CN112475820A - Method for machining blade top of movable blade of hollow blade of gas turbine - Google Patents
Method for machining blade top of movable blade of hollow blade of gas turbine Download PDFInfo
- Publication number
- CN112475820A CN112475820A CN202011318450.7A CN202011318450A CN112475820A CN 112475820 A CN112475820 A CN 112475820A CN 202011318450 A CN202011318450 A CN 202011318450A CN 112475820 A CN112475820 A CN 112475820A
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- blade
- hollow
- machining
- cover plate
- brazing
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23P—METAL-WORKING NOT OTHERWISE PROVIDED FOR; COMBINED OPERATIONS; UNIVERSAL MACHINE TOOLS
- B23P15/00—Making specific metal objects by operations not covered by a single other subclass or a group in this subclass
- B23P15/02—Making specific metal objects by operations not covered by a single other subclass or a group in this subclass turbine or like blades from one piece
Abstract
The invention relates to the technical field of gas turbine hollow blade moving blade tip processing, and particularly discloses a gas turbine hollow blade moving blade tip processing method which comprises the following steps of casting a hollow moving blade; a boss for mounting a cover plate is arranged at the top of the hollow moving blade; welding the cover plate on the boss by brazing, wherein the brazing welding gap is 0.05-0.2 mm; machining a cooling hole on the cover plate; and finishing the processing. The cover plate is connected with the blade top in a brazing mode, and compared with the prior art that the cover plate is integrally formed and cast, the yield of products is effectively improved, and the production and processing cost is reduced.
Description
Technical Field
The invention relates to the technical field of gas turbine hollow blade movable blade top processing, in particular to a gas turbine hollow blade movable blade top processing method.
Background
The high-temperature turbine blade is one of core components of an aeroengine and a heavy-duty gas turbine, has a severe working environment and bears the impact of high-temperature and high-speed gas. The high-temperature turbine blade is generally manufactured in a precision casting mode, the manufacturing difficulty is high, particularly the hollow blade with a complex internal cooling structure is low in manufacturing qualified rate, and the manufacturing cost is greatly improved.
For a hollow moving blade of a turbine, cooling holes are generally arranged at the blade top to realize cooling at the blade top, but because the hole diameter of the cooling holes is small, core fracture is easy to occur at the air film hole when the blade top is produced by a casting method, and the blade casting is unqualified. Through statistics, in the actual production of a certain turbine blade, 99% of core breaking problems occur at the cooling holes of the blade top, and even if the diameter of the cooling holes is increased, the core breaking problems of the blade top cannot be effectively solved.
Disclosure of Invention
The invention aims to solve the technical problem of providing a method for processing the blade top of the movable blade of the hollow blade of the gas turbine, which effectively prevents the occurrence of core breaking of the blade top, improves the qualification rate of blade manufacture and effectively ensures the safe operation of the movable blade of the gas turbine.
The technical problem to be solved by the invention is as follows:
a method for processing the top of a movable blade of a hollow blade of a combustion engine comprises the following steps:
casting a hollow moving blade; a boss for mounting a cover plate is arranged at the top of the hollow moving blade; the shear strength of the brazing point is greater than 270 MPa;
welding the cover plate on the boss by brazing, wherein the brazing welding gap is 0.05-0.2 mm;
machining a cooling hole on the cover plate;
and finishing the processing.
The blade top of the hollow blade is not formed by one-time casting, but a cover plate is arranged at a boss in a brazing mode, wherein the contour shape formed by the boss is the same as the contour shape of the cover plate, the cover plate is arranged on the boss, a brazing welding gap is formed between the cover plate and the boss, and brazing filler metal is used for realizing the connection between the blade top and the cover plate by filling the gap; then, machining cooling holes on the cover plate to finish machining; compared with the prior art that the cooling hole is integrally cast and formed, the blade core does not need to be provided with a structure for casting the cooling hole, and the problem that the cast cooling hole does not meet the requirement due to the fact that the structure of the cast blade top cooling hole is broken in the prior art is solved.
In some possible embodiments, the cast hollow rotor blade is manufactured by casting the blade tip, the blade body and the blade root thereof.
When the hollow moving blade is cast, compared with the prior art, the cover plate and other parts are not cast together; the purpose of doing so is that when casting hollow blade movable vane, because need not consider the position of apron, and the casting of cooling hole on the apron, this will make the mould that is used for processing inside air conditioning passageway wider and thick more, and then the effectual emergence of preventing the core breaking improves the qualification rate of blade manufacturing.
In some possible embodiments, the cover plate is made of nickel-based superalloy and has a thickness of 1-3 mm; during brazing, the protective gas is argon.
In some possible embodiments, the machining of the cooling hole on the cover plate specifically refers to machining the cooling hole on the cover plate by means of electric discharge machining.
