EP0697503B1 - Method for the construction of a turbine blade from an (alpha-beta)-Titanium-base alloy - Google Patents

Method for the construction of a turbine blade from an (alpha-beta)-Titanium-base alloy Download PDF

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Publication number
EP0697503B1
EP0697503B1 EP94112802A EP94112802A EP0697503B1 EP 0697503 B1 EP0697503 B1 EP 0697503B1 EP 94112802 A EP94112802 A EP 94112802A EP 94112802 A EP94112802 A EP 94112802A EP 0697503 B1 EP0697503 B1 EP 0697503B1
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EP
European Patent Office
Prior art keywords
process according
titanium
blade
nitrogen
base alloy
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EP94112802A
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German (de)
French (fr)
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EP0697503A1 (en
Inventor
Claus Dr. Gerdes
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ABB AG Germany
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ABB Asea Brown Boveri Ltd
Asea Brown Boveri AB
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Priority to EP94112802A priority Critical patent/EP0697503B1/en
Priority to DE59406283T priority patent/DE59406283D1/en
Priority to US08/496,188 priority patent/US5573604A/en
Priority to JP7207201A priority patent/JPH08176767A/en
Priority to CN95115293.9A priority patent/CN1119698A/en
Publication of EP0697503A1 publication Critical patent/EP0697503A1/en
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    • 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
    • C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
    • C23C8/06—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases
    • 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

Definitions

  • the invention is based on a method for Manufacture of an erosion-resistant turbine blade from one ( ⁇ / ⁇ ) titanium base alloy according to the introductory part of claim 1.
  • a manufactured by such a method Blade is preferred in low pressure stages of steam turbines used because of their low density even with large Overall lengths meet the requirements placed on mechanical resilience at temperatures up to approx. 150 ° C.
  • the temperature range includes the one entering the turbine Water vapor droplets that hit the water at high speed Surfaces of the turbine blade exposed to the incoming steam hit, in particular the blade leading edge and the parts adjoining the blade leading edge on the suction side the blade surface. The drops can cause erosion damage cause.
  • the area is particularly stressed of the blade tip, because there the Circumferential speed of the blade is greatest.
  • a method of the type mentioned at the outset is in EP-A-0 491 075 described. This process is used to create a protective layer high erosion resistance on a turbine blade made of an ( ⁇ / ⁇ ) titanium base alloy in the area of the blade tip.
  • the protective layer is remelted the ( ⁇ / ⁇ ) titanium base alloy on the surface in a boron, carbon or nitrogen-containing gas atmosphere by means of a Lasers generated.
  • Such a layer points towards the untreated areas of the blade a great hardness on and protects the underlying titanium base alloy effectively against Drop erosion. But it has been shown that such a EDM-protected blade material has a lower fatigue strength exhibits than the unprotected blade material.
  • the invention as defined in claim 1 lies the task is based on a method of the type mentioned to indicate with which in cheaper and in one for one Series production suitable way an erosion-resistant Turbine blade can be made, which can also be found under constantly changing loads due to a long service life distinguished.
  • Structural changes that have a particularly favorable effect on the fatigue strength occur when heat treatment at temperatures between 650 and 700 ° C. Will the heat treatment over at least one hour, preferably between 2 to 6 Hours, executed, occurs due to diffusion processes homogenization between the ⁇ stabilized phases. At the same time, recrystallization occurs in the remelted alloy Protective layer and in the heat-affected zone of it subsequent ( ⁇ / ⁇ ) titanium base alloy, whereby Grain sizes with a diameter between 20 and 100 ⁇ m form. However, the appearance is of particular importance evenly distributed, vanadium-rich ⁇ -excretions. The This is particularly likely due to the low solubility of vanadium in ⁇ -titanium promote.
  • the fatigue strength can also be increased by mechanical Solidification, especially by controlled shot peening, of the heat-treated blade section can be improved.
  • a further improvement in fatigue strength can be achieved when remelting alloys in a gas atmosphere is carried out in addition to a boron, carbon and / or nitrogenous gas contains an inert carrier gas, which Ratio of the partial pressures of carrier gas to boron, carbon and / or nitrogenous gas is at least 2: 1.
  • Ratio of the partial pressures of carrier gas to boron, carbon and / or nitrogenous gas is at least 2: 1.
  • To a gas atmosphere in which the ratio is preferred is greater than 2: 1 and at most 4: 1, and in the noble gas as gases, such as argon in particular, and nitrogen can be used.
  • FIGS. 1 and 2 each show a diagram, in which the erosion resistance or fatigue strength of blade sections according to the prior art were compared with the erosion resistance or the fatigue strength of blade sections, the were produced by the inventive method.
  • the uncoated turbine blade on a horizontal sliding support table.
  • the tip of the blade is in the Area of the blade leading edge of an oxygen-free boron, exposed to carbide and / or nitrogen-containing gas atmosphere and at the same time with a high-performance energy source, in particular with a laser, irradiated.
  • the turbine blade consisted of a titanium-based alloy with 6 percent by weight aluminum and 4 percent by weight vanadium (Ti-6Al-4V) and became a CO 2 gas laser with an output of 1.5 kW and with an energy spectrum according to a Gaussian Distribution used.
  • the preferred width of the laser beams was 1.3 mm.
  • the gas atmosphere contained nitrogen and argon and was carried in the form of a gas stream to the point of laser irradiation on the blade surface.
  • a stream of nitrogen was enveloped by a stream of argon.
  • the nitrogen uptake during remelting alloying was dependent on the partial pressure of nitrogen in the gas stream.
  • the ratio of the partial pressures of argon to nitrogen was varied between 2: 1 and 4: 1.
  • the laser was compared to the turbine blade moved on meandering tracks.
  • the in Point of incidence located on the surface of the ( ⁇ / ⁇ ) titanium base alloy melted and was in the melt Nitrogen alloyed, which with the titanium of the melted Base alloy made of hard titanium nitride.
  • the composition of the gas supplied could accordingly Titanium boride and / or titanium carbide are formed.
  • protective layer essentially contains titanium nitrides, which are embedded in a matrix of ⁇ -titanium. morphology and distribution of the titanium nitrides depend on the process parameters when remelting and from the nitrogen concentration in the gas atmosphere. Depending on the nitrogen concentration in the The titanium nitrides can be plate-shaped or in a gas atmosphere be dendritic.
  • the protective layer formed can a Vickers hardness of 600 to 800 HV have a Vickers hardness of 350 to 370 HV of the ( ⁇ / ⁇ ) titanium base alloy.
  • the erosion resistance was measured in a test machine which essentially contained a rotating double arm, to the free end of which rectangular samples of the blade material to be examined were attached.
  • the double arm was arranged in a chamber which was evacuated to approx. 25 mbar in order to avoid air friction and to be able to reach high speeds.
  • a droplet generator was attached to the periphery of the chamber, which generated three jets with water droplets of the same size. The water drops hit the surface of the samples perpendicularly.
  • the intensity of each impact was determined by the size of the peripheral speed of the rotating arm at the location of the impact.
  • the droplets generated by the generator typically had a diameter of approximately 0.2 mm.
  • the peripheral speed of the arm at the location of the sample to be examined was constant and varied from sample to sample between 300 and 500 m / s.
  • the volume loss [mm 3 ] of the sample examined was determined as a measure of the erosion resistance as a function of the number of impinging drops at a predetermined peripheral speed (FIG. 1).
  • the sample was subjected to an alternating bending load in a servohydraulic testing machine under four-point bending conditions with a frequency of 30 Hz and with a stress ratio R ( ⁇ min / ⁇ max ) of 0.2 over 10 7 cycles.
  • the ( ⁇ / ⁇ ) titanium base alloy in Comparison to that by remelting with a ratio of Partial pressures argon to nitrogen like 2: 1 generated protective layer has a very low erosion resistance.
  • the untreated ( ⁇ / ⁇ ) titanium base alloy is much more ductile and will plastically deformed by the impacting drops of water. It are therefore formed at a very early stage Erosion craters, which later overlap and finally close Cause cracks or detach plate-shaped areas.
  • the one formed by remelting alloys Protective layer has a great hardness and thus largely prevents the unwanted crater formation.
  • the great hardness and accordingly however, the low ductility of the protective layer means a decrease in the fatigue strength of the protective layer in the Compared to the ( ⁇ / ⁇ ) titanium base alloy by approx. 70% (Fig. 2).
  • the coated blade section over 4 h at temperatures heat treated between 650 and 700 ° C.
  • the heat-affected zone was mainly vanadium-rich and uniformly distributed ⁇ -excretions in the alloy Protective layer formed. As can be seen from Figures 1 and 2 is, these structural changes bring about an improvement in Fatigue strength of the protective layer by approx. 10 to 15% (sample A in Fig.2) while maintaining the erosion resistance of the heat-treated protective layer.
  • the protective layer was additionally hardened mechanically heat-treated protective layer with controlled shot peening reached. Typical values of the shot peening used were a ball diameter of 0.3 and compressed air pressures Acceleration of the balls from 3 to 5 bar. With alpine intensities The fatigue strength of the protective layer was 0.2 mm A compared to the not heat-treated and not shot-peened Protective layer can be doubled.

