Analysis of hot strip rolling using exponent velocity field and MY criterion

• A new exponent velocity and corresponding strain rate fields are firstly proposed.
• The analytical solutions of rolling torque and rolling force are obtained.
• The analytical solution has highly prediction precision.
• The neutral point and stress state coefficient are discussed.

Rolling force and torque are critical in hot strip rolling process and they affect the setup rolling schedule, the thickness accuracy and the final product profile. In order to obtain the accurate rolling force and torque, a new exponent velocity and corresponding strain rate field are firstly proposed in this paper. The fields and linear MY (mean yield) criterion, as well as the co-line vector inner product method are used respectively in integration of the internal plastic deformation and friction power terms. Ultimately, an analytical solution of total power functional is given. The analytical expressions of rolling torque, rolling force and stress effective factor are obtained by minimizing the total power functional. To verify the validity of the proposed analytical solution, the calculated rolling forces are compared with on-line measured ones in a hot strip rolling plant. Results show that the analytical solutions are in good agreement with the actual measured ones, and the relative errors are less than 8.39%. Besides, the effects of various rolling conditions such as friction factor, reduction rate and shape factor, on rolling force and torque, location of neutral point, and stress state coefficient are discussed.