(北京交通大学 机械与电子控制工程学院,北京100044)
摘 要: 针对AZ31B铸轧镁合金板材温热拉深性能差的问题,提出预变形温热拉深工艺。对AZ31B铸轧镁合金板材在20~220 ℃进行预变形温热拉深实验研究。结果表明:预变形使铸轧镁合金板材的拉深性能明显改善,使AZ31B铸轧镁合金板材具有最佳拉深性能的冲头温度范围(20~95 ℃);凹模温度选择在160~220 ℃范围内,铸轧镁合金板材具有良好的拉深性能,极限拉深比可达到2.26;随着拉深成形温度的升高,工件中动态再结晶晶粒数量逐渐增加,220 ℃拉深成形时工件中再结晶晶粒分布趋于均匀。
关键字: AZ31B合金;镁合金板材;双辊铸轧;预变形;温热拉深;极限拉深比
warm temperatures by pre-forming
(School of Mechanical, Electronic and Control Engineering, Beijing Jiaotong University, Beijing 100044, China)
Abstract:In order to solve the problem of the poor warm deep drawability of the twin-roll cast AZ31B Mg alloy sheet, a warm deep drawing process by pre-forming was proposed. The warm deep drawing experiments of twin-roll cast AZ31B Mg alloy sheets were examined by pre-forming at temperature of 20−220 ℃. The results indicate that the deep drawing performance is significantly improved by pre-forming. The punch temperature range of 20−95 ℃ is recommended to obtain the best drawability for the twin-roll cast AZ31B Mg alloy sheet. The twin-roll cast AZ31B Mg alloy sheets have good deep drawing formability at die temperature of 160−220 ℃ with the limit drawing ratio up to 2.26. The dynamic recrystallization (DRX) grains of the workpieces increase gradually with increasing temperature. And the DRX grains of the materials distribute evenly, when the workpieces are obtained at temperature of 220 ℃.
Key words: AZ31B alloy; Mg alloy sheet; twin-roll casting; pre-forming; warm deep drawing; limit drawing ratio