# US 11,306,380 B2 · Method for preparing a nickel-based alloy

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- Number: US 11,306,380 B2
- Document ID: US11306380B2
- Status: Granted
- Kind: B2
- Application number: 16/757,810
- Filed: 2018-12-03
- Published: 2021-12-02
- Granted: 2022-04-19
- Earliest claimed: 2017-12-04
- Assignees: VDM Metals International GmbH
- Applicants: VDM Metals International GmbH
- Inventors: Bodo Gehrmann; Burkhard Erpenbeck
- Web page: https://patentgrep.com/patent/US11306380B2

## CPC

- C22C 19/03: based on nickel
- C22F 1/10: of nickel or cobalt or alloys based thereon
- C22B 9/18: Electroslag remelting {(electroslag casting B22D23/10)}
- C22B 9/20: Arc remelting
- C22C 19/056: {with the maximum Cr content being at least 10% but less than 20%}
- C22C: ALLOYS (treatment of alloys C21D, C22F)
- 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)
- C22B: PRODUCTION AND REFINING OF METALS (electrolytic C25); PRETREATMENT OF RAW MATERIALS

## Abstract

In a method for preparing a nickel-based alloy, an electrode is produced by VIM, VOF or VLF, heat-treated in a furnace between 500 and 1300° C. for 10 to 336 hours to reduce stresses and aging, the heat-treatment being conducted for at least 10 hours and at most 48 hours at 1000° C. to 1300° C., and cooled to between room temperature and less than 900° C., then remelted using ESR at 3.0 to 10 kg/minute to form an ESR block which is cooled to between room temperature and less than 900° C., and remelted again using VAR at 3.0 to 10 kg/minute and a remelting rate fluctuation range of less than 15%, preferably 10%, ideally 5%; the remelted VAR block is heat-treated between 500 and 1250° C. for 10 to 336 hours, then shaped into the desired product shape and dimension by hot or cold forming.

## Claims

### Claim 1

A method for the manufacture of a nickel-base alloy, in which
an electrode is produced by VIM, VOD or VLF,
for reduction of stresses and for over-aging, the electrode is subjected in a furnace to a heat treatment in the temperature range between 500 and 1300° C. for a period of 10 to 336 hours, wherein heat treatment is applied for at least 10 hours and at most 48 hours in the temperature range of 1000° C. to 1300° C.
the electrode is cooled in air or in the furnace to a temperature between room temperature and lower than 900° C.,
the cooled electrode is then remelted by ESR at a remelting rate of 3.0 to 10 kg/minute to obtain an ESR ingot,
the ESR ingot is cooled in air or in the furnace to a temperature between room temperature and lower than 900° C.,
the ESR ingot is remelted again by means of VAR at a remelting rate of 3.0 to 10 kg/minute and a range of fluctuation of the remelting rate of smaller than 15%,
the remelted VAR ingot is subjected to a heat treatment in the temperature range between 500 and 1250° C. for a period of 10 to 336 hours, and
the VAR ingot is then brought by hot and/or cold working to the desired product shape and dimension.

### Claim 2 (depends on 1)

The method according to claim 1, wherein, prior to its remelting by ESR, the electrode is subjected to a surface treatment.

### Claim 3 (depends on 1)

The method according to claim 1, wherein, prior to its remelting by VAR, the ESR ingot is subjected to a surface machining.

