Patent ID: 6973954

Claim:
A method for the manufacture of crank cases and cylinder heads from grey cast iron comprising the steps of: providing a molten controlled-content grey iron metal having a carbon equivalent of about 4.05%, comprised of about 3.40% to about 3.45% carbon, about 1.80% to about 1.90% silicon with less than about 0.03% phosphorus, while maintaining base iron sulfur at about 0.05% to about 0.07%, manganese at about 1.7 times the percentage of sulfur plus about 0.30% to about 0.40%, and base iron chromium less than about 0.10%; transferring said molten controlled-content grey iron metal to a pouring ladle; alloying said molten controlled-content grey iron metal with tin in said pouring ladle to a total tin content of about 0.05% to about 0.10% to provide a molten tin-alloyed, controlled-content grey iron metal; inoculating said molten tin-alloyed, controlled-content grey iron metal with a grey iron inoculant to a further silicon addition of from about 0.10% to about 0.12%; pouring said molten, tin-alloyed, inoculated controlled-content grey iron metal as soon as possible after said inoculation into a casting mold; and shaking out the resulting casting out of the casting mold while at a temperature over 1400° F.