# US 2018/0023176 A1 · Method for manufacturing ni-based super-heat-resistant alloy

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- Number: US 2018/0023176 A1
- Document ID: US20180023176A1
- Status: Published application
- Kind: A1
- Application number: 15/548,447
- Filed: 2016-02-03
- Published: 2018-01-25
- Earliest claimed: 2015-02-12
- Assignees: Hitachi Metals, Ltd.; Tohoku University
- Applicants: Hitachi Metals, Ltd.; Tohoku University
- Inventors: Gang HAN; Koji SATO; Tomonori UENO; Akihiko CHIBA
- Web page: https://patentgrep.com/patent/US20180023176A1

## CPC

- C22F 1/10: of nickel or cobalt or alloys based thereon
- C22C 19/05: with chromium
- C22C 19/056: {with the maximum Cr content being at least 10% but less than 20%}
- C22F 1/00: Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working (apparatus for mechanical working of metal B21, B23, B24)
- C22F: CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS (surface treatment of metallic material involving at least one process provided for in class C23 and at least one process covered by this subclass, C23F17/00)
- C22C: ALLOYS (treatment of alloys C21D, C22F)

## Abstract

A method for manufacturing a Ni-based super-heat-resistant alloy includes: a first cold working step for cold working a Ni-based super-heat-resistant alloy ingot, which has a composition in which the γ′ mole ratio is at least 40%, at a working ratio of 5% to less than 30%; and a first heat treatment step for heat-treating the cold worked material, on which the first cold working was performed, at a temperature exceeding the γ′ solid solution temperature. It is preferable that the manufacturing method also includes a second cold working step for performing, after the first heat treatment step, a second cold working on the heat-treated material at a working ratio of at least 20%, and a second heat treatment step for heat-treating the second cold worked material, on which the second cold working has been performed, at less than the γ′ solvus temperature.

## Claims

### Claim 1

A method for producing a Ni-based heat-resistant super alloy, comprising:
preparing an ingot of the Ni-based heat-resistant super alloy having such a composition that the alloy includes not less than 40 mol % of a gamma prime (γ′) phase;
a first cold work step of cold-working the ingot at a working ratio of not less than 5% but less than 30%; and
a first heat treatment step of heat-treating the first-cold-worked material at a temperature exceeding a solid solution temperature of the gamma prime phase.

### Claim 2 (depends on 1)

The method according to claim 1, wherein the first heat treatment is conducted at a temperature not higher than the gamma prime solid solution temperature plus 40° C. and lower than a solidus temperature of the alloy.

### Claim 3 (depends on 1)

The method according to claim 1, further comprising:
a second cold work step of cold-working the first-heat-treated material at a working ratio of not less than 20%; and
a second heat treatment step of heat-treating the second-cold-worked material at a temperature lower than the gamma prime solid solution temperature.

### Claim 4 (depends on 3)

The method according to claim 3, wherein the second heat treatment is conducted at a temperature not lower than the gamma prime solid solution temperature minus 80° C.

### Claim 5 (depends on 1)

The method according to claim 1, wherein the first cold work is conducted by forging, elongation working, or injection working, or a combination thereof.

### Claim 6 (depends on 3)

The method according to claim 3, wherein the first cold working or the second cold working is conducted by forging, elongation working, or injection working, or a combination thereof.

### Claim 7 (depends on 1)

The method according to claim 1, wherein the alloy comprises, by mass:
0.001 to 0.250% C,
8.0 to 22.0% Cr,
not more than 28.0% Co,
2.0 to 7.0% Mo,
not more than 6.0% W,
2.0 to 8.0% Al,
0.5 to 7.0% Ti,
not more than 4.0% Nb,
not more than 3.0% Ta,
not more than 10.0% Fe,
not more than 1.2% V,
not more than 1.0% Hf,
0.001 to 0.300% B,
0.001 to 0.300% Zr, and
the balance of Ni and inevitable impurities.