When rolling, the total pressure given to the roll by the rolled piece is called rolling force, which is the main parameter in the rolling process. Correctly determining the rolling force is of great significance for reasonably arranging rolling process, correctly and safely using rolling equipment and fully tapping the potential of rolling equipment.

The rolling force is not only related to the unit deformation resistance of the rolled piece in the deformation zone, but also related to the contact area between the roll and the rolled piece. However, because the unit deformation resistance of the rolled piece has different values at different positions in the deformation zone, in order to simplify the calculation, the average unit deformation resistance is often used to calculate the rolling force.

At present, it is generally believed that Sims formula based on Orowan's deformation pressure balance theory is a theoretical formula suitable for calculating the rolling force of hot rolled strip. Namely:

P = bc x ld x σc x Qp x KT where P- rolling force KN, BC- average width of rolled piece in deformation zone mm, BC = (B0+b1)/2;

LD refers to the contact arc length between the rolled piece and the roll. If the elastic flattening of the roll is considered, the contact arc length LD after flattening should be calculated;

σ c-average unit deformation resistance depending on the chemical composition and deformation physical conditions of the rolled piece-deformation temperature, deformation speed and deformation degree;

Qp-stress state coefficient caused by external friction or the influence of external area on contact arc;

KT—— Considering the influence coefficient of front and rear tension on rolling force.

In the above formula, Bc ld is the contact area, which is the geometric factor affecting the rolling force; Qp KT is a mechanical factor affecting rolling force; σc is a physical factor affecting rolling force.