Analysis of Process Signals of Resistance Spot Welding for DP590 Steel Using Numerical Calculation

Although the finite element (FE) numerical calculation model has been extensively employed in analyzing metal characteristics, very few works use it to analyze features of the main process signals during the resistance spot welding (RSW) process. Hence, its generality was seriously restricted. In this work, a 2D FE model, which coupled thermal, electrical and mechanical fields, was established with reasonable meshing and parameters and boundary conditions. The parent metal used dual phase (DP) 590 steel, which is commonly employed in automobile lightweight manufacturing process. An actual experiment with the same conditions as the numerical calculation was conducted. The dynamic resistance and electrode displacement obtained from numerical calculation and actual experiment were seriously compared and analyzed. Many important characteristics of process signals have been reasonably explained by combining the results obtained from numerical calculation and experiments. The reasonability and accuracy of the FE numerical calculation were not only verified after the welding process but also examined in depth during the intermediate welding process. Hence, the work can effectively enlarge the applications of the FE model and strengthen the correlation between control strategy design, online quality estimation using main process signals and FE numerical calculation during the RSW process.