Description

Technisches GebietTechnical field

Bei der Erfindung wird ausgegangen von einem Verfahren zur Herstellung einer erosionsbeständigen Turbinenschaufel aus einer (α/β)-Titan-Basislegierung nach dem einleitenden Teil von Patentanspruch 1. Eine nach einem solchen Verfahren hergestellte Schaufel wird bevorzugt in Niederdruckstufen von Dampfturbinen verwendet, da sie wegen ihrer geringen Dichte selbst bei grossen Baulängen den gestellten Anforderungen an die mechanische Belastbarkeit bei Temperaturen bis ca. 150°C entspricht. In diesem Temperaturbereich enthält der in die Turbine eintretende Wasserdampf Tropfen, welche mit grosser Geschwindigkeit auf die dem eintretenden Dampf ausgesetzten Flächen der Turbinenschaufel auftreffen, wie insbesondere die Schaufeleintrittskante und die an die Schaufeleintrittskante saugseitig anschliessenden Teile der Schaufeloberfläche. Hierbei können die Tropfen Erosionsschäden hervorrufen. Besonders beansprucht wird dabei der im Bereich der Schaufelspitze befindliche Schaufelabschnitt, da dort die Umfangsgeschwindigkeit der Schaufel am grössten ist.The invention is based on a method for Manufacture of an erosion-resistant turbine blade from one (α / β) titanium base alloy according to the introductory part of claim 1. A manufactured by such a method Blade is preferred in low pressure stages of steam turbines used because of their low density even with large Overall lengths meet the requirements placed on mechanical resilience at temperatures up to approx. 150 ° C. In this The temperature range includes the one entering the turbine Water vapor droplets that hit the water at high speed Surfaces of the turbine blade exposed to the incoming steam hit, in particular the blade leading edge and the parts adjoining the blade leading edge on the suction side the blade surface. The drops can cause erosion damage cause. The area is particularly stressed of the blade tip, because there the Circumferential speed of the blade is greatest.

