The production process of the cold rolled steel coil

The production process of cold rolled coil is slightly different according to the variety and specification of raw materials and products. The general process of cold rolled steel coil is introduced as follows.

1.Pickling.A continuous pickling unit is used to remove the surface iron oxide scale of hot rolled coil.Acid is now mostly hydrochloric acid.Before pickling, first process is welding and rolling, some also go through continuous "black annealing".After pickling, the next processes are wash, dry, trim and roll.

2.Cold rolling.After the pickling, the strip billet is rolled to the thickness of the finished product on the cold rolling mill, generally without intermediate annealing.The total compression rate of cold rolling of five-stand tandem mill is generally 60 ~ 80%, mainly rolling automobile plate, enamel plate and galvanized plate with thickness of 0.3 ~ 3mm.Six stand tandem mill is mainly used to roll tin-plated sheet with a thickness of 0.15 ~ 0.5mm, and the total compression rate of cold rolling is generally 70 ~ 90%.

3. Annealing.The purpose of annealing is to eliminate cold rolling hardening and to make the steel plate recrystallized and softened with good plasticity.The annealing method is coil annealing with cover furnace and continuous annealing with continuous furnace.Coil annealing is divided into tight coil annealing and loose coil annealing.Continuous furnace annealing is divided into vertical continuous furnace annealing and horizontal continuous furnace annealing.Protective gases are generally introduced into the furnace.At present, most of them adopt cover furnace annealing, because of flexible and saving investment.

4.Leveling.The purpose of leveling is to avoid plastic instability and improve the quality (flatness and surface condition) of the annealed steel sheet during stamping.There are two kinds of leveling mill, single stand reversible and double stand, and the leveling compression rate is 0.5 ~ 4%.Double stand rolling mill with high efficiency and high compression rate can be used for secondary cold rolling and further rolling of thin steel sheet.If cooperate with five stand continuous rolling mill, can produce 0.10 ~ 0.15mm coating, shearing and packaging need coating steel plate sent to galvanized, tin or organic coating unit processing.

5.Shear.General after leveling is shear.There are slitting and cut to length. The slitting is to cut the edge or according to the width of the need, the cut to length is according to the length of the need to be cut into sheets. 6.Packing and delivery,after the inspection and classification of the cold rolled steel coil coated with anti-rust oil and the packing and delivery to the customers.

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