In the production of double sheet foil, aluminum foil rolling is divided into three processes: rough rolling, middle rolling and finishing rolling. From the point of view of the process, it can be roughly divided from the rolling exit thickness. The general classification is that the exit thickness is greater than or equal to 0.05mm for rough rolling, and the exit thickness between 0.013 and 0.05 for middle rolling. The finished sheet and double rolled products with outlet thickness less than 0.013mm are finished rolling. Rough rolling and aluminum strip rolling characteristics are similar, thickness control mainly depends on the rolling force and after tension, rough rolling processing rate thickness is very small, its rolling characteristics have been completely different from aluminum strip rolling, with the particularity of aluminum foil rolling, its characteristics mainly include the following aspects:
1. Aluminum plate and strip rolling. To make the aluminum strip thin mainly depends on the rolling force, so the automatic control mode of plate thickness is based on the control mode of constant roll gap as the main body of AGC. Even if the rolling force changes, adjust the roll gap at any time to keep a certain value of the roll gap, the strip with the same thickness can be obtained. And because to finishing of rolling aluminum foil, aluminum foil thickness is very thin, rolling, rolling force, make the rolls elastic deformation is easier than being rolled material to produce plastic deformation, the elastic flattening of roll can't be ignored, roll play flattening determines the aluminum foil rolling, rolling force has been less than like mill role, Aluminum foil rolling is generally rolled without roll gap under constant pressure, and the adjustment of aluminum foil thickness mainly depends on the adjusted tension and rolling speed.
2. Pack rolling. For the thickness less than 0.012mm(thickness size and the diameter of the work roll) of the very thin aluminum foil, because of the elastic flattening of the roll, with a single rolling method is very difficult, so the use of double rolling method, that is, the two aluminum foil with lubricating oil in the middle, and then together rolling method (also known as rolling). Laminated rolling can not only roll the very thin aluminum foil that can not be produced by single sheet rolling, but also reduce the number of strip breaking, improve labor productivity, using this process can produce 0.006mm ~ 0.03mm single light aluminum foil.
3. Speed effect. During aluminum foil rolling, the phenomenon that the foil thickness decreases with the rise of the rolling system is called velocity effect. The reasons for the speed effect are generally considered as follows:
The friction state between the work roll and the rolled material changes. With the increase of the rolling speed, the amount of lubricating oil is increased, so that the lubrication state between the roll and the rolled material changes. As the friction coefficient decreases, the oil film thickens and the thickness of aluminum foil decreases.
The mill itself changes. In rolling mills with cylindrical bearings, as the rolling speed increases, the roller neck will float in the bearing, so that the two rollers under interaction will move in a direction close to each other.
Processing softening of material when it is deformed by rolling. The rolling speed of high-speed aluminum foil mill is very high. With the increase of the rolling speed, the temperature of the rolling deformation zone increases. According to calculation, the metal temperature in the deformation zone can rise to 200℃, which is equivalent to an intermediate recovery annealing, thus causing the processing softening phenomenon of the rolling material.