New Technologies and Processes Applied in Steel Rolling Production and Welded Pipe Mill in Recent Years – Automation Technology (1)

New technologies aimed at continuous and automated production

• Endless rolling technology and semi endless rolling technology

Headless and semi headless rolling technology is a new technology that has emerged in recent years. Headless rolling is mainly used in the production of hot rolled strip and welded pipe mill while semi headless rolling is mainly used in the production of thin slab continuous casting and rolling. The traditional block rolling method requires frequent biting, throwing, and even speed up and down of the pipe rolling mill, making it difficult to ensure the quality of the steel head and tail. Additionally, the low operating rate of the rolling mill and the control of dimensional accuracy also pose certain difficulties. Endless rolling technology refers to the process of welding the rough rolled strip blank with the tail of the previous strip blank before entering the finishing mill, and continuously passing through the finishing mill. This technology expands the rolling range of traditional hot strip mills and can produce 0.8mm ultra-thin strip steel in bulk. After achieving endless rolling, it is expected to achieve the following results:

• (1) Due to the fact that the entire length of the intermediate billet is rolled under constant tension, the precision of the rolled strip is high, and the fluctuation of the plate shape is reduced. Compared with traditional rolling methods, the yield can be increased by 0.5%～1.0%.

• (2) Continuous rolling of strip steel at a certain rolling speed is not limited by the speed specifications of traditional rolling methods, and can increase productivity by 15%.

• (3) Lubrication rolling and increased reduction rolling can be carried out to create conditions for producing hot-rolled plates with good deep drawing performance. However, due to lubrication rolling, the surface smoothness of the product is also improved.

• (4) Endless rolling ensures that the entire length of the steel strip is rolled under constant tension, ensuring stable running and strong cooling, thus producing thin and high-strength strip steel.（to be continued）