Hot rolled coil produced by hot rolled wide strip mill can not only be used directly for thin sheet and medium plate, but also be used as raw material for cold rolled, welded pipe and cold formed steel in the next process. Hot strip mill has become the main form of strip production in the world since the 1950s. At present, there are more than 200 sets of hot continuous rolling mills and rolling mills with over 1000mm in the world.

 

 

Strip hot rolling mill has the characteristics of high rolling speed, high output and high automation. The rolling speed is 10-12m/s in the 1950s, and 18-30m/s in the 1970s. The product specification is also expanded from the rolled strip with a thickness of 2-8mm and a width of less than 2000mm to the strip with a thickness of 1.2-20mm and a width of 2500mm. The increase of coil weight and the increase of operation rate make the annual output of the existing strip hot rolling mill reach 3.5-6 million tons, and the maximum coil weight is increased from 15t to 70t. The billet size and weight are increased, and more working stands are required. In the past, the working sets of roughing mill and finishing mill groups were 2-4 and 5-6 respectively, which have been increased to 4-6 and 7-8 respectively, and the size of rolling mill also increased accordingly.

 

 

Modern strip hot rolling mill not only adopts automatic control of thickness, but also realizes electronic computer control, thus greatly improving the automation level and product quality.

 

 

Since the 1990s, the short process of iron and steel production has been rapidly developed and popularized. Since the first set of thin slab continuous casting and rolling production line was put into operation at nucor in July 1987, 33 sets have been completed and planned by 1997. The technology of continuous casting and continuous rolling connects the solidification forming and deformation forming of steel, and sends the continuous casting blank into finishing mill group under the hot condition, and directly rolls into strip coil product. The CSP technology of deutsche mark, ISP technology of demark and Conroll technology developed by aogang union have been used by users.