The present invention relates to a heat treatment method of a product required to be subjected to a heat treatment during a manufacturing process.
As a heat treatment carried out during a product manufacturing process, there are known a heat treatment carried out to improve toughness or the like by changing a structure of a product and also a heat treatment carried out to remove any unrequired material applied to the product. An example of the unrequired material is a masking used in performing a coating or the like to a surface of the product, and the masking is decomposed or burned to be removed therefrom by performing an ashing process, which is an example of the heat treatment (see Patent Document 1).
PATENT DOCUMENT 1: Japanese Unexamined Patent Application, First Publication No. 2001-173405 (Page 7)
However, since the heat treatment is carried out in an ambient atmosphere due to the characteristics of the product in some cases, a problem arises in that oxidization occurs on the surface of the product upon performing the heat treatment in an ambient atmosphere. Additionally, since unevenness in color caused by light interference occurs on the surface of the product due to the oxidization in some cases, a problem arises in an external appearance due to the unevenness in color. Then, in the related art, the surface of the product is polished by a polishing device or the like and the oxidized portion is removed. However, a problem arises in that a manufacturing process is complicated. And also it takes much time to perform the polishing.
Therefore, the present invention is contrived to solve the problems, and an object of the invention is to provide a heat treatment method in which oxidization generated by a heat treatment and unevenness in color caused by the oxidization are reduced.
In order to achieve the above-described object, in a heat treatment method of putting and heating a product in a furnace, the product is heated together with a silicon resin.
According to the heat treatment method of the present invention, since the surface of the product is protected by the silicon resin, it is possible to reduce the oxidization or the unevenness in color caused by the oxidization occurring on the surface of the product. For this reason, it is possible to remarkably reduce the work time required to improve an external appearance of the product after the heat treatment thereof.
1: TRANSITION PIECE
1
a: INNER WALL
1
b: OUTER WALL
2: COOLING HOLE
3: COOLING GROOVE
4: RESIN
5: BOND COATING
6: TOP COATING
7: SILICON RESIN
8: CONTAINER
10: GAS TURBINE
10
a: CASING
11: COMBUSTOR
11
a: COMBUSTOR BASKET
11
b: COMBUSTOR COVER
11
c: PILOT NOZZLE
11
d: MAIN NOZZLE
12: COMPRESSOR
13: TURBINE
13
a: TURBINE BLADE
Hereinafter, a heat treatment method according to embodiments of the invention will be described. The heat treatment method according to the embodiments is applicable to various products required to be subjected to heat treatments. However, a transition piece included in a gas turbine is exemplified, and a case will be described in which the heat treatment method according to the embodiments is applied to an ashing process performed on the transition piece. Then, since the treatment before performing the heat treatment according to the embodiments to the transition piece of the combustor is carried out in the same manner in the embodiments, first, the combustor provided with the transition piece will be described, and the treatment before the heat treatment according to the embodiments will be described.
<Combustor>
First, a combustor 11 will be described with reference to
The compressed air generated by the compressor 12 is discharged to the casing 10a as depicted by the arrow P1, and is supplied from a gap between the combustor cover 11b and the combustor basket 11a to the inside of the combustor basket 11a as depicted by the arrow P2. In the inside of the combustor basket 11a, a diffusion combustion and a premixed combustion are carried out by means of the main nozzles 11d and the pilot nozzle 11c to which fuel is supplied to thereby generate high temperature and pressure combustion gas. The generated combustion gas is discharged to the turbine 13 via the inside of the transition piece 1, and the discharged combustion gas is applied to a turbine blade 13a provided in the turbine 13 to be rotated, thereby obtaining power from the gas turbine 10.
<Cooling Structure for Transition Piece>
As described above, since the high temperature and pressure gas passes through the inside of the transition piece 1, the transition piece is made of Ni-base alloy or the like having good heat resistance and corrosion resistance and a wall portion thereof is provided with a cooling structure. Hereinafter, the cooling structure provided in the wall portion of the transition piece will be described with reference to
As depicted by the arrow C shown in
<Thermal Barrier Coating>
Additionally, a thermal barrier coating is performed on the inner wall 1a of the transition piece 1. The thermal barrier coating will be described with reference to
Before performing the thermal barrier coating, first, as shown in
As shown in
Then, the inner wall 1a of the transition piece 1 having the rough surface is subjected to the thermal barrier coating by means of a thermal spray to thereby obtain a thermal barrier coating. Here, two types of coatings are formed as the thermal barrier coating, the two types of coatings being a top coating 6 formed for a thermal barrier and a bond coating 5 formed to obtain good adhesiveness between the top coating 6 and the inner wall 1a of the transition piece 1 as a base or to prevent oxidization of the base.
