US3546084A - Cleaning method for jet engine parts - Google Patents
Cleaning method for jet engine parts Download PDFInfo
- Publication number
- US3546084A US3546084A US830913A US3546084DA US3546084A US 3546084 A US3546084 A US 3546084A US 830913 A US830913 A US 830913A US 3546084D A US3546084D A US 3546084DA US 3546084 A US3546084 A US 3546084A
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- US
- United States
- Prior art keywords
- component
- bath
- metal
- water
- cleaning
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- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25F—PROCESSES FOR THE ELECTROLYTIC REMOVAL OF MATERIALS FROM OBJECTS; APPARATUS THEREFOR
- C25F1/00—Electrolytic cleaning, degreasing, pickling or descaling
- C25F1/02—Pickling; Descaling
- C25F1/04—Pickling; Descaling in solution
Definitions
- Jet engines are formed in their so-called hot section of numerous relatively small components such as turbine blades, discs, vanes and buckets which operate at extremely high temperatures as gases are compressed and the jet fuel burned and the hot gases expelled to provide propulsion.
- these components are formed of specially adapted alloy compositions many of which contain small amounts of'unusual metals for special purposes.
- these components are fabricated to precise tolerances requisite to optimum operation.
- Prior art At present scale removal is accomplished in cleaning baths in the case of easily removed scale and not removed at all or only with protracted effort in the case of obdurate metal oxide, sulfide, nitride and carbide scale which effort may be harmful to the component.
- sand blasting has been used to remove scale after long engine operating periods but this technique is unsatisfactory because much hand labor is required, excessive metal removal occurs, small cracks may be hidden from inspection, abrasive may be retained in complex 3,546,084 Patented Dec.
- the present invention provides a cleaning method which is effective in removal of all manner of metal oxides, suliides, carbides and nitrides and other unwanted metal compounds from multimetallic alloy parts such as components of jet engines and which is elicient to enable rapid removal without damage to the component itself.
- the present method is fast, with cleaning cycles as short as 20-30 minutes for some components. Moreover it is complete; hidden areas such as faying surfaces between spot welds are cleaned. Also the method is safe; metal removal is negligible.
- the method broadly includes sequentially cathodically and anodically treating jet engine components or other parts having surfaces formed of cobalt or nickel-based alloys of surface deposits of metal oxides, metal nitrides, metal carbides and/ or metal sultides and other compounds of alloy metals, by immersing of the component first in a strongly alkaline electroconductive bath at an elevated temperature in which the component forms the cathode and by subsequently immersing the component in a strongly acidic electroconductive bath at an elevated temperature in which the component forms the anode, subjecting the component to ultrasonically cavitating liquid and water washing after each immersing step.
- the ultrasonic liquid cavitation may be elected in a water bath and the water washing effected by high pressure sprays following and preceding component immersion in the ultrasonically activated water bath.
- the alkaline bath may comprise a fluid mass of sodium hydroxide and potassium hydroxide and water and have a higher temperature than the acidic bath which may comprise a mixture of two or more mineral acids eg. chromic acid and phosphoric acid and sulfuric acid.
- current densities in the alkaline bath may be greater than those in the acidic bath and the current directionmay be periodically reversed ineither bath.
- the present effective cleaning method is believed to operate in this manner:
- the component to be cleaned is placed in a hot alkaline solution which is electroconductive.
- the component is made cathodic to an electrode, suitably titanium and of a configuration conforming to the component.
- Hydrogen is evolved from the solution by the current ow. Because the surface metal compounds on the component are nonconductive the hydrogen is evolved as a gas at the metal compound-metal interface; this forces the compound material away from the metal.
- the component is removed from solution, rinsed in water and then rinsed in an ultrasonically cavitated liquid to remove any smut (microscopic particles) and trapped oxides from restricted areas, such as narrow passages.
- the component is then placed in an acid bath and made anodic to a suitable cathode e.g. titanium.
- a suitable cathode e.g. titanium.
- This apparently causes metal ions to be removed from the component surface but in such a controlled manner that microscopic high points or asperites are reduced Iwith little or no reduction in relatively recessed surface areas. This tends to polish and debur the part at the same time as removing any remaining smut.
- This electropolishing reduces the corrosion tendency of the metal component.
- the component is then water rinsed and again ultrasonically treated to remove retained acid and smut from the now electropolished surface.
- the resulting component is clean, as shown by surface resistance tests, even between spot welds.
- the component may have a matte or reective surface as desired in either case highly corrosion resistant and ideally prepared for inspection.
- Components have been cleaned in 35 minutes by the herein disclosed method which have been impossible to clean to any measurable degree by the other known methods.