Stand der TechnikState of the art

Ein Verfahren der eingangs genannten Art ist in EP-A-0 491 075 beschrieben. Dieses Verfahren dient der Herstellung einer Schutzschicht hoher Erosionsbeständigkeit auf einer Turbinenschaufel aus einer (α/β)-Titan-Basislegierung im Bereich der Schaufelspitze. Die Schutzschicht wird hierbei durch Umschmelzlegieren der (α/β)-Titan-Basislegierung an der Oberfläche in einer bor-, kohlenstoff- oder stickstoffhaltigen Gasatmosphäre mittels eines Lasers erzeugt. Eine solche Schicht weist gegenüber den unbehandelten Bereichen der Schaufel eine grosse Härte auf und schützt die darunter liegende Titan-Basislegierung wirksam gegen Tropfenerosion. Es hat sich aber gezeigt, dass ein derart erosionsgeschützter Schaufelwerkstoff eine geringere Ermüdungsfestigkeit aufweist als der ungeschützte Schaufelwerkstoff.A method of the type mentioned at the outset is in EP-A-0 491 075 described. This process is used to create a protective layer high erosion resistance on a turbine blade made of an (α / β) titanium base alloy in the area of the blade tip. The protective layer is remelted the (α / β) titanium base alloy on the surface in a boron, carbon or nitrogen-containing gas atmosphere by means of a Lasers generated. Such a layer points towards the untreated areas of the blade a great hardness on and protects the underlying titanium base alloy effectively against Drop erosion. But it has been shown that such a EDM-protected blade material has a lower fatigue strength exhibits than the unprotected blade material.

Darstellung der ErfindungPresentation of the invention

Der Erfindung, wie sie in Patentanspruch 1 definiert ist, liegt die Aufgabe zugrunde, ein Verfahren der eingangs genannten Art anzugeben, mit dem in preisgünstiger und in einer für eine Serienfertigung geeigneten Weise eine erosionsbeständige Turbinenschaufel hergestellt werden kann, welche sich auch unter ständig wechselnder Beanspruchung durch eine grosse Lebensdauer auszeichnet.The invention as defined in claim 1 lies the task is based on a method of the type mentioned to indicate with which in cheaper and in one for one Series production suitable way an erosion-resistant Turbine blade can be made, which can also be found under constantly changing loads due to a long service life distinguished.

Mit dem erfindungsgemässen Verfahren wird in wenigen leicht auszuführenden Verfahrensschritten, nämlich einer Oberflächenbehandlung der ungeschützten (α/β)-Titan-Basislegierung durch Umschmelzlegieren mittels einer Hochleistungs-Energiequelle sowie durch daran anschliessendes Wärmebehandeln, eine Turbinenschaufel geschaffen, welche sich im Bereich ihrer Schaufelspitze sowohl durch eine hohe Erosionsbeständigkeit als auch durch eine gute Ermüdungsfestigkeit auszeichnet.With the method according to the invention it becomes easy in a few Process steps to be carried out, namely a surface treatment of the unprotected (α / β) titanium base alloy Remelting alloys using a high-performance energy source as well by subsequent heat treatment, a turbine blade created, which are both in the area of their blade tip through a high erosion resistance as well as a good one Fatigue resistance.

Während der Vorteil der Erosionsfestigkeit im wesentlichen durch das Umschmelzlegieren in einer geeigneten Gasatmosphäre hervorgerufen wird, wird die Bildung unerwünschter Risse in der Schutzschicht beim Vorhandensein von äusseren Spannungen und damit eine vorzeitige Werkstoffermüdung durch eine Wärmebehandlung bei Temperaturen zwischen 600 und 750°C vermieden. Bei diesen vergleichsweise geringen Temperaturen treten ganz erhebliche Gefügeänderungen in der umschmelzlegierten Schutzschicht aber nicht im daran anschliessenden Bereich der unbeeinflussten (α/β)-Titan-Basislegierung auf.While the benefit of erosion resistance is essentially due remelting alloys in a suitable gas atmosphere the formation of unwanted cracks in the protective layer in the presence of external tensions and thus a premature material fatigue due to heat treatment Avoid temperatures between 600 and 750 ° C. With these comparatively low temperatures occur very significant structural changes in the remelted protective layer but not in adjoining area of the unaffected (α / β) titanium base alloy on.

Die Ermüdungsfestigkeit besonders günstig beeinflussende Gefügeänderungen treten auf, wenn die Wärmebehandlung bei Temperaturen zwischen 650 und 700°C ausgeführt wird. Wird die Wärmebehandlung über mindestens eine Stunde, vorzugsweise zwischen 2 bis 6 Stunden, ausgeführt, so tritt aufgrund von Diffusionsvorgängen eine Homogenisierung zwischen den α stabilisierten Phasen ein. Zugleich tritt eine Rekristallisation in der umschmelzlegierten Schutzschicht und in der wärmebeeinflussten Zone der daran anschliessenden (α/β)-Titan-Basislegierung auf, wobei sich Korngrössen mit einem Durchmesser zwischen 20 und 100 µm ausbilden. Von besonderer Bedeutung ist jedoch das Auftreten gleichmässig verteilter, vanadinreicher β-Ausscheidungen. Die niedrige Löslichkeit von Vanadin in α-Titan dürfte dies besonders fördern.Structural changes that have a particularly favorable effect on the fatigue strength occur when heat treatment at temperatures between 650 and 700 ° C. Will the heat treatment over at least one hour, preferably between 2 to 6 Hours, executed, occurs due to diffusion processes homogenization between the α stabilized phases. At the same time, recrystallization occurs in the remelted alloy Protective layer and in the heat-affected zone of it subsequent (α / β) titanium base alloy, whereby Grain sizes with a diameter between 20 and 100 µm form. However, the appearance is of particular importance evenly distributed, vanadium-rich β-excretions. The This is particularly likely due to the low solubility of vanadium in α-titanium promote.

