US4404041A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of producing elongated large-size forged article
Assignee: Hitachi Ltd
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Filing: 1982-10-29
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Granted: 1983-09-13
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Expires: 2002-10-29
Abstract
Abstract A method of producing forged article by casting a molten alloy steel containing 0.02 to 0.15 wt % of niobium and 9 to 12 wt % of chromium in a metal mold to form an ingot and subjecting the ingot to a forging. The ingot is formed to have a diameter greater than the height thereby to prevent generation of eutectic NbC and sedimental crystals.
Inventors
- 👤 Kimihiko Akahori
- 👤 Shigeo Maeno
- 👤 Hideyo Kodama
- 👤 Norio Morisada
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 03:11
CPC Classifications
C; C21; C21D; C21D8/00; C21D7/00; C21D7/13; C21D9/00; C21D9/38; C22; C22C; C22C38/00; C22C38/18; C22C38/26; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/4998; Y10T29/49988
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
119 words
A method of producing an elongated large-size forged article comprising: preparing molten metal of an alloy steel containing 0.08 to 0.25 wt% of carbon, 0.02 to 0.15 wt% of niobium, 9 to 12 wt% of chromium and more than 80 wt% of iron, pouring said molten metal and solidifying the same in a metal mold having a ratio H/D of the height H of the body neglecting the hot top portion to the diameter D at the height of 1/2 H falling within a range of not greater than 1, and forging the resulting ingot by applying pressure in the radial direction until the heightwise length of the forged article becomes greater than a diameter of the forged article.
Claim 2
Independent Claim
119 words
A method of producing an elongated large-size forged article comprising: preparing molten metal of an alloy steel containing 0.08 to 0.25 wt% of carbon, 0.02 to 0.15 wt% of niobium, 9 to 12 wt% of chromium and more than 80 wt% of iron, pouring said molten metal and solidifying the same in a metal mold having a ratio H/D of the height H of the body neglecting the hot top portion to the diameter D at the height of 1/2 H falling within a range of not greater than 1, and forging the resulting ingot by applying pressure in the radial direction until the heightwise length of the forged article becomes greater than a diameter of the forged article.
Claim 3
Dependent Claim
27 words
A method of producing an elongated large-size forged article according to claim 1, wherein said body of said ingot has a diameter not smaller than 500 mm.
Claim 4
Dependent Claim
77 words
A method of producing an elongated large-size forged article according to claim 1, wherein said alloy steel consists of 9 to 12 wt% of chromium, 0.02 to 0.15 wt% of niobium, 0.08 to 0.25 wt% of carbon, 0.15 to 0.3 wt% in total of carbon and nitrogen, not greater than 0.5 wt% of silicon, 0.4 to 1 wt% of manganese, 0.7 to 1.5 wt% of molybdenum, 0.15 to 0.3 wt% of vanadium and the balance substantially iron.
Claim 5
Dependent Claim
84 words
A method of producing an elongated large-size forged article according to claim 1, wherein said alloy steel consists of 9 to 12 wt% of chromium, 0.02 to 0.15 wt% of niobium, 0.08 to 0.25 wt% of carbon, 0.15 to 0.3 wt% in total of carbon and nitrogen, not greater than 0.5 wt% of silicon, 0.4 to 1 wt% of manganese, 0.7 to 1.5 wt% of molybdenum, 0.15 to 0.3 wt% of vanadium, not greater than 1 wt% of nickel and the balance substantially iron.
Claim 6
Dependent Claim
26 words
A method of producing an elongated large-size forged article according to claim 3, wherein the chromium equivalent of said alloy steel ranges between 5.0 and 6.5.
Claim 7
Dependent Claim
26 words
A method of producing an elongated large-size forged article according to claim 4, wherein the chromium equivalent of said alloy steel ranges between 5.0 and 6.5.
Claim 8
Dependent Claim
22 words
A method of producing an elongated large-size forged article according to claim 1, wherein said ratio H/D ranges between 0.5 and 1.0.
Claim 9
Dependent Claim
22 words
A method of producing an elongated large-size forged article according to claim 1, wherein said ratio H/D ranges between 0.8 and 1.0.
Claim 10
Dependent Claim
30 words
A method of producing an elongated large-size forged article according to claim 1, wherein the forging is made by applying pressure to said ingot only in the radial direction thereof.
Claim 11
Dependent Claim
36 words
A method of producing an elongated large-size forged article according to claim 1, wherein the forging includes a plurality of forgings applying pressure to said ingot in the radial direction and one cycle of upset forging.