- an alkaline bath comprising one or more alkali metal hydroxide and preferably one part sodium hydroxide, one part potassium hydroxide and one part water at an elevated temperature e.g. 175 275 F. and preferably between 230 and 250 F.
- the component is immersed in this fluid mass for a brief period e.g. at
- time, temperature and current densities may be individually or collectively varied for particular cleaning tasks within externally imposed conditions of metal removal and surface finish desired. It has been found helpful in maintaining cleaning effectiveness to periodically reverse current direction in the two electrochemical baths by changing the electrode polarities for brief periods.
- Jet engine components and other parts which may be cleaned of obdurate oxide deposits in accordance with the invention are generally formed of high temperature resistant cobalt and nickel based alloys.
- cobaltbased and nickel-based herein refer to alloys in which cobalt or nickel, respectively, is the largest single component, in weight percent, although this is not necessarily a major weight portion of the entire alloys.
- suitable cobalt base alloys include those cornposed by weight of cobalt (3S-80%) and tungsten 0- 25%, chromium 040%, iron 0-5%, and/or carbon O- 1.0. Typical alloys are (see chart) line 14.
- nickel base alloys are those composed of nickel -99.5, chromium 0-25, iron 0-25, manganese 0-2, molybdenum 0- 20, cobalt 0-30, silicon 0-2, tungsten 0-15 as well as 0- 20 of columbium, tantalum, aluminum, boron, zirconium, iron and thorium oxide.
- the component is withdrawn and water washed as with high pressure water spray generally at ambient temperature and then the component is immersed in a bath of water at an elevated temperature e.g. 140150 F. which is ultrasonically cavitated e.g. with energy at 16,000 to 100,000 cycles per second and preferably between 18,000 and 22,000 cycles per second to remove trapped soil and smut from the component with the cavitation.
- elevated temperature e.g. 140150 F. which is ultrasonically cavitated e.g. with energy at 16,000 to 100,000 cycles per second and preferably between 18,000 and 22,000 cycles per second to remove trapped soil and smut from the component with the cavitation.
- the component is immersed as the anode in a previously prepared aqueous mineral acid containing bath and preferably one containing by volume 2 parts aqueous chromic acid solution e.g. 62.5% by weight acid solution, 1 part sulfuric acid e.g. 96% by weight acid solution and 7 parts phosphoric acid e.g. 76% by weight acid solution maintained at a temperature between 135 and 165 F. and preferably 150 to 160 F. to loosen surface deposits by chemical attack and to chemically and electrically polish and brighten the metal.
- the current density within the acid bath is generally less than the density in the alkaline bath and may range We claim:
- Method for cleaning parts such as jet engine components having cobalt or nickel-based alloy surfaces of oxides, sulfides, carbides and nitrides of metals of said alloy which includes sequentially cathodically and anodically treating said component, by immersing of the component first in a strongly alkaline electroconductive bath at an elevated temperature in which the component forms the cathode and by subsequently immersing the component in a strongly acidic electroconductive bath at an elevated temperature in which the component forms the anode, subjecting the component to ultrasonically activated liquid and water washing after each immersing step.
- liquid subjecting includes immersing the component in a water bath which is ultrasonically cavitated.
- Method according to claim 2 including also water spray washing the component before and after immersion in the ultrasonically cavitated bath.
- Method according to claim 1 or 8 including also periodically reversing the polarities of the anode and cathode during immersion of the component in the alkaline and acidic baths.
