EP0379699A1 - Method for enhancing the corrosion and erosion resistance of the blade of a rotary thermal apparatus and blade produced ba said method - Google Patents

Method for enhancing the corrosion and erosion resistance of the blade of a rotary thermal apparatus and blade produced ba said method Download PDF

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Publication number
EP0379699A1
EP0379699A1 EP89123291A EP89123291A EP0379699A1 EP 0379699 A1 EP0379699 A1 EP 0379699A1 EP 89123291 A EP89123291 A EP 89123291A EP 89123291 A EP89123291 A EP 89123291A EP 0379699 A1 EP0379699 A1 EP 0379699A1
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EP
European Patent Office
Prior art keywords
blade
corrosion
protective layer
base material
weight
Prior art date
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.)
Granted
Application number
EP89123291A
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German (de)
French (fr)
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EP0379699B1 (en
Inventor
Benno Basler
Tibor Koromzay
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ABB Asea Brown Boveri Ltd
ABB AB
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ABB Asea Brown Boveri Ltd
Asea Brown Boveri AB
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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
    • F01D5/00—Blades; Blade-carrying members; Heating, heat-insulating, cooling or antivibration means on the blades or the members
    • F01D5/12—Blades
    • F01D5/28—Selecting particular materials; Particular measures relating thereto; Measures against erosion or corrosion
    • F01D5/288—Protective coatings for blades
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C4/00—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge
    • C23C4/04—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge characterised by the coating material
    • C23C4/06—Metallic material
    • C23C4/067—Metallic material containing free particles of non-metal elements, e.g. carbon, silicon, boron, phosphorus or arsenic
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S428/00—Stock material or miscellaneous articles
    • Y10S428/922—Static electricity metal bleed-off metallic stock
    • Y10S428/9335—Product by special process
    • Y10S428/937—Sprayed metal
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/12—All metal or with adjacent metals
    • Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
    • Y10T428/12736—Al-base component
    • Y10T428/1275—Next to Group VIII or IB metal-base component
    • Y10T428/12757—Fe

