What are the main production processes of domestic pipeline steel?

The main production processes of pipeline steel in China are: conventional semi continuous hot rolling, CSP continuous casting and rolling, medium and heavy plate mill and coil mill.

1) Semi continuous rolling mill: including 1 stand Steckel mill and 5 stand finishing mill. In the semi continuous rolling mill, the hot rolling of the steel strip in the finishing pass is essentially constant from one end to the other. The time between passes on finishing mill is usually less than 3S.

2) CSP continuous casting and rolling: for the low carbon manganese steel containing Nb, V and Ti composite Microalloying on CSP production line, the proper controlled rolling, controlled cooling and coiling process can ensure that the mechanical properties and microstructure of the steel meet the technical requirements of modern X60 pipeline steel and the development trend of modern pipeline steel.

3) Plate mill:
It mainly produces wide and thick plates, which are used in the production of LSAW pipes. LSAW pipes are of reliable quality and widely used in the main oil and gas high-pressure transmission line.

4) Steckel Mill:
The steckel mill consists of a reciprocating roughing mill and a 4-high reciprocating finishing mill. Two hot coil mills are installed on the conveyor lines on both sides of the finishing mill. The output roller table usually consists of a laminar cooling system and a coiling station. In the steckel mill, the thermo mechanical history of the whole length of the strip changes obviously, especially in the production of microalloyed steel, which will strongly affect the recrystallization degree, grain growth and precipitation on the finishing mill, and lead to dramatic changes in the ultimate microstructure and properties of the whole strip length. The process is characterized by relatively low investment cost.