Zinc-Pot Roll Bearing Design Modification for Increased Life

摘要

All bearings for sink, stabilizer and reflector rolls used inside the zinc-pot of a galvanizing line have a short lifetime from 1 to 4 weeks depending on sheet tension, sheet speed, pot chemistry and temperature. Through extensive testing of many bearing materials it has been determined that bearing wear rate is proportional to the bearing contact pressure to the power ranging from 1.6 to 2. To avoid roll stoppage by bearing friction, the shaft diameter is small and therefore the shaft length is about equal to its diameter so as not to exceed the allowable root bending moment. These short-cantilevered shafts are welded to the end of each roll. By changing the bearing shaft configuration from a rotating to a stationary shaft, clamped at each end to the roll supporting bridle, the bearing length can at least be doubled without an increase in bending moment. With the rotating sleeves welded to the end of the roll, bearing alignment will be assured. The associated reduction in bearing contact pressure should increase bearing life at least five fold.