Description
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US83091369A | 1969-05-19 | 1969-05-19 |
Publications (1)
Publication Number | Publication Date |
---|---|
US3546084A true US3546084A (en) | 1970-12-08 |
Family
ID=25257917
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US830913A Expired - Lifetime US3546084A (en) | 1969-05-19 | 1969-05-19 | Cleaning method for jet engine parts |
Country Status (1)
Country | Link |
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US (1) | US3546084A (en) |
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5167720A (en) * | 1991-04-03 | 1992-12-01 | Northwest Airlines, Inc. | High pressure water treatment method |
WO1995003439A1 (en) * | 1993-07-21 | 1995-02-02 | Dynamotive Corporation | A method for removal of certain oxide films from metal surfaces |
US20060231123A1 (en) * | 2002-10-18 | 2006-10-19 | Nigel-Philip Cox | Method for removing a layer area of a component |
US20080102292A1 (en) * | 2006-11-01 | 2008-05-01 | United Technologies Corporation | Surface treatment for a thin titanium foil |
US20080156898A1 (en) * | 2005-01-25 | 2008-07-03 | Peter Asplund | Probe Cleaning Method and Apparatus |
US7761890B1 (en) | 1981-11-03 | 2010-07-20 | Personalized Media Communications, Llc | Signal processing apparatus and methods |
US20100326466A1 (en) * | 2008-02-14 | 2010-12-30 | Mitsubishi Heavy Industries, Ltd. | Method for regenerating gas turbine blade and gas turbine blade regenerating apparatus |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2308389A (en) * | 1941-11-22 | 1943-01-12 | Rca Corp | Oxide coated cathode |
US3066084A (en) * | 1959-08-10 | 1962-11-27 | Jones & Laughlin Steel Corp | Ultrasonic pickling |
US3135671A (en) * | 1960-12-01 | 1964-06-02 | Rockwell Standard Co | Electrolytic treatment of articles |
US3411999A (en) * | 1965-12-10 | 1968-11-19 | Value Engineering Company | Method of etching refractory metal based materials uniformly along a surface |
-
1969
- 1969-05-19 US US830913A patent/US3546084A/en not_active Expired - Lifetime
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2308389A (en) * | 1941-11-22 | 1943-01-12 | Rca Corp | Oxide coated cathode |
US3066084A (en) * | 1959-08-10 | 1962-11-27 | Jones & Laughlin Steel Corp | Ultrasonic pickling |
US3135671A (en) * | 1960-12-01 | 1964-06-02 | Rockwell Standard Co | Electrolytic treatment of articles |
US3411999A (en) * | 1965-12-10 | 1968-11-19 | Value Engineering Company | Method of etching refractory metal based materials uniformly along a surface |
Cited By (13)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7761890B1 (en) | 1981-11-03 | 2010-07-20 | Personalized Media Communications, Llc | Signal processing apparatus and methods |
US8804727B1 (en) | 1981-11-03 | 2014-08-12 | Personalized Media Communications, Llc | Signal processing apparatus and methods |
US7958527B1 (en) | 1987-09-11 | 2011-06-07 | Personalized Media Communications, Llc | Signal processing apparatus and methods |
US5167720A (en) * | 1991-04-03 | 1992-12-01 | Northwest Airlines, Inc. | High pressure water treatment method |
WO1995003439A1 (en) * | 1993-07-21 | 1995-02-02 | Dynamotive Corporation | A method for removal of certain oxide films from metal surfaces |
US20060231123A1 (en) * | 2002-10-18 | 2006-10-19 | Nigel-Philip Cox | Method for removing a layer area of a component |
US8273187B2 (en) * | 2005-01-25 | 2012-09-25 | Pratt & Whitney Line Maintenance Services, Inc. | Probe cleaning method and apparatus |
US20080156898A1 (en) * | 2005-01-25 | 2008-07-03 | Peter Asplund | Probe Cleaning Method and Apparatus |
US8066816B2 (en) * | 2005-01-25 | 2011-11-29 | Pratt & Whitney Line Maintenance Services, Inc. | Probe cleaning method and apparatus |
US20120031444A1 (en) * | 2005-01-25 | 2012-02-09 | Pratt & Whitney Line Maintenance Services, Inc. | Probe cleaning method and apparatus |
US20080102292A1 (en) * | 2006-11-01 | 2008-05-01 | United Technologies Corporation | Surface treatment for a thin titanium foil |
US20100326466A1 (en) * | 2008-02-14 | 2010-12-30 | Mitsubishi Heavy Industries, Ltd. | Method for regenerating gas turbine blade and gas turbine blade regenerating apparatus |
US8876978B2 (en) * | 2008-02-14 | 2014-11-04 | Mitsubishi Heavy Industries, Ltd. | Method for regenerating gas turbine blade and gas turbine blade regenerating apparatus |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: TP INDUSTRIAL, INC. Free format text: CHANGE OF NAME;ASSIGNOR:PUREX CORPORATION;REEL/FRAME:004561/0588 Effective date: 19860418 |
|
AS | Assignment |
Owner name: TURCO PRODUCTS, INC., CALIFORNIA Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:TP INDUSTRIAL, INC., A CORP OF CA.;REEL/FRAME:004561/0581 Effective date: 19860603 Owner name: PUREX CORPORATION Free format text: CHANGE OF NAME;ASSIGNOR:PUREX CORPORATION, LTD.;REEL/FRAME:004561/0586 Effective date: 19851211 Owner name: TURCO PRODUCTS, INC., 5101 CLARK AVENUE, LAKEWOOD, Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:TP INDUSTRIAL, INC., A CORP OF CA.;REEL/FRAME:004561/0581 Effective date: 19860603 |