There are mainly 2 methods for producing welded steel pipes:
1) Production of seamed steel pipes by welding
The production of welded steel pipes uses straight strips or coiled strips as raw materials. The commonly used welding methods include furnace welding, resistance welding and arc welding. There are two kinds of weld seams: straight seam and spiral seam. The furnace welding method can only produce straight seam welded pipe, and its product diameter is 10-114mm, and the wall thickness is 2-10mm. The diameter of the straight welded pipe produced by the resistance welding method can reach 620mm, and the wall thickness is 0.4-20mm; the diameter of the spiral welded steel pipe can reach 3660mm. The arc welding method is suitable for high-quality steel and alloy steel. and is often used to produce spiral welded pipes with a diameter of more than 1000mm.
2) Production of steel pipes with cold drawing machines
Using hot-rolled seamless steel pipes or welded steel pipes as blanks, steel pipes and small-diameter steel pipes with little change in wall thickness are produced. Steel pipes can be made into circular, rectangular, triangular and other cross-sectional shapes by cold drawing. Usually the product diameter is 6-65mm, and the wall thickness is 1-5mm.
