EP0398121B1 - Process for producing coarse columnar grains directionally oriented along their length in an oxide dispersion hardened nickel base superalloy - Google Patents

Process for producing coarse columnar grains directionally oriented along their length in an oxide dispersion hardened nickel base superalloy Download PDF

Info

Publication number
EP0398121B1
EP0398121B1 EP90108578A EP90108578A EP0398121B1 EP 0398121 B1 EP0398121 B1 EP 0398121B1 EP 90108578 A EP90108578 A EP 90108578A EP 90108578 A EP90108578 A EP 90108578A EP 0398121 B1 EP0398121 B1 EP 0398121B1
Authority
EP
European Patent Office
Prior art keywords
temperature
weight
workpiece
annealed
cooled
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.)
Expired - Lifetime
Application number
EP90108578A
Other languages
German (de)
French (fr)
Other versions
EP0398121A1 (en
Inventor
Reinhard Fried
Peter Dr. Jongenburger
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
ABB Asea Brown Boveri Ltd
ABB AB
Original Assignee
ABB Asea Brown Boveri Ltd
Asea Brown Boveri AB
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by ABB Asea Brown Boveri Ltd, Asea Brown Boveri AB filed Critical ABB Asea Brown Boveri Ltd
Publication of EP0398121A1 publication Critical patent/EP0398121A1/en
Application granted granted Critical
Publication of EP0398121B1 publication Critical patent/EP0398121B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C32/00—Non-ferrous alloys containing at least 5% by weight but less than 50% by weight of oxides, carbides, borides, nitrides, silicides or other metal compounds, e.g. oxynitrides, sulfides, whether added as such or formed in situ
    • C22C32/001—Non-ferrous alloys containing at least 5% by weight but less than 50% by weight of oxides, carbides, borides, nitrides, silicides or other metal compounds, e.g. oxynitrides, sulfides, whether added as such or formed in situ with only oxides
    • C22C32/0015—Non-ferrous alloys containing at least 5% by weight but less than 50% by weight of oxides, carbides, borides, nitrides, silicides or other metal compounds, e.g. oxynitrides, sulfides, whether added as such or formed in situ with only oxides with only single oxides as main non-metallic constituents
    • C22C32/0026—Matrix based on Ni, Co, Cr or alloys thereof
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
    • C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
    • C22F1/10—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of nickel or cobalt or alloys based thereon

Definitions

  • the invention relates to the improvement of the mechanical properties of oxide dispersion-hardened nickel-based superalloys with overall optimal properties with regard to high-temperature strength, long-term stability and ductility. Fatigue resistance and good thermal shock behavior in the medium and high temperature range of the material in the foreground.
  • the invention is concerned with a method for producing coarse longitudinally oriented stem crystals with improved resistance to temperature changes and increased ductility in the transverse direction in a workpiece of any cross-sectional size and cross-sectional shape from an oxide dispersion-hardened nickel-base superalloy present in the initial state in fine-grained, warm-kneaded form by means of a coarse-graining process that triggers secondary recrystallization .
  • Highly heat-resistant blade materials for gas turbines such as oxide dispersion-hardened nickel-based superalloys, are used in the state of coarse longitudinally oriented stem crystals. If the longitudinal axis of these directionally arranged crystallites coincides with the longitudinal axis of the workpiece and the latter is also the main direction of stress, optimal results with regard to creep resistance and fatigue strength at high temperatures are achieved in this direction.
  • the structural condition required for this is achieved by using a zone annealing process for the heat treatment which is decisive for the secondary recrystallization with a preferred direction. As a rule, zone annealing is carried out on comparatively limited cross-sectional dimensions (a few cm2) in a classic manner.
  • EP 0 115 092 A1 Another method for producing a workpiece from an oxide dispersion-hardened nickel-base superalloy which is present in the initial state in fine-grained hot-kneaded form is described in EP 0 115 092 A1.
  • the workpiece is first heated in its edge zone to a temperature of approx. 1100 ° C. and in the core to a temperature of approx. 900 ° C. and treated thermally or thermomechanically at these temperatures.
  • the workpiece is then cooled to room temperature and isothermally annealed.
  • coarse grain annealing the core of the workpiece is kept at a temperature of 1230 to 1280 ° C above the recrystallization temperature of the stem crystals.
  • the edge of the workpiece is kept at a temperature of approx. 1140 ° C below the recrystallization temperature.
  • the core then has coarse longitudinal stem crystals, whereas the edge has a fine-grained structure.
  • the invention achieves the object of specifying a method for producing a workpiece from an oxide dispersion-hardened nickel-base superalloy which is present in the starting state in fine-grained, hot-kneaded form, and which avoids complex process steps and the costly devices necessary for carrying them out, such as zone annealing plants and special ovens, can be easily accomplished in conventional facilities and leads to reproducible results.
  • the method according to the invention is not only characterized by economy, but also by the fact that the workpiece produced thereafter is compared to one according to the prior art Technically manufactured workpiece has improved thermal shock resistance and thus increased ductility transverse to the longitudinal axis of the stem crystals.
  • Another advantage of the method according to the invention is that it is suitable for the production of workpieces of any cross-sectional size and cross-sectional shape.
  • the block diagram corresponds to the method steps according to exemplary embodiment 1. The diagram is self-explanatory and requires no further explanation.
  • the grain axis ratio z / x of the longitudinal stem crystals which occurs after the isothermal coarse grain annealing, strongly depends on the temperature of the previous annealing treatment depends and runs through a maximum comparatively close (approx. 15 ° C) below the solution annealing temperature T ⁇ 'for the ⁇ '-phase in the ⁇ -matrix. After this maximum has been exceeded, the curve drops steeply in order to return practically to 1 at the temperature T ⁇ (no more grain extension!).
  • the workpiece was then further processed according to FIG. 1. For this purpose, it was slowly brought to a temperature of 1130 ° C. in a furnace at a heating rate of 5 ° C./min and kept at this temperature for a period of 1/4 hour. Then the workpiece was cooled in air to room temperature. It was then heated to the temperature of 1230 ° C. necessary for secondary recrystallization and left at this temperature for 1 1/2 hours in order to produce a coarse grain (isothermal annealing). The workpiece was then cooled to room temperature at a rate of approx. 5 ° C / min.
  • Fig. 3 This shows the influence of the grain axis ratio (grain extension ratio) z / x as a function of the annealing temperature held for 1 h of the heat treatment preceding the coarse grain annealing.
  • the subsequent isothermal coarse grain annealing was carried out at 1230 ° C for 1 1/2 hours.
  • the samples worked out from the workpiece showed longitudinal stem crystals of 7 mm medium length, 1.6 mm medium width and 0.9 mm medium thickness.
  • the average grain axis ratio (grain extension ratio) z / x was approx. 7.
  • the 100 h breaking limit in the creep rupture test at 1050 ° C. was approx. 105 MPa.
  • the results of the creep tests are shown in FIG. 4.
  • the corresponding zone-annealed sample reached a corresponding value of 110 MPa.
  • Thermal shock tests did not show any cracks after 3000 cycles according to the program in Example 1, while in zone-annealed comparative samples after just over 400 Cycles hairline cracks could be found on the surface.
  • Example 2 An oxide dispersion hardened nickel-base superalloy was subjected to heat treatment and coarse grain annealing in a manner similar to that of Example 2 (see FIG. 2).
  • the workpiece was cooled to room temperature at a rate of approx. 3 ° C./min.
  • the workpiece was subjected to a further heat treatment.
  • the workpiece was brought to a temperature above the minimum solution annealing temperature for the ⁇ ′-phase of 1220 ° C. within 2 hours, held for 1 hour and then at a cooling rate of approx. 1 ° C./min to a temperature of Cooled down to 600 ° C. The further cooling took place in air down to room temperature.
  • the samples showed longitudinal stem crystals with an average length of 15 mm, 1.5 mm width and 0.9 mm thickness.
  • the average grain axis ratio z / x was approx. 14.
  • a 100 h breaking limit of approx. 100 MPa was measured at a temperature of 1050 ° C.
  • the comparable zone annealed sample was only a few percent above this value. The temperature change resistance was good.
  • 2000 cycles without cracks were achieved, while the zone-annealed comparison samples showed hairline cracks at approximately 400 cycles.
  • the invention is not restricted to the exemplary embodiments.
  • the process for producing coarse longitudinally oriented stem crystals with improved resistance to temperature changes and increased ductility in the transverse direction in a workpiece of any cross-sectional size and cross-sectional shape from a fine-grained one in the initial state The hot-kneaded form of oxide dispersion-hardened nickel-based superalloy is carried out by coarse-grain annealing, which triggers the secondary recrystallization.
  • the workpiece is first annealed in the temperature range between 1000 ° C and 1200 ° C for 1/4 to 10 hours, cooled and 1/4 up to 5 h in the temperature range between 1230 ° C and 1280 ° C isothermally annealed on coarse grain and cooled.
  • the workpiece is preferably additionally subjected to a ductile heat treatment by heating it to the ⁇ ′-solution annealing temperature, maintaining it at least for 1/2 hour and then cooling it to room temperature.
  • the process relates to a dispersion-hardened nickel-based superalloy with the above composition, the workpiece first being annealed at a temperature of 1080 ° C. for 2 hours, cooled in air and then annealed to coarse grains at 1230 ° C. for 1 1/2 hours and is cooled at a rate of at most 5 ° C / min.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Powder Metallurgy (AREA)

