高氮钢TIG焊接工艺研究

摘要本文利用高氮合金焊丝对自制的高氮奥氏体不锈钢薄板进行 TIG 对焊焊接，采用 TIG电弧热源设计合理焊接工艺，通过控制焊接电流、焊接速度、送丝速度等参数对试验进行优化，得到焊缝成形良好的对接接头，对高氮钢焊接接头进行研究。并通过分析了高氮钢 TIG 焊所获得的焊接接头的外观形貌、微观组织、显微硬度以及抗拉强度等接头性能，采用金相显微镜对接头处及固溶接头组织形貌进行观察发现热影响区奥氏体粗大，受热应力影响而长大，主要成分为奥氏体、铁素体以及氮化物；并作显微硬度和抗拉强度检测发现热影响区具有“软化”作用，热影响区硬度为 310Hv 小于母材硬度 320Hv；对于焊接接头的抗拉强度为977Mpa，抗拉强度达到母材的92％。42526
毕业论文关键词高氮钢钨极氩弧焊显微硬度抗拉强度
Title The study on TIG welding process of high nitrogen steel
Abstract This paper uses high nitrogen alloy wire of high nitrogen austeniticstainless steel sheet made of TIG butt welding.TIG arc heat source isadopted to design reasonable welding technology. The parameters of weldingcurrent, welding speed and wire feed rate are controlled to optimize thewelding process.The welding joint of high nitrogen steel wasstudied.Design the reasonable welding process, confirm the welding processof TIG ， Get good weld butt joints, defect analysis of weldedjoint.Microstructure of the joint and the structure of the solid solutionwere observed by metallographic microscope,It is found that the heataffected zone is affected by the thermal stress, the main components ofthe heat affected zone are austenite.Micro hardness test and tensilestrength test show that the heat affected zone has a "softening" effect.Thehardness of the heat affected zone is 310Hv less than the base metalhardness 320Hv.The tensile strength of the welded joint is 977MPa ，thetensile strength reaches 92% of the base metal.
Keywords high nitrogen stainless steels TIG Micro hardness tensilestrength

1引言1

1.1引言1

1.2高氮奥氏体不锈钢性能概述..1

1.3钨极氩弧焊概述...2

1.4高氮钢焊接研究现状...3

1.5本章小结5

2试验材料、设备及方法..6

2.1试验材料6

2.2试验设备.8

2.3试验方法..10

2.4本章小结..13

3高氮奥氏体钢母材的制备14

3.1高氮奥氏体钢母材的冶炼14

3.2高氮奥氏体钢板材的加工14

3.3本章小结..16

4高氮钢TIG焊基础工艺试验...17

4.1焊接速度对焊缝成形的影响17

4.2焊接电流对焊缝成形的影响.18

4.3焊接缺陷及预防措施.19

4.4本章小结..21

5焊接接头组织及力学性能分析23

5.1焊接接头金相制备.23

5.2焊接接头组织特征.24

5.3焊接接头力学性能.25

5.4本章小结..28

结论29

致谢30

参考文献.31
1 引言1.1 引言高氮奥氏体不锈钢利用高含量的N部分或者完全替代贵重合金元素镍且其自身具有良好的力学性能（具有高强度、高韧性、耐腐蚀性强等特点）受到国际冶金届的高度重视[1]，但由于高氮奥氏体不锈钢在焊接的过程中会出现焊缝逸氮、焊接容易产生裂纹、焊接热影响区晶粒粗大等问题，因此对于高氮钢焊接性的研究很有意义。本次试验为探究高氮钢对接焊接特性，利用TIG对接焊接方法进行设计高氮钢焊接接头、试验测定TIG 焊的焊接工艺、分析高氮钢焊缝的逸氮问题、以及对焊接区域形态和组织特征分析，并且对高氮钢TIG 焊焊缝的缺陷和力学性能进行测试分析，进一步分析TIG对焊对高氮钢性能的影响机理。针对高氮奥氏体不锈钢在 TIG 焊接中可能遇到的困难，本此试验的主要目的和内容包括：高氮钢TIG焊接工艺研究:http://www.youerw.com/cailiao/lunwen_43021.html