关键词: 沉淀强化工艺, 多元微合金化, 复合变质处理, 破碎机环锤, 铁砂造型消失模铸造工艺

Abstract: In view of the weakness of ring-hammer such as cracks, breakages, poor wear resistance and short service lifet, a high wear-resistant steel with initial hardness up to HB 210 and impact ductility above 215 J•cm–2 is developed successfully, which is based on the high manganese steel with the addition of alloy agents and composite modification, by designing component, designing processes which include a new lost foam casting process of iron-sand molding & spiral-ring chill and a heat treatment for precipitation strengthening. The results show that after multi-element microalloying and composite modification, second hard phase particles such as alloy carbides are formed and dispersively distributed in the austenitic matrix, thereby strengthening the matrix and improving the initial hardness of material. When iron sand is adopted for molding, it not only has the inherent characteristic of molding sand but also plays the function of metal mold, so that the grains of casting are refined , and the microstructure density is improved. The production practice shows that the properties of the ring-hammer produced on the basis of such technique can be obtained as follows: tensile strength b=724 MPa, impact toughness k=219 J•cm–2, percentage elongation  =37%, Brinell hardness 210 HB respectively after precipitation strengthening treatment by water quenching at 1 080 ℃ for 4 h and tempering at 320 ℃ for 3 h, which can meet the application requirements, the products have good wear-resistant property in practical application and obvious market competitive advantage.

Key words: Composite modification, Crusher ring-hammer, Lost foam casting of iron-sand molding, Multi-element micro-alloying, Precipitation strengthening process