Patent ID: 9708694
Date: 2017-07-18
CPC Classifications: B22D,C21C,C22C,F02F

Claim:
1. A method for manufacturing a high-strength flake graphite cast iron for an engine body, the method comprising: (i) manufacturing molten cast iron that consists of 3.2 to 3.5% of carbon (C), 1.9 to 2.3% of silicon (Si), 0.62 to 0.9% of manganese (Mn), 0.06 to 0.1% of sulfur (S), 0.06% or less of phosphorous (P), 0.6 to 0.8% of copper (Cu), 0.15 to 0.25% of molybdenum (Mo), and a remainder of iron (Fe) and other unavoidable impurities with respect to a total weight %; (ii) adding 0.001 to 0.005% of strontium (Sr) to the melted molten cast iron based on a total weight of the molten cast iron, wherein a ratio (S/Sr) of the content of the sulfur (S) to the content of the strontium (Sr) is adjusted into a range of 16 to 98; and (iii) tapping the molten cast iron in a ladle to put the tapped molten cast iron in a casting mold, wherein a chill depth of a wedge test piece manufactured using the flake graphite cast iron is 3 mm or less.