Simulation Methodology to Analyze Overall Induction Heat Treatment Process of a Crank Shaft to Determine Effects on Structural Performance

Steel crankshafts are subjected to an induction heat treatment process for improving the operational life. Metallurgical phase transformations during the heat treatment process have direct influence on the hardness and residual stress. To predict the structural performance of a crankshaft using Computer Aided Engineering (CAE) early in the design phase, it is very important to simulate the complete induction heat treatment process. The objective of this study is to establish the overall analysis procedure, starting from capturing the eddy current generation in the crank shaft due to rotating inductor coils to the prediction of resultant hardness and the induced residual stress. In the proposed methodology, a sequentially coupled electromagnetic and thermal model is developed to capture the resultant temperature distribution due to the rotation of the inductor coil. Subsequent quenching operation is simulated to capture the metallurgical phase changes and hardness using a subroutine based on continuous cooling transformation diagram. This methodology is focused on predicting the residual stresses due to thermal gradient only and the effect of microstructural changes on residual stress is out of scope of this study. The induction heat treatment simulation methodology has been developed in this work, which can be used in the initial design phases of crankshafts to come up with their robust design.