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US 4,396,442 AGranted
Ductile cast iron roll and a manufacturing method thereof
AssigneeKubota Corporation
InventorsShiro Nakamura, Masahiro Fukuda, Akitoshi Okabayashi
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AssigneeKubota Corporation
InventorsShiro Nakamura, Masahiro Fukuda, Akitoshi Okabayashi
Estimating the term…
The present invention relates to a ductile cast iron roll which is excellent in its resistance breaking and which has the chemical composition comprising 3.0-3.8% C, 1.5-2.5% Si, 0.2-1.0% Mn, 0.01-0.2% P, less than 0.06% S, 0.7-3.0% Ni, 0.1-0.6% Cr, 0.1-0.8% Mo, 0.02-0.1% Mg, balance iron and unavoidable impurities and the base structure having a fine two-phase structure of ferrite mingled with pearlite. The cast iron roll is manufactured by holding the said cast iron roll at the temperature 780.degree..about.850.degree. C. for less than 20 hours; and after that by cooling the same down to 760.degree. C. at the cooling speed 50.about.300.degree. C./Hr; and after that by holding the same at the temperature 450.degree..about.650.degree. C. for less than 20 hours.
A ductile cast iron roll having a base structure of a composition comprising 3.0 to 3.8% C, 1.5 to 2.5% Si, 0.2 to 1.0% Mn, 0.01 to 0.2% P, less than 0.06% S, 0.7 to 3.0% Ni, 0.1 to 0.6% Cr, 0.1 to 0.8% Mo, 0.02 to 0.1% Mg, all percents being weight %, the balance iron and unavoidable impurities, said base structure characterized by being substantially a two-phase structure of ferrite and pearlite.
A method of manufacturing a ductile cast iron roll, said roll produced from a cast iron having a composition comprising 3.0 to 3.8% C, 1.5 to 2.5% Si, 0.2 to 1.0% Mn, 0.01 to 0.2% P, less than 0.06% S, 0.7 to 3.0% Ni, 0.1 to 0.6% Cr, 0.1 to 0.8% Mo, 0.02 to 0.1% Mg, all percents being weight %, balance iron and unavoidable impurities, said method comprising holding the cast iron at a temperature of 780.degree. to 850.degree. C. for less than 20 hours, cooling to 600.degree. C. at a cooling speed of 50.degree. to 300.degree. C./Hr, and then maintaining at 450.degree. to 650.degree. C. for less than 20 hours.
A ductile cast iron roll having a base structure of a composition comprising 3.0 to 3.8% C, 1.5 to 2.5% Si, 0.2 to 1.0% Mn, 0.01 to 0.2% P, less than 0.06% S, 0.7 to 3.0% Ni, 0.1 to 0.6% Cr, 0.1 to 0.8% Mo, 0.02 to 0.1% Mg, all percents being weight %, the balance iron and unavoidable impurities, said base structure characterized by being substantially a two-phase structure of ferrite and pearlite and having a tensile strength in the range of 54 to 62.1 kg/mm.sup.2 and an elongation percent of 1.9 to 2.9.
Dependencies are inferred from the claim text.