Control of the surface quality of work rolls at the hot strip mill of Sidmar

An equipment designed to inspect the surface of work rolls during rolling by means of a TV camera and a stroboscopic lighting system has been developed and tested at the HSM of Sidmar. To obtain pictures not disturbed by the roll cooling water, an original optical coupling arrangement using a water jet between the lens and the target is adopted. The resolution is so accurate that thermal cracks can easily be detected. Very different evolutions of the aspect of the roll surface during rolling have been observed.