基于改进集中热容法的Mg-Gd-Y-Zr-Ag变形镁合金表面换热系数求解方法  

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

作　　者：袁忠禹 吴运新 龚海[1,2,3] 张涛 谢秋敏[2,3,4] 彭顺理 YUAN Zhongyu;WU Yunxin;GONG Hai;ZHANG Tao;XIE Qiumin;PENG Shunli(Research Institute of Light Alloys,Central South University,Changsha 410083,China;State Key Laboratory of High Performance Complex Manufacturing,Central South University,Changsha 410083,China;Nonferrous Metal Advanced Structural Materials and Manufacturing Collaborative Innovation Center,Central South University,Changsha 410083,China;School of Mechanical and Electrical Engineering,Central South University,Changsha 410083,China)

机构地区：[1]中南大学轻合金研究院,湖南长沙410083 [2]中南大学高性能复杂制造国家重点实验室,湖南长沙410083 [3]中南大学有色金属先进结构材料与制造协同创新中心,湖南长沙410083 [4]中南大学机电工程学院,湖南长沙410083

出　　处：《中南大学学报（自然科学版）》2023年第4期1281-1289,共9页Journal of Central South University:Science and Technology

基　　金：国家自然科学基金资助项目(51975596);高性能复杂制造国家重点实验室自主课题(ZZYJKT2020-13)。

摘　　要：表面换热系数作为淬火数值模拟过程的重要边界条件,其求解精度直接影响温度场、热应力场的演变规律。实验通过设计矩形淬火探头并进行单面水浴淬火,根据热电偶记录的温降数据,采用改进的集中热容法对Mg-Gd-Y-Zr-Ag变形镁合金进行表面换热系数的求解。研究结果表明:表面换热系数呈现先增大后减小的趋势且水浴淬火过程存在蒸汽膜沸腾阶段、二次形核阶段以及对流换热阶段3个阶段,在第27秒时表面换热系数达到峰值2496.31 W/(m^(2)·℃),此时淬火面温度为211℃。用此方法计算得到的随温度变化的换热系数以列表的形式代入Abaqus有限元模型的相互作用模块,同一深度处仿真温度与实测温度最大相对误差为15%,平均相对误差仅为6%;采用K-S双样本分布检验对仿真与实验的温度曲线进行分布检验,在合适的显著性水平下4个样本的统计量均不在拒绝域内,验证了改进的集中热容法用来求解水浴淬火过程中表面换热系数的正确性。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 2496.31 W/(m^(2)·℃)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.

关 键 词：变形镁合金 表面换热系数 水浴淬火 集中热容法 数值模拟 

分 类 号：TG166.4[金属学及工艺—热处理]