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为了揭示盘型件双面辗压成形过程中微观组织的演化特征,应用数值模拟方法研究了这一成形过程中所发生的动态再结晶和晶粒长大规律。所研究的盘型件材料为铝合金6061,辗压成形温度为350～500℃。晶粒尺寸演化规律的数值模拟结果与实验结果基本符合。与整体锻造不同,双面辗压成形没有变形死区,并且越靠近盘型件表面晶粒细化效果越好;辗压头通过对盘型件厚度方向压缩和表面环向剪切两种方式驱动盘型件变形。计算结果表明,即使压下量零增量辗压也会在沟槽附近产生显著变形和晶粒细化,这说明盘型件变形和组织演化主要源于辗压头对盘型件表面的环向剪切;多遍次辗压过程中,第1遍次辗压对晶粒细化的贡献最大,后续辗压的贡献较小;提高成形温度可能会出现动态晶粒长大区,在这种情况下,盘型件上的点将交替发生动态再结晶和动态晶粒长大,最终晶粒尺寸会有一定程度增加。
In order to reveal the evolution characteristics of the microstructure during the double-side rolling process of the disk, the dynamic recrystallization and grain growth rules during the forming process were studied by numerical simulation. The disk material studied is aluminum alloy 6061 and the rolling forming temperature is 350 ~ 500 ℃. The results of numerical simulation of grain size evolution are in good agreement with the experimental results. Different from the overall forging, there is no deformation dead zone in the double-side rolling process, and the better the grain refinement effect is, the closer to the surface of the disk. The rolling head passes the thickness direction of the disk and the surface is circumferentially sheared in two ways Drive disc deformation. The calculation results show that even the zero-increment rolling with the reduction will produce significant deformation and grain refinement in the vicinity of the groove, which indicates that the deformation and the evolution of the disk are mainly caused by the ring of the rolling head on the surface of the disk To the shearing; In the multi-pass rolling process, the first-pass rolling contributes the most to the grain refinement while the subsequent rolling contributes less; the dynamic grain growth area may appear to increase the forming temperature, Under these circumstances, the points on the disk will alternate between dynamic recrystallization and dynamic grain growth, and the final grain size will increase to a certain degree.