Maintenance modelling for work rolls in hot finishing mill group with constraint of thermal character

A maintenance model is specially developed for the work rolls equipped in the hot finishing mill group, with the purpose to decrease the total maintenance cost for the roll group under the constraint of the production batches and the roll thermal character. During the maintenance modelling at roll level, the impacts of the surface wear of the work roll on its failure rate state, the production quality and the preventive maintenance cost are deeply discussed. Then, a preventive maintenance grouping method is further proposed at roll group level, with the mutual restriction between the adjustable replacement time of the roll group and the optimal maintenance time of each work roll involved. The case study shows that the proposed maintenance model is practical for the maintenance scheduling of the work rolls in the real rolling production scenario. The total maintenance cost under the proposed maintenance method is always lower that the ones under the individual OM method and the maintenance window-based OM method.