Effect of Higher Temperature Austempering on Properties of Ductile Cast Iron

The paper deals with the structure and properties of 3 80%C,2 46%Si,0 25%Mn,0 026%S,0 036%P,0 051%Mg,0 022%RE ductile cast iron heat treated at higher temperature through conventional austempering,two step austempering or austempering+tempering.It was found that the heat treat processing zone is narrow/disappeared at higher temperature so that the bainitic ductile cast iron without austenite in the matrix can be obtained.The ductile iron has not only high tensile strength and hardness and fatigue limit but also excellent wear resistance and machinability.