Gray Iron

Specifing Spec.TypicalClass orTestTensileHeat Other
ASTM  A 48-03 30-B1.230 When agreed upon
     in writing, special 
 30-C230 requirements can be met
General engineering    such as hardness,
use where tensile 40-B1.240 chemical composition
strength is a major     and microstructure.
consideration.40-C240 Any class or grade
     castings can
 50-B1.250Normalized or be stress relieved
    Quenched andto help maintain
      Tempereddimensional integrity.

Ref. ASTM Book of Standards, Ferrous Castings: Ferroalloys,Most common grades poured at Oil City.
Section 1, Volume 01.02 for additional data.