大直径薄壁5A02铝合金管材旋压生产工艺研究

Research on spinning technology of 5A02 aluminum alloy pipes with large diameter and thin-wall

采用QX63-20卧式强力旋压机对5A02铝合金管坯进行多道次冷旋压,利用光学显微镜、显微硬度计分析旋压过程中大直径5A02铝合金薄壁管材组织性能的变化,并进行不同热处理工艺对其微观组织和力学性能的影响研究。研究结果表明,采用7道次旋压生产工艺可生产出无中间退火的、累积冷旋压减薄率达到80%以上的、表面质量较好、无缺陷的Ф85 mm×2 mm的5A02管材。随着旋压减薄率的增加,原始挤压管坯再结晶态组织逐渐被拉长,纤维组织变得更明显、细小、纤长,管材的显微硬度也由原始的53.3 HV逐渐增加到81.4 HV。将旋压管材在430℃保温60 min热处理后,可以得到组织、性能均满足要求的大直径5A02铝合金管材。

Cold spinning processes with several passes were carried out for the fabrication of 5A02 aluminum alloy pipes by using a QX63 - 20 horizontal power spinning machine. Optical microscope （OP） observation and microhardness testing were employed to investigate the evolution of microstruetures and mechanical properties of 5A02 aluminum alloy pipes with large diameter and thin-wall during spinning process. The influence of heat treatment on the microstrueture and mechanical property of cold spinning 5A02 aluminum alloy pipes were also studied. It is found that the high-quality and defect-free surfaces of 5A02 aluminum alloy pipes with the dimension of Φ85 mm×2 mm can be obtained through cold spinning by seven passes with accumulated reduction rate more than 80% and without intermediate an nealing. With the increasing spinning reduction rate, the original recrystallized grains of the extruded tube are elongated gradually and transformed into small and slim fibrous structures. Meanwhile, the mierohardness of pipes gradually increases from the original microhard- hess of 53.3 HV to 81.4 HV. The mierostructure and mechanical property of SA02 aluminum alloy pipes with large diameter and thin-wall met the application requirements were gained after heat treatment of 430 ℃ for 60 minutes.