Definitions

  • Buckets for rotating thermal machines such as steam turbines, gas turbines, turbo compressors etc. and their effective protection against operational attacks such as oxidation, corrosion, wear and damage.
  • the invention relates to improving the resistance to corrosion and erosion of blades of rotating thermal machines by further developing the methods for applying suitable protective layers.
  • the invention relates to a method for increasing the corrosion and erosion resistance of a blade of a rotating thermal machine, which in consists essentially of a ferritic and / or ferritic-martensitic base material, by applying a firmly adhering surface protective layer.
  • the blades of rotating thermal machines are often provided with protective layers. This is used for both steam and gas turbine blades as well as for compressor blades. The main thing is to increase resistance to corrosion and oxidizing attack as well as erosion and wear (wear and tear).
  • the element Cr, Al, Si forming the oxide cover layers occupy a special position.
  • Layers which have a high Al content have been used, inter alia, as filler material for carbide-containing coatings (Cr2C3; WC) in engine construction.
  • the invention has for its object a method for increasing the corrosion (Cl and SO4 ions) and erosion resistance (particle and drop impact erosion) of a blade of a rotating thermal machine in the presence of H2O steam and comparatively moderate temperatures (450 ° C ) which is particularly suitable for ferritic and / or ferritic-martensitic base material of the blade, a suitable surface layer being to be achieved inexpensively and without great effort.
  • the occurrence of pitting corrosion should be avoided or min be delayed to ensure a longer lifespan for the bucket.
  • a protective layer consisting of 6 to 15% by weight of Si, remainder Al is sprayed onto the surface of the base material by the high-speed process at a particle speed of at least 300 m / s.
  • a compressor blade for an axial compressor was provided with a protective layer.
  • the scoop was first degreased and cleaned in trichloroethane, whereupon the blade and the pale / foot transition were sandblasted.
  • the coating of the blade was carried out using a high-speed flame spraying process with a particle speed of 400 m / s and a gas speed of 1000 m / s with nitrogen as the conveying gas.
  • the aluminum alloy powder was conveyed by means of nitrogen into a combustion chamber operated with propane and oxygen.
  • the liquefied particles were thrown onto the workpiece as fine drops under high excess pressure.
  • the blade stood in a device that covered the blade root.
  • the protective layer was applied with the hand-held spray gun.
  • the applied protective layer was measured using a metallographic cut and was in Average 8 to 15 ⁇ m.
  • a plastic in the present case polytetrafluoroethylene was applied to this metal protective layer using a conventional paint spraying process.
  • This smooth surface layer had an average thickness of 6 to 10 ⁇ m and a roughness of approximately 2 ⁇ m.
  • the coated compressor blade was subjected to a corrosion resistance test. For this purpose, it was immersed in a test solution and then stored in a climatic cabinet for 4 hours. This cycle was repeated a total of 60 times.
  • a compressor blade of the same dimensions and composition was coated according to Example 1 with an aluminum alloy and a plastic. Now a scratch of 10 mm length and a total of 25 ⁇ m depth parallel to the longitudinal axis was made on the coated blade, the profile of which just barely grasped the base material with its tip. The blade was then subjected to the same corrosion tests as in Example 1. Thanks to the local element formation (aluminum layer functions as a "sacrificial anode”), the base material was largely protected, while the aluminum layer on the flanks of the scratch was only slightly degraded.
  • the protective layer according to the invention can be expected to have a long service life under practical conditions of use.
  • a compressor blade was provided with a protective layer.
  • the material of the blade consisted of a martensitic-austenitic two-phase steel with a low austenite content and was available in a tempered condition.
  • the aluminum alloy was sprayed on using an industrial robot. 3 spray coats were carried out. The thickness of the applied layer averaged 90 to 100 ⁇ m. A plastic layer of approx. 10 to 15 ⁇ m thickness was additionally applied to this metal protective layer using a conventional paint spraying process. The coated blade was subjected to the same corrosion test as in Example 1. No attack was then found.
  • a used compressor blade with wing profile was provided with a protective layer.
  • the blade was coated using customary methods and showed considerable operational damage in the form of pitting corrosion, which in some cases also extended to the base material.
  • This used shovel was first degreased, ground and sandblasted to remove the damage. Then the surface zone of the base material was compacted by shot peening.
  • the metal layer was sprayed on by hand using the high-speed flame spraying process.
  • the thickness of the protective layer fluctuated between 25 and 45 ⁇ m.
  • the metallographic tests after the corrosion test indicated above showed an unchanged, unaffected surface zone.
  • the invention is not restricted to the exemplary embodiments.
  • the method for increasing the corrosion and erosion resistance of a blade of a rotating thermal machine which essentially consists of a ferritic and / or ferritic-martensitic base material, is carried out by applying a firmly adhering surface protective layer by a Protective layer consisting of 6 to 15 wt .-% Si, remainder Al is sprayed onto the surface of the base material by the high-speed method with a particle speed of at least 300 m / s.
  • the base material preferably consists of a chromium-containing steel with 12 to 13% by weight of Cr and further additives.
  • the protective layer advantageously contains 10 to 12% by weight of Si, the rest of Al.
  • a cover layer made of a heat-resistant plastic is preferably additionally applied to said protective layer.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Plasma & Fusion (AREA)
  • Physics & Mathematics (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Structures Of Non-Positive Displacement Pumps (AREA)
  • Turbine Rotor Nozzle Sealing (AREA)
  • Coating By Spraying Or Casting (AREA)
  • Other Surface Treatments For Metallic Materials (AREA)

Abstract

Verfahren zur Erhöhung des Korrosions- und Erosionswiderstandes einer Schaufel einer rotierenden thermischen Maschine, welche vorwiegend aus einem ferritischen und/oder ferritisch-martensitischen Grundmaterial besteht, indem eine feste haftende Oberflächenschutzschicht bestehend aus 6 bis 15 Gew.-% Si, Rest Al nach dem Hochgeschwindigkeitsverfahren mit einer Partikelgeschwindigkeit von mindestens 300 m/s auf die Oberfläche des Grundmaterials aufgespritzt wird.Process for increasing the corrosion and erosion resistance of a blade of a rotating thermal machine, which mainly consists of a ferritic and / or ferritic-martensitic base material, by a firmly adhering surface protection layer consisting of 6 to 15% by weight Si, the rest Al according to the high-speed process is sprayed onto the surface of the base material at a particle speed of at least 300 m / s.

Description

Technisches GebietTechnical field

Schaufeln für rotierende thermische Maschinen wie Dampf­turbinen, Gasturbinen, Turbokompressoren etc. und deren wirksamer Schutz gegen betriebliche Angriffe wie Oxyda­tion, Korrosion, Verschleiss und Beschädigung.Buckets for rotating thermal machines such as steam turbines, gas turbines, turbo compressors etc. and their effective protection against operational attacks such as oxidation, corrosion, wear and damage.

Die Erfindung bezieht sich auf die Verbesserung des Widerstandes gegen Korrosion und Erosion von Schaufeln rotierender thermischer Maschinen durch Weiterentwicklung der Verfahren zum Aufbringen von geeigneten Schutzschichten.The invention relates to improving the resistance to corrosion and erosion of blades of rotating thermal machines by further developing the methods for applying suitable protective layers.