Die Ermüdungsfestigkeit kann zusätzlich durch mechanische Verfestigung, insbesondere durch kontrolliertes Kugelstrahlen, des wärmebehandelten Schaufelabschnitts verbessert werden.The fatigue strength can also be increased by mechanical Solidification, especially by controlled shot peening, of the heat-treated blade section can be improved.

Eine weitere Verbesserung der Ermüdungsfestigkeit kann erreicht werden, wenn das Umschmelzlegieren in einer Gasatmosphäre ausgeführt wird, die neben einem bor-, kohlenstoff- und/oder stickstoffhaltigen Gas ein inertes Trägergas enthält, wobei das Verhältnis der Partialdrücke von Trägergas zu bor-, kohlenstoff- und/oder stickstoffhaltigem Gas mindestens 2:1 beträgt. Zu bevorzugen ist hierbei eine Gasatmosphäre, in der das Verhältnis grösser 2:1 und höchstens 4:1 ist, und in der als Gase Edelgas, wie insbesondere Argon, und Stickstoff verwendet werden. A further improvement in fatigue strength can be achieved when remelting alloys in a gas atmosphere is carried out in addition to a boron, carbon and / or nitrogenous gas contains an inert carrier gas, which Ratio of the partial pressures of carrier gas to boron, carbon and / or nitrogenous gas is at least 2: 1. To a gas atmosphere in which the ratio is preferred is greater than 2: 1 and at most 4: 1, and in the noble gas as gases, such as argon in particular, and nitrogen can be used.

Kurze Beschreibung der ZeichnungBrief description of the drawing

Nachfolgend wird die Erfindung anhand der Zeichnung näher erläutert. Hierbei zeigen die beiden Figuren 1 und 2 jeweils ein Diagramm, in dem die Erosionsbeständigkeit bzw. die Ermüdungsfestigkeit von Schaufelabschnitten, die nach dem Stand der Technik hergestellt wurden, verglichen wird mit der Erosionsbeständigkeit bzw. der Ermüdungsfestigkeit von Schaufelabschnitten, die nach dem erfindungsgemässen Verfahren hergestellt wurden.The invention is explained in more detail below with reference to the drawing. The two FIGS. 1 and 2 each show a diagram, in which the erosion resistance or fatigue strength of blade sections according to the prior art were compared with the erosion resistance or the fatigue strength of blade sections, the were produced by the inventive method.

Weg zur Ausführung der ErfindungWay of carrying out the invention

Wie im Stand der Technik gemäss EP-A-0 491 075 beschrieben, wird die unbeschichtete Turbinenschaufel auf einem horizontal verschiebbaren Auflagetisch gelagert. Die Schaufelspitze wird im Bereich der Schaufeleintrittskante einer sauerstofffreien bor-, carbid- und/oder stickstoffhaltigen Gasatmosphäre ausgesetzt und zugleich mit einer Hochleistungs-Energiequelle, insbesondere mit einem Laser, bestrahlt.As described in the prior art according to EP-A-0 491 075 the uncoated turbine blade on a horizontal sliding support table. The tip of the blade is in the Area of the blade leading edge of an oxygen-free boron, exposed to carbide and / or nitrogen-containing gas atmosphere and at the same time with a high-performance energy source, in particular with a laser, irradiated.

In einem bevorzugten Ausführungsbeispiel bestand die Turbinenschaufel aus einer Titan-Basislegierung mit 6 Gewichtsprozent Aluminium und 4 Gewichtsprozent Vanadin (Ti-6Al-4V) und wurde ein CO2-Gaslaser mit einer Leistung von 1,5 kW und mit einem Energiespektrum gemäss einer Gauss-Verteilung eingesetzt. Die bevorzugte Breite der Laserstrahlen betrug 1,3 mm. Die auf der Schaufeloberfläche beim Umschmelzlegieren gebildeten Schmelzspuren überlappten sich zu ca. 50% und wiesen eine Schmelztiefe von ca. 0,5 mm auf. Die Gasatmosphäre enthielt Stickstoff und Argon und wurde im Form eines Gasstroms an den Aufstrahlpunkt des Lasers an der Schaufeloberfläche geführt. Hierbei wurde ein strahlförmiger Stickstoffstrom von einem Argonstrom umhüllt. Es konnten so Sauerstoff und andere unerwünschte Substanzen vom Aufstrahlpunkt und damit vom Umschmelzlegierprozess ferngehalten werden. Die Stickstoffaufnahme beim Umschmelzlegieren war abhängig vom Partialdruck des Stickstoffs im Gasstrom. Das Verhältnis der Partialdrücke von Argon zu Stickstoff wurde zwischen 2:1 und 4:1 variiert.In a preferred exemplary embodiment, the turbine blade consisted of a titanium-based alloy with 6 percent by weight aluminum and 4 percent by weight vanadium (Ti-6Al-4V) and became a CO 2 gas laser with an output of 1.5 kW and with an energy spectrum according to a Gaussian Distribution used. The preferred width of the laser beams was 1.3 mm. The melting marks formed on the blade surface during remelting alloy overlap to about 50% and had a melting depth of about 0.5 mm. The gas atmosphere contained nitrogen and argon and was carried in the form of a gas stream to the point of laser irradiation on the blade surface. Here, a stream of nitrogen was enveloped by a stream of argon. In this way, oxygen and other undesirable substances could be kept away from the point of irradiation and thus from the remelting process. The nitrogen uptake during remelting alloying was dependent on the partial pressure of nitrogen in the gas stream. The ratio of the partial pressures of argon to nitrogen was varied between 2: 1 and 4: 1.

