To solve the problems of interface delamination, composite interface stress concentration, weld stress concentration at pipeline connection (or cracking at inner layer weld), poor stress corrosion resistance and other problems existing in the traditional composite method;

Large diameter seamless steel pipe has a very wide range of use, because of its thick wall, and thus can withstand a larger pressure. Generally can be used as the material of hollow parts, used to withstand pressure and important pipeline use. Specifically, it can be used as a structural pipe for aviation, a drilling pipe for petroleum geology, a pipe for petrochemical industry, and so on.

Shanxi seamless steel pipe wall thickness standard and allowable deviation are different. Generally, pipeline construction depends on the situation. The type of liquid transported, flow rate and static head all affect the selection of steel pipe. The theoretical wall thickness should be calculated in advance. The allowable deviation of the outer diameter of special-purpose steel pipe and cold-rolled (drawn) steel pipe can be used. The allowable deviation of wall thickness is divided into standardized and non-standardized, and the allowable deviation of standardized wall thickness should be preferred.

Alloy seamless steel pipe is mainly used for power plants, nuclear power, high pressure boiler, high temperature superheater and reheater and other high pressure and high temperature pipeline and equipment, it is made of excellent carbon steel, alloy structural steel and stainless steel material, by hot rolling (extrusion, expansion) or cold rolling (drawing).

The raw material for rolling the national standard steel pipe is a round tube blank. The round tube blank is cut by a cutting machine and processed into a blank with a length of about 1 meter, which is sent to the furnace for heating by a conveyor belt. The billet is fed into a furnace and heated at a temperature of about 1200 degrees Celsius.