Spiral steel pipe (SSAW) is a spiral seam welded pipe made of strip steel coil as raw material, extruded at regular temperature, and welded by automatic double-wire double-sided submerged arc welding process.
Submerged arc automatic welding (SAW) is a new welding method invented in 1940. It is the same as the previous manual welding in that it still uses slag protection, but the slag is not the coating of the electrode, but the welding flux specially smelted.
The characteristic of the welding method of the spiral welded pipe is: use an extrusion device to first squeeze the inner surface of the steel plates on both sides of the unwelded weld to eliminate uneven protrusions and ensure that the inner sides of the steel plates on both sides of the unwelded weld are clean and smooth , and then welded.
At the same time, the extrusion device is also used as a positioning device for the welding head, that is, the welding head and the extrusion device are tightly fixed together, and when the extrusion device moves along the unwelded weld, it is ensured that the welding head is also accurately along the The unwelded seam moves to ensure that the welding head is always in the middle of the seam. In this way, it can ensure that the quality of the welds produced by the automatic welding of the production line is stable and excellent, and there is basically no need for manual repairs.
The welding method of spiral welded pipe, the first is to realize automation; the second advantage is that it is welded under submerged arc, so its heat exchange and protection performance is relatively strong, and the quality of welding is relatively high; the third advantage is that since the arc is buried under the flux in submerged arc automatic welding, it can use high current and the welding efficiency is relatively high.
The difference of submerged arc automatic welding is: submerged arc automatic welding does not use welding rods, but welding wires, because the welding wires can be fed continuously; welding rods, we have to throw away a welding rod head after burning a welding rod, and the operation must be stopped. Change the welding rod and weld again. After changing to welding wire, the welding wire feeding device and the welding wire reel will continuously feed the welding wire. This welding method is to continuously feed the welding wire and burn the arc under the cover of the meltable granular flux to make the welding wire and base metal Part of the melting and evaporation of the flux forms a cavity, and the arc burns stably in the cavity, so it is called submerged arc automatic welding.
