US3915756A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process of manufacturing cast steel marine propellers
Assignee: Mitsubishi Heavy Industries Ltd
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Filing: 1972-10-05
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Granted: 1975-10-28
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Expires: 1992-10-05
Abstract
Abstract A tenacious cast steel, is used for manufacturing propellers, and has essentially the following composition: C: between about 0.03-0.07% Cr: between about 10-14% Ni: between about 5-7% Co: between about 3-5% Mo: between about 1.0-2.5% Si: not more than about 0.8% Mn: not more than about 1.2% and IMPURITIES, THE BALANCE BEING Fe, all percentages being by weight on total composition. In the marine propellers, a portion of the nickel content of this cast steel may be replaced by copper. The copper amount, however, should not exceed 3% by weight and the ratio of copper to nickel should be about 1:1. The process produces martensite steels having therein precipitates of molybdenum compounds which reinforce the cast steel propellers improving ductility toughness over conventional cast steels.
Inventors
- 👤 Teishiro Oda
- 👤 Makoto Nakamura
- 👤 Masato Zama
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 01:08
CPC Classifications
C; C21; C21D; C21D9/00; C21D9/0068; C22; C22C; C22C38/00; C22C38/18; C22C38/40; C22C38/52
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
132 words
METHOD OF MAKING MARINE PROPELLERS WHICH COMPRISES A. FORMING AN ALLOY COMPOSITION OF TENACIOUS CAST STEEL COMPRISING THE FOLLOWING ELEMENTS BY WEIGHT: I. FROM ABOUT 0.03 TO ABOUT 0.07% CARBON II. FROM ABOUT 10 TO ABOUT 14% CHROMIUM, III. FROM ABOUT 5 TO ABOUT 7% NICKEL, IV. FROM ABOUT 3 TO ABOUT 5% COBALT, V. FROM ABOUT 1.0 TO 2.5% MOLYBDENUM, VI. NOT MORE THAN ABOUT 0.8% SILICON, VII. NOT MORE THAN ABOUT 1.2% MANGANESE, VIII. SUBSTANTIALLY THE BALANCE BEING IRON, B. CASTING THE AFORESAID ALLOY COMPOSITION IN THE FORM OF A MARINE PROPELLER CONSTRUCTION, C. REHEATING SAID CAST MARINE PROPELLER CONSTRUCTION TO THE AUSTENITIZING TEMPERATURE AFTER CASTING, AND D. COOLING THE SO-OBTAINED MARINE PROPELLER CONSTRUCTION OF SUBSTANTIALLY MARTENSITE STEEL HAVING IMPROVED DUCTILITY, TENSIL STRENGTH AND RESISTANCE TO CRACKING AT WELDING TEMPERATURES,
Claim 2
Dependent Claim
132 words
METHOD OF MAKING MARINE PROPELLERS WHICH COMPRISES A. FORMING AN ALLOY COMPOSITION OF TENACIOUS CAST STEEL COMPRISING THE FOLLOWING ELEMENTS BY WEIGHT: I. FROM ABOUT 0.03 TO ABOUT 0.07% CARBON II. FROM ABOUT 10 TO ABOUT 14% CHROMIUM, III. FROM ABOUT 5 TO ABOUT 7% NICKEL, IV. FROM ABOUT 3 TO ABOUT 5% COBALT, V. FROM ABOUT 1.0 TO 2.5% MOLYBDENUM, VI. NOT MORE THAN ABOUT 0.8% SILICON, VII. NOT MORE THAN ABOUT 1.2% MANGANESE, VIII. SUBSTANTIALLY THE BALANCE BEING IRON, B. CASTING THE AFORESAID ALLOY COMPOSITION IN THE FORM OF A MARINE PROPELLER CONSTRUCTION, C. REHEATING SAID CAST MARINE PROPELLER CONSTRUCTION TO THE AUSTENITIZING TEMPERATURE AFTER CASTING, AND D. COOLING THE SO-OBTAINED MARINE PROPELLER CONSTRUCTION OF SUBSTANTIALLY MARTENSITE STEEL HAVING IMPROVED DUCTILITY, TENSIL STRENGTH AND RESISTANCE TO CRACKING AT WELDING TEMPERATURES,
Claim 3
Dependent Claim
36 words
Method of making marine propellers, according to claim 1, which comprises replacing a portion of the nickel with copper, said copper amounting to not more than 3%, the ratio of copper to nickel being about 1:1.