Description

Technisches GebietTechnical field

Oxyddispersionsgehärtete Superlegierungen auf der Basis von Nickel, welche dank ihrer hervorragenden mechanischen Eigenschaften bei hohen Temperaturen beim Bau thermischer Maschinen Verwendung finden. Bevorzugte Verwendung als Schaufelwerkstoff für Gasturbinen.Oxide dispersion hardened superalloys based on nickel, which thanks to their excellent mechanical properties are used at high temperatures in the construction of thermal machines. Preferred use as a blade material for gas turbines.

Die Erfindung bezieht sich auf die Verbesserung der mechanischen Eigenschaften von oxyddispersionsgehärteten Nickelbasis-Superlegierungen mit insgesamt optimalen Eigenschaften bezüglich Hochtemperaturfestigkeit, Langzeitstabilität und Duktilität. Dabei stehen Ermüdungsfestigkeit und gutes Thermoschockverhalten im mittleren und hohen Temperaturbereich des Werkstoffs im Vordergrund.The invention relates to the improvement of the mechanical properties of oxide dispersion-hardened nickel-based superalloys with overall optimal properties with regard to high-temperature strength, long-term stability and ductility. Fatigue resistance and good thermal shock behavior in the medium and high temperature range of the material in the foreground.

Im engeren Sinne befasst sich die Erfindung mit einem Verfahren zur Erzeugung grober längsgerichteter Stengelkristalle mit verbesserter Temperaturwechselbeständigkeit und erhöhter Duktilität in Querrichtung in einem Werkstück beliebiger Querschnittsgrösse und Querschnittsform aus einer im Ausgangszustand in feinkörniger warmgekneteten Form vorliegenden oxyddispersionsgehärteten Nickelbasis-Superlegierung durch eine die sekundäre Rekristallisation auslösende Grobkornglühung.In the narrower sense, the invention is concerned with a method for producing coarse longitudinally oriented stem crystals with improved resistance to temperature changes and increased ductility in the transverse direction in a workpiece of any cross-sectional size and cross-sectional shape from an oxide dispersion-hardened nickel-base superalloy present in the initial state in fine-grained, warm-kneaded form by means of a coarse-graining process that triggers secondary recrystallization .

Stand der TechnikState of the art

Hochwarmfeste Schaufelwerkstoffe für Gasturbinen wie oxyddispersionsgehärtete Nickelbasis-Superlegierungen werden im Zustand grober längsgerichteter Stengelkristalle verwendet. Fällt die Längsachse dieser gerichtet angeordneten Kristallite mit der Längsachse des Werkstücks zusammen und ist letztere gleichzeitig die Hauptbeanspruchungsrichtung, so werden in dieser Richtung optimale Resultate bezüglich Kriechfestigkeit und Ermüdungsfestigkeit bei hohen Temperaturen erzielt. Der dafür notwendige Gefügezustand wird dadurch erreicht, dass für die die sekundäre Rekristallisation mit bevorzugter Richtung massgebende Wärmebehandlung ein Zonenglühprozess herangezogen wird. In der Regel wird das Zonenglühen an vergleichsweise beschränkten Querschnittsbemessungen (einige cm²) in klassischer Weise durchgeführt.Highly heat-resistant blade materials for gas turbines, such as oxide dispersion-hardened nickel-based superalloys, are used in the state of coarse longitudinally oriented stem crystals. If the longitudinal axis of these directionally arranged crystallites coincides with the longitudinal axis of the workpiece and the latter is also the main direction of stress, optimal results with regard to creep resistance and fatigue strength at high temperatures are achieved in this direction. The structural condition required for this is achieved by using a zone annealing process for the heat treatment which is decisive for the secondary recrystallization with a preferred direction. As a rule, zone annealing is carried out on comparatively limited cross-sectional dimensions (a few cm²) in a classic manner.

Werden grosse Querschnittsabmessungen (10 cm² und mehr) verlangt, dann ergeben sich Schwierigkeiten. Entweder lässt sich das Zonenglühen überhaupt nicht durchführen, indem die Kernzone nicht in der erwünschten Weise grobkörnig rekristallisiert oder es sind aufwendige und komplizierte Verfahren und Vorrichtungen notwendig, um an das erstrebenswerte Ziel heranzukommen. Zudem lässt die Duktilität in Querrichtung der Stengelkristalle und die Temperaturwechselfestigkeit zu wünschen übrig.Difficulties arise when large cross-sectional dimensions (10 cm² and more) are required. Either zone annealing cannot be carried out at all by not coarse-grained recrystallization of the core zone in the desired manner, or complex and complicated methods and devices are necessary in order to achieve the desired goal. In addition, the ductility in the transverse direction of the stem crystals and the resistance to temperature changes leave something to be desired.

Zum Stand der Technik wird folgende Literatur angegeben:

  • G.H. Gessinger, Powder Metallurgy of Superalloys, Butterworths, London, 1984
  • R.F. Singer and E. Arzt, Conf. Proc. "High Temperature Materials for Gas Turbines", Liège, Belgium, Oktober 1986
  • J.S. Benjamin, Metall. Trans. 1970, 1, 2943 - 2951
  • M.Y. Nazmy and R.F. Singer, Effect of inclusions on tensile ductility of a nickel-base oxide dispersion strengthened superalloy, Scripta Metallurgica, Vol. 19, pp. 829 - 832, 1985, Pergamon Press Ltd.
  • T.K. Glasgow, "Longitudinal Shear Behaviour of Several Oxide Dispersion Strengthened Alloys", NASA TM-78973 (1978)
  • R.L. Cairns, L.R. Curwick and J.S. Benjamin, Grain Growth in Dispersion Strengthened Superalloys by Moving Zone Heat Treatments, Metallurgical Transactions A, Vol. 6A, Janauary 1975, p. 179 - 188.
The following literature on the state of the art is given:
  • GH Gessinger, Powder Metallurgy of Superalloys, Butterworths, London, 1984
  • RF Singer and E. Doctor, Conf. Proc. "High Temperature Materials for Gas Turbines", Liège, Belgium, October 1986
  • JS Benjamin, metal. Trans. 1970, 1, 2943-2951
  • MY Nazmy and RF Singer, Effect of inclusions on tensile ductility of a nickel-base oxide dispersion strengthened superalloy, Scripta Metallurgica, Vol. 19, pp. 829-832, 1985, Pergamon Press Ltd.
  • TK Glasgow, "Longitudinal Shear Behavior of Several Oxide Dispersion Strengthened Alloys", NASA TM-78973 (1978)
  • RL Cairns, LR Curwick and JS Benjamin, Grain Growth in Dispersion Strengthened Superalloys by Moving Zone Heat Treatments, Metallurgical Transactions A, Vol. 6A, Janauary 1975, p. 179-188.

Die bekannten Verfahren zur Erzeugung längsgerichteter Stengelkristalle in oxyddispersionsgehärteten Nickelbasis-Superlegierungen genügen den heutigen Anforderungen nicht mehr. Die nach diesen Verfahren erzielten Ergebnisse reichen für einen optimalen Einsatz dieser Werkstoffe nicht mehr aus. Es existiert daher ein starkes Bedürfnis nach Weiterentwicklung und Verbesserung der Herstellverfahren.The known methods for producing longitudinally oriented stem crystals in oxide-dispersion-hardened nickel-based superalloys do not meet today's requirements more. The results obtained with these processes are no longer sufficient for the optimal use of these materials. There is therefore a strong need for further development and improvement of the manufacturing process.

