【作者】 沈华；

【导师】 王克鸿； 张德库；

【作者基本信息】 南京理工大学 ， 材料加工工程， 2012， 硕士

【摘要】 本文针对高强高硬中碳调质钢与大直径螺柱焊接的应用需要,研究采用感应加热／电弧螺柱焊这一焊接方法,开展了复合热源焊接方法、焊接工艺参数、焊接接头力学性能、微观组织等研究工作,充分优化焊接方法,获得实际焊接条件下的最佳工艺参数规范窗口,保证接头强度系数大于0.95。同时为满足现代工业生产高效化、自动化、智能化的发展趋势,研究开发全位置、各种焊接条件下自动送料、焊枪更换、陶瓷环夹持等相应焊接设备,编制程序,实现复合热源螺柱焊高效自动焊接。针对大直径实心螺柱焊接传统手工电弧焊、半自动气体保护焊等方法对焊接过程的严格要求以及焊接效率的低下,为满足现代工业高效智能自动焊接发展趋势,开展机器人自动焊接设备、控制接口、操作程序等研究,实现复合热源螺柱焊自动送料、焊枪更换、陶瓷环夹持等自动化,有效提升焊接效率。针对传统车体炮塔等内表面大量实心螺柱因采用手工电弧焊、半自动气体保护焊等落后焊接方法而伴随出现未熔合、气孔、夹杂等焊接缺陷,采用感应加热与电弧螺柱焊相复合的焊接方法,开展(?)16、22、27mm直径螺柱与30、45、80mm厚度高强高硬中碳调质钢焊接工艺研究,试验表明：在合适的焊接工艺规范窗口下,焊接过程稳定,焊后形成完美的具有外部强化作用的环形凸台,焊接接头强度系数大于0.95；接头微观组织研究表明,螺柱前端与母材表面加热熔化均匀,焊缝没有气孔、夹杂、未熔合、裂纹等缺陷,焊缝组织为马氏体与贝氏体,高强高硬中碳调质钢母材侧焊接热影响区组织为板条马氏体,未出现裂纹。针对实际焊接条件下存在的非对称结构以及高拘束状态条件下大直径螺柱与高强高硬中碳调质钢的焊接接头易出现延迟裂纹的现象,开展厚大构件冷裂模拟试验、焊接工艺试验、焊接接头残余应力分析、焊接接头焊缝组织含氢量分析等研究工作,分析表明高强高硬中碳调质钢自身高碳当量、高淬硬倾向、焊接接头含氢量以及焊接接头所处的拘束状态是高强高硬中碳调质钢焊接过程中出现延迟裂纹的主要原因,试验采用感应加热与螺柱电弧相复合的方式,能有效降低焊接接头残余应力、焊接接头含氢量,试验中试样为出现延迟裂纹。更多还原

【Abstract】 In this paper, in the view of the middle carbon steels in high strength and high hard conditioning with large diameter studs welding application, research use induction heating/arc stud welding this kind of method, and carried out the research work of the compound heat sources welding technology, welding parameters, the mechanical prorerty of the welding joints, microstructure of welding bead, sufficient optimize this welding method, gave out the optimum parameters of standard window in the actual welding conditions, and ensure the strength of welding joints is more than 0.95.As the same time to meet modern industrial production efficiency, automation, intelligent development trend, research and design the equipment of automatic feed, welding torch change, ceramic ring clamping no matter what kinds of diameters of the studs and the welding positons, program and realize the composite heat sources studs welding efficient automatic welding.For large diameter studs welding, traditional methods are manual arc welding or semi-automatic gas shielded welding, such kinds of methods are strict to welding request and the efficiency is low, to meet modern industrial production efficiency, automation, intelligent development trend, research and design the equipment of automatic feed, welding torch change, ceramic ring clamping no matter what kinds of diameters of the studs and the welding positons, program and realize the composite heat sources studs welding efficient automatic welding.In traditional body interior surface of tanks, there are a lot of large diameter studs welding by manual arc welding or semi-automatic gas shielded welding methods, appear incomplete fusion, porosity, mingled, etc welding defects. Research using induction heating/arc stud welding methods, and carry out the welding research of the 16,22,27mm diameter studs and 30,45,80mm thickness of high carbon steel, tests show that:in proper welding process specification window, the welding process stability, form perfect external circular convex platform that can strength the welding joints, the strength coefficient of welding joints is more than 0.95. The microstructure of welding bead shows that the front of the stud and the surface of the high carbon steel are heated and melt even, and do not find incomplete, porosity, crack,etc welding defects, the microstructure of welding bead is martensite and bainite, welding heat affected zone of high carbon steel side do not find crack. In the view of the actual welding conditions of existence asymmetric structure and high restrain of large diameter studs welding with high carbon steels, the welding bead always appears the phenomenon of delay crack. Research carried out the work of delay crack simulation test, welding process test, welding joint residual stress analysis, welding bead organization of hydrogen amount, etc, the analysis shows that the high carbon steel in hard condition, the high carbon equivalent, high hardened tendency, the hydrogen quantity of welding bead, the restrain of the welding joint are the most important elements of the phenomenon of delay crack.Using the method of induction heating/arc sutd welding can effectively reduce the residual stress of welding joint, the amount of hydrogen of welding bead, and test sample do not appear the phenomenon of delay crack.更多还原