In some possible embodiments, the method further comprises the step of performing heat treatment and grinding treatment on the hollow moving blade after the hollow moving blade is cast.
In some possible embodiments, the method further comprises spraying a coating after the cooling hole is machined, wherein the coating is a TBC coating.
TBC coatings have good oxidation resistance, corrosion resistance, fracture toughness, long term tissue stability and machinability.
In some possible embodiments, the welding of the cover plate to the boss by brazing specifically comprises the following steps:
after being heated and melted, the brazing flux flows into a brazing welding gap and generates a physical and chemical action with an oxide on the surface of a base metal, an oxidation film is removed, and the surface of the base metal is cleaned;
along with the increase of the heating temperature, the brazing filler metal begins to melt, wet and spread, and meanwhile, flux residues are removed;
under the action of the molten brazing filler metal, a small part of base metal is dissolved in the brazing filler metal, and meanwhile, the brazing filler metal is diffused into the base metal;
filling the gap with solder, and maintaining the temperature, cooling and solidifying to form a soldered joint; the heat preservation time is at least 15 min.
Compared with the prior art, the invention has the beneficial effects that:
the connection between the cover plate and the top of the blade is realized by adopting a brazing mode, so that the problem that the cover plate and the cooling holes on the cover plate need to be integrally cast when the hollow moving blade is cast is effectively avoided; the structure for casting the cooling hole is arranged on the core in the integral casting process, and the diameter of the cooling hole is small, so that the structure for casting the cooling hole is easy to break when the integral casting process is adopted, the machining of the cooling hole is not satisfactory, and the blade is not satisfactory in manufacturing; compared with the prior art, the yield of blade manufacturing is effectively improved.
Drawings
FIG. 1 is a schematic structural view of a rotor blade according to the present invention;
FIG. 2 is a schematic cross-sectional view taken along line A-A in FIG. 1;
wherein: 1. a leading edge; 2. a pressure surface; 3. a trailing edge; 4. a suction surface; 5. leaf tops; 6. a cover plate; 7. a gap; 8 boss.
Detailed Description
To make the purpose, technical solutions and advantages of the present application clearer, the technical solutions in the present application will be clearly and completely described below with reference to the drawings in the present application, and it is obvious that the described embodiments are some, but not all embodiments of the present application. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
The invention is further illustrated with reference to the following figures and examples.
The invention is realized by the following technical scheme, as shown in figure 1,
a method for processing a movable blade top 5 of a hollow blade of a combustion engine comprises the following steps:
casting a hollow moving blade; a boss for installing a cover plate 6 is arranged at the blade top 5 of the hollow moving blade;
the blade top 5 is provided with a cover plate 6 mounting groove, and the boss is arranged in the mounting groove and used for mounting the cover plate 6;
welding the cover plate 6 on the boss by brazing, wherein the brazing welding gap is 0.05-0.2 mm;
machining cooling holes in the cover plate 6;
and finishing the processing.
The cover plate 6 and the hollow moving blade are not cast together, but a brazing mode is adopted, so that the cover plate 6 is arranged at the top of the blade body, the outline shape formed by the boss is the same as the outline shape of the cover plate 6, the cover plate 6 is arranged on the boss, a brazing welding gap is formed between the cover plate and the boss, and the brazing filler metal is used for realizing the connection between the blade top 5 and the cover plate 6 through the gap; then, machining cooling holes in the cover plate 6 to finish machining; compared with the prior art that the blade is integrally cast, the blade casting mould can effectively avoid the phenomenon that the core is broken to cause unqualified blade casting.
The cover plate 6 is welded in a brazing mode, so that when the hollow blade movable blade is cast, the position of the cover plate 6 is not considered, and the cover plate 6 is cast with cooling holes, a core for machining an internal cooling air channel is made to be wider and thicker, a structure for casting the cooling holes is not required to be made on the core, the core is effectively prevented from being broken in the structure for casting the cooling holes, and the qualified rate of blade manufacturing is improved.
In some possible embodiments, the cast hollow rotor blade is manufactured by casting the blade tip 5, the blade body and the blade root thereof; wherein the blade body comprises a leading edge 1, a pressure surface 2, a trailing edge 3 and a suction surface 4.
In the invention, when the hollow moving blade is cast, compared with the prior art, the cover plate 6 is not cast with other parts;
the purpose of doing so is to make when casting the hollow blade movable vane, because need not consider the position of apron 6, and the casting of cooling hole on apron 6, this will make the mould that is used for processing inside air conditioning passageway wider and thicker, and then the emergence of core breaking is prevented effectively, improves the qualification rate of blade manufacturing.
