An Investigation about the Mechanism of Work Roll Wear at the Cold Rolling

Through an experimental simulation using a large scale Timken tester, the mechanism of work roll wear in cold rolling was studied. The problem of short work roll service life in the cold rolling of aluminum-killed continuous casted (Al-killed CC) steel sheet seems to be caused by fast reduction of surface roughness. The roughness reduction rate can be affected by iron soaps which are formed by the chemical reaction between free fatty acids (F. F. A.) contained in the rolling oil and steel strip. Iron soaps can act to thicken the oil film in the roll bite by increasing the viscosity of the rolling oil, and accelerate the roughness reduction. Additionally, iron soaps are used to create a strong oilness improving effect, so they prevent the metal contact between roll and strip asperities, and restrain the roughnes re-creation by scoring. In the case of Al-killed CC steel rolling, because of its increased chemical activity with FFA, more iron soaps can be formed compared with capped steel, so the work roll service life can be shortened.