Steam turbine and steam turbine blade

Patent metadata

Field	Value
Publication number	US-9309773-B2
Application number	US-97754810-A
Country	US
Kind code	B2
Filing date	Dec 23, 2010
Priority date	Jun 23, 2008
Publication date	Apr 12, 2016
Grant date	Apr 12, 2016

Abstract

A steam turbine 3 includes: a turbine rotor 4 ; a rotor blade 5 implanted to the turbine rotor 4 ; a stator blade 6 provided at an upstream side of the rotor blade 5 ; and a turbine casing 13 supporting the stator blade 6 and including the turbine rotor 4 , the rotor blade 5 and the stator blade 6 , and have a constitution in which a stage 7 is formed by a pair of the rotor blade 5 and the stator blade 6 , and a steam passage 8 is formed by arranging plural stages 7 in an axial direction of the turbine rotor 4 . A surface treatment to suppress an increase of a surface roughness caused by oxidation is performed for at least a part of a surface of the stator blade 6 and a surface of the rotor blade 5.

First claim

What is claimed is:

1. A steam turbine, comprising:
a turbine rotor;
a rotor blade implanted to the turbine rotor;
a stator blade provided at an upstream side of the rotor blade; and
a turbine casing supporting the stator blade and including the turbine rotor, the rotor blade and the stator blade,
wherein a stage is formed by a pair of the rotor blade and the stator blade, and a steam passage is formed by arranging plural stages in an axial direction of the turbine rotor;
wherein a surface treatment including coating a ceramics precursor and decomposing the ceramics precursor by a heat treatment after coating the ceramics precursor is performed to form a ceramic layer directly on at least a part of a surface of the stator blade and a surface of the rotor blade exposed at approximately 350° C. to 610° C. so as to suppress an increase of a surface roughness caused by oxidation; and
wherein the surface roughness is one in which a maximum height Rmax after the surface treatment is 1.6 μm or less.

2. The steam turbine according to claim 1 ,
wherein the surface treatment is performed for at least a part of the surfaces of the stator blades at a high pressure stage and an intermediate pressure stage.

3. The steam turbine according to claim 1 ,
wherein the surface treatment is performed for at least a part of the surfaces of the rotor blades at a high pressure stage and an intermediate pressure stage.

4. The steam turbine according to claim 1 ,
wherein the stator blade and the rotor blade are made up of ferritic steel or super heat-resistant steel.

5. The steam turbine according to claim 1 ,
wherein the surface treatment does not increase the surface roughness of a base material of the stator blade and the rotor blade.

6. The steam turbine according to claim 1 ,
wherein a membrane formed by the surface treatment is oxide ceramics.

7. The steam turbine according to claim 1 ,
wherein an average thickness of a membrane formed by the surface treatment is 0.01 μm or more and 50 μm or less.

8. The steam turbine according to claim 1 ,
wherein a membrane formed by the surface treatment exists at a position of less than 10 mm from a rear edge of the stator blade and the rotor blade toward an upstream side and at a back side.

9. A steam turbine blade, used for a steam turbine including: a turbine rotor; a rotor blade implanted to the turbine rotor; a stator blade provided at an upstream side of the rotor blade; and a turbine casing supporting the stator blade and including the turbine rotor, the rotor blade and the stator blade, in which a stage is formed by a pair of the rotor blade and the stator blade, and a steam passage is formed by arranging plural stages in an axial direction of the turbine rotor, as the stator blade or the rotor blade,
wherein a surface treatment including coating a ceramics precursor and decomposing the ceramics precursor by a heat treatment after coating the ceramics precursor is performed to form a ceramic layer directly on at least a part of a surface of the stator blade and a surface of the rotor blade exposed at approximately 350° C. to 610° C. so as to suppress an increase of a surface roughness caused by oxidation; and
wherein the surface roughness is one in which a maximum height Rmax after the surface treatment is 1.6 μm or less.

10. The steam turbine blade according to claim 9 ,
wherein the steam turbine blade is made up of ferritic steel or super heat-resistant steel.

11. The steam turbine blade according to claim 9 ,
wherein the surface treatment does not increase the surface roughness of a base material.

12. The steam turbine blade according to claim 9 ,
wherein a membrane formed by the surface treatment is oxide ceramics.

13. The steam turbine blade according to claim 9 ,
wherein an average thickness of a membrane formed by the surface treatment is 0.01 μm or more and 50 μm or less.

14. The steam turbine blade according to claim 9 ,
wherein a membrane formed by the surface treatment exists at a position of less than 10 mm from a rear edge of the steam turbine blade toward an upstream side and at a back side.

15. A method of forming the steam turbine blade according to claim 9 , comprising:
preparing a steam turbine blade for a steam turbine including a turbine rotor, a rotor blade implanted to the turbine rotor, a stator blade provided at an upstream side of the rotor blade, and a turbine casing supporting the stator blade and including the turbine rotor, the rotor blade and the stator blade, in which a stage is formed by a pair of the rotor blade and the stator blade, and a steam passage is formed by arranging plural stages in an axial direction of the turbine rotor, as the stator blade or the rotor blade;
coating a ceramics precursor directly on at least a part of a surface of the stator blade and a surface of the rotor blade; and
decomposing the ceramics precursor by a heat treatment at approximately 350° C. to 610° C. to form a ceramic layer directly on at least the part of the surface of the stator blade and the surface of the rotor blade, the ceramic layer having a surface roughness in which a maximum height Rmax is 1.6 μm or less.

Assignees

• Sayano Akio
• Takahashi Masashi
• Saito Masahiro
• Nakajima Kazuyoshi
• Tanuma Tadashi
• Asai Satoru
• Kamimura Kenji
• Toshiba Kk

Inventors

• Sayano Akio
• Takahashi Masashi
• Saito Masahiro
• Nakajima Kazuyoshi
• Tanuma Tadashi
• Asai Satoru
• Kamimura Kenji

Classifications

• F05D2230/90

  Coating; Surface treatment · CPC title

• F05D2250/60

  Structure; Surface texture · CPC title

• C23C18/1208

  Oxides, e.g. ceramics · CPC title

• F01D5/286 Primary

  Particular treatment of blades, e.g. to increase durability or resistance against corrosion or erosion (F01D5/288 takes precedence) · CPC title

• F05D2220/31

  in steam turbines · CPC title