Volchuk V. Development of scientific bases of formation and evaluation of mechanical properties of cast iron section rolling rolls to increase their durability

Subject of the research is the process of assessing the quality criteria of section rolling iron rolls by mathematical modeling. The objective of the thesis is solution to improve the wear resistance of cast iron section rolling roll based on the creation of mathematical models of evaluation criteria of quality, depending on the chemical composition, structure parameters and operational factors. Method of research: methods of formation of passive experiment - to determine the mechanical properties of the workspace iron rolls; active experiment planning, expertise and regression analysis - to determine areas workspace parameters (chemical analysis and structure) roll in which the mechanical properties of stable performance and meet the construction of mathematical models forecasting the quality criteria of the rolls; multifractal analysis of the microstructure - to determine the range of Renyi dimensions of the structural elements of cast iron roll. Theoretical and practical results: evaluated the mechanical properties and wear resistance of the roll according to the chemical composition and structure parameters and operating conditions; defined workspace mechanical properties of the rolls, described by a system of equations, which allows you to quickly monitor and adjust the chemical composition of pig iron, respectively, adopted production technology; the range compromise the mechanical properties of the rolls, which allows, depending on the choice of priority properties, determine the necessary values to predict changes the process and automatically adjust the chemical composition of the roll; developed a method of quantitative evaluation of the structural elements of the rolls with the theory multifraktalov. Scientific novelty: links established between mechanical properties of cast iron rolls execution SPHN (41 ... 65) and SSHHN (41 ... 50) parameters of their structure and chemical composition and developed a scientifically sound and tested a mathematical model for evaluating these properties; the first zone is defined workspace rolls with established content of alloying elements, the ratio of the quantitative parameters of the structure in which they meet the quality criteria of stable performance; first determined the area of compromise with the most effective balance of properties of the working area of performance SPHN roll barrels, SSHHN Boundary content components of the chemical composition and parameters structure; has been further developed a technique to identify the impact of performance on the durability of the work area roll barrels and performance SPHN SSHHN; first theoretically substantiated and experimentally set the sensitivity of the mechanical properties of cast iron rolls for section rolling statistical dimensions of the structural elements of the working area of barrels; for the first time using the theory multifractals defined correlation between the range of the statistical dimensions of the structural elements of the working area of drums section rolling iron rolls and their mechanical properties. Extent of implementation: and an automated method of evaluating the mechanical properties of the rolls and execution SPHN SSHHN enterprise PJSC "Dnipropetrovsk plant rolls", as confirmed by an act of the 10/14/2013, the implementation and calculation of expected annual economic impact of 355.2 thousand UAH and developed a method of forecasting durability of the rolls with an expected annual economic impact of 720 thousand UAH; developed and recommended in production at PJSC "Dnipropetrovsk plant rolls" of a test roll of cast iron, which provide a stable mechanical properties of the working area of the rolls. Sphere of implementation: issue section rolling iron rolls and execution SPHN and SSHHN with stable quality of the working area of the rolls.