HEAT TREATMENT PROCESS FOR COMPONENTS COMPOSED OF NICKEL-BASED SUPERALLOYS

Abstract

Disclosed is process for producing a component of a nickel-based superalloy in which a semifinished part of the component is subjected to a solution heat treatment at a temperature from 1300° C. to 1350° C. and a precipitation heat treatment at a temperature range from 900° C. to 1150° C. The solution heat treatment and/or the precipitation heat treatment are carried out together with further processing of the semifinished part. Also disclosed is a process for treating a component of a nickel-based superalloy after use for some hundreds of hours at a use temperature of more than 500° C. by carrying out a reconditioning heat treatment in the temperature range from 1100° C. to 1280° C.

Claims

1. A process for producing a component of a nickel-based superalloy, wherein the process comprises subjecting a semifinished part of the component to a solution heat treatment at a temperature of from about 1300° C. to about 1375° C. and a precipitation heat treatment at a temperature of from about 900° C. to about 1150° C., the solution heat treatment and/or the precipitation heat treatment being carried out together with further processing of the semifinished part.

2. The process of claim 1, wherein the solution heat treatment is carried out at least partly simultaneously with hot isostatic pressing of the semifinished part.

3. The process of claim 1, wherein the precipitation heat treatment is carried out at least partly simultaneously with coating of the semifinished part.

4. The process of claim 3, wherein Al-containing layers are deposited at least partly during the precipitation heat treatment.

5. The process of claim 3, wherein the coating operation during the precipitation heat treatment is carried out by chemical or physical vapor deposition or by spraying.

6. The process of claim 1, wherein the solution heat treatment is carried out at one or more hold temperatures, where the one or last hold temperature ranges from about 1310° C. to about 1375° C. and is maintained for up to about 15 hours.

7. The process of claim 1, wherein the solution heat treatment is ended with cooling at a cooling rate of at least about 200 K/min.

8. The process of claim 1, wherein the precipitation heat treatment is carried out in a single stage.

9. The process of claim 1, wherein the precipitation heat treatment is carried out for at least about five hours.

10. The process of claim 9, wherein the precipitation heat treatment is carried out at a temperature from about 1000° C. to about 1100° C.

11. The process of claim 1, wherein an alloy having a composition comprising, in percent by weight, from about 3.7% to about 7.0% of Al from about 6% to about 20% of Co from about 2.1% to about 7.2% of Cr from about 1.0% to about 3.0% of Mo from about 5.0% to about 9.2% of Re from about 3.0% to about 8.5% of Ru from about 4.1% to about 11.9% of Ta from 0% to about 3.3% of Ti from about 2.1% to about 4.9% of W from 0% to about 0.05% of C from 0% to about 0.1% of Si from 0% to about 0.05% of Mn from 0% to about 0.015% of P from 0% to about 0.001% of S from 0% to about 0.003% of B from 0% to about 0.05% of Cu from 0% to about 0.15% of Fe from 0% to about 0.5% of Hf from 0% to about 0.015% of Zr from 0% to about 0.001% of Y and nickel and unavoidable impurities as balance, is used as nickel-based superalloy.

12. A process for conditioning a component of a nickel-based superalloy after use for some hundreds of hours at a use temperature of more than about 500° C., wherein the process comprises carrying out a reconditioning heat treatment at a temperature of from about 1080° C. to about 1280° C.

13. The process of claim 12, wherein the reconditioning heat treatment is carried out at a temperature of from about 1125° C. to about 1275° C. and/or for at least about 10 hours.

14. The process of claim 12, wherein a precipitation heat treatment at a temperature of from about 900° C. to about 1150° C. together with or without a coating operation is carried out subsequent to the reconditioning heat treatment.

15. The process of claim 14, wherein Al-containing layers are deposited at least partly during the precipitation heat treatment and/or wherein the coating operation during the precipitation heat treatment is carried out by chemical or physical vapor deposition or by spraying.