Insbesondere betrifft die Erfindung ein Verfahren zur Er­höhung des Korrosions- und Erosionswiderstandes einer Schaufel einer rotierenden thermischen Maschine, die im wesentlichen aus einem ferritischen und/oder ferritisch­martensitischen Grundmaterial besteht, durch Aufbringen einer fest haftenden Oberflächenschutzschicht.In particular, the invention relates to a method for increasing the corrosion and erosion resistance of a blade of a rotating thermal machine, which in consists essentially of a ferritic and / or ferritic-martensitic base material, by applying a firmly adhering surface protective layer.

Stand der TechnikState of the art

Um den zahlreichen Beanspruchungen Genüge leisten zu kön­nen, werden die Schaufeln rotierender thermischer Maschi­nen vielfach mit Schutzschichten versehen. Davon wird sowohl bei Dampf- und Gasturbinenschaufeln wie bei Kom­pressorschaufeln Gebrauch gemacht. Es gilt vor allem, den Widerstand gegen Korrosion und oxydierenden Angriff sowie gegen Erosion und Abnutzung (Verschleiss) zu erhöhen. Unter den verwendeten Stoffen für Schutzschichten nehmen die oxydische Deckschichten bildenden Element Cr, Al, Si eine Sonderstellung ein. Schichten, die einen hohen Al-­Gehalt aufweisen, sind unter anderem als Füllmaterial für karbidhaltige Ueberzüge (Cr₂C₃; WC) im Triebswerkbau ver­wendet worden.In order to be able to meet the numerous demands, the blades of rotating thermal machines are often provided with protective layers. This is used for both steam and gas turbine blades as well as for compressor blades. The main thing is to increase resistance to corrosion and oxidizing attack as well as erosion and wear (wear and tear). Among the substances used for protective layers, the element Cr, Al, Si forming the oxide cover layers occupy a special position. Layers which have a high Al content have been used, inter alia, as filler material for carbide-containing coatings (Cr₂C₃; WC) in engine construction.

Zum Stand der Technik werden folgende Druckschriften angegeben:
- F.N. Davis, C.E. Grinnell, "Engine Experience of Turbine Rotor Blade Materials and Coatings", The American Society of Mechanical Engineers, 345 E. 47 ST. New York, N.Y. 10017, 82-GT-244
- SermeTel Technische Information: "SermaLoy J-Prozess STS", SermeTel GmbH, Weilenburgstrasse 49, D-5628 Heiligenhaus, BRD
- Mark F. Mosser and Bruce G. McMordie, "Evaluation of Aluminium/Ceramic Coating on Fasteners to Eliminate Galvanic Corrosion", Reprinted from SP-649-Corro­sion: Coatings and Steels, International Congress and Exposition, Detroit, Michigan, February 24-28, 1986, ISSN 0148-7191, Copyright 1986 Society of Au­tomotive Engineers, Inc.
- Thomas F. Lewis III, "Gator-Gard, The Process, Coatings, and Turbomachinery Applications", Pre­sented at the International Gas Turbine Conference and Exhibit, Düsseldorf, West Germany - June 8-12, 1986, The American Society of Mechanical Engineers, 345 E. 47 St., New York, N.Y. 10017, 86-GT-306
- H.J. Kolkman, "New Erosion Resistant Compressor Coatings", Presented at the Gas Turbine and Aeroengine Congress, Amsterdam, The Netherlands - June 6-9, 1988, The American Society of Mechanical Engineers, 345 E. 47. St., New York, N.Y. 10017, 88-­GT-186.The following publications are given regarding the state of the art:
- FN Davis, CE Grinnell, "Engine Experience of Turbine Rotor Blade Materials and Coatings", The American Society of Mechanical Engineers, 345 E. 47 ST. New York, NY 10017, 82-GT-244
- SermeTel Technical Information: "SermaLoy J-Process STS", SermeTel GmbH, Weilenburgstrasse 49, D-5628 Heiligenhaus, FRG
- Mark F. Mosser and Bruce G. McMordie, "Evaluation of Aluminum / Ceramic Coating on Fasteners to Eliminate Galvanic Corrosion ", Reprinted from SP-649-Corrosion: Coatings and Steels, International Congress and Exposition, Detroit, Michigan, February 24-28, 1986, ISSN 0148-7191, Copyright 1986 Society of Automotive Engineers, Inc.
- Thomas F. Lewis III, "Gator-Gard, The Process, Coatings, and Turbomachinery Applications", Presented at the International Gas Turbine Conference and Exhibit, Duesseldorf, West Germany - June 8-12, 1986, The American Society of Mechanical Engineers , 345 E. 47 St., New York, NY 10017, 86-GT-306
- HJ Kolkman, "New Erosion Resistant Compressor Coatings", Presented at the Gas Turbine and Aeroengine Congress, Amsterdam, The Netherlands - June 6-9, 1988, The American Society of Mechanical Engineers, 345 E. 47th St., New York , NY 10017, 88-GT-186.

