The concept of optimal bar roll pass design. Report 4. Optimization of roll pass design scheme

Abstract

Roll pass design of shape rolling rolls is considered from the standpoint of system analysis within “UrFU concept of optimal roll pass design” created in the Chair “Metal Forming” of the Ural Federal University. Roll pass design as a technological system can be changed in two methods: 1) changing the structure of the system which corresponds to a change in the groove shape; 2) changing the control of the system, which corresponds to changing reduction through the pass in the grooves, that is, by changing the reduction mode. Roll pass design that compose of the definite grooves and realize the definite reduction mode, which assures of optimal properties of preassigned objective function depending on the specified parameters, is considered optimal. General conception of two-stage optimization of roll pass design: consistent conduct of optimization of roll pass design scheme (first stage of optimization) and mode of reduction (second stage of optimization), was considered in previous reports. Procedures of formation of optimization space for first stage – space of virtual schemes of roll pass design generated by the special generator and set of all possible types of grooves that can be used at this particular stage of rolling, were also described. To calculate the objective function of the optimality criterion of the roll pass design scheme, the authors introduced the concept of “space of grooves efficiency”. Formation of this space is carried out using a formalized procedure for expert evaluation of the degree of influence of various permissible forms of grooves used in roll pass design on the diverse technological, economic and other characteristics of a particular rolling mill. The objective function is calculated as variance of integral performance indicators of the grooves included in the roll pass design relative to the hypothetical “ideal” groove with the best values of the selected performance indicators. The roll pass design scheme corresponding to the minimum value of the objective function is considered the best.