摘要：本次设计任务是设计大高径比镦粗挤压防失稳模具并进行数值模拟，分析零件的成形情况及模具的可行性。正常镦粗的高径比是0.5—3，高径比大于3就是大高径比镦粗，大高径比的坯料镦粗一般都会发生弯曲现象。但是在工业生产中经常用到大高径比坯料一次镦粗成形的零件，直接使用，所以对大高径比坯料的镦粗研究具有非常重要的意义。

本文就是通过设计活动凹模将坯料分为两部分，活动凹模包裹住一部分坯料，使裸露在外面的坯料高径比小于3，这样模具先镦粗裸露再外的部分，再和活动凹模一起向下运动，镦粗包裹在活动凹模里面的坯料，在整体的镦粗过程中高径比一直小于3，毛坯就不会失稳弯曲。模具设计是本文的基础，模拟是重点，用UG软件设计出模具的三维图，用CAD软件绘制二维图，再用DEFORM软件模拟模具的运动过程和金属材料的流动过程。模拟选择了分组对照实验，分别对不同凹模高度、不同毛坯、不同网格和其他参数下的模拟实验，找到最优参数和最合理的毛坯尺寸，根据模拟效果判断模具的可行性，改进模具结构，提高了设计效率。

关键词：大高径比；镦粗；失稳；模具；模拟

Abstract：The design task is to design large diameter ratio upsetting extrusion anti-instability mold and numerical simulation, analysis of parts forming and mold feasibility. Large aspect ratio of the blank upsetting will generally occur in the bending phenomenon, but in the industrial production needs a one-time large diameter ratio of the blank upsetting, making it into the required parts, direct use. Therefore, it is very important to study the upsetting of large diameter ratio blank.

This paper is through the design of the activities of the mold is pided  into two parts of the blank, the activities of the die wrapped around a part of the blank, so that exposed to the outside of the blank diameter ratio of less than 3, so that the first part of the mold up and out of the exposed part, With the downward movement, upsetting wrapped in the active dies inside the blank, in the overall upsetting process, the diameter ratio has been less than 3, the rough will not bend instability. Mold design is the basis of this article, simulation is the key, with UG software design of the mold of the three-dimensional map, with CAD software to draw two-dimensional map, and then use DEFORM software simulation mold movement process and metal material flow process. In the simulation experiment, the experiment is selected, and the optimal parameters and the most reasonable roughness are found for the different dies, different blanks, different grids and other parameters. According to the simulation results, the feasibility of  the mold is improved, Structure, improved design efficiency.

Keywords: Large diameter ratio; Upsetting; Instability; Mold; Simulation

目录

第一章 绪论 1

1.1锻造简述 1

1.2镦粗 1

1.2.1镦粗简介 1

1.2.2镦粗未来的发展方向 2

1.3镦粗挤压 2

1.3.1镦粗挤压简介 2

1.3.2大高径比毛坯的镦粗挤压 3

1.4UGNX建模软件简介 3

1.5DEFORM成形模拟软件 4

1.5.1DEFORM成形模拟软件简介 4

1.5.2DEFORM软件操作流程 4

1.6本文主要内容