摆动辗压件成形过程中产生的缺陷及防止办法

Defects of Workpieces Producing in Forming Process of Rotary Forging and Methods for Preventing Them

本文简述了摆辗变形的特征及其力学分析,同时给出了摆辗变形过程中经常产生的四种缺陷:薄件中心开裂;大头件侧表面开裂;高件失稳折迭及锻不透等缺陷。指出,由于摆辗工艺的特殊性。上模与工件始终有一个接触小区,压力高,且模具在热辗时受热疲劳作用,中心常产生龟裂、塌陷等缺陷。文中最后给出了防止产生缺陷的措施和提高模具寿命的方法。对于厚件和大头带杆件应适当控制每转进给量;对于薄件要适当加大进给量或采用局部加厚的办法;冷辗大头件要注意原始坯料表面质量、控制好模具间隙均可以减少裂缝、失稳折迭等缺陷的产生。

First, the deformation characteristics and their mechanic analysis of rotary forging workpieces are briefly described, and four defects: the centric Cracking in the thin workpiece; the surface cracking on the side of the workpieces with large head; instability and overlap of the long rod and forging not thoroughly, which usually produce in the forming process of rotary forging, are given in this paper. Then, defects such as crazing, press-subsidence, et al, frequently producing in the centre of the upper die are pointed out because the upper die suffers the effect of the thermal fatigue in hot rotaey forging and there is a small contact area throughout between the upper die and the workpiece and high pressure in the contact area, which is the particularity of rotary forging technology Finally, the measures to prevent defects and methods for improving the service life of the die are proposed, i. e., for thick workpieces and workpieces with large head the feed per rotation should be properly controlled; for thin workpieces the suitable feed per rotation should be increased; when the rods with large head being cold rotary forging the surface quality of blank should be noticed and the die-workpieces clearance should be controlled so that the defects such as cracking, instability, overlap, et al, can decreased.