(1. 天津职业技术师范大学 汽车模具智能制造技术国家地方联合工程实验室，天津 300222；
2. 天津市天锻压力机有限公司，天津 300222)
摘 要: 以7075铝合金挡风梁在热成形过程中的减薄率为研究对象，通过热拉伸试验，研究了7075铝合金在变形温度为440~480 ℃、应变速率为0.001~0.1 s-1条件下的真实应力-应变曲线，并将其引入数值模拟模型，分析了板料初始温度(440~500 ℃)、压边力(20~50 kN)、摩擦因数(0.1~0.7)对7075铝合金挡风梁热冲压成形危险区域标记点减薄率的影响规律及其预测模型，并进行了实验验证。结果表明：挡风梁成形件危险区域标记点的减薄率随着板料温度的上升先减小后增大，随着压边力的增大而增加，随着摩擦系数的增大呈上升趋势，且变形过程中标记点减薄率由高到低依次为A＞D＞C＞B。经修正后的预测模型与实验值进行比较，所得最大误差为6.7%，最小误差为1.5%。
关键字: 7075铝合金；热冲压；成形性能；减薄预测
（1. National-Local Joint Engineering Laboratory of Intelligent Manufacturing Oriented Automobile Die and Mould, Tianjin University of Technology and Education, Tianjin 300222, China;
2. Tianjin Tianduan Press Co., Ltd., Tianjin 300222, China）
Abstract:Aiming at the thinning rate of 7075 aluminum alloy windshield in the hot forming process，the true stress-true strain curves of 7075 aluminum alloy were studied by hot tensile tests under the deformation temperature of 440-480 ℃ and strain rate of 0.001-0.1 s-1, and they were introduced into the numerical simulation model. The influence of the initial temperature of sheet metal (440-500 ℃), blank holder force (20-50 kN), and friction coefficient (0.1-0.7) on the thinning rate of hot stamping dangerous zone marked points of 7075 aluminum alloy windshield was analyzed, and the prediction model was verified by experiments. The results show that the thinning rate of marked points in the dangerous area of windshield forming part decreases first and then increases with the increase of sheet metal temperature, increases with the increase of blank holder force, and increases with the increase of friction coefficient. The thinning rates of the marked points are A＞D＞C＞B in the order from high to low during the deformation process. The modified prediction model is compared with the experimental value, and the maximum error obtained is 6.7%, and the minimum error is 1.5%.
Key words: 7075 aluminum alloy; hot stamping; formability; thinning prediction