Ein weiteres Verfahren zur Herstellung eines Werkstücks aus einer im Ausgangszustand in feinkörniger warmgekneteter Form vorliegenden oxiddispersionsgehärteten Nickelbasis-Superlegierung ist in EP 0 115 092 A1 beschrieben. Bei diesem Verfahren wird das Werkstück zunächst in seiner Randzone auf eine Temperatur von ca. 1100°C und im Kern auf eine Temperatur von ca. 900°C aufgeheizt und bei diesen Temperaturen thermisch oder thermomechanisch behandelt. Sodann wird das Werkstück auf Raumtemperatur abgekühlt und isotherm grobkorngeglüht. Beim Grobkornglühen wird der Kern des Werkstückes mit einer Temperatur von 1230 bis 1280°C oberhalb der Rekristallisationstemperatur der Stengelkristalle gehalten. Der Rand des Werkstückes wird hingegen mit einer Temperatur von ca. 1140°C unterhalb der Rekristallisationstemperatur gehalten. Der Kern weist dann grobe längsgerichteter Stengelkristalle auf, wohingegen der Rand feinkörniges Gefüge aufweist.Another method for producing a workpiece from an oxide dispersion-hardened nickel-base superalloy which is present in the initial state in fine-grained hot-kneaded form is described in EP 0 115 092 A1. With this method, the workpiece is first heated in its edge zone to a temperature of approx. 1100 ° C. and in the core to a temperature of approx. 900 ° C. and treated thermally or thermomechanically at these temperatures. The workpiece is then cooled to room temperature and isothermally annealed. In coarse grain annealing, the core of the workpiece is kept at a temperature of 1230 to 1280 ° C above the recrystallization temperature of the stem crystals. The edge of the workpiece, however, is kept at a temperature of approx. 1140 ° C below the recrystallization temperature. The core then has coarse longitudinal stem crystals, whereas the edge has a fine-grained structure.

Darstellung der ErfindungPresentation of the invention

Die Erfindung, wie sie in Patentanspruch 1 angegeben ist, löst die Aufgabe, ein Verfahren zur Herstellung eines Werkstücks aus einer im Ausgangszustand in feinkörniger warmgekneteter Form vorliegenden oxiddispersionsgehärteten Nickelbasis-Superlegierung anzugeben, das unter Vermeidung aufwendiger Verfahrensschritte und der zu ihrer Durchführung notwendigen kostspieligen Vorrichtungen, wie Zonenglühanlagen und Spezialöfen, auf einfache Weise in konventionellen Einrichtungen bewerkstelligt werden kann und zu reproduzierbaren Ergebnissen führt.The invention, as specified in claim 1, achieves the object of specifying a method for producing a workpiece from an oxide dispersion-hardened nickel-base superalloy which is present in the starting state in fine-grained, hot-kneaded form, and which avoids complex process steps and the costly devices necessary for carrying them out, such as zone annealing plants and special ovens, can be easily accomplished in conventional facilities and leads to reproducible results.

Das Verfahren nach der Erfindung zeichnet sich nicht nur durch Wirtschaftlichkeit aus, sondern auch dadurch, dass das danach hergestellte Werkstück gegenüber einem nach dem Stand der Technik hergestellten Werkstück verbesserte Temperaturwechselbeständigkeit und damit erhöhte Duktilität quer zur Längsachse der Stengelkristalle aufweist. Ein weiterer Vorteil des erfindungsgemässen Verfahrens ist darin zu sehen, dass es zur Herstellung von Werkstücken von beliebiger Querschnittsgrösse und Querschnittsform geeignet ist.The method according to the invention is not only characterized by economy, but also by the fact that the workpiece produced thereafter is compared to one according to the prior art Technically manufactured workpiece has improved thermal shock resistance and thus increased ductility transverse to the longitudinal axis of the stem crystals. Another advantage of the method according to the invention is that it is suitable for the production of workpieces of any cross-sectional size and cross-sectional shape.

Weg zur Ausführung der ErfindungWay of carrying out the invention

Die Erfindung wird anhand der durch Figuren näher erläuterten Ausführungsbeispiele beschrieben:The invention is described on the basis of the exemplary embodiments explained in more detail with the figures:

Dabei zeigt:

Fig. 1
ein Fliessbild (Blockdiagramm) des Verfahrens für eine oxyddispersionsgehärtete Nickelbasis-Superlegierung mit 15 % Cr; 4 % W; 2 % Mo; 2,5 % Ti; 4,5 % Al gemäss Beispiel 1,
Fig. 2
ein Fliessbild (Blockdiagramm) des Verfahrens für eine oxyddispersionsgehärtete Nickelbasis-Superlegierung mit 20 % Cr; 3,5 % W; 2 % Mo; 6 % Al gemäss Beispiel 3,
Fig. 3
ein Diagramm des Kornachsenverhältnisses der Stengelkristalle in Funktion der Glühtemperatur für die der isothermen Grobkornglühung vorangehenden Wärmebehandlung für eine oxyddispersionsgehärtete Nickelbasis-Superlegierung mit 15 % Cr; 4 % W; 2 % Mo; 2,5 % Ti; 4,5 % Al,
Fig. 4
ein Diagramm der Zeitstandfestigkeit in Funktion der Zeit für eine isotherm rekristallisierte oxyddispersionsgehärtete Nickelbasis-Superlegierung mit 20 % Cr; 3,5 % W; 2 % Mo; 6 % Al.
It shows:
Fig. 1
a flow diagram (block diagram) of the method for an oxide dispersion hardened nickel-base superalloy with 15% Cr; 4% W; 2% Mo; 2.5% Ti; 4.5% Al according to Example 1,
Fig. 2
a flow diagram (block diagram) of the method for an oxide dispersion hardened nickel-base superalloy with 20% Cr; 3.5% W; 2% Mo; 6% Al according to example 3,
Fig. 3
a diagram of the grain axis ratio of the stem crystals as a function of the annealing temperature for the heat treatment preceding the isothermal coarse grain annealing for an oxide dispersion-hardened nickel-base superalloy with 15% Cr; 4% W; 2% Mo; 2.5% Ti; 4.5% Al,
Fig. 4
a diagram of the creep rupture strength as a function of time for an isothermally recrystallized oxide dispersion hardened nickel-base superalloy with 20% Cr; 3.5% W; 2% Mo; 6% Al.

In Fig. 1 ist ein Fliessbild (Blockdiagramm) des Verfahrens für eine oxyddispersionsgehärtete Nickelbasis-Superlegierung mit der nachfolgenden Zusammensetzung dargestellt:
   Cr = 15 Gew.-%
   W = 4,0 Gew.-%
   Mo = 2,0 Gew.-%
   Al = 4,5 Gew.-%
   Ti = 2,5 Gew.-%
   Ta = 2,0 Gew.-%
   C = 0,05 Gew.-%
   B = 0,01 Gew.-%
   Zr = 0,15 Gew.-%
   Y₂O₃ = 1,1 Gew.-%
   Ni = Rest
   Das Blockdiagramm entspricht den Verfahrensschritten gemäss Ausführungsbeispiel 1. Das Diagramm erklärt sich selbst und bedarf keiner weiteren Erläuterungen.1 shows a flow diagram (block diagram) of the process for an oxide-dispersion-hardened nickel-based superalloy with the following composition:
Cr = 15% by weight
W = 4.0% by weight
Mo = 2.0% by weight
Al = 4.5% by weight
Ti = 2.5% by weight
Ta = 2.0% by weight
C = 0.05% by weight
B = 0.01% by weight
Zr = 0.15% by weight
Y₂O₃ = 1.1% by weight
Ni = rest
The block diagram corresponds to the method steps according to exemplary embodiment 1. The diagram is self-explanatory and requires no further explanation.