Claim 4
Dependent Claim
120 words
TENACIOUS CAST STEEL MARINE PROPELLER FORMED FROM AN ALLOY COMPOSITION CONSISTING ESSENTIALLY OF THE FOLLOWING ELEMENTS BY WEIGHT: I. FROM ABOUT 0.03 TO ABOUT 0.07% CARBON, II. FROM ABOUT 10 TO ABOUT 14% CHROMIUM, III. FROM ABOUT 5 TO ABOUT 7% NICKEL, IV. FROM ABOUT 3 TO ABOUT 5% COBALT, V. FROM ABOUT 1.0 TO ABOUT 2.5% MOLYBDENUM, VI. NOT MORE THAN ABOUT 0.8% SILICON, VII. NOT MORE THAN ABOUT 1.2% MANGANESE, VIII. SUBSTANTIALLY THE BALANCE BEING IRON, SAID ALLOY COMPOSITION BEING CAST IN THE FORM OF A MARINE PROPELLER CONSTRUCTION, REHEATED TO THE AUSTENITIZING TEMPERATURE AFTER CASTING, AND THEREAFTER COOLED, WHEREBY A MARINE PROPELLER CONSTRUCTION IS OBTAINED HAVING IMPROVED DUCTILITY, TENSILE STRENGTH AND RESISTANCE TO CRACKING AT WELDING TEMPERATURES.
Claim 5
Dependent Claim
120 words
TENACIOUS CAST STEEL MARINE PROPELLER FORMED FROM AN ALLOY COMPOSITION CONSISTING ESSENTIALLY OF THE FOLLOWING ELEMENTS BY WEIGHT: I. FROM ABOUT 0.03 TO ABOUT 0.07% CARBON, II. FROM ABOUT 10 TO ABOUT 14% CHROMIUM, III. FROM ABOUT 5 TO ABOUT 7% NICKEL, IV. FROM ABOUT 3 TO ABOUT 5% COBALT, V. FROM ABOUT 1.0 TO ABOUT 2.5% MOLYBDENUM, VI. NOT MORE THAN ABOUT 0.8% SILICON, VII. NOT MORE THAN ABOUT 1.2% MANGANESE, VIII. SUBSTANTIALLY THE BALANCE BEING IRON, SAID ALLOY COMPOSITION BEING CAST IN THE FORM OF A MARINE PROPELLER CONSTRUCTION, REHEATED TO THE AUSTENITIZING TEMPERATURE AFTER CASTING, AND THEREAFTER COOLED, WHEREBY A MARINE PROPELLER CONSTRUCTION IS OBTAINED HAVING IMPROVED DUCTILITY, TENSILE STRENGTH AND RESISTANCE TO CRACKING AT WELDING TEMPERATURES.
Claim 6
Dependent Claim
44 words
Tenacious cast steel propeller formed from an alloy composition, as set forth in claim 3 wherein a portion of nickel is replaced with copper, said copper amounting to not more than 3% by weight, the ratio of copper to nickel therein being about 1:1.
Claim 7
Dependent Claim
52 words
Marine propeller according to claim 4, in which said cast steel consists essentially of: i. about 0.06% carbon, l ii. about 0.28% silicon, iii. about 0.45% manganese, iv. about 12.58% chromium, v. about 1.91% molybdenum vi. about 4.62% nickel, vii. about 4.21% cobalt, and viii. about 1.85% copper and the balance iron.
Claim 8
Dependent Claim
51 words
Marine propeller according to claim 4, in which said cast steel consists essentially of: i. about 0.03% carbon, ii. about 0.23% silicon, iii. about 0.29% manganese, iv. about 0.12% chromium, v. about 2.20% molybdenum, vi. about 4.55% nickel; vii. about 4.03% cobalt, and viii. about 1.95% copper, and the balance iron.
Claim 9
Dependent Claim
51 words
Marine propeller according to claim 4, in which said cast steel consists essentially of: i. about 0.06% carbon, ii. about 0.17% silicon, iii. about 0.50% manganese, iv. about 12.60% chromium, v. about 1.91% molybdenum, vi. about 5.55% nickel, vii. about 4.48% cobalt, and viii. about 1.90% copper, and the balance iron.
Claim 10
Dependent Claim
51 words
Marine propeller according to claim 4, in which said cast steel consists essentially of: i. about 0.06% carbon, ii. about 0.34% silicon, iii. about 0.40% manganese, iv. about 12.6% chromium, v. about 1.96% molybdenum, vi. about 5.57% nickel, vii. about 3.93% cobalt, and viii. about 1.62% copper, and the balance iron.
Claim 11
Dependent Claim
47 words
Marine propeller according to claim 3, in which said cast steel consists essentially of: i. about 0.06% carbon, ii. about 0.46% silicon, iii. about 0.34% manganese, iv. about 11.78% chromium, v. about 1.90% molybdenum, vi. about 5.91% nickel, and vii. about 4.15% cobalt, and the balance iron.
Claim 12
Dependent Claim
47 words
Marine propeller according to claim 3, in which said cast steel consists essentially of: i. about 0.05% carbon, ii. about 0.46% silicon, iii. about 0.37% manganese, iv. about 12.01% chromium, v. about 1.88% molybdenum, vi. about 5.94% nickel, and vii. about 4.12% cobalt, and the balance iron.
References Cited (Backward Citations)
US2499860A
Cited
US2557971A
Cited
US2783169A
Cited
US3192073A
Cited
US3154412A
Cited
US3278298A
Cited
US3650845A
Cited
US3661658A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-10-27 | 1979-04-28 | 1979-10-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-10-27 | 1983-04-28 | 1983-10-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-10-27 | 1987-04-28 | 1987-10-28 | $7700.00 | Window Closed / Lapsed |