Perfection of rolls sizing in bar & wire rod mill 370/150 to ensure accuracy in rolled product profile

Abstract

An actual problem of production bars with increased geometry accuracy at existing mill 370/150 at OJSC “BMZ -management company of Holding “BMC” has been reviewed. The object of research was reducing-sizing mill, composed of three finishing stands. The subject of research was rolling process in finishing stands aiming at achieving highly accurate geometry in the finished profile. In the work, based on empirical data, efficiency of existing methods of sizing by statistical method to produce a profile of regular accuracy and highly accurate profile was assessed. By the method of finite elements the rolling processes were simulated, approximated to real conditions by means of numerical modeling. Empiric and theoretic data revealed drawbacks of existing systems of sizing, as well as let determine further direction of research. Analytical description of key factors of rolling affecting creation of profile enabled to come to conclusion that the basis for achieving geometry sizes of transversal profile depends on pressure of steel on to rolls and the inter-stand tension. On this basis the new method of sizing has been developed. On the basis of the new method of sizing, rolling processes at different frequencies of rolls rotation were simulated. The process of mathematical simulation to the maximum approximated to real conditions of rolling. Thanks to this it became possible to obtain reliable results of research, enabling to achieve highly accurate geometry of transversal profile. Obtained results of research are the basis for further study of inter-stand deformation to be followed by experimental rolling at mill 370/150.