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为了获得热冲压板料和模具的界面换热系数,本文通过设计圆台实验分别获得热冲压淬火过程中5、10、20、30和40 MPa保压压强时的板料中心降温曲线和模具模面中心向下1.5 mm处的升温曲线。在考虑模具热电偶温度响应时间和板料由奥氏体向马氏体转变的相变潜热影响基础上,提出运用有限元反算求解界面换热系数的方法,进而获得界面换热系数与保压压强的对应关系。结果表明,界面换热系数值与压强近似呈直线关系,使用该方法时板料与模具的模拟温度曲线和实验温度曲线的相对误差可控制在15%以内,且二者的平均绝对误差最大不超过24℃。
In order to obtain the heat transfer coefficient between the hot stamping sheet and the mold, this paper obtains the cooling curve of the center of the sheet and the mold surface of the mold at 5, 10, 20, 30 and 40 MPa holding pressure in the process of hot stamping and quenching 1.5 mm center down the temperature curve. Based on the consideration of the temperature response time of the die thermocouple and the latent heat of transformation from the austenite to the martensite, a method of solving the interfacial heat exchange coefficient by inverse finite element method is proposed, and the interfacial heat transfer coefficient The pressure of the corresponding relationship. The results show that there is a linear relationship between the heat transfer coefficient of the interface and the pressure, and the relative error between the simulation temperature curve and the experimental temperature curve can be controlled within 15%, and the average absolute error of the two methods is not More than 24 ℃.