There are two different common aluminum coil manufacturing processes in hot rolling and cold rolling.
Using continuous casting slabs or preliminary rolled slabs as raw materials, heated by a step-type heating furnace, high-pressure water dephosphorization enters the roughing mill, the rough rolling material is cut into the head, tail, and then into the finishing mill, and computer controlled rolling After the final rolling, it is coiled by laminar cooling (computer controlled cooling rate) and coiler to become a straight hair coil. Straight hair curls tend to have tongue and fish-tail shapes, with poor thickness and width accuracy. Waves, folds, and towers are often present at the edges. Its coil weight is heavy and the inner diameter of the steel coil is 760mm. (Commonly used in the tube industry.) After straight hair is processed through cutting, tailing, trimming and multiple straightening and leveling lines, and then cut or re-rolled, it becomes: hot rolling Steel plate, flat hot rolled steel coil, slitting tape and other products. If the hot-rolled finishing coil is pickled to remove scale and oil, it will become a hot-rolled pickled coil.
Hot rolled steel coils are used as raw materials, and the scale is cold rolled after pickling to remove oxide scale. The finished product is rolled hard coils. The cold work hardening caused by continuous cold deformation increases the strength, hardness and toughness index of rolled hard coils. The stamping performance deteriorates and can only be used for parts that are simply deformed. Hard-rolled coils can be used as raw materials for hot-dip galvanizing plants because hot-dip galvanizing units are equipped with annealing lines. The weight of rolled hard coil is generally 6 ~ 13.5 tons, and the inner diameter of steel coil is 610mm. Generally, continuous cold-rolled plates and coils should be de-annealed by continuous annealing (CAPL unit) or bell furnace to eliminate cold work hardening and rolling stress, and meet the mechanical properties specified by the standard. The surface quality, appearance, and dimensional accuracy of cold-rolled steel are better than those of hot-rolled steel.