16. The process of claim 14, wherein the precipitation heat treatment is carried out in a single stage.

17. The process of claim 14, wherein the precipitation heat treatment is carried out for at least about five hours.

18. The process of claim 17, wherein the precipitation heat treatment is carried out at a temperature of from about 1000° C. to about 1100° C.

19. The process of claim 14, wherein prior to the reconditioning heat treatment a stress-relieving heat treatment is carried out at a temperature of from about 850° C. to about 1100° C. for from about one to about five hours.

20. The process of claim 14, wherein an alloy having a composition comprising, in percent by weight, from about 3.7% to about 7.0% of Al from about 6% to about 20% of Co from about 2.1% to about 7.2% of Cr from about 1.0% to about 3.0% of Mo from about 5.0% to about 9.2% of Re from about 3.0% to about 8.5% of Ru from about 4.1% to about 11.9% of Ta from 0% to about 3.3% of Ti from about 2.1% to about 4.9% of W from 0% to about 0.05% of C from 0% to about 0.1% of Si from 0% to about 0.05% of Mn from 0% to about 0.015% of P from 0% to about 0.001% of S from 0% to about 0.003% of B from 0% to about 0.05% of Cu from 0% to about 0.15% of Fe from 0% to about 0.5% of Hf from 0% to about 0.015% of Zr from 0% to about 0.001% of Y and nickel and unavoidable impurities as balance, is used as nickel-based superalloy.

Description

DETAILED DESCRIPTION OF EMBODIMENT OF THE INVENTION

[0109] The particulars shown herein are by way of example and for purposes of illustrative discussion of the embodiments of the present invention only and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the present invention. In this regard, no attempt is made to show details of the present invention in more detail than is necessary for the fundamental understanding of the present invention, the description making apparent to those of skill in the art how the several forms of the present invention may be embodied in practice.

[0110] A rotor blade or guide blade of a low-pressure turbine of an aircraft engine is cast from a nickel-based superalloy TMS-238 and subsequently heated in an HIP furnace, i.e. a heating apparatus which simultaneously allows hot isostatic pressing, to a temperature of 1300° C., then held for ten minutes, subsequently heated to 1310° C. and held there for one hour. Heating to 1335° C. is then carried out and this temperature is held for three hours. To conclude the solution heat treatment, the semifinished part is hot isostatically pressed at 1345° C. for 20 hours and subsequently cooled at a cooling rate of 400 K/min to a temperature below 400° C., preferably room temperature.

[0111] After removal from the HIP furnace, the semifinished part is provided with an AlCr coating by vapor deposition of aluminum and chromium in a coating apparatus, for example a PVD coating chamber, with a diffusion heat treatment, which is at the same time also a precipitation heat treatment, being carried out at a temperature in the range from 1000° C. to 1100° C., for example 1050° C., for from 8 to 24 hours, e.g. 20 hours, in order to finish the coating. After cooling to room temperature, the heat treatment with the solution heat treatment and the precipitation heat treatment is concluded and the component according to the invention is finished. The corresponding rotor blade or guide blade can then be used in a low-pressure turbine of an aircraft engine for several hundred or thousand hours.

[0112] To ensure that no brittle TCP phases are present in the rotor blade or guide blade after operation of the low-pressure turbine over a prolonged period of more than 100 hours, the guide blade or rotor blade concerned is subjected to a reconditioning heat treatment which is carried out at a temperature in the range from 1100° C. to 1200° C., for example 1150° C., for from 10 to 40 hours, e.g. 30 hours, during overhauling of the low-pressure turbine. Since possible TCP phases dissolve at this temperature of the reconditioning heat treatment, it is ensured that there are no longer any brittle phases in the component after a heat treatment but instead that the component can be used again reliably. At the same time, the heat treatment below the temperature for dissolution of the γ′ precipitate phases ensures that the strength of the component is not impaired.

[0113] Although the present invention has been described in detail with the aid of the working examples, the invention is not restricted to these working examples but instead modifications in which individual features can be altered within the indicated scope of protection of the accompanying claims are possible. The disclosure encompasses all combinations of the individual features presented.