METHOD FOR DRY CHROMIZING OF FORMING CHILLED CAST IRON ROLLS Russian patent published in 1997 - IPC

FIELD: chromium coatings. SUBSTANCE: method concerns chromizing cast iron rolls with chilled surface layer to increase their working capacity owing to high deterioration and wear resistance. Rolls with applied electrolytic chromium coating are baked in gaseous media reducing tendency of white irons for graphitization leading to formation free and bound complex carbides opposing oxidation and containing high-purified and dried gases with dew point not higher than -50 C (hydrogen-nitrogen and inert gases). Carbidization of coating 0.02-0.2 mm thick takes place in the course of slow heating to 950-980 C in austenite region. Microhardness in chrome- plated zone achieves 20 GPa. At the same time, in cavity of roll barrel made up of gray cast iron, chemical and physical homogeneity of structure is increased. EFFECT: increased performance characteristics of rolls. 2 cl, 3 dwg