摘要
为克服传统等径角挤压反复多道次累积塑性变形带来多次装料、多次加载以及棒料机械加工等耗时问题,无损伤地制备均匀超细晶结构时效硬化型铝合金,提出旋转通道等径角平行挤压大塑性变形新工艺。该工艺在一个通道内设置多个剪切变形区,通过在两个等径角挤压通道之间设置旋转通道来改变圆棒料剪切方向和剪切角度,实现Bc加工路径,提高变形均匀性。采用正交试验法选取内角Φ、外角Ψ、升角γ、椭圆因子m、第2个通道中第1段直通道长度L_1作为因素,采用有限元模拟法对棒料在16组不同水平的模具中进行有限元挤压模拟。以等效应变、等效应力、损伤量以及变形均匀性系数作为指标值分析其对挤压过程的影响。模拟实验结果表明,良好的挤压通道内角Φ的合理范围为90°~120°,外角Ψ的合理范围为30°~40°,升角γ的合理范围为60°~80°,m的合理范围为1.2~1.4,L_1、L_3的合理范围为(1~1.5)d。
In order to manufacture a uniform ultrafine- grain age- hardening aluminum alloy without damage,and to overcome the severe plastic deformation of traditional extrusion process with equal diameter angle,which brought to time-consuming problems such as multiple loading and charging,mechanical processing of bar,a new parallel extrusion process of rotated channel and equal diameter angle was proposed. Then,multiple shear deformation areas were set up in the channel,and the shear deformation direction and angle of samples were changed by setting rotating channel between extrusion channels with two equal diameter angles. Therefore,the Bc process path was conducted,and the deformation uniformity was improved. According to the orthogonal experiment method,the interior angle Φ,the outer corner Ψ,the lead angle γ,the oval factor m and the length of L_1 were chosen as facts,and extrusion simulations were realized by the finite element method under 16 simulation experiments of different die parameters. Furthermore,the equivalent strain,equivalent stress,damage and deformation uniformity coefficient were analyzed as the indexes of orthogonal experiment method,and the influences of them on extrusion process were conducted. The simulation results show that the reasonable values are angle Φ of 90°- 120°,the outside corners Ψof 30°- 40°,the lead angle γ of 60°- 80° and m of 1. 2- 1. 4,L_1 and L_3 of d- 1. 5d in good extrusion channel respectively.
出处
《锻压技术》
CAS
CSCD
北大核心
2017年第2期160-166,共7页
Forging & Stamping Technology
基金
国家自然科学基金资助项目(51401177)
江苏省自然科学基金资助项目(BK2013222)
江苏省青蓝工程优秀青年骨干教师计划(苏教师2014-23)
徐州工程学院大学生创新创业基金项目(201526)
关键词
旋转通道等径角平行挤压
大塑性变形
变形均匀性
损伤
超细晶
parallel extrusion process of rotated channel and equal diameter angle
severe plastic deformation
deformation uniformity
damage
ultrafine crystal
