Production process of API 5L X60 pipeline steel

The basic production processes of API 5L X60 pipeline steel mainly include: conventional semi-continuous hot rolling, CSP continuous casting and rolling, medium and heavy plate unit, and coil unit.

1)Semi-continuous rolling mill. Including 1-stand Steckel Mill and 5-stand Finishing Mill. On the semi-continuous rolling mill, the hot rolling experienced by the API 5L X60 pipeline steel strip in the finishing pass is constant. The time between passes of API 5L X60 pipeline steel on the finishing mill is usually less than 3s.

2)CSP continuous casting and rolling. Appropriate controlled rolling, controlled cooling and coiling process for API 5L X60 pipeline steel on the CSP production line can ensure that the mechanical properties and microstructure of API 5L X60 pipeline steel meet modern technical requirements and new development trends. Its technological feature is that there is central segregation in the continuous casting thin slab, and eliminating the segregation is a key technical issue for further improving the quality of API 5L X60 pipeline steel.

3)Medium and thick plate unit. It mainly produces wide and thick plates, which are used in the production of longitudinal submerged arc welded pipes for API 5L X60 pipeline steel.

4) Steckel rolling mill. Steckel rolling mill includes a reciprocating rough rolling mill and a 4-high reciprocating finishing mill. Two hot coil rolling mills are installed on the conveying lines on both sides of the finishing mill. API 5L X60 pipeline steel strip has a significant thermo-mechanical history throughout its length, especially in the production of microalloyed steels, which will strongly affect the degree of recrystallization, grain growth and precipitation occurring in the finishing mill , and lead to drastic changes in the ultimate microstructure and properties throughout the length of the API 5L X60 pipeline steel strip. Its process is characterized by relatively low investment cost.