Fig. 2 bezieht sich auf ein Fliessbild (Blockdiagramm) des Verfahrens für eine oxyddispersionsgehärtete Nickelbasis-Superlegierung mit der nachfolgenden Zusammensetzung:
   Cr = 20,0 Gew.-%
   Al = 6,0 Gew.-%
   Mo = 2,0 Gew.-%
   W = 3,5 Gew.-%
   Zr = 0,19 Gew.-%
   B = 0,01 Gew.-%
   C = 0,01 Gew.-%
   Y₂O₃ = 1,1 Gew.-%
   Ni = Rest
   Das Blockdiagramm entspricht den Verfahrensschritten gemäss Ausführungsbeispiel 3. Es bedarf keiner weiteren Erklärungen.2 relates to a flow diagram (block diagram) of the method for an oxide dispersion-hardened nickel-based superalloy with the following composition:
Cr = 20.0% by weight
Al = 6.0% by weight
Mo = 2.0% by weight
W = 3.5% by weight
Zr = 0.19% by weight
B = 0.01% by weight
C = 0.01% by weight
Y₂O₃ = 1.1% by weight
Ni = rest
The block diagram corresponds to the method steps according to embodiment 3. No further explanations are required.

Fig. 3 zeigt ein Diagramm des Kornachsenverhältnisses der Stengelkristalle in Funktion der Glühtemperatur für die der isothermen Grobkornglühung vorangehenden Wärmebehandlung für eine oxyddispersionsgehärtete Nickelbasis-Superlegierung mit der nachfolgenden Zusammensetzung:
   Cr = 15 Gew.-%
   W = 4,0 Gew.-%
   Mo = 2,0 Gew.-%
   Al = 4,5 Gew.-%
   Ti = 2,5 Gew.-%
   Ta = 2,0 Gew.-%
   C = 0,05 Gew.-%
   B = 0,01 Gew.-%
   Zr = 0,15 Gew.-%
   Y₂O₃ = 1,1 Gew.-%
   Ni = Rest
   Das isotherme Glühen auf Grobkorn wurde bei einer Temperatur von 1230 °C während 1 1/2 h durchgeführt.Es zeigt sich, dass das Kornachsenverhältnis z/x der längsgerichteten Stengelkristalle, das sich nach der isothermen Grobkornglühung einstellt, stark von der Temperatur der vorangegangenen Glühbehandlung abhängt und vergleichsweise dicht (ca. 15 °C) unterhalb der Lösungsglühungstemperatur Tγ′ für die γ′-Phase in der γ-Matrix ein Maximum durchläuft. Nach Ueberschreiten dieses Maximums fällt die Kurve steil ab, um bei der Temperatur Tγ′ praktisch auf 1 (keine Kornerstreckung mehr!) zurückzugeben.Fig. 3 shows a diagram of the grain axis ratio of the stem crystals as a function of the annealing temperature for the isothermal coarse grain annealing preceding heat treatment for an oxide dispersion hardened nickel-based superalloy with the following composition:
Cr = 15% by weight
W = 4.0% by weight
Mo = 2.0% by weight
Al = 4.5% by weight
Ti = 2.5% by weight
Ta = 2.0% by weight
C = 0.05% by weight
B = 0.01% by weight
Zr = 0.15% by weight
Y₂O₃ = 1.1% by weight
Ni = rest
The isothermal annealing on coarse grains was carried out at a temperature of 1230 ° C for 1 1/2 hours. It can be seen that the grain axis ratio z / x of the longitudinal stem crystals, which occurs after the isothermal coarse grain annealing, strongly depends on the temperature of the previous annealing treatment depends and runs through a maximum comparatively close (approx. 15 ° C) below the solution annealing temperature Tγ 'for the γ'-phase in the γ-matrix. After this maximum has been exceeded, the curve drops steeply in order to return practically to 1 at the temperature T γ (no more grain extension!).

In Fig. 4 ist die Zeitstandfestigkeit in Funktion der Zeit für eine isotherm rekristallisierte oxyddispersionsgehärtete Nickelbasis-Superlegierung mit der nachfolgenden Zusammensetzung dargestellt:
   Cr = 20,0 Gew.-%
   Al = 6,0 Gew.-%
   Mo = 2,0 Gew.-%
   W = 3,5 Gew.-%
   Zr = 0,19 Gew.-%
   B = 0,01 Gew.-%
   C = 0,01 Gew.-%
   Y²O₃ = 1,1 Gew.-%
   Ni = Rest
   Die nach Fig. 2 hergestellten Proben aus diesem Werkstoff zeigten unter einer Zugbelastung bei einer Temperatur von 1050 °C und einer Zugspannung von 100 MPa eine Beanspruchungsdauer von ca. 100 h. Zum Vergleich: Bei zonengeglühtem Material betrug die ertragene Zugspannung für die gleiche Beanspruchungsdauer ca. 106 MPa.4 shows the creep rupture strength as a function of time for an isothermally recrystallized oxide-dispersion-hardened nickel-base superalloy with the following composition:
Cr = 20.0% by weight
Al = 6.0% by weight
Mo = 2.0% by weight
W = 3.5% by weight
Zr = 0.19% by weight
B = 0.01% by weight
C = 0.01% by weight
Y²O₃ = 1.1% by weight
Ni = rest
The samples made from this material according to FIG. 2 showed a stress duration of approx. 100 h under a tensile load at a temperature of 1050 ° C. and a tensile stress of 100 MPa. For comparison: With zone annealed material, the tensile stress withstood for the same stress duration was approx. 106 MPa.

Ausführungsbeispiel 1:Example 1: Siehe Fig. 1!See Fig. 1!

An einer oxyddispersionsgehärteten Nickelbasis-Superlegierung mit der Handelsbezeichnung MA 6000 von INCO wurden Versuche zur Erzielung längsgerichteter Stengelkristalle vorgenommen. Die zuvor aus einer Pulvermischung durch mechanisches Legieren, Verdichten und Warmkneten pulvermetallurgisch hergestellte Legierung hatte die nachfolgende Zusammensetzung:
   Cr = 15 Gew.-%
   W = 4,0 Gew.-%
   Mo = 2,0 Gew.-%
   Al = 4,5 Gew.-%
   Ti = 2,5 Gew.-%
   Ta = 2,0 Gew.-%
   C = 0,05 Gew.-%
   B = 0,01 Gew.-%
   Zr = 0,15 Gew.-%
   Y₂O₃ = 1,1 Gew.-%
   Ni = Rest
   Nach dem Warmkneten lag ein Werkstück in feinkörnigem Zustand vor.Attempts were made to achieve longitudinally oriented stem crystals on an oxide dispersion-hardened nickel-base superalloy with the trade name MA 6000 from INCO. The alloy previously produced from a powder mixture by mechanical alloying, compression and hot kneading using powder metallurgy had the following composition:
Cr = 15% by weight
W = 4.0% by weight
Mo = 2.0% by weight
Al = 4.5% by weight
Ti = 2.5% by weight
Ta = 2.0% by weight
C = 0.05% by weight
B = 0.01% by weight
Zr = 0.15% by weight
Y₂O₃ = 1.1% by weight
Ni = rest
After hot kneading, a workpiece was in a fine-grained state.

Die Abmessungen des Werkstücks waren wie folgt:
   Länge = 160 mm
   Breite = 90 mm
   Dicke = 50 mm
   Das Werkstück wurde nun gemäss Fig. 1 weiterbehandelt. Zu diesem Zweck wurde es in einem Ofen langsam mit einer Aufheizgeschwindigkeit von 5 °C/min auf eine Temperatur von 1130 °C gebracht und bei dieser Temperatur während einer Zeit von 1/4 h belassen. Dann wurde das Werkstück in Luft auf Raumtemperatur abgekühlt. Daraufhin wurde es auf die für die sekundäre Rekristallisation notwendige Temperatur von 1230 °C erwärmt und zwecks Erzeugung eines groben Korns auf dieser Temperatur während 1 1/2 h belassen (isothermes Glühen). Dann wurde das Werkstück mit einer Geschwindigkeit von ca. 5 °C/min auf Raumtemperatur abgekühlt.The dimensions of the workpiece were as follows:
Length = 160 mm
Width = 90 mm
Thickness = 50 mm
The workpiece was then further processed according to FIG. 1. For this purpose, it was slowly brought to a temperature of 1130 ° C. in a furnace at a heating rate of 5 ° C./min and kept at this temperature for a period of 1/4 hour. Then the workpiece was cooled in air to room temperature. It was then heated to the temperature of 1230 ° C. necessary for secondary recrystallization and left at this temperature for 1 1/2 hours in order to produce a coarse grain (isothermal annealing). The workpiece was then cooled to room temperature at a rate of approx. 5 ° C / min.

