# US 7,744,709 B2 · Welding repair method for full hoop structures

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- Number: US 7,744,709 B2
- Document ID: US7744709B2
- Status: Granted
- Kind: B2
- Application number: 11/208,801
- Filed: 2005-08-22
- Published: 2007-02-22
- Granted: 2010-06-29
- Earliest claimed: 2005-08-22
- Assignees: United Technologies Corporation
- Inventors: James A. Dierberger
- Web page: https://patentgrep.com/patent/US7744709B2

## CPC

- B23K 31/00: Processes relevant to this subclass, specially adapted for particular articles or purposes, but not covered by any single one of main groups B23K1/00 - B23K28/00
- B23P 6/002: {Repairing turbine components, e.g. moving or stationary blades, rotors, (B23P6/045 takes precedence)}
- C21D 9/50: for welded joints
- B23K 2101/001: {Turbines}
- Y10T 428/12: All metal or with adjacent metals
- 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
- B23P: METAL-WORKING NOT OTHERWISE PROVIDED FOR; COMBINED OPERATIONS; UNIVERSAL MACHINE TOOLS (arrangements for copying or controlling B23Q)
- C21D: MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING (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; unidirectional solidification of eutectic materials or unidirectional demixing of eutectoid materials C30B)
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

A unique heat treat method for relieving stresses caused by a repairing weld joint in a full hoop part heat treats locally, at the location of the weld joint, and at a diametrically opposed location. By providing the diametrically opposed heat treat location, the present invention relieves stresses caused by the weld joint, without creating any additional residual stress in the weld joint.

## Claims

### Claim 1

A method of treating a full hoop part comprising the steps of;
(1) identifying a defect in a part, said part extending for 360° about an axial center line;
(2) performing a weld treatment on said defect to correct said defect; and
(3) performing heat treatment at a first band associated with said weld treatment, and at a second band, said second band being selected to be spaced about said axial center line from said first band, and said second band also being spaced from a location of said weld treatment.

### Claim 2 (depends on 1)

The method as set forth in claim 1, wherein said second band includes a location spaced by 180° about said axial center line from said first band.

### Claim 3 (depends on 1)

The method as set forth in claim 1, wherein said first and second bands receive the heat treatment concurrently.

### Claim 4 (depends on 1)

The method as set forth in claim 1, wherein said second band has a greater circumferential extent than said first band.

### Claim 5 (depends on 4)

The method as set forth in claim 4, wherein said second band is heat treated at a lower temperature than said first band.

### Claim 6 (depends on 1)

The method as set forth in claim 1, wherein said first and second bands are selected to be of roughly equal circumferential extent.

### Claim 7 (depends on 1)

The method as set forth in claim 1, wherein said part extends for an axial distance, and said first and second bands extending for the entirety of said axial distance.

### Claim 8 (depends on 1)

The method as set forth in claim 1, wherein a circumferential extent of said first band is selected to only be wide enough to provide a stress relief in said weld joint.

### Claim 9 (depends on 1)

The method as set forth in claim 1, wherein said part is a gas turbine engine part.

### Claim 10 (depends on 5)

The method as set forth in claim 5, wherein said part is a diffuser case.

### Claim 11 (depends on 5)

The method as set forth in claim 5, wherein said part is a turbine exhaust case.

### Claim 12 (depends on 1)

The method as set forth in claim 1, wherein heat treatment is also performed at a third band spaced from both said first and second bands.

### Claim 13 (depends on 12)

The method as set forth in claim 12, wherein said second and third bands are positioned to be equally spaced from said first band.