模具参数对楔横轧铝合金轧件内部空洞的影响(英文)

通过分析楔横轧内部空洞(疏松)缺陷的物理性质和形成特征,将内部空洞视为多孔材料,利用多孔材料的刚塑性有限元方法,建立7075铝合金坯料内部空洞缺陷的数值模型。采用相对密度研究成形角、展宽角、断面收缩率对内部空洞缺陷的影响规律。结果显示:内部空洞的扩展主要发生在展宽段,楔入段对它的影响很小。展宽角是影响内部空洞产生的主要因素,而断面收缩率的影响较小。成形角、展宽角、断面收缩率越大,越不易发生内部空洞缺陷。在模具设计时,为了防止铝合金坯料轧制后产生内部空洞缺陷,断面收缩率应选择在55%～65%之间,展宽角在8°～10°之间,成形角在29°～32°之间。

Influence of tool parameters on internal voids in cross wedge rolling of aluminum alloy parts

The internal void of cross wedge rolling (CWR) part can be treated as porous material due to their similar physical property and deformation characteristics. Aiming at the CWR process of aluminum alloy 7075 workpiece, the numerical simulation model for internal void was established by means of the rigid-plastic FEM method for the porous material. The relative density was used to research the influence of three primary parameters on the internal void in CWR process, including the forming angle α1, the stretching angle β and the area reduction △A. The experimental results show that the expansion of internal void occurs in the stretching zone, and the knifing zone just has a little influence on it. The stretching angle has a great influence on the internal void, while the area reduction has a small influence on it. The size of internal voids decreases with the increase of area reduction, stretching angle and forming angle. When designing the CWR tool geometry and operating conditions, to prevent the internal void, the area reduction is suggested to be 55%-65%, the stretching angle to be 8°-10°, and the forming angle to be 29°-32°.