摘要随着现代工业的不断发展，对异种金属的焊接要求越来越高，尤其是对两种物理 及化学性能相差较大的异种金属焊接更为困难。铜与不锈钢是两种物理和化学性能差 别极大的两种金属，焊接接头两侧的温度场和熔池流场对焊接接头质量有着重要影响。 本课题主要研究铜/钢等离子弧焊熔池流场行为，具有重要的理论意义。

本次实验选取的材料是 2mm 厚的 T2 紫铜板和 304 不锈钢板，采用的焊接方法 是等离子弧焊，通过焊接电流、焊接速度和等离子气流量之间的不同参数搭配对试板 进行焊接。经过多次的实验确定了铜/钢等离子弧焊的参数搭配，通过扫描电镜和金 相实验验证了焊接接头的成分组织和力学性能，通过显微硬度对材料焊接接头的接头 性能进行了研究分析。

众所周知，焊接过程是一个十分不稳定的过程，对等离子弧焊接熔池流场的直接 测量研究是很不现实的，不仅浪费时间还浪费人力物力，而焊接熔池流场的数值模拟 则能很好的解决上面的问题。通过建立焊接熔池流场的三维模型在计算机上进行模拟 焊接过程，通过有限元分析软件进行分析，可以更好的研究等离子弧焊接熔池流场。 这对优化等离子弧焊焊接参数，提高焊接接头的力学性能以及使铜/钢异种金属焊接 的应用更加便捷具有深远的意义。

毕业论文关键词：等离子弧焊；焊接熔池流场；数值模拟

ABSTRACT With the continuous development of the modern industry, the welding of dissimilar metals have become increasingly demanding in our work, but in the welding process it is difficult to find suitable welding method and welding parameters now。 Therefore, for welding tie-in, copper and stainless steel two kinds of physical and chemical properties of relatively large difference materials need us to research。 This has important significance for the application of dissimilar materials such as copper and stainless steel。

This paper selects material is 2mm thick T2 copper and 304 stainless steel plate and plasma arc welding method is used。 We choose different collocations of welding current, welding speed and plasma gas to test。 After a lot of experiments, we have established the parameters of the plasma arc welding of copper and stainless steel, and the microstructure and properties of the welded joints were clearly defined by SEM。 The mechanical properties of the welded joints of the materials were investigated by hardness test and tensile test specimen。

As all of us know, welding procedure is a very unstable process。 The direct measurement of weld pool parameters is very unrealistic, it is not only cost a lot of time but also wasting money。 However, welding temperature field numerical simulation is very good to solve the above problems and the best method is to establish the mathematical model of molten pool and Simulating welding process on computer。 Through the finite element analysis software to carry on the analysis。 It is important to improve the optimization of welding parameters and the properties of welded joint。 and it has far-reaching significance on copper and steel dissimilar metal welding application。

Keywords: plasma arc welding; welding molten pool flow field; numerical simulation

目  录

第一章  绪论 1

1。1  选题背景及意义 1

1。2  等离子弧焊特点及发展现状 2

1。3  铜/钢异种金属焊接特点及发展现状 2

1。4  铜/钢数值模拟研究 4

1。5 流体软件 Fluent 的介绍 5

1。6  本课题研究内容