Characteristics of excess phase in cast high-manganese steel

Abstract

The formation of the excess phase in high-manganese steel is considered over a wide range of cooling rates. This phase, which consists of a phosphide eutectic and secondary carbides, may be deposited both along the grain boundaries and within the grains. At low cooling rates, the phosphide eutectic is mainly formed, with a small quantity of secondary carbides. In addition, excess phase with mixed morphology is encountered. It consists of the eutectic and secondary carbide, with a coherent boundary between them. With increase in the cooling rate, the excess phase consists primarily of secondary carbides; its size is reduced. The influence of the cooling rate on the chemical composition of the excess phase is also of interest. Increase in cooling rate is found to reduce the manganese content in the secondary carbides deposited. The ratio between iron and manganese in the phosphide eutectic does not depend on the cooling rate and is practically constant.