In some possible embodiments, the cover plate 6 is made of nickel-based high-temperature alloy and has a thickness of 1-3 mm; during brazing, the protective gas is argon.
In some possible embodiments, the machining of the cooling holes on the cover plate 6 specifically refers to machining the cooling holes on the cover plate 6 by means of electric discharge machining. The use of electric discharge machining for machining cooling holes is a very well known technique, and how to implement the machining of cooling holes by electric discharge machining is not described in detail here.
In some possible embodiments, the method further comprises the step of performing heat treatment and grinding treatment on the hollow moving blade after the hollow moving blade is cast.
Preferably, the heat treatment comprises hot isostatic pressing and solution treatment.
In some possible embodiments, the method further comprises spraying a coating after the cooling hole is machined, wherein the coating is a TBC coating.
TBC coatings have good oxidation resistance, corrosion resistance, fracture toughness, long term tissue stability and machinability.
In some possible embodiments, the welding of the cover plate 6 to the boss by brazing includes the following steps:
after being heated and melted, the brazing flux flows into a brazing welding gap and generates a physical and chemical action with an oxide on the surface of a base metal, an oxidation film is removed, and the surface of the base metal is cleaned;
along with the increase of the heating temperature, the brazing filler metal begins to melt, wet and spread, and meanwhile, flux residues are removed;
under the action of the molten brazing filler metal, a small part of base metal is dissolved in the brazing filler metal, and meanwhile, the brazing filler metal is diffused into the base metal;
after the brazing filler metal is filled in the gap and is kept warm for a certain time, the brazing filler metal is cooled and solidified to form a brazing joint; the heat preservation time is at least 15 min.
In contrast, as shown in tables 1, 2 and 3,
wherein table 1 is the microhardness of different areas of the shear test plate with a gap of 0.05 mm;
table 2 shows the microhardness of different areas of the shear test plate with a gap of 0.10 mm;
table 3 shows the brazing shear strength of the two gaps;
after a large number of tests are carried out on the lap joint part by carrying out Penetration Testing (PT) and ray inspection (RT) tests on the shear strength tests of different brazing gaps and different heat preservation times, the penetration inspection result shows that the test sample has no obvious defects and is qualified; and (4) carrying out RT inspection on the test piece (inspection standard: ASME volume V acceptance standard: ASME volume IV), and not finding that the test piece has an overproof defect, meets the standard requirement and is qualified.
The brazing structure test is carried out in a mode of adopting a circular cover plate 6, different heat preservation time tests are respectively carried out by adopting different gaps, and finally, penetrant inspection (PT) and radiographic inspection (RT) are carried out.
Test results show that except the defect of unqualified cover plate 6 body caused by casting porosity, other samples are all qualified, and the brazing is suitable for the manufacturing process of the gas turbine hollow moving blade tip 5.
TABLE 1
TABLE 2
TABLE 3
It was found from the above test that when the welding gap is less than 0.05mm, the welding gap is too small, the brazing filler metal is difficult to flow in due to non-uniform contact surface, and slag inclusions and non-penetration are formed in the brazing gap, resulting in a decrease in joint strength; when the welding gap is larger than 0.2mm, the capillary action is weakened, the brazing filler metal cannot fill the gap, the compactness of the joint is deteriorated, the welding strength is sharply reduced from 279Mpa when the gap is 0.2mm to 133Mpa when the gap is 0.25mm, and further the shearing strength is not satisfactory. Only if a reasonable joint gap is ensured, the capillary action can be smoothly carried out, and the shearing strength after brazing meets the requirement of a product, and the test proves that when the gap is 0.05-0.2mm, the shearing strength is greater than 270Mpa, so that the manufactured moving blade meets the requirement.
The foregoing detailed description of the embodiments of the present application has been presented, and specific examples have been applied in the present application to explain the principles and implementations of the present application, and the above description of the embodiments is only used to help understand the method and the core ideas of the present application; meanwhile, for a person skilled in the art, according to the idea of the present application, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present application.
Claims (8)
1. A method for processing the top of a movable vane of a hollow vane of a gas turbine is characterized by comprising the following steps: the method comprises the following steps:
casting a hollow moving blade; a boss for mounting a cover plate is arranged at the top of the hollow moving blade;
welding the cover plate on the boss by brazing, wherein the brazing welding gap is 0.05-0.2 mm;
machining a cooling hole on the cover plate;
and finishing the processing.
2. The method for machining the blade top of the movable blade of the hollow blade of the combustion engine as claimed in claim 1, wherein the method comprises the following steps: the cast hollow moving blade is manufactured by adopting a casting method on the blade top, the blade body and the blade root.
3. The method for machining the blade top of the movable blade of the hollow blade of the combustion engine as claimed in claim 1, wherein the method comprises the following steps: the cover plate is made of nickel-based high-temperature alloy and is 1-3 mm thick; during brazing, the protective gas is argon.
