楔横轧铝合金轧件内部空洞演变

采用数值模拟的手段,研究了楔横轧轧制铝合金时轧件内部空洞演化的一般规律和工艺参数对空洞演化的影响.结果表明:轧件内部单空洞演化的一般规律是球形—椭球形—轧件内部轴向贯通的孔腔;多空洞演化时,位于轧件中心的空洞的变化规律和单空洞时相似,但其余位置的空洞发生了闭合,它们对中心空洞有正作用方面的影响;在模具的各个阶段中,楔入段的后期和展宽段的前期是内部空洞演化的关键阶段;在楔横轧加工的工艺参数方面,展宽角是影响空洞演化的最敏感因素,其次是断面收缩率,再次是成形角.研究证明了小的成形角、展宽角和断面收缩率均有利于轧件内部空腔的扩展.

Evolution of internal holes in aluminum alloy parts by cross wedge rolling

The general evolution rules of internal holes in aluminum alloy parts and the influence of process parameters on the internal holes in cross wedge rolling were studied by means of numerical simulation.The results show that the general evolution law of a single hole is firstly spherical,then ellipsoid,and finally a hole through the rolled piece at the axial direction.As for multi-holes,the evolution law of the center hole is similar to that of a single hole;however,holes lied in other positions finally become closed and have a positive effect on the center hole.The later segment of the knifing zone and the former segment of the stretching zone are the crucial evolution stage to the expansion of internal holes.Among the process parameters of cross wedge rolling,stretching angle is the most sensitive factor,followed by reduction in area and then forming angle.It is proved that the small forming angle,stretching angle and reduction in area are conducive to the expansion of internal holes.