Influence of Primary Austenite Dendrite on the Microstructure and Mechanical Properties of Gray Cast Iron

The formation of the microstructure of gray cast iron is a complex process. There remains many unanswered questions about the process. Using annealing method, the first crystallized primary austenite dendrites from the molten iron was displayed. The room temperature microstructures of gray cast iron with and without Cu, Cr addition were studied. The relationship between microstructure and mechanical property was discussed. The results show that the amount of primary austenite dendrites of the multi-alloyed gray cast iron increases significantly and the secondary dendrite arm spacing seems narrow. The microstructure at room temperature is fine and homogeneous. Tensile strength increases significantly, up to 300MPa with adding 0.58%Cu and 0.29%Cr.