Differences and Applications of Cold rolling and Hot rolling aluminum sheet

- Nov 05, 2018-

The difference in aluminum sheet processing is as follows:

1. Different production processes: Cold rolling is processed by a casting machine into a casting coil (8mm thickness) processed by a cold rolling mill, while hot rolling is an aluminum ingot (400-500mm thickness) heating, at high temperature Hot rolling mill rolling;

2. Different raw material supply: the difference between the two is different in the supply of the blank. The hot rolled billet is cast aluminum ingot--heating-rolling into a coil for cold rolling, and the cold-rolled billet is cast-rolling--cold rolling;

3. Different performance: The surface quality of hot-rolled aluminum sheet is good, and the mechanical properties and elongation properties are strong, and the oxidation effect is good.

4. Different application.

Hot rolling - using continuous casting slab as raw material, heating by step heating furnace, descaling of high pressure water, entering rough rolling mill, rough rolling material passes through cutting head, tail, and then into finishing rolling mill to implement computer The rolling is controlled, and after the final rolling, it is subjected to laminar cooling (computer controlled cooling rate) and the coiler is taken up to become a straight hair roll. The head and tail of the straight hair roll tend to be tongue-shaped and fish-tail-shaped, and the thickness and width are poorly accurate. The edge often has defects such as a wave shape, a folded edge, and a tower shape. The weight of the coil is heavier and the inner diameter of the coil is 760 mm. (Generally, the tube industry likes to use it.) After the straight hair is wound through the cutting, cutting, trimming and multi-pass straightening, leveling and other finishing lines, then cutting or rewinding, it becomes: hot rolling Steel plates, flat hot rolled steel coils, slitting belts and other products. If the hot-rolled finishing rolls are pickled to remove scale and oiled, they are hot-rolled pickled rolls.

Cold rolling - using hot-rolled steel coil as raw material, after pickling to remove scale and then cold-rolling, the finished product is rolled hard roll, and the cold work hardening caused by continuous cold deformation increases the strength and hardness of the rolled hard roll. The toughness and plasticity index is lowered, and the punching performance is deteriorated, and it can only be used for parts that are simply deformed. Rolled hard rolls can be used as raw materials for hot-dip galvanizing plants because the hot-dip galvanizing units are provided with an annealing line. The hard roll weight is generally 6~13.5 tons, and the inner diameter of the steel coil is 610mm. Generally, the continuous rolling mill and coil should be subjected to annealing treatment (CAPL unit) or hood furnace to eliminate annealing work and rolling stress, and meet the mechanical properties specified in the standard. The surface quality, appearance and dimensional accuracy of cold rolled steel sheets are superior to those of hot rolled sheets.