Popova O. The evaluation and prediction of microstructure, working layer properties of roll made from high-chromium cast iron

The subject of research: production of massive rolls with preassigned qualities. The aim of the work is development of estimation criteria of quality ensuring predictionability of microstructure, properties and high operational resistance of centrifugal casted two-layer rolls with working layer made of high-chromium cast iron. Investigation methods: metallographic, measuring microhardness, X-ray spectral microanalisis, determining coercitive force, worked out procedure of phase compoosition estimation using PC. Theoretical and practical results: on the basis developed estimation criteria optimum conditions of formation of working layer were proposed; recommendations on choice of optimum chemical composition, parameters of heat treatment for high-chromium alloy in dependence on consumer demands and field of roll application were devised.The novelty of results received: estimation criteria of quality that delowed forecasting structure, mechaniical and service properties of roll material were proposed; ma thematical model relating chemical composition, relationship of microconstituents,conditions of working layer formation to properties of roll material was suggested; regularities in distribution of alloying elements between phases in depth of working layer in casting state and after heat treatment were emerged; temperature gradients appearing during heat treatment have been revealed using theoretical evaluations; the level of thermal stresses and possibility of chromium redistribution in field of stresses were determined. The degree of redaction to practice: the industrial introduction of developments was carried out at Lutugin's Union for Production of Roll and at metallurgical works of Ukraine and Russia. Economic effect comprised 2 millions grivnas per year. The field of application is machine building plants.