7075铝板多道次轧制和固溶时效工艺优化

Process optimization of multi-pass rolling and solution aging for 7075 aluminum plate

为优化7075铝板的生产工艺,进行了累计压下率为92%的4道次+二次加热+4道次的轧制试验,并对不合格的成品板进行了固溶时效参数优化试验。采用阳极覆膜偏光观察法观察了成品板的微观组织,对成品板进行了力学性能测试、布氏硬度检测、元素能谱分析和电导率测量,并将力学性能检测结果与GB/T 3880.2—2012中对7075铝合金T6处理后铝板的力学性能要求进行了对比。试验结果表明:在7075铝板的8道次轧制工艺中,在二次加热前的4道次累计压下率为71%时,所获得的成品板力学性能达到国标要求,为最优轧制工艺;对二次加热前的4道次累计压下率为62%的轧板,在500℃固溶可以获得更好的综合力学性能。二次加热前后的累计压下率不同,对最终成品板的力学性能有明显影响,可以作为调节成品板组织和性能的工艺手段。同时,在轧制工艺不理想的情况下,通过优化固溶时效工艺仍可以使成品板的力学性能达到国标要求。

In order to optimize the production process of 7075 aluminum plate,a rolling test was conducted with the cumulative reduction rate of 92% for four passes+secondary heating+four passes,and the solution and aging parameters optimization test was conducted on the unqualified finished plates.Then,the microstructure of the finished plates was observed by polarizing observation with anodic coating,and the mechanical properties,Brinell hardness testing,elemental energy spectrum analysis and electrical conductivity measurement of the finished plates were conducted.Furthermore,the mechanical properties measurement results were compared with those of 7075 T6-treated aluminum plate in GB/T 3880.2—2012.The results show that in the 8-pass rolling process of 7075 aluminum plate,when the cumulative reduction rate is 71% in the first four-passes before secondary heating,the mechanical properties of the finished plate meet the national standard requirements,which is the optimal rolling process.For the rolled plate with the cumulative reduction rate of 62% in the first four-passes before secondary heating,better comprehensive mechanical properties are obtained by the solid solution at 500 ℃.Thus,the different cumulative reduction rates before and after secondary heating have a significant impact on the mechanical properties of the final finished plate,which can be used as a process mean to adjust the microstructure and properties of the finished plate.At the same time,when the rolling process is not ideal,the mechanical properties of the finished plate can meet the national standard requirements by optimizing the solution and aging process.