辊速差对连铸连轧7075铝板显微组织、织构及力学性能的影响

研究辊速差对连铸连轧7075铝板显微组织、织构及力学性能的影响。采用3种不同上辊/下辊转速比(ω/ω0,ω为上辊转速,ω0为下辊转速)1:1、1:1.2及1:1.4进行多次试验。结果显示,在最大辊速差条件下(ω/ω0=1:1.4),7075铝板在轧制方向的屈服强度和极限抗拉强度分别提高41.5%和21.9%。此外,当辊速比ω/ω0为1:1.4时,成品轧制板的平均晶粒尺寸减小36%,横剖面平均硬度增加约9.2%。织构研究结果显示,辊速差越大,成品各向同性及硬度越大。然而,采用不同辊速度的连铸连轧会导致变形板伸长率降低约6%。

Influence of roll speed difference on microstructure,texture and mechanical properties of 7075 aluminum plates produced via combined continuous casting and rolling process

The influences of the dissimilarity in the roll speeds on the microstructure, texture and mechanical properties of 7075 aluminum plates produced via combined continuous casting and rolling (CCCR) process were investigated. Several experiments were conducted with three different upper/lower roll rotational speed ratios (ω/ω₀, ω is the upper roll rotational speed and ω₀ is the lower roll rotational speed), namely 1:1, 1:1.2 and 1:1.4. It was found that the greatest dissimilarity in the roll speed (ω/ω₀=1:1.4) improved the yield strength and ultimate tensile strength of 7075 Al plate in the rolling direction by 41.5% and 21.9%, respectively. Moreover, at a roll speed ratio of ω/ω₀=1:1.4, the average grain size was decreased by 36% whereas the mean hardness of the transverse cross-section of the finally rolled plate was increased by about 9.2%. Texture studies also revealed that the more the difference in the roll speeds was, the greater the isotropy and the hardness of the final product were. Nevertheless, conducting CCCR operation with different roll speeds resulted in about 6% reduction in the elongation of the deformed plate.