Common large diameter steel pipe size range: outer diameter: 114mm-1440mm wall thickness: 4mm-30mm. Length: It can be made to fixed length or irregular length according to customer requirements. Large-diameter steel pipes are widely used in various industrial sectors such as energy, electronics, automobiles, and light industry, and are an important welding process.

The main processing methods of large-diameter steel pipes are Forged steel: A pressure processing method that uses the reciprocating impact of a forging hammer or the pressure of a press to change the blank into the shape and size we require. Extrusion: It is a steel processing method in which metal is placed in a closed extrusion cylinder and pressure is applied on one end to extrude the metal from a specified die hole to obtain a finished product of the same shape and size. It is mostly used to produce non-ferrous metals and steel. Rolling: A pressure processing method in which a steel metal blank is passed through the gap between a pair of rotating rollers (of various shapes). Due to the compression of the rollers, the cross-section of the material is reduced and the length is increased. Drawing steel: It is a processing method that draws the rolled metal blank (shaped, tube, product, etc.) through the die hole into a reduced cross-section and an increased length. Most of them are used for cold processing.

Large-diameter steel pipes are mainly completed through tension reduction and continuous rolling of the hollow base material without a mandrel. On the premise of ensuring the spiral steel pipe, the entire spiral steel pipe is heated to a high temperature above 950°C and then rolled into seamless steel pipes of various specifications through a tension reducer. Documents for standard setting and production of large-diameter steel pipes show that deviations are allowed when manufacturing and producing large-diameter steel pipes: Length deviation: When steel bars are delivered to a fixed length, the length deviation shall not be greater than +50mm. Curvature and ends: The bending strain of straight steel bars does not affect normal use, and the total curvature is not greater than 40% of the total length of the steel bars; the ends of the steel bars should be sheared straight, and local deformation should not affect use. Length: Steel bars are usually delivered in fixed lengths, and the specific delivery length should be specified in the contract; when steel bars are delivered in coils, each coil should be one steel bar, and 5% of the coils in each batch are allowed to be composed of two steel bars. composition. The disc weight and disc diameter are determined by negotiation between the supply and demand parties.