The welded steel pipe is a steel pipe produced by welding a steel plate or a steel strip into a cylindrical shape. According to the welding method, it can be divided into arc welded pipe, high frequency or low frequency electric resistance welded pipe, gas welded pipe, furnace welded pipe, etc.; according to the weld form, it can be divided into straight welded pipe and spiral welded pipe. A welded steel pipe is a steel pipe which is welded and formed by a steel strip or a steel plate and deformed into a circular shape or a square shape,welded steel pipe supplier and has a joint on the surface. The blank used for welded steel pipes is steel or strip.
The reason why the market price of welded steel pipe is sometimes unstable
As the price of welded steel pipes remained weak and the price of welded steel pipes continued to decline, even if the price of iron ore also declined, the profit of steel mill smelting was still greatly reduced, and some steel mills were once again in a state of losing money. At the same time, the resistance of steel mills to the increase of welded steel pipes is increasing. At present, the pricing power is still in the hands of steel mills. As the purchase price of welded steel pipes falls again under the pressure of steel mills, it will create for welded steel pipes. Further downside space.
In the process of welding process of welded pipe, different welding processes can be selected according to actual conditions. At present, nine different welding processes can be mainly used. Firstly, high-frequency resistance welding can be used. The welding method utilizes the skin effect and the proximity effect of the high-frequency current to rapidly heat the edge of the steel strip to the molten state, and The welding is performed by extruding the molten metal under the action of a squeeze roller.
The second is submerged arc welding. In the process of processing the welded pipe by this welding method, the arc welding is mainly carried out under the coverage of the flux by the welding arc. The weld metal bath is solidified into a weld under the protection of the flux coating, and the molten layer of the flux is cooled to cover the outer surface of the weld. The third welding method is called tungsten inert gas shielded welding, which refers to inert gas shielded welding of tungsten inert gas shielded welding using pure tungsten or activated tungsten (tungsten tungsten, tantalum tungsten, etc.) as an electrode.
In the process of using the process for the welded pipe, it is necessary to weld the base material and the filler wire by the arc heat generated between the tungsten electrode and the weldment under the protection of the inert gas. It is also possible to use a molten inert gas protective welding method, that is, an inert gas shielded welding using a welding wire as a molten electrode.
In addition, carbon dioxide gas can also be used as gas shielded welding, which is usually a gas shielded gas shielded welding using CO2 having a purity of 99.8% or more as a shielding gas. It is also possible to use a welding method of mixed gas shielded welding. At this time, two or more gases are mainly used, and a mixed gas composed of a certain ratio is used as a protective gas for gas shielded welding to complete the welded pipe welding process.tinplate suppliers
In addition to the above methods, the welding processes that can be used for welding of welded pipes include: argon arc welding, pulsed argon arc welding, plasma arc welding, and hot brazing. Among them, plasma arc welding refers to a method of obtaining a high energy density plasma arc for welding by means of a water-cooling nozzle to restrain the arc.