DE-112017005115-B4 - Method for manufacturing a turbine blade

Abstract

Method for manufacturing a turbine blade, the method comprising: a brazing treatment for joining a brazing material to a substrate of a turbine blade by heating the substrate with the brazing material placed on it and melting the brazing material after the substrate has been subjected to a solution annealing treatment at a temperature above the solidus temperature of the brazing material; a stabilization treatment for heating the substrate material undergoing brazing; and an aging treatment to heat the substrate material undergoing stabilization treatment at a temperature below the solidus temperature of the brazing material, where the brazing treatment and the stabilization treatment are carried out by means of a sequential heat treatment.

Inventors

• Daisuke Yoshida
• Masaki Taneike
• Yoshiyuki Inoue
• Hisataka Kawai
• Hisashi KITAGAKI

Assignees

• MITSUBISHI HEAVY INDUSTRIES, LTD.

Dates

Publication Date

20260513

Application Date

20171005

Priority Date

20161007

Claims (10)

1. A method for manufacturing a turbine blade, comprising: a brazing treatment for joining a brazing material to a substrate of a turbine blade by heating the substrate with the brazing material placed thereon and melting the brazing material after the substrate has been subjected to a solution annealing treatment at a temperature above the solidus temperature of the brazing material; a stabilization treatment for heating the substrate subjected to the brazing treatment rials; and an aging treatment for heating the support material undergoing the stabilization treatment at a temperature below the solidus temperature of the brazing material, wherein the brazing treatment and the stabilization treatment are carried out by means of a sequential heat treatment.
2. Method for manufacturing a turbine blade according to Claim 1 , wherein the brazing treatment and the stabilization treatment are carried out at a first temperature above the liquidus temperature of the brazing material, at which a γ' phase precipitated in the support material is enlarged.
3. Method for manufacturing a turbine blade according to Claim 1 or 2 , whereby the brazing treatment, the stabilization treatment and the aging treatment are carried out sequentially.
4. Method for manufacturing a turbine blade according to Claim 1 or 2 , furthermore comprising an adjustment treatment to adjust a heating temperature for the aging treatment to a second temperature after the brazing treatment and the stabilization treatment have been carried out at the first temperature.
5. Method for manufacturing a turbine blade according to Claim 4 , where the second temperature is lower than the first temperature.
6. Method for manufacturing a turbine blade according to Claim 4 or 5 , wherein the brazing treatment, the stabilization treatment and the aging treatment are carried out in a predetermined heating furnace comprising a heating device, and wherein, during the adjustment treatment, the furnace internal temperature is lowered by stopping the heating device or by stopping the heating device and supplying cooling air to the heating furnace.
7. Method for manufacturing a turbine blade according to one of the Claims 4 until 6 , wherein during the setting treatment the heating device is operated and the oven internal temperature rises to the second temperature after the oven internal temperature has been lowered to a third temperature which is lower than the second temperature.
8. Method for manufacturing a turbine blade according to one of the Claims 1 until 7 , wherein the process further comprises: forming a sublayer on a surface of the support material using a metallic material having a higher oxidation resistance property than the support material; and forming a top layer on a surface of the sublayer after the sublayer has been formed, wherein the top layer is formed after the support material has been subjected to brazing and stabilization treatment, and wherein the aging treatment is carried out after the top layer has been formed.
9. Method for manufacturing a turbine blade according to Claim 8 , whereby the underlayer is formed after the brazing treatment and the stabilization treatment have been carried out.
10. Method for manufacturing a turbine blade according to one of the Claims 1 until 7 , wherein the process further comprises: forming a sublayer on a surface of the support material using a metallic material having a higher oxidation resistance property than the support material; and forming a top layer on a surface of the sublayer after the sublayer has been formed, wherein the top layer is formed after the sublayer has been formed and the support material has been subjected to brazing, stabilizing and aging treatments.

