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.