The Microstructure Prediction during the Welding Process of Fe–C–Si Steel Using Physical and Numerical Simulation: A Comparative Study

Abstract

Overall, medium‐carbon, multiphase steels subjected to welding processes can be described as difficult and require dedicated process conditions. In these investigations, an attempt is made to characterize the welding process of commercial 55Si7 steel with a high carbon equivalent (CE = 0.73). An experimental tungsten inert gas (TIG) welding process is performed by the use of preheating. Then, to understand and explain the processes during welding, a numerical (finite element method [FEM]) and physical (dilatometry) simulation is carried out. Measurement points located in the heat‐affected zone (HAZ) are selected based on the obtained data of thermal cycles. Significant differences in the results obtained with the three approaches are assessed and indicated. The cause of the discrepancies in the test results is also identified. The essence of the implementation of material data, which precisely defines the kinetics of phase transformation, is confirmed. A detailed analysis of the contribution of the phases is performed, together with their morphological assessment, as well as the hardness distributions are conscientiously compared. Moreover, it seems that the segregation of the chemical composition of austenite and the initial microstructure plays a crucial role in terms of the quality of the prediction.