熔丝钨极氩弧焊工艺研究

发布时间：2018-05-26 03:34

本文选题：熔丝钨极氩弧焊 + 工艺　；参考：《沈阳理工大学》2017年硕士论文

【摘要】：传统钨极氩弧(TIG)焊虽然焊接过程稳定,焊接质量好,但是焊接效率低;传统的熔化极氩弧(MIG)焊虽然焊接效率相对于传统TIG焊较高,但是焊接过程不稳定,有飞溅存在。熔丝钨极氩弧焊(Tungsten Inert Gas)的焊接方法是在总结了传统TIG焊和MIG焊的优缺点的基础上提出的,其工作原理为:焊丝和工件同时并联接在电源的正极,钨极接在电源的负极。焊接开始时,钨极与焊丝和工件都产生电弧,并且钨极与工件产生的电弧可以熔化工件,钨极与焊丝产生的电弧用来熔化焊丝,因此可以提高焊接效率。本论文设计了熔丝TIG焊系统,实现了稳定的熔丝TIG焊接。使用ER50-6焊丝在Q235钢板上进行了熔丝TIG堆焊,研究了焊接工艺参数对焊接过程的稳定性以及焊缝成形的影响,并且对合适工艺参数下的对接接头进行了组织和力学性能的分析,并计算了焊接过程中的飞溅率。与合适工艺参数下的MIG焊和TIG焊进行了飞溅率以及焊接接头的组织和力学性能的对比。在Q235钢板上堆焊了304不锈钢焊丝,测量了合适工艺参数下熔丝TIG焊的熔合比,并与MIG焊进行了对比。熔丝TIG对接焊的合适工艺参数为:焊接设定电流150A,焊接电压20V,焊接速度210mm/min,钨极距离工件6~8mm,MIG焊枪与TIG焊枪同时通气,气体流量分别为10~12L/min。熔丝TIG焊焊缝的组织为珠光体和铁素体,垂直于熔合区呈柱状晶长大,并带有少量的渗碳体,在焊缝上部为等轴晶,焊缝组织较细小。熔丝TIG焊焊缝的硬度为200~230HV,低于MIG焊和TIG焊焊缝硬度;接头拉伸强度500MPa,稍高于MIG焊接头拉伸强度,和TIG焊接头拉伸强度相当;焊缝冲击吸收功27.5J,高于MIG焊和TIG焊焊缝冲击吸收功;室温下的冷弯角可达180°,与MIG焊和TIG焊接头相当。熔丝TIG焊的飞溅量与TIG焊非常接近,飞溅率仅有0.057%,远低于MIG焊的2.984%,焊接过程比较稳定。熔丝TIG焊的熔合比达到17.34%,低于MIG堆焊的23.532%。
[Abstract]:Although the traditional TIG welding process is stable and the welding quality is good, but the welding efficiency is low, the traditional welding efficiency is higher than that of the traditional TIG welding, but the welding process is unstable and spatter exists. The welding method of Tungsten Inert Gas is put forward on the basis of summarizing the advantages and disadvantages of traditional TIG welding and MIG welding. The working principle is as follows: the wire and workpiece are connected to the positive electrode of the power source at the same time, and the tungsten electrode is connected to the negative electrode of the power source. At the beginning of welding, both tungsten electrode and welding wire and workpiece produce arc, and the arc produced by tungsten electrode and workpiece can melt the workpiece, and the arc produced by tungsten electrode and welding wire can be used to melt the wire, so the welding efficiency can be improved. In this paper, a fuse TIG welding system is designed, and a stable fuse TIG welding is realized. Fuse TIG surfacing welding was carried out on Q235 steel plate with ER50-6 wire. The effect of welding parameters on the stability of welding process and weld forming was studied, and the microstructure and mechanical properties of butt joint were analyzed. The spatter rate in welding process is calculated. The spatter rate, microstructure and mechanical properties of the welded joints were compared with those of MIG welding and TIG welding under appropriate process parameters. 304 stainless steel wire was surfaced on Q235 steel plate. The fusion ratio of TIG welding was measured and compared with that of MIG welding. The suitable technological parameters of TIG butt welding are as follows: welding current 150A, welding voltage 20V, welding speed 210 mm / min, tungsten electrode distance 6 mm ~ 8 mm and TIG welding torch simultaneously ventilating, gas flow rate is 10 ~ 12 L / min. The microstructure of the weld of TIG welding is pearlite and ferrite. The microstructure of the weld is columnar crystal growth perpendicular to the fusion zone and a small amount of cementite. In the upper part of the weld is equiaxed crystal and the microstructure of the weld is smaller. The hardness of welding seam of fuse TIG welding is 200230HVwhich is lower than that of MIG welding and TIG welding weld, the tensile strength of joint is 500MPa, which is a little higher than that of MIG welding joint, and the tensile strength of TIG welding joint is equivalent to that of TIG welding joint, the impact absorption energy of weld seam is 27.5J, which is higher than that of MIG welding and TIG welding weld. The cold bend angle can reach 180 掳at room temperature, which is equivalent to that of MIG welding and TIG welding. The spatter amount of fuse TIG welding is very close to that of TIG welding, and the spatter rate is only 0.057, which is much lower than that of MIG welding, and the welding process is relatively stable. The fusion ratio of fuse TIG welding is 17.34, which is lower than that of MIG surfacing welding.
【学位授予单位】：沈阳理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG444.74

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