### Claim 4

A method for the manufacture of a nickel-base alloy, in which
an electrode is generated by VIM,
if the Ni-base alloy forms a gamma prime phase: the electrode is introduced into a furnace before the electrode becomes cooler than 200° C.,
for reduction of stresses and for over-aging, the electrode is subjected in a furnace to a heat treatment in the temperature range between 500 and 1250° C. for a period of 10 to 336 hours,
the electrode is cooled in air or in the furnace to a temperature between room temperature and lower than 900° C.,
the surface of the electrode is machined for removal of defects and is cleaned,
the cooled electrode is then remelted by ESR at a remelting rate of 3.0 to 10 kg/minute to obtain an ESR ingot with a diameter of 400 to 1500 mm,
the ESR ingot is cooled in air or in the furnace to a temperature between room temperature and lower than 900° C.,
if necessary, the surface of the ESR ingot is machined for removal of defects and is cleaned,
the cooled ESR ingot is subjected to a further heat treatment in the temperature range between 500 and 1250° C. for a period of 10 to 336 hours;
the ESR ingot is cooled in air or in the furnace to a temperature between room temperature and lower than 870° C.,
the ESR ingot is remelted again by means of VAR at a remelting rate of 3.0 to 10 kg/minute and a range of fluctuation of the remelting rate of smaller than 15% to obtain a VAR ingot with a diameter of 400 to 1500 mm,
if the Ni-base alloy forms a gamma prime phase: the VAR ingot is introduced into a furnace before it the VAR ingot becomes cooler than 200° C. in the top region,
the remelted VAR ingot is subjected to a heat treatment in the temperature range between 500 and 1250° C. for a period of 10 to 336 hours,
the VAR ingot is cooled in air or in the furnace to a temperature between room temperature and lower than 900° C., or while still hotter than 850° C. is delivered to a hot-working process, and
the VAR ingot is then brought by hot and/or cold working to the desired product shape and dimension.

### Claim 5 (depends on 1)

The method according to claim 1, wherein the VAR ingot is remelted in further steps of remelting by VAR at a remelting rate of 3.0 to 10 kg/minute and is then subjected to a heat treatment in the temperature range between 500 and 1300° C. for a period of 10 to 336 hours.

### Claim 6 (depends on 1)

The method according to claim 1, wherein, after the last heat treatment, the VAR ingot is cooled in air or in the furnace to a temperature between room temperature and lower than 900° C.

### Claim 7 (depends on 1)

The method according to claim 1, wherein, after the last heat treatment, the VAR ingot is delivered while still hot to a hot working at a temperature of higher than 800° C.

### Claim 8 (depends on 1)

The method according to claim 1, wherein an alloy of the following composition (in wt %) is used:
C
max. 0.25%
S
max. 0.03%
Cr
17-32%
Ni
33-72%
Mn
max 1%
Si
max. 1%
Mo
0 to 10%
Ti
up to 3.25%
Nb
up to 5.5%
Cu
up to 0.5%
Fe
up to 25%
P
max. 0.03%
Al
up to 3.15%
V
max. 0.6%
Zr
max. 0.1%
Co
up to 35%
B
max. 0.02%
and manufacturing-related impurities.

### Claim 9 (depends on 1)

The method according to claim 1, wherein an alloy of the following composition (in wt %) is used:
C
max. 0.08
S
max. 0.015
Cr
17-21
Ni
50-55
Mn
max. 0.35
Si
max. 0.35
Mo
2.8-3.3
Ti
0.65-1.15
Nb
4.75-5.5
Cu
max. 0.3
Fe
6-25
P
max. 0.015
Al
0.2 to 0.8
Co
max. 1
B
max. 0.006
Pb
max. 0.001
Se
max. 0.0005
Bi
max. 0.00005
Nb + Ta
4.75 to 5.5%
and manufacturing-related impurities.

### Claim 10 (depends on 1)

The method according to claim 1, wherein an alloy of the following composition (in wt %) is used:
C
max. 0.1
S
max. 0.015
N
max. 0.03
Cr
16-20
Ni
26-62
Mn
max. 0.5
Si
max. 0.3
Mo
2-4
Ti
0.1-1
Cu
max. 0.5
Fe
max. 10
P
max. 0.03
Al
1 to 3
Mg
max. 0.01
Ca
max. 0.01
Zr
max. 0.05
Co
15-28
B
max. 0.02
O
max. 0.02
Nb + Ta
4-6
and manufacturing-related impurities.

### Claim 11 (depends on 1)

The method according to claim 1, wherein the diameter of the produced VAR ingot is >450 mm.

### Claim 12 (depends on 1)

The method according to claim 1, wherein the diameter of the produced VAR ingot is >500 mm.

### Claim 13 (depends on 1)

The method according to claim 1, wherein the produced ingot is free of remelting defects and in the ultrasonic inspection has a comparison defect size of <0.8 mm.

### Claim 14 (depends on 1)

The method according to claim 1, in which the heat treatment of the VIM ingot was applied for at least 10 hours and at most 48 hours in the temperature range of 1000° C. to 1300° C.