Rolling Mill Rolls
Gamma Rolls offers service consisting of roll supply finished grooving and all rolling mill conditions. Our technical department advise and assist on the choice of roll quality for any specific application and also to help with general rolling problems. We also give our technical service prior to the selection ofa quality.
The Principles of Cooling
Cooling water pressure should be about 4 to 6 Bar for Long product mills. A too high thermal gradient increases the risk of roll breakage (thermal stress).
Heat should not penetrate the roll and therefore, the roll surface should be cooled as soon as possible at the exit side of the rolling gap. The cooling water must never rebound of the roll surface. lf the flow of cooling water is interrupted, there is chance of roll breakage due to thermal stress. lnsufficient water used increases the roll temperature until it exceeds 100° C on the surface, when the heating up process accelerates resulting in unstable rolling conditions. Too much water should not be a problem. High volume and low pressure is essential.
Over cooling may result in roll surface material becoming more bristle and have a negative influence on the maximum bite angle possible.
More water must be supplied to the earlier passes than to the finishing passes.
in case of flat products, more cooling water concentrated in the centre part of the rolls than on the edges. More water is applied to the grooves and anti collars of section mill rolls than to the rest portion of the roll.
When rolling non-symmetrical sections there are high axial forces which have to be compensated by the rolls. The collars which take these axial forces are highly loaded and stressed and show significant wear. The friction areas between the roll is should be lubricated, not by oil but by some grease of low viscosity.