Method of applying braze materials to a substrate

• US 6,575,349 B2
• Filed: 02/22/2001
• Issued: 06/10/2003
• Est. Priority Date: 02/22/2001
• Status: Expired due to Term

• Current Assignee: Sulzer Turbo Services Houton Incorporated
• Original Assignee: Hickham Industries Incorporated
• Inventors: Van Esch, Hans
• Primary Examiner(s): Dunn, Tom
• Assistant Examiner(s): Stoner, Kiley
• Application Number:
  US09/791,951
• Publication Number:
  US 20020153405A1
• Time in Patent Office: 838 Days
• Field of Search: 228/119, 228/199, 228/256, 228/260, 228/261, 427/456, 427/142, 298/891
• US Class Current: 228/119
• CPC Class Codes: B23K 1/0018 Brazing of turbine parts
• CPC Class Codes: B23K 2101/001 Turbines
• CPC Class Codes: B23K 35/0244 Powders, particles or spheres; Preforms made therefrom
• CPC Class Codes: B23K 35/383 mainly containing noble gases or nitrogen
• CPC Class Codes: B23P 6/007 using only additive methods, e.g. build-up welding
• CPC Class Codes: C23C 4/067 containing free particles of non-metal elements, e.g. carbon, silicon, boron, phosphorus or arsenic
• CPC Class Codes: C23C 4/073 containing MCrAl or MCrAlY alloys, where M is nickel, cobalt or iron, with or without non-metal elements
• CPC Class Codes: C23C 4/18 After-treatment
• CPC Class Codes: F01D 5/005 Repairing methods or devices
• CPC Class Codes: F01D 5/288 Protective coatings for blades
• CPC Class Codes: Y10T 29/49318 Repairing or disassembling

Abstract

A HVOF process is used for applying brazing materials to repair surfaces of a substrate such as a turbine blade. The brazing material is applied in powdered form and is free of binders and adhesives. The brazing materials may be any one or more of a nickel based, cobalt based or ferrous based high temperature brazing material. Alloys of these elements may be used together with a temperature depressing melting point element such as boron or silicon.

Claims

1. A method of applying braze materials to a substrate, said method comprising the steps of

obtaining a substrate requiring repair;

generating a high velocity combustion gas stream;

passing binder-free high temperature brazing material into said gas stream to entrain and melt the brazing material therein;

directing the brazing material entrained gas stream against and along at least one portion of the substrate requiring repair to form a deposit of brazing material thereon; and

thereafter heat treating the substrate to bring the brazing material to a brazing temperature and then lowering the temperature.

2. A method as set forth in claim 1 wherein the brazing material is selected from the group consisting of at least one of nickel-based, cobalt-based and ferrous-based brazing material.

3. A method as set forth in claim 1 wherein the brazing material is selected from the group consisting of at least one of a nickel alloy, cobalt alloy and ferrous alloy and at least one temperature depressing melting point element.

4. A method as set forth in claim 3 wherein said temperature depressing melting point element is selected from the group consisting of boron and silicon.

5. A method as set forth in claim 1 wherein said brazing material is passed into said gas stream in powder form.

6. A method as set forth in claim 1 wherein said deposit has a thickness of from 0.030 inches to 0.040 inches.

7. A method as set forth in claim 1 wherein said deposit has a thickness of at least 0.100 inch.

8. A method as set forth in claim 1 wherein said step of heat treating is conducted in a vacuum furnace.

9. A method as set forth in claim 1 wherein said gas stream is generated from hydrogen gas.

10. A method as set forth in claim 1 wherein said gas stream is generated from natural gas.

11. A method as set forth in claim 2 wherein the brazing material includes an alloy selected from the group consisting of at least one of a nickel alloy, cobalt alloy and ferrous alloy.

12. A method as set forth in claim 11 wherein the brazing material includes at least one temperature depressing melting point element.

13. A method as set forth in claim 1 wherein said gas stream is directed at the substrate at an application rate of less than 0.4 mil per pass.

14. A method of repairing a turbine blade having at least one surface crack therein, said method comprising the steps of

generating a high velocity combustion gas stream;

passing binder-free high temperature brazing material into said gas stream to entrain and melt the brazing material therein;

directing the brazing material entrained gas stream against and along the crack in the turbine blade to form a deposit of brazing material in the crack; and

thereafter heat treating the turbine blade to bring the brazing material to a brazing temperature and then lowering the temperature.

15. A method as set forth in claim 14 wherein the brazing material is selected from the group consisting of at least one of nickel-based, cobalt-based and ferrous-based brazing material.

16. A method as set forth in claim 14 wherein said repair deposit is characterized in being binder-free and carbon-free and in having a porosity of less than 2%.