Claim 12
Independent Claim
159 words
A method of producing a steam turbine rotor shaft comprising: preparing molten metal of an alloy steel containing 0.08 to 0.25 wt% of carbon, 0.02 to 0.15 wt% of niobium, 9 to 12 wt% of chromium and more than 80 wt% of iron, pouring said molten metal and solidifying the same in a metal mold having a ratio H/D of the height H of the body neglecting the hot top portion to the diameter D at the height of 1/2 H falling within a range of not greater than 1, forging the ingot by applying pressure in the radial direction until the heightwise length of a forged article becomes greater than a diameter of the forged article, subjecting the forged article to an annealing, subjecting the annealed forged article to a machining to form a half-finished rotor shaft, subjecting the machined half-finished rotor shaft to a hardening/tempering treatment and subjecting the treated half-finished rotor shaft to a finish machining.
Claim 13
Independent Claim
159 words
A method of producing a steam turbine rotor shaft comprising: preparing molten metal of an alloy steel containing 0.08 to 0.25 wt% of carbon, 0.02 to 0.15 wt% of niobium, 9 to 12 wt% of chromium and more than 80 wt% of iron, pouring said molten metal and solidifying the same in a metal mold having a ratio H/D of the height H of the body neglecting the hot top portion to the diameter D at the height of 1/2 H falling within a range of not greater than 1, forging the ingot by applying pressure in the radial direction until the heightwise length of a forged article becomes greater than a diameter of the forged article, subjecting the forged article to an annealing, subjecting the annealed forged article to a machining to form a half-finished rotor shaft, subjecting the machined half-finished rotor shaft to a hardening/tempering treatment and subjecting the treated half-finished rotor shaft to a finish machining.
Claim 14
Dependent Claim
22 words
A method of producing a steam turbine rotor shaft according to claim 11, wherein said ratio H/D ranges between 0.5 and 1.0.
Claim 15
Dependent Claim
22 words
A method of producing a steam turbine rotor shaft according to claim 11, wherein said ratio H/D ranges between 0.8 and 1.0.
Claim 16
Dependent Claim
76 words
A method of producing a steam turbine rotor shaft according to claim 11, wherein said alloy steel consists of 9 to 12wt% of chromium, 0.02 to 0.15 wt% of niobium, 0.08 to 0.25 wt% of carbon, 0.15 to 0.3 wt% in total of carbon and nitrogen, not greater than 0.5 wt% of silicon, 0.4 to 1 wt% of manganese, 0.7 to 1.5 wt% of molybdenum, 0.15 to 0.3 wt% of vanadium and the balance substantially iron.
Claim 17
Dependent Claim
84 words
A method of producing a steam turbine rotor shaft according to claim 11, wherein said alloy steel consists of 9 to 12 wt% of chromium, 0.02 to 0.15 wt% of niobium, 0.08 to 0.25 wt% of carbon, 0.15 to 0.3 wt% in total of carbon and nitrogen, not greater than 0.5 wt% of silicon, 0.4 to 1 wt% of manganese, 0.7 to 1.5 wt% of molybdenum, 0.15 to 0.3 wt% of vanadium, not greater than 1 wt% of nickel and the balance substantially iron.
Claim 18
Dependent Claim
26 words
A method of producing a steam turbine rotor shaft according to claim 14, wherein the chromium equivalent of said alloy steel ranges between 5.0 and 6.5.
Claim 19
Dependent Claim
26 words
A method of producing a steam turbine rotor shaft according to claim 15, wherein the chromium equivalent of said alloy steel ranges between 5.0 and 6.5.
Claim 20
Dependent Claim
30 words
A method of producing a steam turbine rotor shaft according to claim 11, wherein the forging is made by applying pressure to said ingot only in the radial direction thereof.
Claim 21
Dependent Claim
35 words
A method of producing a steam turbine rotor shaft according to claim 11, wherein said forging is conducted by effecting both forging by applying pressure in the radial direction of said ingot and upset forging.
Claim 22
Dependent Claim
37 words
A method of producing a steam turbine rotor shaft according to claim 19, wherein said forging includes one cycle of upset forging and a plurality of forgings applying pressure to said ingot in the radial direction thereof.
Claim 23
Dependent Claim
26 words
A method of producing a steam turbine rotor shaft according to claim 11, wherein said molten metal is poured in said metal mold under a vacuum.
Claim 24
Dependent Claim
31 words
A method of producing a steam turbine rotor shaft according to claim 11 further comprising subjecting said molten metal of alloy steel to an electric furnace refining and a ladle refining.
References Cited (Backward Citations)
US1150401A
Cited
US1734930A
Cited
US3151979A
Cited
US3139337A
Cited
US4026727A
Cited
JPS54146211A
Cited
JPS5623367A
Cited
US4286986A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-09-12 | 1987-03-14 | 1987-09-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-09-12 | 1991-03-14 | 1991-09-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-09-12 | 1995-03-14 | 1995-09-13 | $7700.00 | Window Closed / Lapsed |