芯轴超塑性挤压成形试验分析

Study on forming a Mandril Piece by the Superplastic Extrusion Process

此文研究了名称为"芯轴"的零件采用超塑性挤压成形时的变形过程,并分析了产生缺陷的原因。指出:ZnAl27材料在超塑性挤压条件下,有很好的成形性及充满性,选用合理的模具形状,可以用最简单的毛坯实现零件的一次挤压成形。

The mandril which is a part of a bicyle gear changing device (see attached drawing), has a complicated shape, being tubular with a stepped inner hole , and having four small raised spots ( Φ2. 5×1. 8mm)on a rather large flange. There are also six grooves on the M8 threading, where the thinnest wall thickness at the bottom of the grooves is only 0. 5mm. Such a piece cannot be formed in one step by common extrusion processes, but by using ZnA127 alloy as materal in the superplastic extrusion process, one step formation is realized (except the M8 threading). During the experiment, the dimensions of the slug, the structure of the dies ,the process of deformation have been studied and the defects have been analyzed.