Description

Technical field The present invention relates to a method for manufacturing a turbine blade. State of the art A gas turbine comprises a compressor, a combustion chamber, and a turbine. The compressor draws in air and compresses it to produce high-temperature, high-pressure compressed air. The combustion chamber combusts the compressed air by adding fuel. As a turbine within a vehicle's airframe, it consists of several guide vanes and rotor blades arranged alternately. Inside the turbine, the rotor blades are rotated by a high-temperature, high-pressure combustion gas generated from the compressed air. This rotation converts thermal energy into rotational energy. The turbine blades, such as the guide vanes and rotor blades, are exposed to a high-temperature environment and are therefore made of metallic materials with high heat resistance. When manufacturing the turbine blades, a substrate material is produced by casting, forging, or similar processes and undergoes a heating and solution annealing treatment, as described, for example, in patent document 1. A brazing material is then applied to the substrate and heated. The substrate is subsequently brazed. After cooling, the substrate undergoes heat treatment for stabilization and aging. Patent document 2 discloses a method for closing a recess in a workpiece, such as a turbine blade. A solder foil is used to cover the opening of the recess. The solder foil consists of a mixture of a material that does not melt at soldering temperature and a solder material that does melt. This composition prevents cracking caused by shrinkage during cooling. The closing can be carried out during a heat treatment of the workpiece that is already being performed, such as precipitation hardening or solution annealing. Patent document 3 describes a heat treatment process for a ruthenium-containing nickel-based single-crystal superalloy to improve its yield strength in a medium temperature range. The process comprises a solution annealing step, a first aging step, and a second aging step. The second aging step is carried out at a temperature in the range of 600–800°C to precipitate a secondary γ' phase at the grain boundaries of the primary γ' phase, thereby increasing the strength in this temperature range. Patent document 4 discloses a multiphase intermetallic compound based on Ni₃Si - Ni₃Ti - Ni₃Nb , which exhibits high strength and ductility over a wide temperature range. The compound has a multiphase microstructure consisting of an L₁₂ phase and a D₂₄ phase, or of an L₁₂ , D₂₄ , and D₂₁a phase . To manufacture the compound, a melt with a specific composition is prepared and subsequently subjected to a homogenizing heat treatment to achieve the desired phase distribution. Patent document 5 presents a combined device that enables heat treatment and vapor deposition in a single chamber. The device allows for the continuous execution of heat treatment and vapor deposition at temperatures up to 1200°C. Temperature, time, atmosphere (inert gas or vacuum), and cooling rate can be precisely controlled. This enables the efficient combination of processes such as aging or diffusion annealing with a subsequent coating process. Patent document 6 describes a method for forming an aluminide coating on a selected area of a heat-resistant superalloy substrate. The method includes exposing the base metal, forming an aluminum film by means of non-aqueous electroplating, and subsequent heat treatment to diffuse the aluminum into the substrate. A non-aqueous plating fluid is used for the electroplating, which is protected from the atmosphere, for example, by an overlying hydrophobic liquid. This method is particularly suitable for the local repair of components such as turbine blades. List of objections Patent document Patent document 1: JP 2002-103031 APatent document 2: WO 03/053622 A1Patent document 3: JP 2013-133505 APatent document 4: JP 2006-299410 APatent document 5: JP 2006-299378 APatent document 6: EP 2 966 190 A1 Summary of the invention Problem to be solved by the invention In the manufacturing process described in patent document 1, the stabilization treatment involves heat treatment at a temperature higher than the liquidus temperature of the brazing material used for brazing. Therefore, when the substrate material undergoing brazing is subsequently stabilized, there is a possibility that the brazing material will remelt upon heating, potentially causing it to fracture. Thus, in the prior art, the stabilization treatment necessitates the laborious process of adding brazing material to the substrate. The present invention was made in view of the aforementioned problem and aims to provide a method for manufacturing a turbine blade which is able to reduce the effort in manufacturing steps. Solution to the problem The present invention provides a method for manufacturing a turbine blade according to independent claim 1. Advantageous modifications are found in dependent claims 2 to 10