using thermocouple measurements. There was good agreement between the predicted and measured weld bead profiles and thermal cycles for square butt joint. The investigation on the effect of copper back up plate on the peak temperature and the cooling rate has revealed that the peak temperature decreased by 147℃ and the cooling rate increased by 35%.