After the hot rolled steel strip is pickled, it enters the cold rolling process, and the strip steel undergoes plastic deformation when passing through the work rolls. The thickness is reduced from about 2 mm to about 0.2 mm. In cold rolling, in order to reduce the friction between the strip and the work roll and to take away a large amount of thermal energy due to plastic deformation, cold rolling oil and coolant are sprayed on the strip.
A single-stand reversing mill is used. In order to effectively maintain the shape of the roll, the temperature control of the coolant is more important.
(1) Control parameters of the rolling mill:
Roll level, roll gap, rolling speed, etc.
The main factors affecting rolling:
Raw material thickness, width, hardness, finished product thickness, roll crown, etc.
(2) Cold rolled shape control:
The work rolls of a rolling mill are generally pre-processed to have a crown of about 0.05 mm. In the cold rolling process, after a certain degree of rolling, the temperature in the center of the roll is increased to form an actual crown. When the crown is small, the strip is generally easy to form side waves; on the contrary, when the crown is large, middle waves or wrinkles are formed. In addition, when the strip running is off-center or when the roll level is poor, one-sided waves will be generated on one side due to the single-side extension.
(3) Cold rolled surface defects:
Most of the surface defects that occur during the cold rolling process are caused by scratches or marks on the work rolls. It is important to keep the mill clean.