活性剂辅助激光焊接组织性能研究

发布时间：2018-01-10 16:48

本文关键词：活性剂辅助激光焊接组织性能研究　出处：《哈尔滨理工大学》2015年硕士论文　论文类型：学位论文

更多相关文章： 活性剂 激光焊接 焊缝成形 不锈钢

【摘要】：活性剂辅助TIG焊(A-TIG焊)自2000年在我国开始研究和开发以来，已经在不锈钢、钛合金等材料上得到了应用。使用活性剂后焊缝熔深得到提高，焊缝成形得到改善，并且提高了生产效率。激光焊接在国内外越来越得到广泛的重视，其焊接速度快，热影响区小，焊缝性能好。但受制于激光功率和成本的限制，如果需要焊接相对厚板，需要大的激光功率，这就意味着高成本的投入。本论文以不锈钢为研究对象，采用激光焊接方法，研究单一和混合活性剂对激光焊缝熔深、组织性能的影响规律，并通过高速摄像手段分析在活性剂应用前后激光焊接等离子体的形态的变化规律。通过半导体活性激光焊接试验和活性光纤激光焊接试验，对不同波长激光和活性剂作用进行了分析和论述。针对304奥氏体不锈钢采用对接和堆焊的激光活性焊接，通过进行金相显微分析、能谱EDS分析等方法，研究涂覆活性剂前后304奥氏体不锈钢焊缝熔深、深宽比、微观组织、焊缝化学成分的影响规律。结果表明，无论是半导体激光焊还是光纤激光焊，微观组织成分并没有改变，均为奥氏体枝晶。使用活性剂的焊缝组织中的柱状晶的生长方向与焊缝熔合线方向相互垂直，焊缝中心存在一部分等轴晶。活性剂在激光焊接中是有一定作用的，，四种活性剂的使用增加了熔深，其中SiO2活性剂、Cr2O3活性剂和混合活性剂分别使熔深增加50%、59%、75%，TiO2增加熔深不明显。在熔宽的变化方面，Cr2O3使得熔宽增加了3%，而涂敷其它三种活性剂的焊缝熔宽都减小了，复合活性剂的熔宽减少的最明显，减少了11%。
[Abstract]:Activity-assisted TIG welding (A-TIG welding) has been in stainless steel since its research and development began in China in 2000. Titanium alloy and other materials have been applied. With the use of active agent, weld penetration is improved, weld formation is improved, and production efficiency is improved. Laser welding has been paid more and more attention at home and abroad. The welding speed is fast, the heat affected zone is small, and the weld performance is good, but it is limited by the laser power and cost. If it needs to weld the relative thick plate, it needs large laser power, which means the high cost investment. In this paper, stainless steel is taken as the research object, and the influence of single and mixed active agent on the penetration depth, microstructure and properties of laser weld is studied by laser welding method. The changes of plasma morphology of laser welding before and after the application of active agent were analyzed by high speed camera. The experiments of semiconductor active laser welding and active fiber laser welding were carried out. The interaction of different wavelengths of laser and active agent was analyzed and discussed. In view of 304 austenitic stainless steel, laser active welding of butt and surfacing welding was adopted. Metallographic microanalysis, energy spectrum EDS analysis and so on were carried out. The effects of active agent on the weld penetration depth, aspect ratio, microstructure and chemical composition of 304 austenitic stainless steel were studied. The results showed that both semiconductor laser welding and fiber laser welding were used to weld 304 austenitic stainless steel. The microstructure of the weld is not changed, all of them are austenitic dendrites. The growth direction of columnar crystal in the weld with active agent is perpendicular to the direction of weld fusion line. There is a part of equiaxed crystal in the center of weld seam. The active agent has certain function in laser welding, and the use of four kinds of active agent increases the penetration depth, among which SiO2 active agent. The Cr2O3 active agent and the mixed active agent increase the penetration by 50%, respectively. The melting width is increased by 3% when Cr _ 2O _ 3 is used in the variation of the melting width. However, the weld width of the other three kinds of active agents was decreased, and that of the composite active agent was decreased by 11.1%.
【学位授予单位】：哈尔滨理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TG456.7

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