US4396442A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ductile cast iron roll and a manufacturing method thereof
Assignee: Kubota Corp
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Filing: 1981-05-15
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Granted: 1983-08-02
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Expires: 2001-05-15
Abstract
Abstract 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°˜850° C. for less than 20 hours; and after that by cooling the same down to 760° C. at the cooling speed 50˜300° C./Hr; and after that by holding the same at the temperature 450°˜650° C. for less than 20 hours.
Inventors
- 👤 Shiro Nakamura
- 👤 Masahiro Fukuda
- 👤 Akitoshi Okabayashi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 21:11
CPC Classifications
C; C22; C22C; C22C37/00; C22C37/06; C22C37/08
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
74 words
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.
Claim 2
Dependent Claim
74 words
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.
Claim 3
Dependent Claim
23 words
A ductile cast iron roll as described in claim 1 wherein a Al less than 0.3% is contained in the said cast iron.
Claim 4
Dependent Claim
28 words
A ductile cast iron roll as described in claim 1 or 2 wherein a total of 0.05% of rare earth elements are added to the said cast iron.
Claim 5
Dependent Claim
45 words
A ductile cast iron roll as described in claim 1, further containing calibers, wherein the hardness of the bottom surface of said calibers is higher by Hs 1-5 than that of the flange portion which is on the same radius as the said bottom surface.
Claim 6
Independent Claim
112 words
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° to 850° C. for less than 20 hours, cooling to 600° C. at a cooling speed of 50° to 300° C./Hr, and then maintaining at 450° to 650° C. for less than 20 hours.
Claim 7
Independent Claim
112 words
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° to 850° C. for less than 20 hours, cooling to 600° C. at a cooling speed of 50° to 300° C./Hr, and then maintaining at 450° to 650° C. for less than 20 hours.
Claim 8
Dependent Claim
23 words
The method of claim 5 wherein said cast iron contains, in addition, a positive amount of aluminum of less than 0.3% by weight.
Claim 9
Dependent Claim
28 words
The method of claim 5 wherein said cast iron contains, in addition, a positive amount of rare earth elements in an amount of less than 0.5% by weight.
Claim 10
Dependent Claim
16 words
The method of claim 5 further including calibers, said calibers formed prior to said heat treatment.
Claim 11
Dependent Claim
96 words
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 2 and an elongation percent of 1.9 to 2.9.
Claim 12
Dependent Claim
96 words
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 2 and an elongation percent of 1.9 to 2.9.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-08-01 | 1987-01-31 | 1987-08-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-08-01 | 1991-01-31 | 1991-08-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-08-01 | 1995-01-31 | 1995-08-02 | $7700.00 | Window Closed / Lapsed |