This specification covers standards for castings of ferritic, pearlitic, tempered pearlitic, and tempered martensitic grades of malleable iron used in automotive products and industries. Castings shall be heat treated and shall be of Grades M3210, M4504, M5003, M5503, M7002, and M8501. Materials shall conform to the specified hardness range. Materials shall follow specified microstructure requirements based on distribution of temper-carbon nodules in the metal matrix. All grades shall have a minimum concentration of spheroidal primary carbides in the microstructure.