Darstellung der ErfindungPresentation of the invention

Der Erfindung liegt die Aufgabe zugrunde, ein Verfahren zur Erhöhung des Korrosions- (Cl- und SO₄-Ionen) und Ero­sionswiderstandes (Partikel- und Tropfenschlagerosion) einer Schaufel einer rotierenden thermischen Maschine bei Anwesenheit von H₂O-Dampf und vergleichsweise mässigen Temperaturen (450 °C) auzugeben, welches sich besonders für ferritisches und/oder ferritisch-martensitisches Grundmaterial der Schaufel eignet, wobei kostengünstig und ohne grossen Aufwand eine geeignete Oberflächen­schicht erzielt werden soll. Es soll insbesondere das Auftreten von Lochfrass-Korrosion vermieden oder min­ destens hinausgezögert werden, um der Schaufel eine längere Lebensdauer zu gewährleisten.The invention has for its object a method for increasing the corrosion (Cl and SO₄ ions) and erosion resistance (particle and drop impact erosion) of a blade of a rotating thermal machine in the presence of H₂O steam and comparatively moderate temperatures (450 ° C ) which is particularly suitable for ferritic and / or ferritic-martensitic base material of the blade, a suitable surface layer being to be achieved inexpensively and without great effort. In particular, the occurrence of pitting corrosion should be avoided or min be delayed to ensure a longer lifespan for the bucket.

Diese Aufgabe wird dadurch gelöst, dass im eingangs er­wähnten Verfahren eine Schutzschicht bestehend aus 6 bis 15 Gew.-% Si, Rest Al nach dem Hochgeschwindigkeitsver­fahren mit einer Partikelgeschwindigkeit von mindestens 300 m/s auf die Oberfläche des Grundmaterials aufge­spritzt wird.This object is achieved in that, in the process mentioned at the outset, a protective layer consisting of 6 to 15% by weight of Si, remainder Al is sprayed onto the surface of the base material by the high-speed process at a particle speed of at least 300 m / s.

Weg zur Ausführung der ErfindungWay of carrying out the invention

Die Erfindung wird anhand der nachfolgenden Ausführungs­beispiele beschrieben:The invention is described using the following exemplary embodiments:

Ausführungsbeispiel 1:Example 1:

Eine Verdichterschaufel für einen Axialkompressor wurde mit einer Schutzschicht versehen. Die Schicht hatte Traflügelprofil, wobei das Schaufelblatt folgende Abmes­sungen aufwies:
Breite = 80 mm
Grösste Dicke = 9 mm
Profilhöhe = 14 mm
Radiale Länge = 210 mmA compressor blade for an axial compressor was provided with a protective layer. The layer had a wing profile, and the airfoil had the following dimensions:
Width = 80 mm
Biggest thickness = 9 mm
Profile height = 14 mm
Radial length = 210 mm

Der Werkstoff der Schaufel war ein martensitischer Stahl, der im voll vergüteten Gefügezustand vorlag und folgende Zusammensetzung aufwies:
Cr = 12 Gew.-%
Mo = 1 Gew.-%
Ni = 0,5 Gew.-%
C = 0,25 Gew.-%
Fe = RestThe material of the blade was a martensitic steel, which was in the fully tempered structural state and had the following composition:
Cr = 12% by weight
Mo = 1% by weight
Ni = 0.5% by weight
C = 0.25% by weight
Fe = rest

Die Schaufel wurde zunächst in Trichloräthan entfettet und gereinigt, worauf das Blatt und der Uebergang Blass/Fuss sandgestrahlt wurde. Die Beschichtung der Schaufel wurde nach einem Hochgeschwindigkeits-Flamm­spritzverfahren mit einer Partikelgeschwindigkeit von 400 m/s und einer Gasgeschwindigkeit von 1000 m/s mit Stickstoff als Fördergas durchgeführt. Als Beschichtungsmaterial wurde eine Aluminiumlegierung der nachfolgenden Zusammen-setzung verwendet, die in Pulverform vorlag:
Si = 12,8 Gew.-%
Mn = 0,22 Gew.-%
Mg = 0,34 Gew.-%
Ti = 0,1 Gew.-%
Al = RestThe scoop was first degreased and cleaned in trichloroethane, whereupon the blade and the pale / foot transition were sandblasted. The coating of the blade was carried out using a high-speed flame spraying process with a particle speed of 400 m / s and a gas speed of 1000 m / s with nitrogen as the conveying gas. An aluminum alloy of the following composition, which was in powder form, was used as the coating material:
Si = 12.8% by weight
Mn = 0.22% by weight
Mg = 0.34% by weight
Ti = 0.1% by weight
Al = rest

