Spiral steel pipe

Spiral steel pipe specification table there are two main methods, one that is the diameter * wall thickness, the other is the nominal diameter (DN). This representation is the most common, diameter refers to the spiral steel pipe outside diameter, usually with Ф, wall thickness refers to the thickness of the spiral pipe, are generally in mm (mm) mark, such as diameter 219mm wall thickness 6mm Spiral steel pipe that is 219 * 6.