Large-diameter steel pipes are steel pipes with an outer diameter of 1000MM or more. Large-diameter steel pipes are mainly completed by tension reduction and continuous rolling of hollow base metals without mandrels. On the premise of determining the welded steel pipe, the whole welded steel pipe is heated to a high temperature above 950°C, and then rolled into seamless steel pipes of various specifications through a tension reducing machine.

Welded pipes can be divided into carbon steel welded pipes and stainless steel welded pipes in terms of material. Carbon steel welded pipe can also be called carbon welded steel pipe, and carbon steel can also be called magnet alloy steel.

Galvanized degaussing steel pipe is used as a material for pre-embedded threading in subways, high-speed rail stations, civil air defense construction, and high-voltage substations. It has a wide range of applications. Degaussing steel pipes can effectively prevent signal loss caused by wires and cables passing through pipes.

The galvanized square tube is a hollow steel tube with a square cross-section shape and size made of hot-rolled or cold-rolled galvanized strip steel or galvanized coil as a blank, which is formed by cold bending and then high-frequency welding.

Precision seamless pipe is a kind of high-precision seamless steel pipe processed by cold drawing or hot rolling. Because there is no oxide layer on the inner and outer walls of the precision steel pipe, it can withstand high pressure without leakage, high precision, high finish, cold bending without deformation, flaring, flattening without cracks, etc.

When welding stainless steel pipes, in order to reduce the tendency of thermal cracking, the microstructure design of the weld generally contains a small amount of ferrite, and the control of the ferrite content is mainly realized by the alloy composition. Austenitic stainless steel welds contain more than 3% ferrite, which can effectively avoid solidification cracks, but too much ferrite will have an adverse effect on performance.