Spiral steel pipe is a kind of spiral seam steel pipe which is made of strip steel coil as raw material, often formed by warm extrusion and welded by automatic double-wire double-side submerged arc welding process. The spiral steel pipe will feed the strip steel into the welding pipe unit. After ro

Generally speaking, the diameter of spiral steel pipe can be divided into outer diameter, inner diameter, and nominal diameter. The outer diameter of a spiral steel pipe is indicated by the letter D, followed by the size and wall thickness of the outer diameter. For example, a seamless steel pipe wi