Hot rolling method

A method for the regulation of at least one parameter (α) of a hot rolling process of a semi-finished metal product in at least one rolling mill stand having at least two work rolls, the regulation method comprises the steps of:

• calculating a forward slip ratio (FWS) by means of the following equation:
• FWS
• =
• |
• v
• exit
• -
• v
• stand
• |
• v
• stand
• where vexit is a speed of the semi-finished product at an exit of a respective stand and vstand is a linear velocity of two work rolls;
• calculating an estimated coefficient of friction (μreal) as a function of a measured value of a screwdown force (F) of the two work rolls in the stand and of the forward slip ratio (FWS) calculated previously;
• and
• regulating the at least one parameter (α) based on the calculated estimated coefficient of friction (μreal);
• and wherein
• during the step of calculating the estimated coefficient of friction (μreal), a target value of the coefficient of friction (μtarget) is predetermined, and the coefficient of friction (μreal) is calculated in real time;
• during the regulating step, when |μtarget−μreal| is greater than a predetermined value (Δ), the corresponding at least one parameter (α) is adjusted so that |μtarget−μreal| becomes less than or equal to the predetermined value (Δ).