Gemäss dem hier angewendeten Beschichtungsverfahren mit der Markenbezeichnung "Jet-Kote" wurde das Aluminiumlegie rungspulver mittels Stickstoff in eine mit Propan und Sauerstoff betriebene Brennkammer gefördert. Die verflüssigten Partikel wurden als feine Tropfen unter hohem Ueberdruck auf das Werkstück geschleudert. Dabei stand die Schaufel in einer Vorrichtung, die den Schaufelfuss abdeckte. Die Aufbringung der Schutzschicht erfolgte mit der von Hand geführten Spritzpistole. Die aufgetragene Schutzschicht wurde anhand eines metallographischen Schliffes gemessen und betrug im Mittel 8 bis 15 µm. Auf diese Metall-Schutzschicht wurde nach einem herkömmlichen Lackspritzverfahren ein Kunststoff (im vorliegenden Fall Polytetrafluoräthylen) aufgetragen. Diese glatte Oberflächenschicht hatte eine durchschnittliche Dicke von 6 bis 10 µm und eine Rauheit von ca. 2 µm.According to the coating process used here with the brand name "Jet-Kote", the aluminum alloy powder was conveyed by means of nitrogen into a combustion chamber operated with propane and oxygen. The liquefied particles were thrown onto the workpiece as fine drops under high excess pressure. The blade stood in a device that covered the blade root. The protective layer was applied with the hand-held spray gun. The applied protective layer was measured using a metallographic cut and was in Average 8 to 15 µm. A plastic (in the present case polytetrafluoroethylene) was applied to this metal protective layer using a conventional paint spraying process. This smooth surface layer had an average thickness of 6 to 10 µm and a roughness of approximately 2 µm.

Die beschichtete Verdichterschaufel wurde einer Prüfung auf Korrosionsbeständigkeit unterworfen. Zu diesem Zweck wurde sie in eine Prüflösung getaucht und danach in einem Klimaschrank während 4 h ausgelagert. Dieser Zyklus wurde insgesamt 60 x wiederholt. Die Prüflösung bestand aus einer wässrigen Lösung der folgenden Salze:
220 g/l (NH₄)₂FeSO₄ . 6H₂O
50 g/l NaCl
pH = 3 - 3,5
Temperatur Klimaschrank = 45 °C
Luftfeuchtigkeit = 100 %
Prüfdauer/Zyklus = 4 h
Zahl der Zyklen = 60The coated compressor blade was subjected to a corrosion resistance test. For this purpose, it was immersed in a test solution and then stored in a climatic cabinet for 4 hours. This cycle was repeated a total of 60 times. The test solution consisted of an aqueous solution of the following salts:
220 g / l (NH₄) ₂FeSO₄. 6H₂O
50 g / l NaCl
pH = 3 - 3.5
Temperature cabinet = 45 ° C
Humidity = 100%
Test duration / cycle = 4 h
Number of cycles = 60

Die metallographischen Untersuchungen zeigten, dass nach diesen Korrosionsversuchen weder an den aufgebrachten Schichten noch am Grundmaterial irgendwelche Veränderun­gen festgestellt werden konnten.
Zum Vergleich wurde eine nach einem herkömmlichen Spritzverfahren mit je einer Aluminiumschicht und einer Kunststoffschicht versehene Verdichterschaufel geprüft. Nach 60 Prüfzylen waren die Schutzschichten weitgehend zerstört und lamellenförmige Schuppen herausgebrochen.The metallographic examinations showed that after these corrosion tests, no changes could be found either on the applied layers or on the base material.
For comparison, a compressor blade was tested using a conventional spraying method, each with an aluminum layer and a plastic layer. After 60 test cycles, the protective layers were largely destroyed and lamellar scales broke out.

