The Optimization Of The Head Of Multi-wire Submerged Arc Welding And The Research On Welding Technique Of Q235

With the optimization and repairing of rolls, pressure vessels, pipes becoming more and more important, the application of cladding in industrial field put forward higher and higher standards and requirements. Because of the traditional strip cladding on the choice of materials, equipment maintenance, manufacturing cost is still the inevitable problems, therefore, this paper puts forward a new method of welding process with parallel wires named multi-wire submerged arc welding and use Q235 low carbon steel, 309 L austenitic stainless steel as the welding materials to analyze and study the direction of head design, process parameters and organizational performance.The optimal design of the equipment and the welding head is the key factors to guarantee the process’ s stability of multi-wire submerged arc welding. The experiment includes LincolnPower Wave AC/DC 1000 SD power supply, XM controller, X-Feeder four wires feeding system, and through the analysis of the power supply module, the structure of the wire conduit, the structure of the gasket, the influence factors of several aspects, to design the overall structure of the torch body. Experiment chooses CV-DC+5/64 steel power supply module, using the wire feed tube of Teflon and the structure of tight on the wire rack, the wire conduit and contact position using chamfering structure, wire feeding machine and control the Angle between wire feeding machine and wire conduit at 85 °, wire conduit clearance is 12 mm, the welding process can be stable, efficient, dilution rate of surfacing after welding is minimal.Multi-wire submerged arc welding in the welding parameters are mainly include the beginning segmental arc voltage, welding voltage, welding speed and wire feed speed. Using larger beginning segmental arc voltage, the smaller welding voltage and the matching welding speed and feeding speed can get good forming. Reduce the welding speed, improve test plate thickness, increasing preheat temperature can reduce the welding layer crack. The HAZ of multi-wire submerged arc welding include the overheated zone, fully recrystallization zone, incomplete recrystallization zone; Surfacing layer includes the flat crystal area, the columnar crystal area, mixed crystal area. When large amount of heat input, overheated zone appears obviously widmanstatten structure; With the increase of the amount of heat input, the decarburization layer carburizing layer near the fusion is increased, fully recrystallization zone and incomplete recrystallization zone also increases; Multi-layer welding, the overheat region of heat affected zone will not form massive ferrite organization, instead of tiny composed of isometric zone of ferrite and pearlite, and formed larger area of complete recrystallization zone. In bending test, when the line energy is small, cladding layer are prone to crack; when the line energy is larger, the fusion line will be easy to crack. A little effects on the tensile properties of the workpiece after welding heat input, the main changes of the tensile strength due to the quality of the parent metal. Surfacing layer with the increase of heat input, average hardness reduced gradually; Hardness of surfacing layer in the middle of transverse section presents the wavy distribution, the area below the wire conduit get the higher hardness value. Multi-layer welding, the microhardness of welding layer and heat affected zone have no obvious linear relationship. Multi-layer welding, with the increase of surfacing welding layer, the dilution rate of surfacing welding layer reduced, heat input on burning effect of alloy elements remains.