Beim Bestrahlen wurde der Laser gegenüber der Turbinenschaufel auf mäanderförmigen Bahnen bewegt. Hierbei wurde der im Aufstrahlpunkt gelegene Teil der Oberfläche der (α/β)-Titan-Basislegierung aufgeschmolzen und wurde in die Schmelze Stickstoff einlegiert, welcher mit dem Titan der aufgeschmolzenen Basislegierung hartes Titannitrid bildete. Bei geeigneter Zusammensetzung des zugeführten Gases könnten entsprechend auch Titanborid und/oder Titancarbid gebildet werden.During the irradiation, the laser was compared to the turbine blade moved on meandering tracks. Here, the in Point of incidence located on the surface of the (α / β) titanium base alloy melted and was in the melt Nitrogen alloyed, which with the titanium of the melted Base alloy made of hard titanium nitride. With more suitable The composition of the gas supplied could accordingly Titanium boride and / or titanium carbide are formed.

Aus Röntgenbeugungsdiagrammen, Mikrohärtemessungen, raster- und durchstrahlungs-elektronenmikroskopischen Untersuchungen sowie aus Mikrosondenauswertungen wurde festgestellt, dass die hierbei gebildete und typischerweise eine Dicke zwischen 0,4 und 1 mm aufweisende Schutzschicht im wesentlichen Titannitride enthält, welche in eine Matrix aus α-Titan eingebettet sind. Morphologie und Verteilung der Titannitride hängen von den Verfahrensparametern beim Umschmelzlegieren und von der Stickstoffkonzentration in der Gasatmosphäre ab. Je nach Stickstoffkonzentration in der Gasatmosphäre können die Titannitride plattenförmig oder dendritisch ausgebildet sein. Die gebildete Schutzschicht kann je nach den Bedingungen beim Umschmelzlegieren eine Vickershärte von 600 bis 800 HV aufweisen gegenüber einer Vickershärte von 350 bis 370 HV der (α/β)-Titan-Basislegierung.From X-ray diffraction patterns, microhardness measurements, grid and radiographic electron microscopic examinations as well from micro-probe evaluations it was found that this formed and typically a thickness between 0.4 and 1 mm containing protective layer essentially contains titanium nitrides, which are embedded in a matrix of α-titanium. morphology and distribution of the titanium nitrides depend on the process parameters when remelting and from the nitrogen concentration in the gas atmosphere. Depending on the nitrogen concentration in the The titanium nitrides can be plate-shaped or in a gas atmosphere be dendritic. The protective layer formed can a Vickers hardness of 600 to 800 HV have a Vickers hardness of 350 to 370 HV of the (α / β) titanium base alloy.

An einem solchermassen hergestellten Schaufelwerkstoff wurden nach dem Polieren der Schutzschicht die Erosionsbeständigkeit und die Ermüdungsfestigkeit gemessen.On such a manufactured blade material after polishing the protective layer the erosion resistance and the fatigue strength measured.

Die Messung der Erosionsbeständigkeit wurde in einer Testmaschine durchgeführt, welche im wesentlichen einen rotierenden Doppelarm enthielt, an dessen freien Ende rechteckig ausgebildete Proben des zu untersuchenden Schaufelwerkstoffs angebracht waren. Der Doppelarm war in einer Kammer angeordnet, welche auf ca. 25 mbar evakuiert wurde, um so Luftreibung zu vermeiden und hohe Geschwindigkeiten erreichen zu können. Am Umfang der Kammer war ein Tropfengenerator angebracht, welcher drei Strahlen mit jeweils gleich grossen Wassertropfen erzeugte. Die Wassertropfen prallten senkrecht auf die Oberfläche der Proben auf. Die Intensität jedes Aufpralls wurde durch die Grösse der Umfangsgeschwindigkeit des rotierenden Arms am Ort des Aufpralls festgelegt. Die von Generator erzeugten Tropfen wiesen typischerweise einen Durchmesser von ca. 0,2 mm auf. Die Umfangsgeschwindigkeit des Arms am Ort der zu untersuchenden Probe war konstant und variierte von Probe zu Probe zwischen 300 und 500 m/s. Als Mass für die Erosionsbeständigkeit wurde der Volumenverlust [mm3] der untersuchten Probe in Abhängigkeit von der Zahl der aufprallenden Tropfen bei einer vorgebenen Umfangsgeschwindigkeit bestimmt (Fig.1).The erosion resistance was measured in a test machine which essentially contained a rotating double arm, to the free end of which rectangular samples of the blade material to be examined were attached. The double arm was arranged in a chamber which was evacuated to approx. 25 mbar in order to avoid air friction and to be able to reach high speeds. A droplet generator was attached to the periphery of the chamber, which generated three jets with water droplets of the same size. The water drops hit the surface of the samples perpendicularly. The intensity of each impact was determined by the size of the peripheral speed of the rotating arm at the location of the impact. The droplets generated by the generator typically had a diameter of approximately 0.2 mm. The peripheral speed of the arm at the location of the sample to be examined was constant and varied from sample to sample between 300 and 500 m / s. The volume loss [mm 3 ] of the sample examined was determined as a measure of the erosion resistance as a function of the number of impinging drops at a predetermined peripheral speed (FIG. 1).