Ausführungsbeispiel 2:Example 2:

Eine Verdichterschaufel gleicher Abmessungen und Zusam­mensetzung wurde gemäss Beispiel 1 mit einer Aluminium­legierung und einem Kunststoff beschichtet. Nun wurde auf der beschichteten Schaufel ein der Längsachse paralleler Kratzer von 10 mm Länge und total durchschnittlich 25 µm Tiefe angebracht, dessen Profil also mit seiner Spitze gerade noch das Grundmaterial knapp erfasste. Dann wurde die Schaufel den gleichen Korrosionsprüfungen wie in Beispiel 1 unterworfen. Dank der Lokalelementbildung (Aluminiumschicht funktioniert als "Opferanode") wurde das Grundmaterial weitgehend geschützt, während die Alu­miniumschicht an den Flanken des Kratzers nur geringfügig abgebaut wurde. Durch die Wanderung der Al-Ionen im kor­rosiven Medium als "Elektrolyt" und deren Entladung an der elektropositiven Elektrode (Fe) des Grundmaterials kommt der korrosive Angriff in vielen Fällen zum Still­stand. Durch diese Simulierung der Oberflächenbeschädi­gung durch auftreffende Partikel im Betrieb und deren Verhalten unter korrosiver Atmosphäre wurde bewiesen, dass die erfindungsgemässe Schutzschicht unter prakti­schen Einsatzbedingungen eine lange Lebensdauer zu er­warten lässt.A compressor blade of the same dimensions and composition was coated according to Example 1 with an aluminum alloy and a plastic. Now a scratch of 10 mm length and a total of 25 µm depth parallel to the longitudinal axis was made on the coated blade, the profile of which just barely grasped the base material with its tip. The blade was then subjected to the same corrosion tests as in Example 1. Thanks to the local element formation (aluminum layer functions as a "sacrificial anode"), the base material was largely protected, while the aluminum layer on the flanks of the scratch was only slightly degraded. Due to the migration of the Al ions in the corrosive medium as an "electrolyte" and their discharge at the electropositive electrode (Fe) of the base material, the corrosive attack comes to a standstill in many cases. By simulating the surface damage caused by impinging particles during operation and their behavior under a corrosive atmosphere, it was proven that the protective layer according to the invention can be expected to have a long service life under practical conditions of use.

Ausführungsbeispiel 3:Example 3:

Eine Verdichterschaufel wurde mit einer Schutzschicht versehen. Der Tragflügel des Schaufelblattes hatte die nachfolgenden Abmessungen:
Breite = 100 mm
Grösste Dicke = 10,5 mm
Profilhöhe = 18 mm
Radiale Länge = 265 mmA compressor blade was provided with a protective layer. The airfoil wing had the following dimensions:
Width = 100 mm
Greatest thickness = 10.5 mm
Profile height = 18 mm
Radial length = 265 mm

Der Werkstoff der Schaufel bestand aus einem martensi­tisch-austenitischen Zweiphasenstahl mit geringem Austenitanteil und lag im vergüteten Zustand vor. Die Zusammensetzung war die folgende:
CR = 15,5 Gew.-%
Mo = 1,28 Gew.-%
Ni = 5,4 Gew.-%
C = 0,2 Gew.-%
Fe = RestThe material of the blade consisted of a martensitic-austenitic two-phase steel with a low austenite content and was available in a tempered condition. The composition was as follows:
CR = 15.5% by weight
Mo = 1.28% by weight
Ni = 5.4% by weight
C = 0.2% by weight
Fe = rest

Nach dem üblichen Entfetten, Reinigen und Sandstrahlen wurde das Schaufelblatt zusätzlich gezielt kugelge­strahlt. Durch diese Oberflächenbehandlung wurde die Randzone des Grundmaterials kaltverformt und verdichtet, so dass sie Druckeigenspannungen aufwies. Damit wurde er­reicht, dass die Wechselfestigkeit (Ermüdungsfestigkeit) durch Abbau der Spannungen auf der Zugseite im Betrieb erhöht wurde. Für die Beschichtung der Schaufel nach dem Hochgeschwindigkeits-Flammspritzverfahren mit einer Par­tikelgeschwindigkeit von 450 m/s und einer Gas­geschwindigkeit von 1200 m/s mit Stickstoff als Förder­mittel wurde eine Aluminiumlegierung der nachfolgenden Zusammensetzung verwendet:
Si = 10,65 Gew.-%
Mn = 0,37 Gew.-%
Mg = 0,1 Gew.-%
Al = RestAfter the usual degreasing, cleaning and sandblasting, the airfoil was also shot peened. As a result of this surface treatment, the edge zone of the base material was cold worked and compressed so that it had residual compressive stresses. It was thus achieved that the fatigue strength was increased by reducing the tension on the train side during operation. An aluminum alloy of the following composition was used to coat the blade using the high-speed flame spraying process with a particle speed of 450 m / s and a gas speed of 1200 m / s with nitrogen as the conveying medium:
Si = 10.65% by weight
Mn = 0.37% by weight
Mg = 0.1% by weight
Al = rest