Aus dem Werkstück wurden Proben herausgeschnitten und einer Prüfung unterzogen. Die metallographische Untersuchung ergab längsgerichtete Stengelkristalle von durchschnittlich 8 mm Länge, 1,5 mm Breite und 0,8 mm Dicke. Das mittlere Kornachsenverhältnis (Kornerstreckungsverhältnis) z/x betrug ca. 8 (siehe Fig. 3!). Die 100 h-Bruchgrenze im Zeitstandversuch bei 1050 °C lag bei ca. 110 MPa, was nahezu 95 % des Wertes einer vergleichsweise kleineren zonengeglühten Vergleichsprobe ausmachte. Es wurden Thermoschockversuche zur Bestimmung der qualitativen Temperaturwechselfestigkeit durchgeführt. Ein Probestab von 100 mm Länge, 50 mm Breite und 25 mm Dicke wurde einem Temperaturzyklus wie folgt unterworfen:

  • Erwärmen von 200 °C auf 1000 °C innerhalb von 2 min
  • Halten bei 1000 °C während 1 min
  • Abkühlen auf 200 °C innerhalb von 1 min
  • Halten bei 200 °C während 1 min
   Nach 2500 Zyklen konnten keinerlei Risse beobachtet werden. Vergleiche mit zonengeglühten Probekörpern gleicher Abmessungen zeigten nach durchschnittlich 500 bis 600 Zyklen in der Längsrichtung der Stengelkristalle verlaufende Haarrisse an der Oberfläche. Die Temperaturwechselfestigkeit, welche indirekt ein Mass für die Duktilität des Werkstoffs quer zur Längsachse der Stengelkristalle darstellt, ist somit für isotherm geglühtes Material ca. 5 Mal höher als für zonengeglühtes Material. Dies ist ein entscheidender Faktor für die Verwendung als Schaufelwerkstoff in hochbeanspruchten Gasturbinen.Samples were cut out of the workpiece and subjected to a test. The metallographic examination revealed longitudinal stem crystals with an average length of 8 mm, a width of 1.5 mm and a thickness of 0.8 mm. The average grain axis ratio (grain extension ratio) z / x was approximately 8 (see FIG. 3!). The 100 h break limit in creep rupture tests at 1050 ° C was approximately 110 MPa, which was almost 95% of the value of a comparatively smaller zone-annealed comparison sample. Thermal shock tests were carried out to determine the qualitative resistance to temperature changes. A test bar 100 mm long, 50 mm wide and 25 mm thick was subjected to a temperature cycle as follows:
  • Warm up from 200 ° C to 1000 ° C within 2 min
  • Hold at 1000 ° C for 1 min
  • Cool to 200 ° C within 1 min
  • Hold at 200 ° C for 1 min
No cracks were observed after 2500 cycles. Comparisons with zone-annealed specimens of the same dimensions showed hair cracks on the surface in the longitudinal direction of the stem crystals after an average of 500 to 600 cycles. The thermal shock resistance, which indirectly represents a measure of the ductility of the material transversely to the longitudinal axis of the stem crystals, is therefore about 5 times higher for isothermally annealed material than for zone-annealed material. This is a crucial factor for use as a blade material in highly stressed gas turbines.

Mit dem Werkstoff MA6000 wurden zusätzliche Versuche durchgeführt, um dem Einfluss der dem isothermen Rekristallisationsglühen vorgeschalteten Wärmebehandlung zu untersuchen. Dabei wurde festgestellt, dass diese Wärmebehandlung einen entscheidenden Einfluss auf die beim nachfolgenden Grobkornglühen (Rekristallisationsglühen) erzielte Gefügeausbildung hat. Sowohl Korngrösse wie Kornform können durch diese Wärmebehandlung entscheidend beeinflusst werden. Eine vergleichsweise niedrige Glühtemperatur und lange Glühdauer (z.B. 950 °C/100 h) führt bei der nachfolgenden Grobkornglühung zu verhältnismässig breiten, groben, jedoch nicht wesentlich gestreckten Körnern (kleines Kornerstreckungsverhältnis). Demgegenüber ergibt eine vergleichsweise hohe Glühtemperatur und kurze Glühdauer (z.B. 1130 °C/15 min) verhältnismässig schmale, grobe längsgestreckte Körner (grosses Kornerstreckungsverhältnis).Additional tests were carried out with the material MA6000 to investigate the influence of the heat treatment prior to the isothermal recrystallization annealing. It was found that this heat treatment has a decisive influence on the microstructure obtained in the subsequent coarse grain annealing (recrystallization annealing). Both grain size and grain shape can be decisively influenced by this heat treatment will. A comparatively low annealing temperature and long annealing time (e.g. 950 ° C / 100 h) leads to relatively broad, coarse, but not significantly elongated grains in the subsequent coarse grain annealing (small grain extension ratio). In contrast, a comparatively high annealing temperature and short annealing time (eg 1130 ° C./15 min) result in relatively narrow, coarse elongated grains (large grain extension ratio).

Einige Versuchsergebnisse sind in Fig. 3 dargestellt. Diese zeigt den Einfluss des Kornachsenverhältnisses (Kornerstreckungsverhältnis) z/x in Funktion der während 1 h gehaltenen Glühtemperatur der der Grobkornglühung vorangehenden Wärmebehandlung. Die nachfolgende isotherme Grobkornglühung (Rekristallisationsglühung) erfolgte bei 1230 °C während 1 1/2 h.Some test results are shown in Fig. 3. This shows the influence of the grain axis ratio (grain extension ratio) z / x as a function of the annealing temperature held for 1 h of the heat treatment preceding the coarse grain annealing. The subsequent isothermal coarse grain annealing (recrystallization annealing) was carried out at 1230 ° C for 1 1/2 hours.

Ausführungsbeispiel 2:Example 2: Siehe Fig. 2!See Fig. 2!

An einer oxyddispersionsgehärteten Nickelbasis-Superlegierung mit der Handelsbezeichnung MA 760 (MA 17) von INCO wurden versuche zur Erzielung längsgerichteter Stengelkristalle vorgenommen. Die Legierung war aus einer Pulvermischung durch mechanisches Legieren, Verdichten und Strangpressen nach herkömmlichen pulvermetallurgischen Methoden hergestellt worden und hatte die nachfolgende Zusammensetzung:
   Cr = 20,0 Gew.-%
   Al = 6,0 Gew.-%
   Mo = 2,0 Gew.-%
   W = 3,5 Gew.-%
   Zr = 0,19 Gew.-%
   B = 0,01 Gew.-%
   C = 0,01 Gew.-%
   Y₂O₃ = 1,1 Gew.-%
   Ni = Rest
   Nach dem Strangpressen lag das Werkstück in feinkörnigem Zustand vor. Seine Abmessungen entsprachen demjenigen von Beispiel 1. Das Werkstück wurde gemäss Fig. 2 weiterbehandelt. Es wurde zunächst in einem Ofen mit einer Aufheizgeschwindigkeit von 3 °C/min auf eine Temperatur von 1150 °C gebracht und auf dieser Temperatur während einer Zeit von 3/4 h gehalten. Dann wurde das Werkstück in Luft auf Raumtemperatur abgekühlt. Daraufhin wurde es auf die für die sekundäre Rekristallisation notwendige Temperatur von 1250 °C erhitzt und zwecks Erzeugung eines langgestreckten Grobkorn auf dieser Temperatur während 1 h gehalten. Nach diesem isothermen Glühen wurde das Werkstück mit einer Geschwindigkeit von ca. 4 °C/min auf Raumtemperatur abgekühlt.Experiments were carried out on an oxide dispersion-hardened nickel-base superalloy with the trade name MA 760 (MA 17) from INCO in order to achieve longitudinally oriented stem crystals. The alloy was produced from a powder mixture by mechanical alloying, compression and extrusion according to conventional powder metallurgical methods and had the following composition:
Cr = 20.0% by weight
Al = 6.0% by weight
Mo = 2.0% by weight
W = 3.5% by weight
Zr = 0.19% by weight
B = 0.01% by weight
C = 0.01% by weight
Y₂O₃ = 1.1% by weight
Ni = rest
After extrusion, the workpiece was in a fine-grained state. Its dimensions corresponded to those of Example 1. The workpiece was further processed according to FIG. 2. It was first brought to a temperature of 1150 ° C. in a furnace at a heating rate of 3 ° C./min and was kept at this temperature for a period of 3/4 h. Then the workpiece was cooled in air to room temperature. It was then heated to the temperature of 1250 ° C. required for secondary recrystallization and kept at this temperature for 1 h in order to produce an elongated coarse grain. After this isothermal annealing, the workpiece was cooled to room temperature at a rate of approx. 4 ° C./min.

