The total processing rate refers to the total degree of deformation after recrystallization annealing, and the total processing rate is not a certain value. There are great differences in the production of the same alloy and the same specification with different production methods and equipment.
Due to the different thickness of finished products, the rolling of the foil is generally 2 to 6 passes. Rolling passes are determined according to the efficiency of rolling mill, the specification and organization of finished foil, and the balance of production capacity between the front and back processes. The total processing rate of pure aluminium foil is generally 99%, and that of aluminium alloy box is generally not more than 90%. The selection principles of pass processing rate are as follows:
(1) The plasticity of rolling metals should be fully utilized to increase the productivity of rolling mills by using large pass processing rate as far as possible, on the premise that the equipment capacity permits, the good performance of lubricated oil and cooling rolling oil, good surface quality and shape quality can be obtained.
(2) The factors such as mill performance, process lubrication, tension, original roll profile, rolling speed, surface quality, shape quality and thickness fluctuation should be fully taken into account. The rolling pass processing rate of soft or semi-hard aluminium foil blank is 40% to 65%, and that of hard aluminium foil blank is 20% to 40%.
(3) For products which requires high thickness deviation, surface quality and shape quality, it is advisable to select smaller pass processing rate.
(4) For rolling mills with automatic gauge control system and automatic shape control system, larger pass processing rate can be appropriately adopted.
(5) In order to obtain products with uniform thickness and good smoothness, the rolling force of each pass should be close to constant pressure rolling.
(6) The selection of pass processing rate should proceed from reality and be determined after continuous exploration and summary according to equipment, quality and production efficiency in field practice.
Post time: Mar-15-2019