Line pipe used plates 60 to 70 years using the Anshan Iron and Steel and other major manufacturers A3,16Mn, with diameter pipeline delivery pressure increases and progress strength steel can not meet demand. 80 years after each oil pipe plant started by the United States API standard production pipeline steel, because of the domestic pipeline board manufacturing plant immature technology, mainly imported plate. Enter the 1990s, the domestic plate production line developed rapidly, Baosteel, Wuhan Iron and Steel, Anshan, Benxi Iron and Steel, Panzhihua Iron and Steel and other enterprises have developed and produced a series of high-grade steel X pipeline.
In the domestic pipeline steel production process are: a conventional semi-continuous hot rolling, CSP continuous casting and rolling, plate units, Steckel unit.
1) Semi-continuous rolling mill: Includes 1 rack 5 rack Steckel mill and finishing mill. In the semi-continuous rolling mills, strip the finish rolling experienced hot-rolled steel strip from one end to the other end is substantially constant. On finishing mill time between passes is generally less than 3s.
2) CSP continuous casting and rolling: in CSP production line containing niobium, vanadium, titanium composite micro-alloyed carbon steel, the use of appropriate controlled rolling and cooling and coiling process can ensure the mechanical properties and microstructure of steel modern organizations meet the technical requirements of X60 pipeline steel, pipeline steel in line with modern trends. Our CSP continuous casting and rolling production line has been developed to X60 steel, while the United States and other foreign manufacturers CSP has developed and produced high-grade pipeline steel X60, X65 and the X70. Which process is characterized by the presence of thin slab centerline segregation, eliminate thin slab centerline segregation is to further improve the quality of key pipeline technical problems.
3) Plate Unit: The main production of heavy plate for LSAW pipe production, reliable straight seam submerged arc welded pipe, widely used in high-voltage transmission and gas trunk line.
4) Steckel: Steckel mill comprises a reciprocating roughing mill and a finishing mill 4 roll back and forth. In the finishing mill both sides of the conveyor line installed two hot roll mill. Output roller typically comprises a laminar cooling system and a take-up station. On the Steckel mill, thermo-mechanical history of the entire length of the strip on the significant changes, especially in the micro-alloyed steel production, will strongly influence the degree of recrystallization generated in the finishing mill, grain growth and precipitation, and cause the entire dramatic changes in the final microstructure and mechanical properties of the strip length. Which process is characterized by relatively low investment costs.
