A method for solving surface heat transfer coefficient of Mg-Gd-Y-Zr-Ag wrought magnesium alloy based on improved lumped heat capacity method

As an important boundary condition of quenching numerical simulation process, the surface coefficient of heat transfer has a direct influence on the evolution of temperature field and thermal stress field. According to the temperature drop data recorded by thermocouple, the improved lumped heat capacity method was adopted to solve the surface heat transfer coefficient of Mg-Gd-Y-Zr-Ag wrought magnesium alloy. The results show that the surface heat transfer coefficient firstly increases and then decreases, and there are three stages in the water bath quenching process: steam film boiling stage, secondary nucleation stage and convective heat transfer stage. The surface coefficient of heat transfer reaches the peak value of 2 496.31 W/(m2·℃) at 27 s, and the quenched surface temperature is 211 ℃. The calculated heat transfer coefficients with temperature are substituted into the interaction module of Abaqus finite element model in the form of a list. The maximum relative error between simulated temperature and measured temperature at the same depth is 15%, and the average relative error is only 6%; K−S two-sample distribution test is used to test the distribution of simulation and experimental temperature curves, and it is found that the statistics of the four samples are not in the rejection domain at the appropriate significance level, which verifies the correctness of the improved lumped heat capacity method use to solve the surface heat transfer coefficient in water bath quenching process. © 2023 Central South University of Technology. All rights reserved.