# US 2013/0240607 A1 · Friction stir tool

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- Number: US 2013/0240607 A1
- Document ID: US20130240607A1
- Status: Published application
- Kind: A1
- Application number: 13/783,018
- Filed: 2013-03-01
- Published: 2013-09-19
- Earliest claimed: 2009-09-17
- Inventors: Seunghwan PARK; Satoshi HIRANO; Shinya IMANO; Jun SATO; Hiroyuki KOKAWA; Yutaka SATO; Kiyohito ISHIDA; Toshihiro OMORI
- Web page: https://patentgrep.com/patent/US20130240607A1

## CPC

- B23K 20/1245: {characterised by the apparatus}
- B23K 20/1255: {Tools therefor, e.g. characterised by the shape of the probe}
- B23K 35/22: characterised by the composition or nature of the material
- C22C 19/07: based on cobalt
- C22F 1/10: of nickel or cobalt or alloys based thereon
- B23K: SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- 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)

## Abstract

A friction stir tool excellent in productivity, high temperature strength, and wear resistance at high temperatures. The friction stir tool is formed of a Co-based alloy comprising crystal grains containing a γ′ precipitate phase dispersed and precipitated therein, and a crystal grain boundary region and a precipitate phase between adjacent crystal grains, in which the precipitate phase is at least one phase selected from a μ phase, a Laves phase and a carbide phase.

## Claims

### Claim 1

A friction stir tool formed of a Co-based alloy having a γ phase with an A1 structure and a γ′ phase with an L12 structure precipitated in the γ phase, the γ′ phase comprising (Co, X)3(Al, W, Z), and the γ′ phase being contained in the γ phase in an amount of 10% to 80% in terms of volume fraction, the Co-based alloy including 30-50 at. % of Ni, and the γ′ phase thereof having a solid solution forming temperature higher than 1,000° C., wherein the Co-based alloy contains a precipitate selected from a μ phase, a Laves phase and a carbide, where X includes mainly Ni, and Z includes mainly Cr and Ta.

### Claim 2 (depends on 1)

The friction stir tool according to claim 1, being formed by precision casting.

### Claim 3 (depends on 1)

The friction stir tool according to claim 1, wherein the Co-based alloy contains Co in an amount of 25 at. % or more.

### Claim 4 (depends on 1)

The friction stir tool according to claim 1, comprising a cylindrical shank, a shoulder formed in an end portion of the shank, and a pin formed in an end portion of the shoulder.

### Claim 5 (depends on 4)

The friction stir tool according to claim 4, being an integrally formed article of the Co-based alloy produced by the precision casting.

### Claim 6 (depends on 5)

The friction stir tool according to claim 5, being a machined product of the Co-based alloy made of the integrally formed article.

### Claim 7 (depends on 1)

A friction stir welding apparatus comprising the friction stir tool according to claim 1.

### Claim 8 (depends on 1)

The friction stir tool according to claim 1, wherein the Co-based alloy includes about 10 at. % of Al, about 7.5 at. % of W, about 3 at. % of Ta, about 10 at. % of Cr, about 0.06 at. % of B, about 0.6 at. % of C, and at least 25 at. % of Co.

### Claim 9 (depends on 1)

The friction stir tool according to claim 1, having a property of being capable of joining, by friction stir welding, high-melting point materials selected from the group consisting of steel materials, titanium and alloys thereof, and zirconium and alloys thereof.

### Claim 10 (depends on 1)

The friction stir tool according to claim 1, being heat-treated and air-cooled after the precision casting.

### Claim 11 (depends on 1)

The friction stir tool according to claim 1, wherein the cobalt-based alloy contains precipitates that include each of the μ phase, the Laves phase and the carbide.