| The back-up roll is one of important parts of the mill, and its characteristicsdirectly affect mill production, strip quality and production costs. In this issue, weanalyze the problems about abrasion of back-up roll in hot strip mill factory of Xinyusteel cooperation. Aimed to solve this problem, we optimized the design, whichobviously improved the situation.Through analyzing a large number of data, we found some causes which can causethese problems. First, the abrasion of back-up roll may cause by itself for its characters,such as the order of the roller in the finishing mill process, the hardness of the roller,and its roll forming. Besides, the work roll which paired with its also can affect theabrasion of back-up roll, such as the shape of the WR, the temperature of the WR,andthe interaction of them. There are also some other reasons which can cause abrasion.Aimed to these reasons, we optimized the design to back-up roll from some point.According to abrasion theory, we refined the hardness of the roll from60HSD-70HSDto63HSD-67HSD. This change solves some problems.We build a multi-objective optimization model based on the theory of flatness andactual production condition. Established two objective functions, and one of themaimed to uniform stress distribution between the back-up roll, and another functionaimed to get smallest strip tensile stress. We put the two functions together with themethod of weighted mean. Then we optimize the design of the pressure distributionand the shape of the back-up roll, and we worked out the shape of back-up roll withgenetic algorithm. At last, according to the abrasion of rolls in different frame,combined with finishing work rolls CVC rolling curve, using the three-Backup Roll design model, integrated to determine the finishing support roll VCR-plus curve. Theabrasion of the back-up rolls is significantly improved, as the abrasion of the barrel issignificantly lower, and the situation of contact stress of shoulder is improved. |
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