Rolling mill is the main machine of direct rolling metal. It uses rotating roll to roll billets to produce plastic deformation of metal according to the specified requirements. Rolling is a metal forming method with high productivity and low cost, which is suitable for rolling strip or plate material with the same cross section or periodic changes. Special rolling mills can roll machine parts or their blanks as well as certain non-metallic materials. The rolling mill mainly has two ways of hot rolling and cold rolling, usually the rolling process with the rolling temperature above the metal recrystallization temperature is called hot rolling, and the rolling process below the metal recrystallization temperature is called cold rolling. This paper mainly introduces the hot rolling process.
Hot rolling is carried out at a higher temperature to reduce the rolling pressure, which can greatly reduce the cross-sectional area of the workpiece, suitable for billet opening, cold rolling operating temperature is low, the product surface quality is good, the dimensional accuracy is high, the thickness is uniform, and can improve the mechanical properties of the rolled parts, but the equipment strength and precision are required, and the energy consumption is large.
Hot rolling is based on slab (mainly continuous casting billet) as raw material. After heating, strip steel is made by roughing mill and finishing mill. The hot steel strip from the finishing mill is cooled to the set temperature by laminar flow, and then rolled into steel strip coil by coiler. After different finishing lines (leveling, straightening, crosscutting or slitting, inspection, weighing, packaging and marking, etc.) processing into steel plate, flat coil and slitting steel strip products. To put it simply, the billet is heated and rolled several times, and then trimmed and straightened into a steel plate, which is called hot rolling.