4. The method for machining the blade top of the movable blade of the hollow blade of the combustion engine as claimed in claim 1, wherein the method comprises the following steps: the step of machining the cooling hole on the cover plate specifically refers to the step of machining the cooling hole on the cover plate in an electric spark machining mode.
5. The method for machining the blade top of the movable blade of the hollow blade of the combustion engine as claimed in claim 1, wherein the method comprises the following steps: and the method also comprises the steps of carrying out heat treatment and polishing treatment on the hollow moving blade after the hollow moving blade is cast.
6. The method for machining the blade top of the movable blade of the hollow blade of the combustion engine as claimed in claim 1, wherein the method comprises the following steps: and spraying a coating after the cooling hole is machined, wherein the coating is a TBC coating.
7. The method for machining the blade top of the movable blade of the hollow blade of the combustion engine as claimed in claim 1, wherein the method comprises the following steps: the step of welding the cover plate on the boss by brazing specifically comprises the following steps:
after being heated and melted, the brazing flux flows into a brazing welding gap and generates a physical and chemical action with an oxide on the surface of a base metal, an oxidation film is removed, and the surface of the base metal is cleaned;
along with the increase of the heating temperature, the brazing filler metal begins to melt, wet and spread, and meanwhile, flux residues are removed;
under the action of the molten brazing filler metal, a small part of base metal is dissolved in the brazing filler metal, and meanwhile, the brazing filler metal is diffused into the base metal;
filling the gap with solder, and maintaining the temperature, cooling and solidifying to form a soldered joint; the heat preservation time is at least 15 min.
8. The method for machining the blade top of the movable blade of the hollow blade of the combustion engine as claimed in claim 1, wherein the method comprises the following steps: the aperture of the cold air hole is 1-3 mm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011318450.7A CN112475820A (en) | 2020-11-23 | 2020-11-23 | Method for machining blade top of movable blade of hollow blade of gas turbine |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011318450.7A CN112475820A (en) | 2020-11-23 | 2020-11-23 | Method for machining blade top of movable blade of hollow blade of gas turbine |
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| CN112475820A true CN112475820A (en) | 2021-03-12 |
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| CN202011318450.7A Pending CN112475820A (en) | 2020-11-23 | 2020-11-23 | Method for machining blade top of movable blade of hollow blade of gas turbine |
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Citations (7)
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| CN1525046A (en) * | 2003-01-24 | 2004-09-01 | 联合工艺公司 | Turbine blade |
| CN1719002A (en) * | 2004-07-08 | 2006-01-11 | 联合工艺公司 | Turbine blade |
| CN102099135A (en) * | 2008-07-16 | 2011-06-15 | 斯奈克玛 | Method of manufacturing a blading component |
| CN107405735A (en) * | 2015-03-03 | 2017-11-28 | 西门子公司 | Firm hollow component with the plate for producing cavity |
| CN107716863A (en) * | 2017-09-12 | 2018-02-23 | 东方电气集团东方汽轮机有限公司 | A kind of combustion engine turbine bucket casting method |
| CN108884716A (en) * | 2016-03-31 | 2018-11-23 | 西门子股份公司 | Turbine airfoil with the internal cooling channel for having current divider feature |
| WO2020027822A1 (en) * | 2018-07-31 | 2020-02-06 | General Electric Company | Cooled airfoil and method of making |
-
2020
- 2020-11-23 CN CN202011318450.7A patent/CN112475820A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1525046A (en) * | 2003-01-24 | 2004-09-01 | 联合工艺公司 | Turbine blade |
| CN1719002A (en) * | 2004-07-08 | 2006-01-11 | 联合工艺公司 | Turbine blade |
| CN102099135A (en) * | 2008-07-16 | 2011-06-15 | 斯奈克玛 | Method of manufacturing a blading component |
| CN107405735A (en) * | 2015-03-03 | 2017-11-28 | 西门子公司 | Firm hollow component with the plate for producing cavity |
| CN108884716A (en) * | 2016-03-31 | 2018-11-23 | 西门子股份公司 | Turbine airfoil with the internal cooling channel for having current divider feature |
| CN107716863A (en) * | 2017-09-12 | 2018-02-23 | 东方电气集团东方汽轮机有限公司 | A kind of combustion engine turbine bucket casting method |
| WO2020027822A1 (en) * | 2018-07-31 | 2020-02-06 | General Electric Company | Cooled airfoil and method of making |
Non-Patent Citations (3)
| Title |
|---|
| 童庆东: "《电焊工工艺与技能训练》", 31 July 2009, 北京理工大学出版社 * |
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Application publication date: 20210312 |
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