This specification covers four zinc alloys in ingot form, namely: Spin Casting Alloy SC-A, Spin Casting Alloy SC-B, Spin Casting Alloy SC-C, and ZA-73, for remelting for the manufacture of spin castings. The alloys may be made by any approved process, shall be of uniform quality, and shall be free from dross or other harmful contamination. The ingots shall conform to the chemical composition limits prescribed for aluminum, magnesium, copper, iron, lead, cadmium, tin, nickel, and zinc. Chemical analysis requirements for determination and for verification (if needed) of chemical composition are detailed.