块体材料连续变断面循环挤压形状参数的优化

采用连续变断面循环挤压(Continuous Variable Cross-section Recycled Extrusion,CVCE)法对矩形截面的铸态铅块进行挤压和回复镦粗变形,研究了原始坯料高径比、挤压角度等形状参数对块体变形后的外部形状和内部金属流动规律的影响。结果表明:经CVCE工艺镦粗后的试样,由于金属的径向流动和侧面金属翻平的共同作用,导致上底面面积增大,这种变形自上而下依次渗透并逐层减少;坯料在竖直方向上受到挤压而产生的变形有传递的作用,自上而下,各层的压缩量逐渐减少。当挤压角度为6°、原始坯料高径比为1.83时,循环挤压回复到原始形状的效果最好,且制品表面质量更好,内部金属流动较为均匀。

Optimization on shape parameters of continuous variable cross-section recycled extrusion for bulk material

The extrusion and recovery upsetting deformation of as-cast plumbum bulk with rectangle cross section were realized by continu-ous variable cross-section recycled extrusion ( CVCE) , and the influences of shape parameters including height-diameter ratio of original billet and extrusion angle on external form and internal metal flow law of bulk after deformation were investigated. The results show that the combined effects of metal flow along the radial and lateral metal flatting lead to bottom area enlargement of top surface after upsetting by CVCE process, which permeates in sequence from up to down and decreases layer by layer. From up to down, the compression of each layer gradually decreases for the transmission effects of deformation produced by the extrusion on billet in vertical direction. When the compression angle is 6° and the height-diameter ratio of original billet is 1. 83, the effect of recovery to original shape after cyclic extru-sion is the best, and the product is of better-quality surface and uniform metal flow.