Die aus dem Werkstück herausgearbeiteten Proben zeigten längsgerichtete Stengelkristalle von 7 mm mittlerer Länge, 1,6 mm mittlere Breite und 0,9 mm mittlerer Dicke. Das durchschnittliche Kornachsenverhältnis (Kornerstreckungsverhältnis) z/x betrug ca. 7. Die 100 h-Bruchgrenze im Zeitstandversuch bei 1050 °C lag bei ca. 105 MPa. Die Ergebnisse der Zeitstandversuche sind in Fig. 4 dargestellt. Zum Vergleich erreichte die entsprechende zonengeglühte Probe einen entsprechenden Wert von 110 MPa. Thermoschockversuche zeigten nach 3000 Zyklen gemäss Programm in Beispiel 1 noch keine Anrisse, während in zonengeglühten Vergleichsproben bereits nach etwas über 400 Zyklen Haarrisse an der Oberfläche festgestellt werden konnten.The samples worked out from the workpiece showed longitudinal stem crystals of 7 mm medium length, 1.6 mm medium width and 0.9 mm medium thickness. The average grain axis ratio (grain extension ratio) z / x was approx. 7. The 100 h breaking limit in the creep rupture test at 1050 ° C. was approx. 105 MPa. The results of the creep tests are shown in FIG. 4. For comparison, the corresponding zone-annealed sample reached a corresponding value of 110 MPa. Thermal shock tests did not show any cracks after 3000 cycles according to the program in Example 1, while in zone-annealed comparative samples after just over 400 Cycles hairline cracks could be found on the surface.

Ausführungsbeispiel 3:Example 3:

Es wurde eine oxyddispersionsgehärtete Nickelbasis-Superlegierung einer Wärmebehandlung und einer Grobkornglühung in ähnlicher Weise wie unter Beispiel 2 (vgl. Fig. 2) unterzogen. Die pulvermetallurgisch durch mechanisches Legieren, Verdichten und Strangpressen hergestellte Legierung hatte die nachfolgende Zusammensetzung:
   Cr = 17,0 Gew.-%
   Al = 6,0 Gew.-%
   Mo = 2,0 Gew.-%
   W = 3,5 Gew.-%
   Ta = 2,0 Gew.-%
   Zr = 0,15 Gew.-%
   B = 0,01 Gew.-%
   C = 0,05 Gew.-%
   Y₂O₃ = 1,1 Gew.-%
   Ni = Rest
   Nach dem Strangpressen lag das Werkstück in feinkörniger Struktur vor. Die Abmessungen entsprachen denjenigen von Beispiel 1. Das Werkstück wurde ähnlich Fig. 2 behandelt. Zunächst wurde es in einen Ofen eingesetzt und mit einer Aufheizgeschwindigkeit von 5 °C/min auf eine Temperatur von 1130 °C erhitzt und auf dieser Temperatur während einer Zeit von 1 1/2 h gehalten. Dann wurde das Werkstück in Luft auf Raumtemperatur abgekühlt. Zwecks sekundärer Rekristallisation wurde es langsam auf eine Temperatur von 1270 °C erhitzt und zur Erzeugung eines langgestreckten Grobkorns während 1/2 h auf dieser Temperatur gehalten.An oxide dispersion hardened nickel-base superalloy was subjected to heat treatment and coarse grain annealing in a manner similar to that of Example 2 (see FIG. 2). The alloy produced by powder metallurgy by mechanical alloying, compression and extrusion had the following composition:
Cr = 17.0% by weight
Al = 6.0% by weight
Mo = 2.0% by weight
W = 3.5% by weight
Ta = 2.0% by weight
Zr = 0.15% by weight
B = 0.01% by weight
C = 0.05% by weight
Y₂O₃ = 1.1% by weight
Ni = rest
After extrusion, the workpiece was in a fine-grained structure. The dimensions corresponded to those of Example 1. The workpiece was treated similarly to FIG. 2. First, it was placed in an oven and heated at a heating rate of 5 ° C / min to a temperature of 1130 ° C and held at this temperature for a period of 1 1/2 hours. Then the workpiece was cooled in air to room temperature. For secondary recrystallization, it was slowly heated to a temperature of 1270 ° C. and held at this temperature for 1/2 hour to produce an elongated coarse grain.

Nach diesem isothermen Glühen wurde das Werkstück mit einer Geschwindigkeit von ca. 3 °C/min auf Raumtemperatur abgekühlt.After this isothermal annealing, the workpiece was cooled to room temperature at a rate of approx. 3 ° C./min.

Um die Duktilität in der Querrichtung zu erhöhen, wurde das Werkstück einer weiteren Wärmebehandlung unterworfen. Zu diesem Zweck wurde das Werkstück innerhalb von 2 h auf eine oberhalb er minimalen Lösungsglühtemperatur für die γ′-Phase gelegenen Temperatur von 1220 °C gebracht, 1 h gehalten und dann mit einer Abkühlungsgeschwindigkeit von ca. 1 °C/min auf eine Temperatur von 600 °C abgekühlt. Die weitere Abkühlung erfolgte in Luft bis auf Raumtemperatur herunter.In order to increase the ductility in the transverse direction, the workpiece was subjected to a further heat treatment. For this purpose, the workpiece was brought to a temperature above the minimum solution annealing temperature for the γ′-phase of 1220 ° C. within 2 hours, held for 1 hour and then at a cooling rate of approx. 1 ° C./min to a temperature of Cooled down to 600 ° C. The further cooling took place in air down to room temperature.

Die Proben zeigten längsgerichtete Stengelkristalle von durchschnittlich 15 mm Länge, 1,5 mm Breite und 0,9 mm Dicke. Das mittlere Kornachsenverhältnis z/x betrug ca. 14. Im Zeitstandversuch wurde bei einer Temperatur von 1050 °C eine 100 h-Bruchgrenze von ca. 100 MPa gemessen. Die vergleichbare zonengeglühte Probe lage nur wenige Prozente über diesem Wert. Die Temperaturwechselfestigkeit war gut. Nach Programm gemäss Beispiel 1 wurden 2000 Zyklen ohne Anrisse erreicht, während die zonengeglühten Vergleichsproben bei ca. 400 Zyklen Haarrisse zeigten.The samples showed longitudinal stem crystals with an average length of 15 mm, 1.5 mm width and 0.9 mm thickness. The average grain axis ratio z / x was approx. 14. In the creep rupture test, a 100 h breaking limit of approx. 100 MPa was measured at a temperature of 1050 ° C. The comparable zone annealed sample was only a few percent above this value. The temperature change resistance was good. According to the program according to Example 1, 2000 cycles without cracks were achieved, while the zone-annealed comparison samples showed hairline cracks at approximately 400 cycles.

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

Das Verfahren zur Erzeugung grober längsgerichteter Stengelkristalle mit verbesserter Temperaturwechselbeständigkeit und erhöhter Duktilität in Querrichtung in einem Werkstück beliebiger Querschnittsgrösse und Querschnittsform aus einer im Ausgangszustand in feinkörniger warmgekneteten Form vorliegenden oxyddispersionsgehärteten Nickelbasis-Superlegierung durch eine die sekundäre Rekristallisation auslösende Grobkornglühung wird durchgeführt, indem das Werkstück nach erfolgter Erwärmung zunächst im Temperaturbereich zwischen 1000 °C und 1200°C während 1/4 h bis 10 h geglüht, abgekühlt und während 1/4 bis 5 h im Temperaturbereich zwischen 1230 °C und 1280 °C isotherm auf Grobkorn geglüht und abgekühlt wird. Vorzugsweise wird das Werkstück zusätzlich einer Duktilisierungs-Wärmebehandlung unterzogen, indem es bis auf die γ′-Lösungsglühtemperatur erhitzt, auf dieser Temperatur wenigstens während 1/2 h gehalten und dann auf Raumtemperatur abgekühlt wird.The process for producing coarse longitudinally oriented stem crystals with improved resistance to temperature changes and increased ductility in the transverse direction in a workpiece of any cross-sectional size and cross-sectional shape from a fine-grained one in the initial state The hot-kneaded form of oxide dispersion-hardened nickel-based superalloy is carried out by coarse-grain annealing, which triggers the secondary recrystallization. After heating, the workpiece is first annealed in the temperature range between 1000 ° C and 1200 ° C for 1/4 to 10 hours, cooled and 1/4 up to 5 h in the temperature range between 1230 ° C and 1280 ° C isothermally annealed on coarse grain and cooled. The workpiece is preferably additionally subjected to a ductile heat treatment by heating it to the γ′-solution annealing temperature, maintaining it at least for 1/2 hour and then cooling it to room temperature.