Das Aufspritzen der Aluminiumlegierung erfolgte mit einem Industrieroboter. Es wurden 3 Spritzgänge durchgeführt. Die Dicke der aufgetragenen Schicht betrug im Durchschnitt 90 bis 100 µm. Auf diese Metall-­Schutzschicht wurde zusätzlich eine Kunststoffschicht von ca. 10 bis 15 µm Dicke nach einem üblichen Lackspritzver­fahren aufgetragen.
Die beschichtete Schaufel wurde der gleichen Prüfung auf Korrosion unterzogen wie in Beispiel 1. Es konnte danach keinerlei Angriff festgestellt werden.The aluminum alloy was sprayed on using an industrial robot. 3 spray coats were carried out. The thickness of the applied layer averaged 90 to 100 μm. A plastic layer of approx. 10 to 15 µm thickness was additionally applied to this metal protective layer using a conventional paint spraying process.
The coated blade was subjected to the same corrosion test as in Example 1. No attack was then found.

Ausführungsbeispiel 4:Example 4:

Eine gebrauchte Verdichterschaufel mit Tragflügelprofil wurde mit einer Schutzschicht versehen. Das Schaufelblatt hatte die nachfolgenden Abmessungen:
Breite = 63 mm
Grösste Dicke = 8 mm
Profilhöhe = 12 mm
Radiale Länge = 140 mmA used compressor blade with wing profile was provided with a protective layer. The airfoil had the following dimensions:
Width = 63 mm
Biggest thickness = 8 mm
Profile height = 12 mm
Radial length = 140 mm

Das Grundmaterial der Schaufel war ein martensitischer Stahl im hochfest vergüteten Gefügezustand, dessen Zusam­mensetzung nachstehend wiedergegeben ist:
Cr = 11,73 Gew.-%
Mo = 0,8 Gew.-%
V = 0,1 Gew.-%
C = 0,22 Gew.-%
Fe = RestThe base material of the shovel was a martensitic steel in a highly strengthened structural state, the composition of which is shown below:
Cr = 11.73% by weight
Mo = 0.8% by weight
V = 0.1% by weight
C = 0.22% by weight
Fe = rest

Im vorliegenden Fall handelte es sich um eine nach üblichen Verfahren beschichtete Schaufel, welche be­trächtliche Betriebsschäden in Form von Lochfrass-Korro­sion, die sich teilweise auch auf das Grundmaterial er­streckte, aufwies. Diese gebrauchte Schaufel wurde zunächst entfettet, überschliffen und sandgestrahlt, um die Schäden zu beseitigen. Dann wurde die Oberflächenzone des Grundmaterials durch Kugelstrahlen verdichtet. Die Beschichtung erfolgte mit einer Aluminiumlegierung fol­gender Zusammensetzung:
Si = 6,84 Gew.-%
Mn = 0,3 Gew.-%
Mg = 0,36 Gew.-%
Ti = 0,1 Gew.-%
Al = RestIn the present case, the blade was coated using customary methods and showed considerable operational damage in the form of pitting corrosion, which in some cases also extended to the base material. This used shovel was first degreased, ground and sandblasted to remove the damage. Then the surface zone of the base material was compacted by shot peening. The coating was made with an aluminum alloy of the following composition:
Si = 6.84% by weight
Mn = 0.3% by weight
Mg = 0.36% by weight
Ti = 0.1% by weight
Al = rest

Das Aufspritzen der Metallschicht erfolgte von Hand nach dem Hochgeschwindigkeits-Flammspritzverfahren. Die Dicke der Schutzschicht schwankte zwischen 25 und 45 µm. Die metallographischen Prüfungen nach dem oben angegebenen Korrosionsversuch ergaben eine unveränderte, nicht ange­griffene Oberflächenzone.The metal layer was sprayed on by hand using the high-speed flame spraying process. The thickness of the protective layer fluctuated between 25 and 45 µm. The metallographic tests after the corrosion test indicated above showed an unchanged, unaffected surface zone.

Die Erfindung ist nicht auf die Ausführungsbeispiele beschränkt.The invention is not restricted to the exemplary embodiments.

