Formability determination of AZ31B tube for IHPF process at elevated temperature  

AZ31B管材热态内高压成形性能的测试(英文)

作　　者：林艳丽[1] 何祝斌[1] 苑世剑[1] 吴佳 

机构地区：[1]哈尔滨工业大学材料科学与工程学院,哈尔滨150001 [2]SWANSON School of Engineering,University of Pittsburgh

出　　处：《Transactions of Nonferrous Metals Society of China》2011年第4期851-856,共6页中国有色金属学报（英文版）

基　　金：Project(50805033)supported by the National Natural Science Foundation of China;Project(E200804)supported by the Natural Science Foundation of Heilongjiang Province of China

摘　　要：Ring hoop tension test and tube bulging test were carried out at elevated temperatures up to 480 ℃to evaluate the formability of AZ31B extruded tube for internal high pressure forming （IHPF） process. The total elongation along hoop direction and the maximum expansion ratio （MER） of the tube were obtained. The fracture surface after bursting was also analyzed. The results show that the total elongation along hoop direction and the MER value have a similar changing tendency as the testing temperature increases, which is quite different from the total elongation along axial direction. Both the total elongation along hoop direction and the MER value increase to a peak value at about 160 ℃. After that, they begin to decrease quickly until a certain rebounding temperature is reached. From the rebounding temperature, they begin to increase rapidly again. Burnt structure appears on the fracture surface when tested at temperatures higher than 420 ℃. Therefore, the forming temperature of the tested tube should be lower than 420 ℃, even though bigger formability can be achieved at higher temperature.为测试AZ31B挤压管材的内高压成形性能,分别进行管材环向拉伸实验和管材胀形实验,实验温度最高达480°C。通过实验获得管材的环向总延伸率和最大胀形率,同时对胀破后的断口形貌进行分析。结果表明,随着实验温度的变化,环向总延伸率和最大胀形率的变化趋势类似,而和轴向总延伸率的变化趋势差别很大。在160°C左右,环向总延伸率和最大胀形率都达到一个极值,此后两者迅速降低。当达到转变温度后,环向总延伸率和最大胀形率又开始迅速增加。当实验温度超过420°C时,在断口上出现过烧组织。因此,尽管在更高的温度下可以获得更好的成形性能,所测试管材的成形温度还是应低于420°C。

关 键 词：AZ31B tube FORMABILITY HYDROFORMING tube bulging test maximum expansion ratio 

分 类 号：TG379[金属学及工艺—金属压力加工]