Das Verfahren bezieht sich insbesondere auf eine dispersionsgehärtete Nickelbasis-Superlegierung mit der nachfolgenden Zusammensetzung:
   Cr = 15 Gew.-%
   W = 4,0 Gew.-%
   Mo = 2,0 Gew.-%
   Al = 4,5 Gew.-%
   Ti = 2,5 Gew.-%
   Ta = 2,0 Gew.-%
   C = 0,05 Gew.-%
   B = 0,01 Gew.-%
   Zr = 0,15 Gew.-%
   Y₂O₃ = 1,1 Gew.-%
   Ni = Rest,
wobei das Werkstück zunächst während 1/4 h bei einer Temperatur von 1130 °C geglüht, an Luft abgekühlt und dann während 1 1/2 h bei 1230 °C auf Grobkorn geglüht und mit einer Geschwindigkeit von höchstens 5 °C/min abgekühlt wird. Ausserdem bezieht sich das Verfahren auf eine dispersionsgehärtete Nickelbasis-Superlegierung mit der obigen Zusammensetzung, wobei das Werkstück zunächst während 2 h bei einer Temperatur von 1080 °C geglüht, an Luft abgekühlt und dann während 1 1/2 h bei 1230 °C auf Grobkorn geglüht und mit einer Geschwindigkeit von höchstens 5 °C/min abgekühlt wird. Das Verfahren gilt ferner für eine dispersionsgehärtete Nickelbasis-Superlegierung mit der nachfolgenden Zusammensetzung:
   Cr = 20,0 Gew.-%
   Al = 6,0 Gew.-%
   Mo = 2,0 Gew.-%
   W = 3,5 Gew.-%
   Zr = 0,19 Gew.-%
   B = 0,01 Gew.-%
   C = 0,01 Gew.-%
   Y₂O₃ = 1,1 Gew.-%
   Ni = Rest,
wobei das Werkstück zunächst während 3/4 h bei einer Temperatur von 1150 °C geglüht, an Luft abgekühlt und dann während 1 h bei 1250 °C auf Grobkorn geglüht und mit einer Geschwindigkeit von höchstens 5 °C/min abgekühlt wird. Ebenfalls gilt das Verfahren für eine dispersionsgehärtete Nickelbasis-Superlegierung mit der nachfolgenden Zusammensetzung:
   Cr = 17,0 Gew.-%
   Al = 6,0 Gew.-%
   Mo = 2,0 Gew.-%
   W = 3,5 Gew.-%
   Ta = 2,0 Gew.-%
   Zr = 0,15 Gew.-%
   B = 0,01 Gew.-%
   C = 0,05 Gew.-%
   Y²O₃ = 1,1 Gew.-%
   Ni = Rest,
wobei das Werkstück zunächst während 1 1/2 h bei einer Temperatur von 1130 °C geglüht, an Luft abgekühlt und dann während 1/2 h bei 1270 °C auf Grobkorn geglüht und mit einer Geschwindigkeit von höchstens 5 °C/min abgekühlt wird.The method relates in particular to a dispersion-hardened nickel-based superalloy with the following composition:
Cr = 15% by weight
W = 4.0% by weight
Mo = 2.0% by weight
Al = 4.5% by weight
Ti = 2.5% by weight
Ta = 2.0% by weight
C = 0.05% by weight
B = 0.01% by weight
Zr = 0.15% by weight
Y₂O₃ = 1.1% by weight
Ni = rest,
the workpiece being initially annealed at a temperature of 1130 ° C. for 1/4 h, cooled in air and then annealed to coarse grain at 1230 ° C. for 1 1/2 h and with is cooled at a maximum speed of 5 ° C / min. In addition, the process relates to a dispersion-hardened nickel-based superalloy with the above composition, the workpiece first being annealed at a temperature of 1080 ° C. for 2 hours, cooled in air and then annealed to coarse grains at 1230 ° C. for 1 1/2 hours and is cooled at a rate of at most 5 ° C / min. The method also applies to a dispersion-hardened nickel-based superalloy with the following composition:
Cr = 20.0% by weight
Al = 6.0% by weight
Mo = 2.0% by weight
W = 3.5% by weight
Zr = 0.19% by weight
B = 0.01% by weight
C = 0.01% by weight
Y₂O₃ = 1.1% by weight
Ni = rest,
wherein the workpiece is first annealed at a temperature of 1150 ° C for 3/4 h, cooled in air and then annealed to coarse grain at 1250 ° C for 1 h and cooled at a maximum speed of 5 ° C / min. The procedure also applies to a dispersion-hardened nickel-based superalloy with the following composition:
Cr = 17.0% by weight
Al = 6.0% by weight
Mo = 2.0% by weight
W = 3.5% by weight
Ta = 2.0% by weight
Zr = 0.15% by weight
B = 0.01% by weight
C = 0.05% by weight
Y²O₃ = 1.1% by weight
Ni = rest,
wherein the workpiece is first annealed at a temperature of 1130 ° C for 1 1/2 h, cooled in air and then annealed to coarse grain at 1270 ° C for 1/2 h and cooled at a maximum rate of 5 ° C / min.

Claims (6)

  1. Process for producing a workpiece from an oxide-dispersion-strengthened nickel-base superalloy which exists in the initial condition in fine-grained hot-worked form, in which, to produce coarse, longitudinally directed column crystals, the workpiece is annealed for coarse grain for ¼ to 5 h in a temperature range between 1230°C and 1280°C and then cooled to room temperature, characterized in that, to modify the microstructure formation produced during the coarse-grain annealing, the workpiece, which exists in fine-grained hot-worked form, is first heated, before the coarse-grain annealing, to a temperature between 1000°C and 1200°C, preannealed in this temperature range for ¼ to 10 h and then cooled to room temperature, and in that the preannealed workpiece is then isothermally annealed for coarse grain to produce the column crystals.
  2. Process according to Claim 1, characterized in that the workpiece is additionally subjected to a ductilization heat treatment by heating it to the γ' solution annealing temperature, holding it at this temperature at least for ½ h and then cooling it to room temperature.
  3. Process according to Claim 1, characterized in that the dispersion-strengthened nickel-base superalloy has the following composition
       Cr = 15 % by wt.
       W = 4.0 % by wt.
       Mo = 2.0 % by wt.
       Al = 4.5 % by wt.
       Ti = 2.5 % by wt.
       Ta = 2.0 % by wt.
       C = 0.05 % by wt.
       B = 0.01 % by wt.
       Zr = 0.15 % by wt.
       Y₂O₃ = 1.1 % by wt.
       Ni = remainder
    and in that the workpiece is first annealed for ¼ h at a temperature of 1130°C, cooled in air and then annealed for 1½ h at 1230°C for coarse grain and cooled at a rate of not more than 5°C/min.
  4. Process according to Claim 1, characterized in that the dispersion-strengthened nickel-base superalloy has the following composition
       Cr = 15 % by wt.
       W = 4.0 % by wt.
       Mo = 2.0 % by wt.
       Al = 4.5 % by wt.
       Ti = 2.5 % by wt.
       Ta = 2.0 % by wt.
       C = 0.05 % by wt.
       B = 0.01 % by wt.
       Zr = 0.15 % by wt.
       Y₂O₃ = 1.1 % by wt.
       Ni = remainder
    and in that the workpiece is first annealed for 2 h at a temperature of 1080°C, cooled in air and then annealed for 1½ h at 1230°C for coarse grain and cooled at a rate of not more than 5°C/min.
  5. Process according to Claim 1, characterized in that the dispersion-strengthened nickel-base superalloy has the following composition
       Cr = 20.0 % by wt.
       Al = 6.0 % by wt.
       Mo = 2.0 % by wt.
       W = 3.5 % by wt.
       Zr = 0.19 % by wt.
       B = 0.01 % by wt.
       C = 0.01 % by wt.
       Y₂O₃ = 1.1 % by wt.
       Ni = remainder
    and in that the workpiece is first annealed for 3/4 h at a temperature of 1150°C, cooled in air and then annealed for 1 h at 1250°C for coarse grain and cooled at a rate of not more than 5°C/min.
  6. Process according to Claim 1, characterized in that the dispersion-strengthened nickel-base superalloy has the following composition:    Cr = 17.0 % by wt.
       Al = 6.0 % by wt.
       Mo = 2.0 % by wt.
       W = 3.5 % by wt.
       Ta = 2.0 % by wt.
       Zr = 0.15 % by wt.
       B = 0.01 % by wt.
       C = 0.05 % by wt.
       Y₂O₃ = 1.1 % by wt.
       Ni = remainder
    and in that the workpiece is first annealed for 1½ h at a temperature of 1130°C, cooled in air and then annealed for ½ h at 1270°C for coarse grain and cooled at a rate of not more than 5°C/min.
EP90108578A 1989-05-16 1990-05-07 Process for producing coarse columnar grains directionally oriented along their length in an oxide dispersion hardened nickel base superalloy Expired - Lifetime EP0398121B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CH181989 1989-05-16
CH1819/89 1989-05-16

