TIG焊用几种钨电极的焊接性能研究

发布时间：2018-06-26 11:37

本文选题：TIG焊 + 钨电极　；参考：《稀有金属》2014年05期

【摘要】：随着国家对具有放射性危害的钍资源有计划性的管理,钍的价格不断上升,推动了焊接领域环保钨电极替代钍的发展。对市场上现有替代钍钨的Ce-W,三元稀土W电极(La-Ce-Y)以及美国市场上积极推广的E3电极的焊接性能进行研究,采用钨极氩弧焊(TIG)直流正接(DCSP)的方法研究了几种电极的高温抗烧损性能,尺寸稳定性以及静特性曲线,并对燃弧后电极尖端的表面形貌进行了扫描电镜(SEM)观察,对稀土添加相La2O3,Y2O3,CeO2在电极尖端轴向分布进行了能谱分析(EDX)。对比试验结果发现,在焊接电流200 A工作5 h后,E3和WX电极的烧损量明显小于Th-W,Ce-W电极,且质量损失随时间呈近似的线性关系,尺寸稳定性好。从金相组织可以看出Th-W,Ce-W电极再结晶晶粒粗大,E3和WX电极的再结晶晶粒小,再结晶程度较弱,从侧面说明E3和WX电极工作温度较低,电子发射能力强。几种稀土氧化物的行为揭示了电极性能差异的本质原因,多元电极中,CeO2的扩散速率最快,使得其在小电流焊接和起弧过程中作用明显。Y2O3和La2O3热稳定性好,只有在较高温度时其扩散速率才明显增加,因此它们在大电流长时间焊接时作用突出。由于几种元素的协同作用,降低了电极表面的逸出功,并使得电子发射过程稳定。因此,三元稀土钨电极(WX)具有优异的焊接性能。
[Abstract]:With the planned management of radioactive thorium resources, the price of thorium is rising, which promotes the development of environmental protection tungsten electrode to replace thorium in welding field. The weldability of Ce-W, La-Ce-Y and E3 electrodes, which are used to replace thorium tungsten in the market, is studied. The DC direct current (DCSP) method of TIG welding is used to study the high temperature burn resistance of several kinds of electrodes. The size stability and static characteristic curve of the electrode tip were observed by scanning electron microscopy (SEM). The axial distribution of La _ 2O _ 3O _ 3Y _ 2O _ 3C _ 2O _ 2 at the tip of the electrode was analyzed by energy dispersive spectroscopy (edX). The results show that the burning loss of E3 and WX electrodes is obviously smaller than that of Th-WN Ce-W electrode after working at 200A for 5 h, and the mass loss is approximately linear with time, and the dimension stability is good. It can be seen from the metallographic structure that the recrystallization grains of Th-WCe-W and WX electrodes are small and the recrystallization degree is weak. It is shown from the side that the working temperature of E _ 3 and WX electrodes is lower and the electron emission ability is strong. The behavior of several rare earth oxides reveals the essential reason for the difference of electrode performance. The diffusion rate of CeO2 is the fastest in the multicomponent electrode, which makes it play an obvious role in the low-current welding and arc starting process. Y2O3 and La2O3 have good thermal stability. Only when the temperature is high, the diffusion rate increases obviously, so they play an important role in long time welding with high current. Because of the synergistic action of several elements, the escape work on the electrode surface is reduced, and the electron emission process is stabilized. Therefore, ternary rare earth tungsten electrode (WX) has excellent weldability.
【作者单位】：北京工业大学材料科学与工程学院;
【基金】：国家自然科学青年基金项目(50901003) 科技部国家科技支撑计划项目(2012BAE06B02)资助
【分类号】：TG434.5

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