First, as shown in
Then, as shown in
As described above, the thermal barrier coating is performed on the inner wall 1a of the transition piece 1 by means of the thermal spray. After performing the thermal barrier coating to the transition piece 1, it is necessary to perform an ashing process as one of the heat treatments to the transition piece 1 in order to remove the resin 4 inserted in the cooling holes 2a. Then, the present invention relates to a heat treatment method of the product required to be subjected to the heat treatment, the product being, for example, the transition piece 1. In the following embodiments, a case will be exemplified in which the ashing process as the heat treatment is performed on the transition piece 1.
Hereinafter, the heat treatment method according to a first embodiment will be described by means of the example of the ashing performed on the transition piece and
In the heat treatment method according to this embodiment, as shown in
As shown in
Then, since the remaining silicon resin 7 protects the outer wall 1b of the transition piece 1, it is possible to reduce oxidization of the outer wall 1b or an unevenness in color caused by the oxidization. For this reason, even when the resin 4 inserted in the cooling holes 2a is removed by performing the ashing process to the transition piece 1, the unevenness in color hardly occurs in the outer wall 1b of the transition piece 1, and thus the time required to perform a polishing to the outer wall 1b becomes unnecessary or short. Accordingly, it is possible to remarkably reduce the time required to improve an external appearance after the ashing process by applying the heat treatment method according to this embodiment to the ashing process performed on the transition piece 1.
Additionally, even when the silicon resin 7 is non-uniformly applied or a large amount of the silicon resin is applied, it is possible to easily remove the remaining silicon resin 7. For this reason, it is possible to further reduce the work time after the ashing process compared with a case in which the unevenness in color is removed by means of a polishing device according to the related art. Further, when the silicon resin 7 is uniformly applied or an appropriate amount of the silicon resin is applied, it is possible to satisfactorily keep the external appearance of the transition piece 1 after the ashing process without removing the remaining silicon resin 7.
Further, the silicon resin 7 being in a paste state is directly applied to the transition piece 1, but the silicon resin 7 being in a liquid state and having low viscosity may be applied. Further, in addition to the direct application method, the application method may be a method of spraying the silicon resin 7 in a mist state to the outer wall 1b of the transition piece 1 by means of a spray. Since it is possible to easily and promptly apply the silicon resin 7, it is possible to simplify a work process and to reduce work time.
Furthermore, it is possible to uniformly apply the silicon resin 7 to the outer wall 1b of the transition piece 1 by means of the spray. Moreover, it is possible to easily apply the silicon resin to a minute gap or the like by means of the spray, as the minute gap is a portion where the direct application method is difficult to be used.
Next, a heat treatment method according to a second embodiment will be described in the same manner as the first embodiment by means of the example of the ashing process performed on the transition piece and
Regarding the transition piece 1 subjected to the thermal barrier coating as shown in
Additionally, the containers 8 are capable of withstanding an ashing temperature in the transition piece 1, and are disposed at the position around four corners of the transition piece 1. At this time, the containers 8 equipped with the silicon resin 7 and disposed at the position around four corners of the transition piece 1 is distanced from the transition piece 1, for example, by about 10 cm, and a sectional area of the container 8 is set to be several tens to several hundreds of cm2. Then, the transition piece 1 is heated together with the container 8 equipped with the silicon resin 7 in the atmosphere furnace to perform the ashing process.
When such an ashing process is carried out, as described in the first embodiment, a part of the silicon resin 7 remains in the container 8, but a part thereof is decomposed or evaporated by a heat in the furnace to be thereby discharged to the atmosphere in the furnace. Then, the surface of the transition piece 1 is protected by the discharged silicon resin 7.
In this manner, when the surface of the transition piece 1 is protected by the silicon resin 7 discharged to the atmosphere in the furnace, it is possible to reduce the unevenness in color caused by the oxidization occurring on the surface of the transition piece 1. For this reason, even when the ashing process is performed on the whole part of the transition piece 1 so as to remove the resin, the unevenness in color caused by the oxidization hardly occurs in the outer wall of the transition piece 1, and thus the time required to perform a polishing to the outer wall of the transition piece 1 before the shipment becomes unnecessary or short. Accordingly, it is possible to remarkably reduce the work time after the ashing process by performing the heat treatment method according to this embodiment.
