Hadfield manganese austenitic steel: a review of manufacturing processes and properties

In this paper, manufacturing processes and properties of Hadfield manganese steel was studied. Due to good flexibility and excellent resistance to wear, the high strength steel is widely used in various industries such as cement, mining, road construction and railroads. Induction furnace is suitable for melting of Hadfield steel. Typically, silica, olivine and chromite sand are used to make mold in the casting process of Hadfield steel. This steel is in standard state, an alloy of Fe, C and Mn. But in certain applications, other elements such as Cr, Ti, Al, Mo, B, V, etc are added. Mn is used as the most important austenite stabilizer in Hadfield steel and its role is to delay the austenite to martensite transformation. Mn is a carbide forming element and forms Mn₃C and (Fe, Mn)₃C in Hadfield steel. The optimal structure for the Hadfield steels is the fully austenite structure and the single-phase. In non-heat-treated castings, the structure of the unit consists of austenitic and grain boundary carbide phase. To provide optimum toughness, the structure of the Hadfield steel should be austenitic single-phase. Twin strain has a great contribution to plastic deformation of this steel. Two phenomena of dislocation accumulation and the formation of twins during plastic deformation of these steels are the main reason of the strain hardness of this steel. The high rate of work hardening in Hadfield steel is due to strain induced transformation of γ to α or ε martensite, mechanical twinning, dynamic strain aging, and the confrontation between dislocations with stacking faults. In the early stages of wear and slow wear conditions, the wear resistance of Hadfield steel is low. In conditions of slow wear, the surface is not sufficiently work hardening and thus the wear resistance of this steel is low. But with the work hardening of the surface, wear resistance rises sharply. The welding and weldability of this steel are strongly influenced by the heat input. In any case, the formation of carbide phases in the weld metal is acceptable, and often the weld metal has higher strength and lower toughness than the base metal. Carbides deposited in the heat affected zone (HAZ) of welded Hadfield steel, usually are Mn₇C₃ and Mn₂₃C₆. (paper)