上偏心距对等通道球形转角挤压影响的有限元分析
Finite element analysis of the effect of upper eccentricity on the extrusion of equal-channel spherical corners
佟鑫龙 1王晓溪 1唐环 1张飞1
作者信息
- 1. 徐州工程学院 机电工程学院,江苏 徐州 221018
- 折叠
摘要
等通道球形转角挤压(Equal Channel Angular Extrusion With Spherical Cavity,ECAE-SC)是集耦合剪切应变和正应变于一体的新型复合大塑性变形工艺,具有复合、连续、高效变形等优点.偏心距作为该工艺模具结构的重要参数之一,对金属的成形过程和变形行为有着重要影响.本文以塑性性能较好的工业纯铝作为研究对象,利用DEFORM-3D有限元软件对不同上偏心距条件下的ECAE-SC单道次室温变形行为进行有限元模拟,分析了挤压载荷、金属流动、等效应变、平均应力等场量的分布及变化规律.结果表明,上偏心距对挤压载荷变化趋势的影响不大,稳定变形阶段下坯料的最大挤压载荷约为3.15 kN.随着上偏心距的增加,金属的流动性得到显著提高,填充效果更好.当上偏心距增大时,坯料可获得较大的应变累积和良好的变形均匀性.同时,坯料保持高静水压力状态的时间更长,这对于提高材料塑性变形能力,获得理想的晶粒细化效果十分有利.本文模拟条件下,当上偏心距为2.5mm时,坯料整体成形效果最好.
Abstract
The Equal Channel Angular Extrusion With Spherical Cavity(ECAE-SC) process is a novel compound severe plastic deformation technique that integrates coupled shear strain and normal strain, having the advan-tages of compound, continuous and efficient deformation. The eccentricity, as one of the critical parameters of die structure in this process, has significant influence on the forming process and deformation behavior of the metal. In this study, commercial pure aluminum was taken as the research object due to good plasticity. Finite element simulations of single-pass-deformation of ECAE-SC process at room temperature under different upper eccentricity conditions were conducted by DEFORM-3D software. The distribution and variation of variables such as extrusion load, metal flow, effective strain, and mean stress were analyzed. The results indicated that the upper-eccentricity has little effect on the variation trend of extrusion load, and the maximum extrusion load of the blank in the stable deformation stage was about 3.15 KN. With the increase of the upper-eccentricity, the metal fiow was significantly improved, and the filling effect was better. When the upper eccentricity in-creased, the billet can obtain large strain accumulation and good deformation uniformity. Meanwhile, the billet maintained high hydrostatic pressure for a longer time, which was very beneficial to improve the plastic defor-mation ability of the material and obtain the ideal grain refinement effect. When the upper eccentricity was 2.5mm under the simulated conditions in this paper,the overall forming effect of the billet was the best.
关键词
复合大塑性变形/等通道球形转角挤压/上偏心距/有限元模拟Key words
Compound large plastic deformation/Equal channel spherical corner extrusion/Upper eccentrici-ty/Finite element simulation引用本文复制引用
出版年
2024
NETL
NSTL
万方数据