Das Verfahren zur Erhöhung des Korrosions- und Erosion­swiderstandes einer Schaufel einer rotierenden thermi­schen Maschine, die im wesentlichen aus einem ferriti­schen und/oder ferritisch-martensitischen Grundmaterial besteht, wird durch Aufbringen einer fest haftenden Ober­flächenschutzschicht durchgeführt, indem eine Schutzschicht bestehend aus 6 bis 15 Gew.-% Si, Rest Al nach dem Hochgeschwindigkeitsverfahren mit einer Par­tikelgeschwindigkeit von mindestens 300 m/s auf die Ober­fläche des Grundmaterials aufgespritzt wird. Vorzugsweise besteht das Grundmaterial aus einem chromhaltigen Stahl mit 12 bis 13 Gew.-% Cr und weiteren Zusätzen. Die Schutzschicht enthält in vorteilhafter Weise 10 bis 12 Gew.-% Si, Rest Al. Auf die besagte Schutzschicht wird zur Verfeinerung der Oberfläche vorzugsweise zusätzlich eine Deckschicht aus einem wärmebständigen Kunststoff aufgetragen.The method for increasing the corrosion and erosion resistance of a blade of a rotating thermal machine, which essentially consists of a ferritic and / or ferritic-martensitic base material, is carried out by applying a firmly adhering surface protective layer by a Protective layer consisting of 6 to 15 wt .-% Si, remainder Al is sprayed onto the surface of the base material by the high-speed method with a particle speed of at least 300 m / s. The base material preferably consists of a chromium-containing steel with 12 to 13% by weight of Cr and further additives. The protective layer advantageously contains 10 to 12% by weight of Si, the rest of Al. To refine the surface, a cover layer made of a heat-resistant plastic is preferably additionally applied to said protective layer.

Claims (5)

1. Verfahren zur Erhöhung des Korrosions- und Erosions­widerstandes einer Schaufel einer rotierenden ther­mischen Maschine, die im wesentlichen aus einem fer­ritischen und/oder ferritisch-martensitischen Grund­material besteht, durch Aufbringen einer fest haf­tenden Oberflächenschutzschicht, dadurch gekenn­zeichnet, dass eine Schutzschicht bestehend aus 6 bis 15 Gew.-% Si, Rest Al nach dem Hochgeschwindigkeitsverfahren mit einer Par­tikelgeschwindigkeit von mindestens 300 m/s auf die Oberfläche des Grundmaterials aufgespritzt wird.1. A method for increasing the corrosion and erosion resistance of a blade of a rotating thermal machine, which essentially consists of a ferritic and / or ferritic-martensitic base material, by applying a firmly adhering surface protective layer, characterized in that a protective layer consisting of 6 to 15 % By weight Si, remainder Al is sprayed onto the surface of the base material by the high-speed method with a particle speed of at least 300 m / s. 2. Verfahren nach Anspruch 1, dadurch gekennzeichnet, dass der Grundmaterial aus einem chromhaltigen Stahl mit 12 bis 13 Gew.-% Cr und weiteren Zusätzen besteht.2. The method according to claim 1, characterized in that the base material consists of a chromium-containing steel with 12 to 13 wt .-% Cr and other additives. 3. Verfahren nach Anspruch 1, dadurch gekennzeichnet, dass die Schutzschicht 10 bis 12 Gew.-% Si, Rest Al enthält.3. The method according to claim 1, characterized in that the protective layer contains 10 to 12 wt .-% Si, balance Al. 4. Verfahren nach Anspruch 1, dadurch gekennzeichnet, dass auf die Schutzschicht zusätzlich eine Deckschicht aus einem wärmebeständigen Kunststoff aufgetragen wird.4. The method according to claim 1, characterized in that a cover layer made of a heat-resistant plastic is additionally applied to the protective layer. 5. Schutzschicht mit erhöhtem Korrosions- und Erosions­widerstand für eine Schaufel einer rotierenden ther­mischen Maschine, hergestellt nach dem Verfahren gemäss Anspruch 1.5. Protective layer with increased corrosion and erosion resistance for a blade of a rotating thermal machine, produced by the method according to claim 1.
EP89123291A 1989-01-26 1989-12-15 Method for enhancing the corrosion and erosion resistance of the blade of a rotary thermal apparatus and blade produced ba said method Expired - Lifetime EP0379699B1 (en)

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CH252/89A CH678067A5 (en) 1989-01-26 1989-01-26

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WO2000070190A1 (en) * 1999-05-14 2000-11-23 Siemens Aktiengesellschaft Component and method for producing a protective coating on a component

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FR2978931B1 (en) 2011-08-10 2014-05-09 Snecma METHOD FOR PRODUCING A PROTECTIVE REINFORCEMENT ON THE EDGE OF A BLADE
US9309895B2 (en) 2012-06-18 2016-04-12 Kennametal Inc. Closed impeller with a coated vane
US9737933B2 (en) 2012-09-28 2017-08-22 General Electric Company Process of fabricating a shield and process of preparing a component
KR20160053121A (en) * 2014-10-31 2016-05-13 현대자동차주식회사 Coating method for shift fork and shift fork with amorphous coating layer by using the same
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US5120613A (en) 1992-06-09
JPH02230902A (en) 1990-09-13
CH678067A5 (en) 1991-07-31
DE58905843D1 (en) 1993-11-11
EP0379699B1 (en) 1993-10-06
JP2895135B2 (en) 1999-05-24

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