American Society for Testing and Materials (ASTM). Current edition approved Nov. 1, 2008. Published December 2008. Originally approved in 1946. Last previous edition approved in 2008 as A297/A297M – 08. 4 p. This specification covers iron-chromium and iron-chromium-nickel alloy castings for heat-resistant service. The grades covered by this specification are general purpose alloys and no attempt has been made to include heat-resisting alloys used for special production application.