Abstract
Problem Statement (Relevance): Today’s rolling industry faces ever increasing requirements for the surface quality of rolled products and, consequently, the quality of rolls. Cast iron indefinite chill rolls used in the finishing stands of rolling mills should offer a high wear resistance and a high resistance to surface microcracking. The working layer properties of cast iron indefinite chill rolls are determined by the structure of cast iron they are made of. The properties of indefinite chill cast iron can be enhanced through an optimized chemical composition. Objectives: This study focuses on the effect of the chemical composition on the working layer structure and hardness in the cast iron indefinite chill rolls as illustrated by industrial data. The work also attempts to identify what concentrations of the chemical elements will help enhance the roll performance. Methods Applied: Artificial neural networks were used for the purpose of the study. Neural network software based on the dual functioning algorithm was applied for database processing, which can process data arrays with numerous input and output data. Originality: As a result of processing, a neuromodel was obtained that can predict the properties of indefinite chilled cast iron within the chemical composition variation ranges being studied. The authors analysed a combined effect of carbon, silicon, manganese, chromium, nickel, molybdenum, vanadium, niobium and boron on the structure and hardness of indefinite chilled cast iron. The effect of each element is non-linear and depends on the concentrations of the other elements. Findings: Graphs were drawn that show the effect of each chemical element at constant concentrations of the other elements. The article describes how the ratio between the structural phases and hardness changes within the studied range of varying chemical composition of indefinite chilled cast iron. The authors determined the optimum concentrations of the chemical elements within the focus range. Practical Relevance: There was an adjustment done to the chemical composition of the working layer of the cast iron indefinite chill rolls produced at the Kushva Roll Manufacturing Factory CJSC. The improved rolls showed a good performance when utilized in roll mills both in Russia and abroad.
Keywords
Mill rolls, indefinite chilled cast iron, chemical composition, hardness, structure, wear resistance.
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