激光焊接TA2板材气孔及耐蚀性能

摘要本文通过改变激光功率、焊接电流以及焊接速度等工艺参数，进行 TA2 板材激光焊接，并通过金相和 SEM 及计算气孔率，来获得不同焊接工艺参数对焊缝气孔的影响。同时，本文采用氢氟酸腐蚀，对 TA2 工业纯钛激光焊接焊缝的耐腐蚀性能进行测试与分析。结果表明，当焊接速度不变时，随激光功率的增大，焊缝的平均气孔率呈先上升后下降的趋势；当激光功率不变时，随着焊接速度的增大，焊缝的平均气孔率呈先上升后明显下降的趋势； TA2焊缝的平均气孔率由氢的扩散程度和熔池液相存在时间两种控制因素决定，当这两种控制机制的影响均较弱时，焊缝的平均气孔率达到最大值。并且，由于气孔的出现，会引起耐蚀性能的降低。而在腐蚀性能方面，TA2纯钛母材的耐蚀性比 TA2 工业纯钛激光焊接焊缝的耐腐蚀性能能更加优良。在酸性的海水环境中，随着酸性的提高，焊缝的耐蚀性能降低。而在焊缝金相组织中，粗大的柱状α晶粒比针状α晶粒、锯齿状α晶粒和少量孪晶的耐蚀性能更优良。58956
毕业论文关键词：激光焊；TA2工业纯钛；气孔；耐蚀性能
Abstract In this paper, the laser power, welding current and welding speed and other parameters are changed in order. By means of metallographic, SEM and calculation of porosity, the effect of different welding parameters on the weld porosity was studied. At the same time, this paper uses hydrofluoric acid to corrode, corrosion resistance of weld test and analysis of the TA2 pure titanium laser welding. The results show that when the welding speed is constant, with the increase of the laser power, the average porosity of the weld increases first and then decreases. When the laser power is constant, with the increase of the welding speed, the average porosity of the weld increases first and then decreases obviously. The average porosity of TA2 weld is determined by the degree of diffusion of hydrogen and the existence time of molten pool liquid. When the two control mechanisms are weak, the average porosity of the weld can reach the maximum value. And, due to the appearance of pores, the corrosion resistance will be reduced. In terms of corrosion resistance, the corrosion resistance of TA2 pure titanium substrate is better than that of TA2 titanium laser welded joint. In the acidic seawater environment, the corrosion resistance of the weld is decreased with the increase of the acidity. In the microstructure of welded joint, the coarse columnar alpha grains are better than the corrosion resistant properties of needle like alpha grains, serrated alpha grains and a small amount of twins.
Keywords: laser welding; TA2 industrial pure titanium; porosity; corrosion resistance

第一章绪论.1

1.1激光焊接的发展与现状.1

1.2钛的性能特点及应用..2

1.3钛的耐蚀性能..5

1.3.1钛在酸性材料中的耐蚀性能.5

1.3.2钛的几种局部腐蚀特性6

1.4激光焊钛合金的主要缺陷7

1.5主要研究内容..8

第二章实验材料及方法10

2.1实验材料..10

2.2实验设备..10

2.3实验方法..12

2.3.1激光焊接实验气孔研究.12

2.3.2腐蚀实验.12

第三章实验结果与分析15

3.1激光焊接实验气孔分析..15

3.1.1焊缝气孔分布与形貌特征分析.15

3.1.2激光功率对气孔的影响.17

3.1.3焊接速度对气孔的影响.18

3.1.4气孔形成影响机理19

3.2腐蚀实验分析20

3.2.1失重法测腐蚀速率20

3.2.2焊缝及母材腐蚀形貌SEM分析..21

3.2.3腐蚀焊缝金相分析23

结论.26 激光焊接TA2板材气孔及耐蚀性能:http://www.youerw.com/cailiao/lunwen_63980.html