三通件多向加载成形热力耦合有限元分析

多向加载是通过在轴向和侧向同时或顺序地施加载荷,可以一次成形出多个方向上具有空腔的复杂构件,减少了加工工序,且提高了成形质量,为高效率、高质量成形复杂整体构件(如三通件)提供了有效途径。然而,三通件多向加载成形影响参数多、机理复杂,本文基于DEFORM-3D,建立了三通件多向加载成形热力耦合刚粘塑性有限元模型,并验证了其可靠性。在此基础上确定了加载方案,获得40Cr钢三通件多向加载成形过程中行程载荷曲线及速度场、温度场、应力-应变场的分布规律。结果表明,按本文确定的加载方案,成形初期在水平支管上出现明显的分流线,分流线处易出现裂纹;水平支管先于垂直支管成形完毕,在水平支管成形完毕时水平冲头的载荷迅速升高,而当整体成形快完毕时,水平冲头和垂直冲头的载荷都急剧升高;成形过程中坯料芯部为大变形区,变形速率大,塑性变形热使坯料芯部出现明显温升。该研究为三通件多向加载成形工艺参数的优化,以及缺陷的控制,提供了指导。

Coupled thermal-mechanical FEM analysis on multi-way loading forming process of triple valve body

Multi-way loading forming process is a effective way to form the complex structure integral components (such as triple valve body), with loading in axial direction and lateral direction at the same time or in sequential. During the forming process, not only the procedures were decreased but also the quality of the product was improved. Considering the complicated forming mechanical and the numerous influence factors in the multi-way loading forming process, a sound 3D coupled thermal-mechanical rigid-viscoplasticity FEM model for multi-way loading forming process of triple valve body is established based on the software DEFROM-3D, and its reliability is validated. Then, a reasonable loading program is established, and the distribution of velocity field, temperature field, effective stress field, effective strain field and the load during the multi-way loading forming process of 40Cr triple valve body are discussed and analyzed. The result show that the diversion line appear on the horizontal branch tube at the loading program in the text, where crack is easy to appear. The horizontal branch tube is formed before the upright branch tube. The load of horizontal punch increase rapidly when the horizontal branch tube is formed completely, but the load of hori-zontal and upright punches increases rapidly together when the forming is completed. The high temperature region centralizes in the center of the billet with large deformation and deformation velocity, where the temperature increases obviously because of the plastic deformation energy. The achievements of this research provide guidelines for the controlling of disfigurement and the opti-mization of parameters.