Zur Messung der Ermüdungsfestigkeit wurde die Probe in einer servohydraulischen Prüfmaschine unter Vierpunkt-Biege-Bedingungen mit einer Frequenz von 30 Hz und bei einem Spannungsverhältnis R (σmin/σmax) von 0,2 über 107 Zyklen einer Biegewechselbelastung unterworfen. Die hierbei ermittelte maximale Spannungsamplitude σmax [MPa], die die Probe ohne zu brechen aufnehmen konnte, wurde als Mass für die Ermüdungsfestigkeit verwendet (Fig.2).To measure the fatigue strength, the sample was subjected to an alternating bending load in a servohydraulic testing machine under four-point bending conditions with a frequency of 30 Hz and with a stress ratio R (σ min / σ max ) of 0.2 over 10 7 cycles. The maximum stress amplitude σ max [MPa] determined in this way, which the sample could absorb without breaking, was used as a measure of the fatigue strength (FIG. 2).

Aus Fig.1 ist ersichtlich, dass die (α/β)-Titan-Basislegierung im Vergleich zu der durch Umschmelzlegieren mit einem Verhältnis der Partialdrücke Argon zu Stickstoff wie 2:1 erzeugten Schutzschicht eine sehr geringe Erosionsbeständigkeit aufweist. Die unbehandelte (α/β)-Titan-Basislegierung ist wesentlich duktiler und wird durch die aufprallenden Wassertropfen plastisch deformiert. Es bilden sich daher bereits zu einem sehr frühen Zeitpunkt Erosionskrater, welche sich später überlagern und schliesslich zu Rissen führen oder das Ablösen plattenförmiger Bereiche bewirken. Im Unterschied dazu weist die durch Umschmelzlegieren gebildete Schutzschicht eine grosse Härte auf und verhindert so weitgehend die unerwünschte Kraterbildung. Die grosse Härte und dementsprechend die geringe Duktilität der Schutzschicht bedingt jedoch eine Abnahme der Ermüdungsfestigkeit der Schutzschicht im Vergleich zur (α/β)-Titan-Basislegierung um ca. 70% (Fig.2).From Fig. 1 it can be seen that the (α / β) titanium base alloy in Comparison to that by remelting with a ratio of Partial pressures argon to nitrogen like 2: 1 generated protective layer has a very low erosion resistance. The untreated (α / β) titanium base alloy is much more ductile and will plastically deformed by the impacting drops of water. It are therefore formed at a very early stage Erosion craters, which later overlap and finally close Cause cracks or detach plate-shaped areas. In contrast, the one formed by remelting alloys Protective layer has a great hardness and thus largely prevents the unwanted crater formation. The great hardness and accordingly however, the low ductility of the protective layer means a decrease in the fatigue strength of the protective layer in the Compared to the (α / β) titanium base alloy by approx. 70% (Fig. 2).

Um die Ermüdungsfestigkeit der Schutzschicht zu verbessern, wurde der beschichtete Schaufelabschnitt über 4 h bei Temperaturen zwischen 650 und 700°C wärmebehandelt. Neben einer Homogenisierung und Rekristallisation des Gefüges der Schutzschicht bzw. der wärmebeeinflussten Zone wurden hierbei vor allem vanadinreiche und gleichförmig verteilte β-Ausscheidungen in der auflegierten Schutzschicht gebildet. Wie aus den Figuren 1 und 2 zu ersehen ist, bewirken diese Gefügeänderungen eine Verbesserung der Ermüdungsfestigkeit der Schutzschicht um ca. 10 bis 15 % (Probe A in Fig.2) unter Beibehalt der Erosionsbeständigkeit der nicht wärmebehandelten Schutzschicht.In order to improve the fatigue strength of the protective layer, the coated blade section over 4 h at temperatures heat treated between 650 and 700 ° C. In addition to homogenization and recrystallization of the structure of the protective layer or The heat-affected zone was mainly vanadium-rich and uniformly distributed β-excretions in the alloy Protective layer formed. As can be seen from Figures 1 and 2 is, these structural changes bring about an improvement in Fatigue strength of the protective layer by approx. 10 to 15% (sample A in Fig.2) while maintaining the erosion resistance of the heat-treated protective layer.

Eine weitere Verbesserung der Ermüdungsfestigkeit praktisch unter Beibehalt der Erosionsbeständigkeit der nicht wärmebehandelten Schutzschicht wurde zusätzlich durch mechanisches Verfestigen der wärmebehandelten Schutzschicht mit kontrolliertem Kugelstrahlen erreicht. Typische Werte des hierbei verwendeten Kugelstrahlens waren ein Kugeldurchmesser von 0,3 und Pressluftdrücke zur Beschleunigung der Kugeln von 3 bis 5 bar. Mit Almen-Intensitäten von 0,2 mm A konnte so die Ermüdungsfestigkeit der Schutzschicht gegenüber der nicht wärmebehandelten und nicht kugelbestrahlten Schutzschicht verdoppelt werden.Practically taking another improvement in fatigue strength Maintains the erosion resistance of the non-heat treated The protective layer was additionally hardened mechanically heat-treated protective layer with controlled shot peening reached. Typical values of the shot peening used were a ball diameter of 0.3 and compressed air pressures Acceleration of the balls from 3 to 5 bar. With alpine intensities The fatigue strength of the protective layer was 0.2 mm A compared to the not heat-treated and not shot-peened Protective layer can be doubled.