Publications (2)

Publication Number Publication Date
EP0398121A1 EP0398121A1 (en) 1990-11-22
EP0398121B1 true EP0398121B1 (en) 1994-11-23

Family

ID=4219340

Family Applications (1)

Application Number Title Priority Date Filing Date
EP90108578A Expired - Lifetime EP0398121B1 (en) 1989-05-16 1990-05-07 Process for producing coarse columnar grains directionally oriented along their length in an oxide dispersion hardened nickel base superalloy

Country Status (4)

Country Link
US (1) US5067986A (en)
EP (1) EP0398121B1 (en)
JP (1) JPH03115548A (en)
DE (1) DE59007734D1 (en)

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4037827A1 (en) * 1990-02-14 1992-06-04 Metallgesellschaft Ag METHOD FOR PRODUCING HEAT-TREATED PROFILES
DE59105546D1 (en) * 1990-03-20 1995-06-29 Asea Brown Boveri Process for the production of longitudinally coarse-grained stem crystals in a workpiece consisting of an oxide dispersion hardened nickel-based superalloy.
DE4110543A1 (en) * 1991-03-30 1992-10-01 Pm Hochtemperatur Metall Gmbh OXIDE DISPERSION HARDENED ELIGIBLE CHROME CHROME ALLOY
DE69327826T2 (en) * 1992-04-17 2000-10-12 Owens Corning, Toledo DISPERSION Tempered Alloys
AT902U1 (en) * 1995-08-28 1996-07-25 Plansee Ag METHOD FOR PRODUCING SEAMLESS TUBES
US10661370B2 (en) 2015-09-21 2020-05-26 Siemens Energy, Inc. Formation and repair of oxide dispersion strengthened alloys by alloy melting with oxide injection

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA705385A (en) * 1965-03-09 R. Bird Jack Method of heat treating alloys
US3067030A (en) * 1958-08-13 1962-12-04 Dunn Eugene Ludwick Nickel base alloy
EP0045984B1 (en) * 1980-08-08 1984-03-14 BBC Aktiengesellschaft Brown, Boveri & Cie. Process for manufacturing an article from a heat-resisting alloy
EP0115092B1 (en) * 1983-02-01 1987-08-12 BBC Brown Boveri AG Structural element with a high corrosion and oxidation resistance made from a dispersion-hardened superalloy, and process for its manufacture
US4497669A (en) * 1983-07-22 1985-02-05 Inco Alloys International, Inc. Process for making alloys having coarse, elongated grain structure
DE3665030D1 (en) * 1985-06-11 1989-09-21 Bbc Brown Boveri & Cie Process for joining dispersion-hardened superalloy building elements by way of the press-bonding method
EP0260465B1 (en) * 1986-09-08 1992-01-02 BBC Brown Boveri AG Oxide dispersion-strengthened nickel-base superalloy with improved corrosion resistance
CH671583A5 (en) * 1986-12-19 1989-09-15 Bbc Brown Boveri & Cie

Also Published As

Publication number Publication date
DE59007734D1 (en) 1995-01-05
JPH03115548A (en) 1991-05-16
EP0398121A1 (en) 1990-11-22
US5067986A (en) 1991-11-26

Similar Documents

Publication Publication Date Title
DE69203791T2 (en) Method for producing a workpiece from a titanium alloy with a modified hot processing stage and manufactured workpiece.
EP2386663B1 (en) Method for producing a component and component from a gamma-titanium-aluminium base alloy
DE3023576C2 (en)
DE69017574T2 (en) High strength fatigue crack resistant alloy workpiece.
DE68915095T2 (en) Nickel-based alloy and process for its manufacture.
DE69017339T2 (en) Alloys resistant to creep, breaking load and fatigue cracking.
EP0513407B1 (en) Method of manufacture of a turbine blade
DE69707027T2 (en) Regulation of the grain size of nickel-based superalloys
DE102015103422B3 (en) Process for producing a heavy-duty component of an alpha + gamma titanium aluminide alloy for piston engines and gas turbines, in particular aircraft engines
DE2264997C2 (en) Precipitation hardenable iron-nickel alloy
DE69805148T2 (en) Titanium-based intermetallic alloys of the Ti2AlNb type with high yield strength and good creep resistance
AT393842B (en) METHOD FOR FORGING NICKEL-BASED SUPER ALLOYS AND AN OBJECT FROM A NICKEL-BASED SUPER ALLOY WITH IMPROVED LUBRICABILITY
DE3445768C2 (en)
DE69903224T2 (en) Monocrystalline nickel-based superalloy with a high gamma prime phase
DE68916414T2 (en) Titanium aluminide alloys.
DE3926289A1 (en) OBJECT OF A NICKEL BASE ALLOY, ALLOY AND METHOD FOR PRODUCING THEM RESISTING TO GROWTH OF FATIGUE CRACKS
CH637165A5 (en) NICKEL-BASED SINGLE CRYSTAL ALLOY OBJECT AND METHOD FOR THE PRODUCTION THEREOF.
DE69319530T2 (en) TiAl based intermetallic compound
DE69922332T2 (en) Thermomechanical process for the production of superalloys with high strength and high thermal stability
CH703386A1 (en) A process for the preparation of a composed of a nickel-base superalloy monocrystalline component.
DE60008116T2 (en) Superalloy with optimized high-temperature performance in high-pressure turbine disks
DE19756354B4 (en) Shovel and method of making the blade
DE2219275C3 (en) Process for producing a columnar crystal structure and device for carrying out the process
EP0274631B1 (en) Process for increasing the room temperature ductility of an oxide dispersion hardened nickel base superalloy article having a coarse columnar grain structure directionally oriented along the length
EP0398121B1 (en) Process for producing coarse columnar grains directionally oriented along their length in an oxide dispersion hardened nickel base superalloy

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): CH DE FR GB LI SE

17P Request for examination filed

Effective date: 19910521

17Q First examination report despatched

Effective date: 19930713

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): CH DE FR GB LI SE

REF Corresponds to:

Ref document number: 59007734

Country of ref document: DE

Date of ref document: 19950105

GBT Gb: translation of ep patent filed (gb section 77(6)(a)/1977)

Effective date: 19950130

ET Fr: translation filed
PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed
PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: GB

Payment date: 19960415

Year of fee payment: 7

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 19960419

Year of fee payment: 7

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: SE

Payment date: 19960425

Year of fee payment: 7

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 19960518

Year of fee payment: 7

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: CH

Payment date: 19960604

Year of fee payment: 7

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Effective date: 19970507

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: SE

Effective date: 19970508

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: LI

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 19970531

Ref country code: CH

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 19970531

GBPC Gb: european patent ceased through non-payment of renewal fee

Effective date: 19970507

REG Reference to a national code

Ref country code: CH

Ref legal event code: PL

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: FR

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 19980130

EUG Se: european patent has lapsed

Ref document number: 90108578.7

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 19980203

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST