TC4板料电辅助加热数控渐进成形时摩擦和润滑的研究

难成形板料局部自阻电辅助加热数控渐近成形是一种新技术,由于该技术涉及高温、电流和塑性变形等因素,摩擦机理复杂,因此选择正确的润滑方式对提高加工件的表面质量至关重要。笔者首先对渐近成形的摩擦机理进行了分析,提出摩擦分为3个区域,黏着摩擦、边界摩擦和流体润滑。然后又对电辅助加热渐近成形的摩擦机理进行分析,指出摩擦主要由黏着摩擦和边界摩擦组成,并提出了摩擦力计算公式。为了提高电辅助加热渐进成形加工件的表面质量,关键是增加润滑剂与板料之间的结合力。通过选用不同润滑剂进行实验,对比加工件表面质量,发现用电沉积制备的铜基二硫化钼复合材料具有良好的自润滑性能,加工的TC4钛合金钣金件表面质量良好。

A Study of the Friction and Lubrication in Electric Hot Incremental Forming of TC4 Sheet

Electric hot incremental forming of mental sheet is a new technique. Since it involves high temperature, electrical current,plastic deformation and other factors,the friction mechanism is complex. In order to enhance the surface quality,it is very important to select proper lubricant. In this paper,the friction mechanism during incremental forming is analyzed,and the friction region is divided into three parts——adhesion friction and boundary friction; fluid lubrication. Then the friction mechanism during electric hot incremental forming is analyzed,and the friction region is divided into two parts——adhesion friction and boundary friction; a formula for calculating friction is also given. In order to improve the surface quality,the most important is to increase the adhesive attraction between lubricant and sheet metal. Different lubricants were selected in processing to compare the effect,copper matrix with MoS2 self-lubricating material is superior in TC4 titanium workpiece forming.