When the wire is determined (usually depends on in the welding of steel), supporting the use of the flux has become key material, it has a direct impact on and low temperature toughness of weld metal mechanical properties (especially of plastic), anti cracking performance, welding defect rate and welding productivity. Welding wire and flux is equipped with the weight ratio for flux cored wire is flux 1 to 1.6, depending on the type of weld joint, kinds of flux, welding parameters and decide. Compared with the flux melting, sintering flux amount is saved, can use less about 20%.
Single wire submerged arc welding in welded pipe welding due to the welding molten pool has the advantages of small volume, small mass, exists for only a short time, fast crystallization rate of cooling, under certain welding specification, welding speed is restricted, generally 300~600mm/min, fast welding speed very easily lead to cooling crystallization rate of molten pool and fast production welding defects, slow speed and lead to heat input and heat affected zone broadening and the joint performance degradation, the production efficiency is low. And submerged arc welding are mostly longitudinal multiwire tandem. In the process of the formation of a common molten pool during the welding, three wire welding weld pool length can be reached more than 80 to 100mm, molten pool exists for a long time, metallurgical reaction fully, there is plenty of time for gas and impurities emerge. The welding quality is good, as long as the technology and standard control is good, the welding defects are few. Welding speed can reach 1.0~2m/min or more, the production efficiency is high. 3~5 times higher than single wire submerged arc welding.
Submerged arc welding (including submerged arc surfacing and electro slag surfacing, etc.) is a kind of arc welding process under the welding flux layer. The inherent welding quality and stability, welding, high productivity, no arc and soot few advantages, make it become a pressure container and pipe manufacture, box beams, and other important structural steel production of the main welding method. In recent years, although there have been many kinds of efficient, high-quality new welding methods, but the application of submerged arc welding is still not affected by any.
Refers to the pipe submerged arc welding submerged arc welding using two or more to complete the same weld wire. Welded pipe submerged arc welding machine group welding device: internal welding apparatus consisting of a mechanical system, an electrical control system, welding system, flux supply and recovery system, video monitoring system is composed of five parts. The mechanical system mainly include: welding head, the cantilever beam and a cantilever beam supporting mechanism, a welding seam tracking control system, a frame and a ground wire lifting frame and so on.
The tilt direction of welding wire is divided into forward and backward. The direction and size of the dip angle is different, the arc is different to the weld pool's force and heat, thus affecting the welding process. When after the welding wire inclination angle, due to arc pointing to the direction of welding, welding molten pool in front of have the function of preheating, arc to molten pool of liquid metal discharge effect is reduced, which led to the weld width and penetration depth becomes shallower. On the contrary, the weld width is small and the penetration depth is larger, but it is easy to cause the weld edge to produce incomplete fusion and undercut, and to make the weld form variation.
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