Thermal metallurgical analysis of GMA welded AH36 steel using CFD-FEM framework

A temporal combination of CFD mass and heat transfer, and FEM conductive heat transfer analysis was conducted using a proper temperature history implantation scheme. The phase distribution in an AH36 steel weldment was predicted and compared with experimental results. The numerical phase fraction estimation was performed using the critical austenite temperature model in the heating process as a function of heating rate. The CCT information based transformation starting and finishing temperature, and the maximum phase fraction models were utilized with instant cooling rate in the cooling process. The thermal analysis result agreed well with the FZ shape and measured temperature history. The calculated hardness slightly overestimated the measured hardness. The steep reduction of hardness in the HAZ and the tempered zone was much more affected by the change in austenite critical temperature than the cooling rate. Based on the potential results of this work, predicting weldment deformation by considering phase transformation will be extended.