MILLING BODY FOR BALL MILLS Russian patent published in 2004 - IPC

FIELD: mechanical engineering; milling bodies for ball mills; metallurgy; cement and coal industries; manufacture of refractory and building materials. SUBSTANCE: proposed milling body is made from structural steel at low hardenability and content of carbon ranging from 0.40 to 0.80 mass-%; milling body is subjected to volume surface hardening at self-tempering or tempering in furnace. Microstructure of ball surface layer is tempered nartensite at size of actual grain of austenite of 11-14; depth of layer of tempered martensite is equal to 0.05-0.35 of its diameter and hardness of surface layer is more than 59 HRC_e; microstructure of ball core is just troostite or troosto-sorbite at hardness more than 30 HRC_e. Depth of layer of surface tempered martensite of ball surface layer is equal to 0.25-0.35 of ball diameter and microstructure of ball core is just troosto-martensite or troostite at hardness more than 45 HRC_e. EFFECT: enhanced wear resistance and resistance to breaking at impacts; improved strength characteristics. 2 cl