Eine weitere Verbesserung der Ermüdungsfestigkeit der Schutzschicht unter Beibehalt der guten Erosionsbeständigkeit der nicht wärmebehandelten Schutzschicht wurde auch dadurch erreicht, dass in der Gasatmosphäre das Verhältnis der Partialdrücke von Argon zu Stickstoff grösser 2:1 ist und bei 4:1 liegt. Wie aus Fig. 2 am Beispiel B zu ersehen ist, konnte durch diese Massnahme die Ermüdungsfestigkeit gegenüber der ebenfalls wärmebehandelten Schutzschicht gemäss dem Beispiel A um ca. 20% gesteigert werden. (Figuren 1 und 2).Another improvement in the fatigue strength of the protective layer while maintaining the good erosion resistance of the heat-treated protective layer was also achieved in that the ratio of the partial pressures of argon in the gas atmosphere to nitrogen is greater than 2: 1 and is 4: 1. As from Fig. 2 As can be seen from example B, this measure enabled the Fatigue resistance compared to that also heat-treated Protective layer according to Example A can be increased by approximately 20%. (Figures 1 and 2).

Von besonderem Vorteil für eine hohe Ermüdungsfestigkeit des Gefüges ist eine Ausführung des Kugelstrahlen mit mindestens zweifacher vollständiger Deckung. Ferner ist es äusserst günstig, die Intensität beim kontrollierten Kugelstrahlen grösser 0,2 und kleiner 0,45 mm A zu wählen. Durch Kugelstrahlen mit einer Almen-Intensität von ca. 0,3 mm A konnte die Ermüdungsfestigkeit der Schutzschicht gemäss dem Beispiel B gegenüber der entsprechenden Schutzschicht, welche jedoch nur mit Kugelstrahlen der Almen-Intensität 0,2 mm A verfestigt wurde, um ca. 15-20% verbessert werden, wodurch eine Schutzschicht erreicht wurde, welche praktisch die gleiche Erosionsbeständigkeit aufweist wie die unbehandelte Schutzschicht und welche zugleich ca. 85 % der Ermüdungsfestigkeit der Titan-Basislegierung erreicht (Fig.2).Of particular advantage for a high fatigue strength of the Microstructure is a version of shot peening with at least double full coverage. Furthermore, it is extremely cheap the intensity of controlled shot peening is greater than 0.2 and less than 0.45 mm A. By shot peening with an alpine intensity The fatigue strength of approx. 0.3 mm A Protective layer according to example B compared to the corresponding one Protective layer, which, however, only with shot-blasting of the alpine intensity 0.2 mm A was solidified, improved by approx. 15-20% by which a protective layer has been achieved which has practically the same erosion resistance as that untreated protective layer and which at the same time approx. 85% of the Fatigue strength of the titanium base alloy reached (Fig. 2).

Claims (10)

  1. Process for manufacturing an erosion-resistant turbine blade made of a vanadium-containing (α/β)-titanium base alloy by remelt alloying a blade section, which is situated in the region of the blade tip and comprises the leading edge of the blade, in a boron-, carbon- and/or nitrogen-containing gas atmosphere with the aid of a high-power energy source, a protective layer being formed which is made of a material which is more erosion-resistant than the titanium base alloy and is based on a titanium boride, titanium carbide and/or titanium nitride, characterized in that the remelt alloyed blade section is subjected to a heat treatment at a temperature between 600 and 750°C with the formation of a vanadium-rich β-titanium phase.
  2. Process according to Claim 1, characterized in that the heat treatment is carried out between 650 and 700°C.
  3. Process according to any one of Claims 1 or 2, characterized in that the heat treatment is carried out for at least 1 h.
  4. Process according to Claim 3, characterized in that the heat treatment is carried out for from 2 to 6 h.
  5. Process according to any one of Claims 1 to 4, characterized in that the heat-treated blade section is mechanically strengthened.
  6. Process according to Claim 5, characterized in that the blade section is subjected to controlled shot peening.
  7. Process according to Claim 6, characterized in that said shot peening is carried out with at least a two-fold complete overlap.
  8. Process according to any one of Claims 6 or 7, characterized in that said shot peening is carried out with an Almen intensity greater than 0.2 and smaller than 0.45 mm A.
  9. Process according to any one of Claims 1 to 8, characterized in that the gas atmosphere, in addition to the boron-, carbon- and/or nitrogen-containing gas contains a carrier gas, the ratio of the partial pressures of carrier gas to boron-, carbon- and/or nitrogen-containing gas being at least 2:1.
  10. Process according to Claim 9, characterized in that the gas atmosphere contains nitrogen and noble gas, in particular argon, the ratio of the partial pressures of noble gas to nitrogen being greater than 2:1 and smaller than 4:1.
EP94112802A 1994-08-17 1994-08-17 Method for the construction of a turbine blade from an (alpha-beta)-Titanium-base alloy Expired - Lifetime EP0697503B1 (en)

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EP94112802A EP0697503B1 (en) 1994-08-17 1994-08-17 Method for the construction of a turbine blade from an (alpha-beta)-Titanium-base alloy
DE59406283T DE59406283D1 (en) 1994-08-17 1994-08-17 Process for producing a turbine blade made of an (alpha-beta) titanium-based alloy
US08/496,188 US5573604A (en) 1994-08-17 1995-06-28 Process for manufacturing a turbine blade made of an (alpha/beta)-titanium base alloy
JP7207201A JPH08176767A (en) 1994-08-17 1995-08-14 Method of fabricating turbine blade from alloy based on (alpha/beta)-titanium
CN95115293.9A CN1119698A (en) 1994-08-17 1995-08-16 Making of blade of gas turbine made of 2/beta titan-based alloy

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EP94112802A EP0697503B1 (en) 1994-08-17 1994-08-17 Method for the construction of a turbine blade from an (alpha-beta)-Titanium-base alloy

