The Research On The Technology Of Ultra-narrow Gap Arc Welding With Transport And Lay The Chain Of Flux Plates

Ultra narrow gap welding has a wide application prospect because of its incomparable advantages over conventional welding methods and has roused wide attention. Among them, arc flux plates constraints welding technology has been developed, but the stability of welding process needs to be further improved. How to accurately and reliably transport and lay the flux plates to the bottom of the groove is the key problem of ultra narrow gap welding arc flux plates constraints. At the same time, the relative position of flux plates in the groove is a critical factor on arc flux plates constraints, the distance between the welding wire with flux plates directly affects the stability of arc. The technology of Ultra-narrow gap arc welding with transport and lay the chain of flux plates will be put forward in this paper.Firstly, the device of Ultra-narrow gap arc welding with transport and lay the chain of flux plates was designed and manufactured which consists of the flux plates automatic transmission device and welding torch. The flux plates automatic transporting device brings about the automatic feeding of the flux plates and the precise control of the relative position of the welding wire and the flux plates, and the flux plates transporting speed can be adjusted so as to keep pace with the welding speed. Based on the preliminary design of the welding torch, the welding gun head and welding torch insulation has been redesigned in order to ensure the wire and conductive mouth reliable contact and the welding gun perform good insulation under the high temperature environment.Secondly, based on this device, the influence of the distance between the welding wire and the flux plates and the arc voltage on the arc stability is studied. The arc characteristics under different gap distances are analyzed by collecting the welding current and voltage waveforms. In certain groove width and the appropriate welding process parameters, obtaining the distance range between welding wire and flux plates when flux plates constraint arc effectively, and the groove sidewalls and root are complete fusion. The range of arc voltage and the changing tendency of the welding voltage are determined by changing the welding voltage in the range of the gap distance.Thirdly, U71 Mn rail has been welded in order to test the welding feasibility of this equipment in the special circumstances. The results show that the device can weld smoothly and efficiently in a width of 4mm, 176 mm depth of the I-shaped groove. The welded joint has no obvious weld defect and welding quality is reliable. It’s structure maintain stable at preheat temperature of 400℃ and welding process is smooth.Finally, designing and producing the ultra narrow gap weld grinding device in order to solve the ultra narrow gap weld grinding problems, which can grind weld effectively in a 200 mm depth of I-shaped. The operation is simple and convenient.