(1) to ensure the realization of the processing process. In the rolling process, the rolling mill can be driven into the roll gap rolling, plastic deformation occurs, is due to the role of friction after the role of sliding area, otherwise rolling can not achieve natural bite. In the field production, in order to increase the yield and increase the road pressure down the scene, often in the roll scoring, spot welding or adding to the deformation zone phosphide and other methods to increase friction, to strengthen the rolling.
(2) to change the stress state of the object, resulting in metal deformation resistance and energy consumption increased. Due to the existence of friction, rolling denatured K objects in the three-way stress state, and mostly two-way compressive stress state.
The friction changes the object from a one-way stress state to a three-way stress state. The required deformation force U1) greatly exceeds the deformation force in the uniaxial stress state. If the friction coefficient is larger in the contact surface, the greater the friction force, that is, the greater the hydrostatic pressure, the required deformation force increases Large, and thus consumed by the deformation of the work (energy consumption) increased.