A297 HI

Grade HI is an austenitic stainless steel casting alloy specified by ASTM A297/A297M, designed for high-temperature applications requiring resistance to both oxidation and carburization. With a typical composition of approximately 28% chromium and 5% nickel, HI offers improved oxidation resistance compared to lower nickel grades, while maintaining good structural stability under thermal cycling. It is commonly used in furnace hardware, heat-treat fixtures, and other components exposed to high temperatures in oxidizing or carbon-rich environments. HI provides a cost-effective solution where moderate strength and enhanced resistance to environmental attack are required over extended service periods.