摘要堆焊是焊接的一个重要组成部分，堆焊自 50 年代发展至今，已经有了很大的发 展且应用很广。堆焊过程中材料的组织和化学成分会发生改变同时材料的性能会发生改善材料 组织中的夹杂物会使材料的性能发生变化。材料中的非金属夹杂物会降低钢的塑性、 韧性和疲劳寿命，使钢的某些物理性能降低，对钢的强度、延伸性、韧性、切削性、 抗腐蚀性能、表面光洁度、焊接性能等各方面的性能有着直接的影响。80639

在药芯焊丝中加入一定量的稀土元素，分别加入量为 0%、2%、4%、6%、8%，通 过对堆焊后组织中夹杂物的研究，掌握夹杂物与稀土元素添加量的关系。试验结果表 明，堆焊后焊缝中夹杂物的数量随着稀土元素的增加而减少且夹杂物的尺寸也会减少。 稀土的添加量为 4%左右时，焊缝的力学性能相对较好，强度较大。同时适当添加稀 土元素可以细化组织中的共晶碳化物。因此，本论文通过金相分析，扫描电镜，能谱 分析和硬度测试，提出最佳优化材料性能的稀土元素添加量，以获得高质量的产品。

毕业论文关键字：堆焊，稀土元素，铈，夹杂物

Abstract Surfacing is an important composition of welding, since the 50s, surfacing has been a great development and has used widely。

In the process of surfacing, the chemical composition of the material can change and the material performance will improve at the same time。 Inclusion in the material organization can change the material performance。 Non-metallic inclusion of material will reduce the plasticity, toughness and fatigue life of steels, reduce some of the physical properties of steel, ductility, toughness, machinability, resistance, welding performance and so on。

Add a certain amount of rare earth elements in flux-cored wire, addition amount are 0%, 0%, 4%, 6% and 8% respectively。 By the research of the inclusion in the organization after welding, we grasp the relationship between the inclusion and the amount of rare earth elements。 The test results show that the inclusions in the weld after welding will increased because of the increase of rare earth elements and the number of inclusions size can also be reduced。 While the rare earth content is 4%, the mechanical properties of the weld is relatively good and the intensity is bigger。 At the same time, appropriate amount of rare earth can refine the organization of eutectic carbides。 Therefore, in order to obtain high quality products, this study through metallographic analysis, SEM test, spectrum analysis and hardness test to put forward the optimal amount of rare earth elements which added to optimize material performance。

Keywords: surfacing, rare earth, Ce, inclusions

目录

第 1 章绪论 1

1。1 研究背景 1

1。2 研究的实际意义 2

1。3 夹杂物对焊缝性能的影响 2

1。3。1 夹杂物对强度的影响 3

1。3。2 夹杂物对塑韧性的影响 3

1。3。3 夹杂物对疲劳性能的影响 4

1。3。4 夹杂物对抗腐蚀性能的影响 4

1。4 稀土的作用机理 4

1。4。1 稀土对堆焊层组织和性能的影响 5

1。4。2 稀土在钢中的作用 6

1。5 本文研究的主要内容 7

第 2 章实验材料与方案 9

2。1 实验材料