This standard covers the hardness and microstructural requirements for gray iron sand mold castings used in automotive and allied industries. The chemical requirements for alloy gray iron automotive camshafts are included in the standard under casting for special application with controlled composition and microstructure. The Appendix provides general information on application of gray iron in automotive castings and general information on application of gray iron in automotive casting and chemical composition to meet hardness@ microstructural@ and other properties needed for particular service conditions. The mechanical properties in the Appendixare provided for design purposes. Note: This document was rewritten in June 1970. The materials described by the grade numbers are different than in the former writing.