摘要本次的课题是镦粗挤压防失稳模具结构设计。众所周知，在镦粗细长杆件的时候， 由于杆件的高径比大于 3，导致镦粗时发生失稳，严重影响了镦粗的成本和效率。一 次镦粗防失稳模具还没普遍应用工厂之中。因此，研究镦粗防失稳模具具有重要的意 义。通过模具的改进来使这种高径比大于 3 的细长杆件可以被一次加工。本文论述的 一种方案是通过活动凹模来固定杆件，使杆件满足镦粗的高径比。杆件露出活动凹模 的部分高径比满足防失稳的要求，活动凹模是通过凹模固定套来固定，活动凹模的起 始位置高于凹模固定套，墩头先将露出部分给镦粗；随后，当镦粗到镦头与活动凹模 接触的时候，活动凹模的作用体现出来了。在活动凹模随镦头下压的过程中，被活动 凹模包裹的需要镦粗的一部分金属就会向上流动，从而达到镦粗的目的。使用 UG 绘 图软件来对构想的模具建模。然后，使用 DEFORM 分析软件来对模具成形分析。模 拟模具的运动过程以及产品的成形过程，验证了方案是可行的。82595

毕业论文关键词： 失稳；高径比；镦粗；活动凹模

Abstract This is the topic I studied in the cold forging upsetting extrusion stabilization die structure design。 As we all know, when the thickness of long rod is upsetting, the bar height diameter ratio greater than 3 resulted in instability upsetting。 It makes serious impact on the cost and efficiency of upsetting。 An upsetting stabilization is not widely used in mould factory。。 Therefore, the research has important significance to prevent upsetting die instability。 Through the improvement of the mold to make this high diameter ratio of more than 3 of the slender rod can be processed once。 A scheme of this paper is a fixed bar through the activities to die, to meet the bar upsetting ratio of height to diameter。 The height diameter ratio of the bar out of the movable concave die is satisfied with the requirement of anti- buckling。 The movable concave die is fixed by the concave die fixing ring。 The starting position of the movable concave die is higher than that of the concave die fixing ring。 The pier head first exposed to upsetting。 When the upsetting to head contact with the movable concave die, the action of the movable concave die is reflected。 In the process of the movable concave die moving down with the heading , part of the metal which be encapsulated by active cavity and need upsetting will flow upward, so as to achieve the purpose of upsetting。 Using UG drawing software to design the concept of mold。 Then, DEFORM analysis software is used to analyze the die forming process。 The movement process of the mold and the forming process of the product are simulated to verify the feasibility of the method。

Keywords: Instability; Height to diameter ratio; Upsetting; Active concave die

目 录

第一章    绪论 1

1。1 镦粗 1

1。1。1 镦粗的介绍 1

1。1。2 镦粗的裂纹与防治 2

1。2 镦粗的现状及未来 2

1。3 细长杆件的镦粗 3

1。4 UG 的概要和在镦粗模具计算机辅助设计方面应用 4

1。4。1 UG 的简介 4

1。5 DEFORM 的简介以及操作功能 5

1。6 本文主要内容 7

第二章    零件分析以及防失稳模具方案的选择 8

2。1 镦粗模具设计流程