镦挤拔模斜度对成形的影响规律研究

由于坯料在镦挤变形过程中要经过镦粗和挤压变形，给模具参数的选择带来一定的难度。凹模的拔模斜度是影响成形工艺的一个重要参数，关于拔模斜度大小的选取，目前尚无准确的公式、曲线或表格。论文以数值仿真技术为依托，建立了基于刚粘塑性有限元法的镦挤热成形工艺有限元模拟模型，利用塑性成形仿真软件DEFORM-3D对镦挤工艺进行模拟仿真，分析讨论了不同拔模斜度对镦挤热成形过程的影响以及成形过程中可能产生的缺陷，建立了基于数值模拟仿真模拟结果的最佳拔模斜度成形规律曲线，为指导镦挤工艺设计中凹模拔模斜度的选择提供了理论依据，也为其它挤压凹模斜度的选择提供了参考。

Study on the law of influence of drafting angle on upset-extruding

Upset extruding is a process often used in forging manufactureBut there are some difficulties in designing the mould parameters because of the complicated deformation in upset extruding processOne of the important parameters influencing the forming process is drafting anglesThere is no precise formulae, curves or tables, up to now, to direct the designingIn this paper, a rigid visco plastic model is constructed to describe the process of upset extruding, and then,analysis of the influence on the forming process results and defects produced in the process by employing different drafting angle are presentedAt the first time, curves based on numerical analysis and simulation technique are given to describe the relation between drafting angles and results of upset extrudingThese curves could be used not only as the theoretical support in optimizing the drafting angle of the upset extruding process, but also as a reference for other extruding processes