钛合金钣金件脉冲电流辅助热压成形精度控制

针对钛合金钣金件冷加工成形精度低、热成形机成形成本高的问题,提出一种采用脉冲电流辅助热压成形工艺。以TC1钛合金U型件为对象,研究了脉冲电流辅助热压成形工艺对钛合金钣金件的缺陷、尺寸精度及力学性能的影响。结果表明,脉冲电流加热可提高成形效率,当脉冲电流密度为9.2A/mm^2,合模速度为15mm/s时,补偿了成形过程的热量损失,使钛合金钣金件保持在良好的成形温度区间,增加其成形极限,得到零件表面质量良好、无裂纹。在成形过程中,随着成形压力、保压时间、模具预热温度的升高,零件的尺寸精度逐渐提高,当成形压力10t、保压时间10s、模具不预热时,零件的尺寸精度即可达到±0.2mm。脉冲电流辅助热压成形后零件的晶粒尺寸比热成形机成形的细小,且力学性能也较好。

Accuracy Control of Pulse Current Assisted Hot Pressing Forming for Titanium Alloy Sheet Metal Parts

A pulse current assisted hot pressing forming is designed to solve the problem of low accuracy of cold forming and high cost of heat forming machine.In this paper,the influence of pulse current assisted hot pressing process on defects,dimensional accuracy and mechanical property of TC1 titanium alloy U-shaped parts was studied.The results show that the pulse current heating can improve the forming efficiency.When the pulse current density is 9.2 A/mm^2 and the closing speed is 15 mm/s,the heat loss in the forming process is compensated,the titanium alloy sheet metal parts are kept in a good forming temperature range and the forming limit is increased.During the forming process,with the rise of forming pressure,holding time and mould preheating temperature,the dimensional accuracy of the parts is gradually improved.When the shape pressure is 10 t,holding time is 10 s and the mould is not preheated,the dimensional accuracy of the parts reaches±0.2 mm.The grain size of the part after pulse current assisted hot pressing is smaller than that of the hot forming machine,and the mechanical property is better.