Resistance seam welding of original zinc plate steel drum Jiangyin Wuxing Welding Copper Co., Ltd. Wang Jindong Mr. Wang Jindong gave a speech at the 2012 Steel Barrel Industry Conference In order to improve the corrosion resistance of products, various types of galvanized steel sheets are used more and more widely in automobiles, home appliances, including our barrels. According to galvanizing processes and galvanizing compositions, galvanized steel sheets are classified into: Galvanized sheet, hot-dip galvanized sheet, Zn-Ni alloy coated sheet, Zn-Fe alloy coated sheet, and the like. Since the physical properties and electrical conductivity of the coated metal are different from those of the low carbon steel, the resistance welding performance of the galvanized steel sheet is greatly different from that of the same type of steel sheet which is not galvanized, and the joint quality is required from the viewpoint of its use performance. That is, it is necessary to ensure that the joints of sufficient strength are produced when welding, and the plating layer should be reasonably protected. There are certain difficulties in the seam welding of galvanized steel sheets. Over the years, Jiangyin Wuxing Company has made a lot of experiments on the welding performance of galvanized steel sheets around the welding process specifications, numerical simulation of welding process, electrode life and so on. research work. Seam welding of galvanized sheets, because the surface of the galvanized sheet is plated with zinc, there are five factors that directly affect the quality of the weld: 1, galvanized sheet improves the surface finish and increases the surface conductivity, which makes the intermediate resistance significantly lower. 2. The melting point of zinc is low (about 420 ° C). During the seam welding process, the zinc layer on the surface of the workpiece is first melted, and white zinc oxide is formed to cover the surface of the rolling plate, and zinc ZnZ(OH)ZCO3 is formed, which becomes a wear-resistant intermediate layer through pressure and temperature. The oxide coating on the surface of the roller increases the transition resistance, so that the welding heat at the contact between the roller and the workpiece is relatively increased, and the surface of the workpiece is easily burned. This makes the seam-welded galvanized sheet easily break down and cracks when it is welded to the lower plate. 3. When seam welding of galvanized sheet, due to the flow of zinc layer between the sheets, the contact area is increased and the current density is reduced. 4. The zinc layer has a boiling point of about 960 ° C, and the welding heat at the contact of the two workpieces is as high as 1150 ° C, so the zinc layer is easily evaporated. Pores or cracks are formed in the nugget. 5, spot welding is not the same as seam welding, the spot weld nugget is crystallized under pressure and static state. In the seam welding, since the roller continuously leaves the welding zone, the nugget crystallizes under the reduced pressure, so surface overheating, shrinkage and cracking are easily generated. At the end of the above-mentioned galvanized sheet seam welding, the heat distribution along the cross section of the weldment changes correspondingly due to the increase of the transition resistance. The relative reduction of heat at the contact between the two workpieces has the problem that congenital heating is insufficient and it is difficult to form a nugget. Welded galvanized sheet with seam welding ordinary cold plate welding, the welding parts tend to be only slightly bonded without fusion, the surface is not visible, and the chisel is gently smashed and opened, and the leak will occur seriously. The leakage occurred and there was a virtual weld. In order to avoid solder joints, the welding current must be appropriately increased during seam welding of galvanized sheets. However, it has been proved by a large number of experiments that the lower the penetration rate (10%-20%), the less crack defects. The welding speed is too fast, the surface heat dissipation conditions are poor, and cracks are likely to occur. Therefore, under the condition of ensuring the diameter of the nugget and the strength of the joint, a small current should be selected as much as possible, and the cooling is small (the heating range is small). At present, we are basically mature in the welding process of galvanized steel sheets. We use the following three advanced processes for the welding of original zinc sheets for different workpieces; 1, welding power supply uses AC frequency conversion technology, it has the following advantages: a. Three-phase AC power input, using power balance, improving the power factor; b. For the same welded workpiece, the welding time is shortened, the power is saved; the welding stability zone is increased; the electrode life is increased; c. Rapid response control to current improves the quality of the solder joint. d. The welding current can be adjusted in six stages, which greatly improves the control precision. 2, resistance welding wire welding, using two about 2mm welding wire respectively embedded in the middle groove of the upper and lower welding wheels, using the welding wire to press the workpiece for welding. 3, the effective positioning of the barrel, the special design of the welding wheel, that is, to ensure reliable electrical conductivity, but also low friction and smooth operation. Silk film cloth facial mask,Deep cleansing mask,Serum enrichment facial mask,Repairing skin mask HomeSafe Group , https://www.homesafebio.com
Resistance seam welding of original zinc plate steel drum (Wang Jindong)