Prykhodko I. Technology, Calculation Methods and Parameters Control Development and Implementation for the Production Processes Dedicated to Manufacturing Cold-Rolled Strips of High Flatness and High Quality of Surface

The focus of the research is operating procedures and equipment for mass production of thin cold-rolled strips on industrial high-speed rolling mills. The objective is to develop scientific foundations and implement the methods of control for strip flatness, surface state, strip thickness; to improve operating procedures for manufacturing cold-rolled strips on high-speed rolling mills on the basis of the newly found rules of influence of the process key factors, thermal and dynamic effects on the said quality metrics. The subject of the research is mechanisms of formation of stress-strain state of metal and its quality metrics (thickness accuracy, flatness and surface state) during processes of cold-rolling and skin-passing of strips with regard to thermal effects, dynamic effects and stability factors. The theoretical research was based on the classic principles of the theory of elasticity, plasticity, rolling, engineering, quantitative approach, solution methods for optimization tasks and mathematical statistics. Experimental studies were focused on physical modeling in laboratory and industrial conditions using the methods of thermography, tensometry, plastometry, determining topography for roll cooling, evaluation of geometrics, including flatness, surface state, mechanical properties and other quality metrics of cold-rolled strips. For the first time ever the effect of temperature of cold-rolled strips during coiling on stress state of coils and formation of defects of strip surface was established both theoretically and experimentally. For the first time the mechanism of strip thermal flattening process was found. For the first time it was suggested that in conditions of cold-rolling of strips with lubrication the thermal state of the rolls and strip depends on the factor which characterizes fullness of contact between rolls and strip. For the first time the rule of burst-type increase of vibrations of continuous strip cold-rolling mills was established. The method of optimization of strain multiple-pass rolling schedule with pre-set initial and final strip thickness was improved. The method of calculation of intermediate sicknesses and interstand tensions as per the continuous mill settings was improved, and the deterministic and probabilistic mathematical model of the process of continuous strip cold-rolling was further developed. The ideas of rollability of local bulges of lateral sections of semifinished products during the process of continuous cold-rolling of thin strips were further developed. For the first time the rules were found for implementation of the process of cold rolling of thin strips: with minimum force or minimum energy consumption. Area of application: manufacturing of cold-rolled steel strips on high-speed rolling mills.