The basic equation of the cold tandem rolling process

The basic equation of the cold tandem rolling process
　　 From the point of view of plastic deformation of rolled products, two main process parameters of cold rolling are discussed-rolling force and forward slip value. But for the process control of slab milking, only studying the plastic deformation of the slabs cannot fully understand the actual phenomena of thickness control and flatness control. This is due to the plastic deformation of the milk piece, while the rolling mill will also undergo significant elastic deformation. The thickness and crown of the strip rolled by the rollers will be determined by the combined effect of the plastic deformation of the slab and the elastic deformation of the rolling mill (roll system). When the rolled piece is bitten into the roll system, the roll tries its best to thin the rolled piece and cause it to undergo plastic deformation. For this reason, the roll will give the rolled piece a rolling force of thousands of tons. But the acting force is equal to the reaction force (in the opposite direction). Therefore, at the same time, the rolling piece will also exert thousands of tons of force on the roll system, and try to open the roll, so that the rolling mill will be elastically deformed (including the bending deformation of the roll system). If the mill housing and roll system have infinite rigidity, the rolled shape will be equal to the roll gap shape at no load. But in fact, the rolling mill (roll system) not only has limited rigidity, but also the rigidity is quite 'soft'. For example, the longitudinal rigidity of the general hot and cold strip rolling mill is only 5000-6000kN/mm, so when the total rolling force is 25000-30000kN , The total elastic deformation of the archway and roller system will reach 5-6mm. This will have a huge impact on the 0.2-2mm cold hot zone material. Therefore, the thickness setting and thickness control functions have to analyze the deformation of the rolling stock and the deformation of the rolling mill at the same time.
　　 This chapter will discuss the five basic equations of cold tandem rolling from the perspective of the elastic deformation of the rolling mill and the speed coordination between the tandem mill stands, namely the bounce equation, the roll gap equation, the flatness equation, the flow equation and the tandem rolling tension equation.