1.1 Form This specification covers a corrosion and heat-resistant steel in the form of investment castings. 1.2 Application These castings have been used typically for parts requiring corrosion and heat resistance up to 800 °F (427 °C) especially when such parts are welded during fabrication, for parts requiring oxidation resistance up to 1500 °F (816 °C) but useful at that temperature only when stresses are low, and for parts requiring resistance to fuming nitric acid, but usage is not limited to such applications.