贴覆焊剂片超窄间隙焊

【作者】 那雪冬；

【导师】 朱亮；

【作者基本信息】 兰州理工大学 ， 材料学， 2004， 硕士

【摘要】 超窄间隙焊接采用间隙尽量小的I形坡口得到高质量焊接接头的一种高效率焊接技术，受到各国广泛关注。超窄间隙焊解决的技术关键是侧壁熔合问题，各国的焊接专家在攻克这一技术难关上，发明了各种电弧摆动或旋转方法，但这些方法使焊接过程的控制及设备更为复杂，因此，限制了窄间隙焊在某些领域中的实际应用。，本论文研究的窄间隙焊接技术，通过将坡口间隙减小到5mm以下，保证坡口侧面熔透。为了防止电弧沿坡口侧壁攀升，将自制的焊剂片贴覆于坡口面上，对电弧起到绝缘和保护作用，保证了电弧的稳定性。实现不需任何电弧摆动的每层一道超窄间隙焊接。本论文对这相焊接新技术进行了工艺试验研究和机理探索。 首先对坡口间隙宽度、焊剂片厚度及成分对焊缝成形的影响进行了试验研究，确定出本超窄间隙焊合适的焊接间隙是3.5mm，合适的焊剂片厚度是0.5mm。焊剂片成分对贴覆焊剂片超窄间隙焊至关重要，本文将钛钙型、氧化铁型、低氢型等八种配方用于超窄间隙焊剂片的可行性试验。最终确定以大理石和萤石为主体的低氢型焊剂片比较适合本方法的窄间隙焊接，研究发现当超窄间隙焊焊剂片具有熔点较高、渣的含量较少、黏度适中时、凝固温度较低时焊缝成形较好。 本文采用大理石和萤石为主体的焊剂片成分，进行了焊接规范参数对焊缝成形及焊接缺陷影响的试验研究。发现超窄间隙焊的焊接电压范围在21～24V，电流在210～270A能够得到较好的焊缝成形。同时，当焊接电压、焊接电流与焊接速度满足一定的匹配关系时可以避免焊缝中的缺陷。如果不满足这样的匹配关系，可能引起电弧的攀升和铁水的溢流现象，造成焊缝搭桥和夹渣缺陷。进一步研究表明，焊接电压增加，电弧对坡口侧壁作用加强，母材熔宽增加；焊接电流增加，熔高增加；焊接速度降低，熔宽与熔高都会增加。更多还原

【Abstract】 The ultra-narrow-gap welding is a high efficient welding technology whose gap is shape I and is widely concerned by many nations. The technical key of the ultra-narrow-gap welding is that gap always gets bad fusion. Many experts from different nations have invented many kinds of methods, such as arc oscillating and arc rotating, but these methods made control of the welding process and equipment more complex. Thus, the application of the ultra-narrow-gap welding is limited in many fields. The paper is researching the ultra-narrow-gap welding whose width of gap is reduced to 5mm or less to make sure that the gap is fused. The self-regulating boned flux is stuck on the gap , which can prevent welding welding arc burning up along the gap and ensure arc stabilization. The ultra-narrow-gap welding ,which weld one time on one layer without arc scillating is realized. The paper studied the new technology and explored principle by process experiment.First of all, we studied the influences of the width of gap, thickness and the component of boned flux through experiment. We found that the most appropriate width of the gap is 3.5mm, and the thickness of boned flux is 0.5mm in the ultra-narrow-gap welding. The component of flux is very important to the ultra-narrow-gap welding process with the boned flux on groove adopted. We adopted eight kinds of prescription to experiment in the paper and draw a conclusion that the prescription whose primary component is marble and fluorite is more appropriate to the ultra-narrow-gap welding. We have carried out many demonstration experiment to show that the molding of welding line is better when the boned flux has high molten point, the ingredient of slag is small and the freezing point is lower.Using the boned flux with marble and fluorite as primary component, we have studied the influences of the welding process parameters on the welding line and weld defect by many experiments. We discover that appropriate welding voltage is 21~24V,and appropriate welding current is 210-270A in the ultra-narrow-gap welding. When welding voltage is between 21V and 24V and welding current is between 210A and 270A, better welding line can be obtained. At the same time, welding defect can be avoided when welding voltage , welding current and welding velocity are better matched. If this relationship of matching cannot be satisfied well, the welding arc will burn up along the gap and molten steel is likely to overflow, resulting that the slay is larded in welding line. More research show that if welding voltage is increased, the influence of arc on groove of gap will increase. If welding current is increased, the molten highness will increase, and if welding velocity is decreased, molten width and molten highness will both increase.更多还原