Additionally, since the surface of the transition piece 1 is protected by discharging a part of the silicon resin 7 to the atmosphere in the furnace, it is possible to easily protect a minute part where the silicon resin 7 cannot be directly applied to the transition piece 1. Further, since the surface of the transition piece 1 is protected just by heating the transition piece 1 together with the silicon resin 7 in the furnace, it is possible to perform the ashing process while protecting the surface of the transition piece in a simple manner.
Further, a heating device such as a heater may be provided in the container 8 equipped with the silicon resin 7 so that the temperature of the container 8 and the silicon resin 7 is equal to a temperature at which the decomposition and the evaporation of the silicon resin 7 are optimally carried out. With such a configuration, since it is possible to discharge a sufficient amount of the silicon resin 7 to the atmosphere in the furnace in terms of the decomposition or the evaporation, it is possible to efficiently protect the surface of the transition piece 1.
Furthermore, the transition piece 1 and the container 8 equipped with the silicon resin 7 may have a positional relationship different from that shown in
Moreover, upon performing the ashing process to the transition piece 1, the silicon resin 7 may be maintained for a predetermined time at a temperature at which the silicon resin is easily discharged to the atmosphere in the furnace, and the temperature may increase up to a temperature at which the ashing process is carried out. When the two-stage heat treatment is carried out in this manner, the surface of the transition piece 1 is capable of being protected by sufficiently discharging the silicon resin to the atmosphere in the furnace, and the ashing process is capable of being carried out so as to burn or decompose the resin. Accordingly, it is possible to more efficiently reduce the oxidization or the unevenness in color caused by the oxidization.
In the first and second embodiments, a case is exemplified in which the heat treatment method is applied to the ashing process performed on the transition piece provided in the combustor of the gas turbine. However, the heat treatment method according to the first and second embodiments is not limited to the application to the ashing process for burning or decomposing the resin inserted in the cooling holes of the transition piece, but may be applied to the whole product required to be subjected to the heat treatment maintained at a high temperature in order to prevent the oxidization of the surface thereof or the unevenness in color caused by the oxidization. For example, the oxidization or the unevenness in color caused by the oxidization may be prevented in such a manner that the heat treatment method according to the first and second embodiments is applied to a product required to be subjected to the heat treatment such as a tempering or an annealing. Additionally, the heat treatment method according to the first and second embodiments is not limited to the application to the transition piece as an example of a product made of Ni-base alloy, but may be applied to, for example, a product made of cobalt-base alloy or iron-base alloy.
Additionally, the protection may be more efficiently carried out by appropriately selecting the type of the silicon resin in accordance with the heat treatment temperature or the heat treatment method. Particularly, a temperature at which the silicon resin is decomposed or evaporated by the heating is changed in accordance with the type of the silicon resin, that is, a bonding type such as a bonding degree of a main chain and a type of a side chain and an additive or the like applied to the resin. For this reason, since it is possible to efficiently protect the surface of the product by selecting the appropriate silicon resin in accordance with the heat treatment temperature, it is possible to perform the efficient heat treatment to all products.
For example, in the second embodiment, in a case where the two-stage heat treatment is carried out in such a manner that the temperature is maintained at a certain temperature and increases up to an ashing temperature in order to discharge the silicon resin to the atmosphere in the furnace, the silicon resin discharged to the atmosphere in the furnace at a lower temperature may be used. Then, when such silicon resin is selected, it is possible to prevent a case in which the oxidization or the undesired deformation of the product occurs during the time when the temperature is maintained at a certain temperature in order to discharge the silicon resin to the atmosphere in the furnace.
Additionally, in the example of the ashing process performed on the transition piece, the atmosphere furnace is used, but the heat treatment method according to the first and second embodiments may be carried out by means of a furnace being in a vacuum atmosphere or in an inactive gas atmosphere, the inactive gas being nitrogen or argon. With such a configuration, it is possible to protect the product from a small amount of oxygen remaining in the furnace, and thus to prevent the oxidization or the unevenness in color caused by the oxidization from occurring in the product.
The present invention is applicable to the heat treatment method of the product required to be subjected to the heat treatment, and is applicable to, for example, the ashing process for removing the unnecessary material applied to the product or the tempering and the annealing for changing the structure of the product.
Number | Date | Country | Kind |
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2006-347236 | Dec 2006 | JP | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/JP2007/067905 | 9/14/2007 | WO | 00 | 2/13/2009 |
Publishing Document | Publishing Date | Country | Kind |
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WO2008/078434 | 7/3/2008 | WO | A |
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