Method for restoring the microstructure of a textured article and for refurbishing a gas turbine blade or vane
AssigneeSiemens Aktiengesellschaft
InventorsRalf Buergel, Winfried Esser, Michael Ott, Der-Yan Frank Roan
Life of this patent
Estimating the term…
Abstract
During a solution heat treatment grain recrystallization may occur of a textured article, especially at the surface rim. The present invention provides a method for restoring the microstructure of a textured article, such as a gas turbine engine blade, which comprises coating the surface of the article with a high temperature stable surface coating or by a controlled development of an oxide scale and subsequently performing a solution heat treatment, thereby maintaining said thermally stable surface coating.
Claims16
A method for recovering texture of a textured article which is made from a superalloy, comprising the steps of:
- creating on a surface of the article a high temperature stable surface coating;
- and
- performing a solution heat treatment on said article wherein a γ-phase and a γ′-phase are present in said superalloy and wherein the temperature of said solution heat treatment is at least the solution temperature of the γ′-phase, thereby maintaining said high temperature stable surface coating, restoring the microstructure of the textured article, and suppressing grain recrystallization by providing bulk conditions which assure a higher temperature threshold for grain recrystallization.
A method for refurbishing a gas turbine blade made from a textured superalloy body coated with a first protective coating, the method comprising the steps of:
- coating areas of a surface of said body where an old protective coating has been eroded with a high temperature stable surface coating, thereby covering said first protective coating;
- performing a solution heat treatment on the body wherein a γ-phase and a γ′-phase are present in said superalloy and wherein the temperature of said solution heat treatment is at least the solution temperature of the γ′-phase, and wherein grain recrystallization is suppressed by providing bulk conditions which assure a higher temperature threshold for grain recrystallization,
- thereby maintaining said high temperature stable surface coating;
- removing jointly said surface coating and said first protective coating;
- and
- providing a second protective coating on said body.
A method for refurbishing a gas turbine blade made from a textured superalloy body coated with a first protective coating, the method comprising the steps of:
- removing the protective coating;
- coating areas of a surface of said body where the protective coating has been removed with a high temperature stable surface coating;
- performing a solution heat treatment on the body wherein a γ-phase and a γ′-phase are present in said superalloy and wherein the temperature of said solution heat treatment is at least the solution temperature of the γ′-phase, and wherein grain recrystallization is suppressed by providing bulk conditions which assure a higher temperature threshold for grain recrystallization,
- thereby maintaining said high temperature stable surface coating;
- removing the surface coating;
- and
- providing a second protective coating on said body.
Dependencies are inferred from the claim text.