摘要本课题对2mm厚的锆R60702试板的等离子焊接工艺进行了探究，通过试验找到了等离子焊接的最佳工艺参数，并对焊接后的焊缝进行了力学性能测试，显微硬度检测，显微金相观察及扫描电镜成分分析。67487

试验结果表明，当电流为100A，焊速50cm/min，离子气流量2.0L/min，可得到良好的焊缝外观成型。通过拉伸试验和显微硬度检测，焊缝区的强度较高，抗拉强度为445.13Mpa，符合标准；在焊缝区硬度值最高，约为170HV0.3，热影响区约为160 HV0.3，母材区约为150 HV0.3。金相观察发现R60702进行等离子弧焊后，焊缝区为针状马氏体组织，热影响区组织与焊缝相似，晶粒更加粗大，母材区为等轴晶组织，。扫描电镜成分分析结果表明，焊缝区及热影响区内部组织成分与母材相均为Zr，焊缝内部未受污染，焊接工艺较好。

毕业论文关键词  锆R60702  等离子弧焊  机械性能   微观组织

毕业设计说明书（论文）外文摘要

Title    Study on weldability of Zirconium alloys                     

Abstract

This paper mainly studies weldability of 2mm thick plate of zirconium R60702 through plasma arc welding. And the optimum process parameters of plasma welding was found. mechanical properties, microhardness testing, Metallographic observation and scanning electron microscopy component analysis of the weld has been tested.

The results show that, in the welding current of 100A, the welding velocity

 of 50cm/min, the plasma gas flow rate of 2.0L/min, the appearance molding is the best. Through tensile test and hardness test, the tensile strength is 445.13Mpa in weld zone, which is conform to the standard. In the weld zone, hardness value is about 170 HV0.3, which is the highest. In heat affected zone, it is about 160 HV0.3. In  the parent metal zone, it is about 150 HV0.3. Metallographic observation found that the microstructure is acicular martensite in the weld zone. the grains of heat affected zone is similar to weld zone, but more coarse, the microstructure of parent metal zone is equiaxed grains. SEM analysis showed that internal components of weld zone, heat affected zone and parent metal are all Zr. It tells that the weld seam is unpolluted and the welding procedure is good.

Keywords   Zirconium R60702    plasma arc welding     microstructure

Mechanical properties     

目  录

1  绪论 1

1.1  锆及锆合金特性及应用现状 1

1.2  锆及锆合金焊接性研究现状 2

1.3  等离子弧焊技术 4

1.4  课题的研究意义与研究内容 6

2  试验材料及设备 8

2.1  试验材料 8

2.2  试验设备 8

3  锆R60702等离子焊接工艺及焊缝成型分析 12

3.1  锆R60702等离子弧焊工艺设计 12

3.2  锆R60702等离子弧焊工艺试验 13

3.3  焊缝成型分析 15

3.4  本章小结 17

4  锆R60702焊接接头机械性能及组织成分分析 18

4.1  锆R60702焊接接头机械性能分析 18