Influence of the carbon content on the microstructure and properties of heat-resistant cast steels

Abstract

Abstract Two heat-resistant ferritic cast steels, 1.4476 and 1.4777 with a similar high Cr concentration, have been analyzed regarding their microstructures, mechanical properties, corrosion resistance and aging behavior. The differences observed between the grades are related to their different C contents. A higher C concentration ensures a higher mechanical resistance, in particular at high temperature (850°C) and also a better high-temperature (850°C) corrosion resistance. This is related to the formation of numerous carbides. However, this study also reveals that the microstructure of these steels is greatly affected by aging. In particular, the precipitation of the sigma phase and the formation of nitride precipitates could lead to failure during service at high temperature.