Formation of Deformation Modes During Metal Rolling in Broadband Mills

Abstract

o increase the energy efficiency of the process of hot rolling of metal in the finishing groups of stands of wide-strip mills, the reduction mode is traditionally assigned with the maximum load of the first working stands with a gradual decrease towards the last stand, neglecting the hardening of the strip material. This approach can be applied only in the development of rolling modes for ordinary steel grades. It has been established that during the deformation of highstrength steels in the finishing group of the 2000 mill, the greatest work hardening is observed in stands Nos. 7 and 8, thereby, it is not advisable to use increased reductions in them, in this case it is most efficient to load the stands Nos. 6, 9 and 10. In cold rolling, according to classical approaches, higher reductions are used on the first stands, and lower ones, due to the increasing work hardening of the metal, on the last ones. It is shown that when designing energy-efficient modes, it is necessary to take into account the ratio of the volumes of metal in adjacent stands, avoiding the possibility of the conditions of rolling the strip with undercutting. It is possible to ensure stable rolling of strip with tension in the conditions of a 5-stand mill 1700 by reducing relative reductions in stands Nos. 2 and 3, as well as increasing the speed ratio in the second and third interstand intervals. As a result of the research, it was found that interstand specific tensions are an additional tool for reducing the energy intensity of the cold rolling process. When assigning a tension mode with an increase from the first and last intervals to the average, additional energy savings of up to 4.5% can be obtained. Industrial approbation of metal rolling regimes in wide-strip mills, formed on the basis of the above principles, showed that they can reduce the energy consumption for the deformation process without additional capital costs in the range from 2% to 6%, depending on the grade and profile dimensions of the rolled strips.