钛合金发动机壳体等离子焊接工艺研究

摘要本毕业论文采用小孔型等离子弧焊接工艺对板厚3mm的TC4钛合金板材进行焊接。分析了不同工艺参数条件下焊接接头成形及组织特点，并测定焊接接头的显微文氏硬度。研究结果表明：当热输入较大、等离子气流量较小时，等离子弧焊焊缝成形效果较好。热输入大小对焊接接头组织影响很大。热输入大时，焊接接头中焊缝区柱状晶晶粒长大明显，粗晶区晶粒粗大、晶界明显，细晶区变窄，细晶区与母材的分界线更为清晰。焊接接头粗晶区显微硬度下降，焊缝区平均显微硬度与母材基本一致。用选出的焊接工艺参数对钛合金板材进行对接，能得到成形良好的焊缝。
关键词 TC4钛合金等离子弧焊接微观组织显微硬度10188
毕业设计说明书（论文）外文摘要
Title   study on plasma welding to titanium alloy engine case
Abstract
This paper adopts the keyhole plasma arc welding process on the plate thickness of 3mm TC4titanium alloy sheet for welding. Analysis of the different parameters of welded joint forming and characteristics of the organization, and determination of micro Vickers hardness of welded joint. The results show that: when the heat input is larger, plasma gas flow is smaller, plasma arc welding seam forming effect is better. Heat input size has a great impact on the structure of welded joint. heat input, welded joints weld columnar grain growth significantly, coarse grained zone of coarse grains, grain boundaries obviously, fine grain zone is narrowed, fine grained zone and base material boundaries more clearly. Heat input size on the welding joint have great influence on the organization. When the heat input welded joint weld zone, columnar grain growth significantly, coarse grained zone of coarse grains, grain boundaries obviously, fine grain zone is narrowed, fine grained zone and base material boundaries more clearly. Welded joint of coarse grain zone the hardness decreased, the weld zone average hardness and parent material and consistent. With the selected welding parameters for titanium alloy sheet for docking, can get good weld forming.
Keywords TC4 titanium alloy plasma welding microstructure
           microhardness目   次
1   引言   1
1．1   课题的意义   1
1．2   钛合金的性能及其应用   1
1．3   钛合金焊接的主要问题   3
1．4   钛合金常见焊接方法   4
1．5   钛合金采用等离子弧焊接的优点   6
1．6   论文研究的内容   7
2   试验材料及试验方法   8
2．1   试验材料   8
2．2   试验设备   8
2．3   实验方案设计   10
3   小孔型等离子焊焊缝成形及微观组织分析   11
3．1   焊缝成形分析   11
3．2   接头宏观金相分析   13
3．3   接头微观金相分析   14
3．4   本章小结   18
4   小孔型等离子焊焊接接头力学性能分析   19
4．1   接头硬度分析   19
4．2   本章小结   20
5   等离子对接焊接试验   21
结论   24 钛合金发动机壳体等离子焊接工艺研究:http://www.751com.cn/cailiao/lunwen_9171.html