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Families Citing this family (29)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5792289A (en) * 1993-10-06 1998-08-11 The University Of Birmingham Titanium alloy products and methods for their production
GB2328221A (en) * 1997-08-15 1999-02-17 Univ Brunel Surface treatment of titanium alloys
US6064031A (en) * 1998-03-20 2000-05-16 Mcdonnell Douglas Corporation Selective metal matrix composite reinforcement by laser deposition
US6395327B1 (en) * 1999-03-12 2002-05-28 Zimmer, Inc. Enhanced fatigue strength orthopaedic implant with porous coating and method of making same
GB2365078B (en) * 2000-07-27 2004-04-21 Rolls Royce Plc A gas turbine engine blade
SE522722C2 (en) * 2001-03-28 2004-03-02 Seco Tools Ab Cutting tool coated with titanium diboride
JP2005530929A (en) * 2002-06-27 2005-10-13 メムリー コーポレーション Beta titanium compounds and their production
US20040168751A1 (en) * 2002-06-27 2004-09-02 Wu Ming H. Beta titanium compositions and methods of manufacture thereof
US20040261912A1 (en) * 2003-06-27 2004-12-30 Wu Ming H. Method for manufacturing superelastic beta titanium articles and the articles derived therefrom
JP3716236B2 (en) * 2002-08-09 2005-11-16 三菱重工業株式会社 Turbine deposit removal equipment
WO2004046262A2 (en) * 2002-11-15 2004-06-03 University Of Utah Integral titanium boride coatings on titanium surfaces and associated methods
US7509734B2 (en) * 2003-03-03 2009-03-31 United Technologies Corporation Repairing turbine element
US8122600B2 (en) * 2003-03-03 2012-02-28 United Technologies Corporation Fan and compressor blade dovetail restoration process
GB0412915D0 (en) * 2004-06-10 2004-07-14 Rolls Royce Plc Method of making and joining an aerofoil and root
DE102004033342A1 (en) * 2004-07-09 2006-02-02 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. Process for producing wear-resistant and fatigue-resistant edge layers in titanium alloys and components produced therewith
US7195455B2 (en) * 2004-08-17 2007-03-27 General Electric Company Application of high strength titanium alloys in last stage turbine buckets having longer vane lengths
JP4888628B2 (en) * 2004-10-01 2012-02-29 Ｎｏｋ株式会社 Manufacturing method of fuel cell component
DE102004050474A1 (en) 2004-10-16 2006-04-20 Mtu Aero Engines Gmbh Process for producing a component coated with a wear protection coating
US7459105B2 (en) * 2005-05-10 2008-12-02 University Of Utah Research Foundation Nanostructured titanium monoboride monolithic material and associated methods
US20060289088A1 (en) * 2005-06-28 2006-12-28 General Electric Company Titanium treatment to minimize fretting
US7506440B2 (en) * 2005-06-28 2009-03-24 General Electric Company Titanium treatment to minimize fretting
US7931446B2 (en) * 2007-02-14 2011-04-26 X-Treme Aerospace Inc. Treatment of turbine blades to increase hardness
WO2010028060A1 (en) * 2008-09-02 2010-03-11 Zimmer, Inc. Method for enhancing fretting fatigue resistance of alloys
BRPI0919209A8 (en) * 2008-09-29 2016-08-23 D Hurst William APPLIANCE FOR ALLOY COATING AND METHOD FOR INTERMETALIZATION
US20100176339A1 (en) * 2009-01-12 2010-07-15 Chandran K S Ravi Jewelry having titanium boride compounds and methods of making the same
GB0906850D0 (en) * 2009-04-22 2009-06-03 Rolls Royce Plc Method of manufacturing an aerofoil
JP5411120B2 (en) * 2010-12-27 2014-02-12 株式会社日立製作所 Titanium alloy turbine blade
US9737933B2 (en) 2012-09-28 2017-08-22 General Electric Company Process of fabricating a shield and process of preparing a component
CN107429570B (en) * 2015-04-17 2020-06-09 三菱日立电力系统株式会社 Steam turbine rotor blade and method for manufacturing steam turbine rotor blade

Family Cites Families (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE289293C (en) *
JPS57198259A (en) * 1981-05-28 1982-12-04 Toshiba Corp Surface treatment of titanium or titanium alloy
FR2599384B1 (en) * 1986-05-28 1988-08-05 Alsthom METHOD OF LAYING A COBALT-CHROME-TUNGSTEN PROTECTIVE COATING ON A TITANIUM ALLOY BLADE COMPRISING VANADIUM AND A COATED BLADE
US5068003A (en) * 1988-11-10 1991-11-26 Sumitomo Metal Industries, Ltd. Wear-resistant titanium alloy and articles made thereof
JPH0441662A (en) * 1990-06-07 1992-02-12 Hakko:Kk Formation of titanium nitride film on pure titanium using laser irradiating method
EP0491075B1 (en) * 1990-12-19 1995-07-05 Asea Brown Boveri Ag Method for producing a turbine blade made of titanium based alloy
JPH04289154A (en) * 1991-03-18 1992-10-14 Fuji Electric Co Ltd Turbine blade made of ti alloy and surface modifying method therefor
US5290368A (en) * 1992-02-28 1994-03-01 Ingersoll-Rand Company Process for producing crack-free nitride-hardened surface on titanium by laser beams
FR2696759B1 (en) * 1992-10-09 1994-11-04 Alsthom Gec Process for nitriding a piece of titanium alloy and device for spraying nitrogen and neutral gas.
ES2173912T3 (en) * 1992-12-21 2002-11-01 Purdue Research Foundation UNLOCK OF THE COMMON ROADS OF SYNTHESIS OF AROMATIC AMINO ACIDS.

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