JP2000290072A - Brazing jig - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a brazing jig which is not strained by thermal deformation in spite of being incessantly and repetitively subjected to a history accompanied by a rapid temperature change from temperature in excess of 600 deg.C up to room temperature (about 22 deg.C) and in spite of continuous use for at least >=1 year, is easy to handle, is light in weight and has a high thermal conductivity. SOLUTION: This brazing jig consists of a composite material composed of carbon and silicon carbide and metal silicon or the carbon and the silicon carbide obtained by impregnating the carbon fibers which have a specific gravity of about 2 g/cc and a coefficient of thermal expansion of <=2.0×10-6/ deg.C and are substantially not strained in spite of such a heat history by which the carbon fibers are exposed repetitively to a high temperature exceeding 600 deg.C and carbon exclusive of the carbon fibers with metal silicon.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brazing jig used in a brazing step when manufacturing various automotive parts made of aluminum or the like.

[0002]

2. Description of the Related Art As demands for improving fuel efficiency and the like become more severe, a substantial portion of automobile parts are replaced with aluminum parts in order to reduce the weight of automobiles.
Various parts are manufactured from aluminum.
As a matter of course, the brazing process is indispensable for the production of these parts due to the complicated shape. Currently, SUS3 is used for brazing aluminum parts.
Stainless steel brazing jigs such as 04 are used. However, since the brazing temperature is higher than 600 ° C., these jigs are used at temperatures higher than 600 ° C. to room temperature (about 22 ° C.). ) Due to the thermal deformation,
Distortion occurs, and about 45 days later, there is a problem that the flatness required for the brazing jig cannot be maintained, and the brazing jig needs to be frequently replaced.

Further, in the case of a brazing jig made of stainless steel such as SUS304, the specific gravity is as large as 8.0 g / cc, and the coefficient of thermal expansion is as high as 18.5 × 10 ⁻⁶ / ° C. For this reason, there is a disadvantage that the jig requires a large amount of energy for handling, and the jig is deformed within a relatively short period of time due to a repetition of a heating cycle with a large fluctuation range of high-temperature heating and cooling.

[0004]

SUMMARY OF THE INVENTION Even if iteratively repeats a itinerary accompanied by a rapid temperature change from a temperature exceeding 600 ° C. to room temperature (about 22 ° C.), or if it is used continuously for at least one year or more, An object of the present invention is to provide a light-weight brazing jig which does not generate distortion due to deformation and is easy to handle.

[0005]

Means for Solving the Problems The present inventors have made various studies in view of the above-mentioned current situation, and as a result, completed the present invention. That is, according to the present invention, the specific gravity is about 2
g / cc, a thermal conductivity of 50 W / m · K or more, a thermal expansion coefficient of 2.0 × 10 ⁻⁶ / ° C. or less, and even a thermal history that is repeatedly exposed to a high temperature exceeding 600 ° C. for a long time. A brazing material that does not substantially cause distortion and is obtained by impregnating carbon fibers and carbon other than carbon fibers with metallic silicon, and that is made of a composite material composed of carbon and silicon carbide and metallic silicon or carbon and silicon carbide. An attachment jig is provided. In the case of the brazing jig according to the present invention, since the specific gravity is as light as about 2 g / cc, it is easy to handle, and the thermal conductivity is 50 W.
/ M · K or more, so that the heating energy required for brazing can be saved. Further, the thermal expansion coefficient is 2.0 × 10 ⁻⁶ / ° C. or less,
Since it does not substantially cause distortion even by thermal itinerary such as repeated exposure to high temperatures exceeding ℃,
For example, even if it is used continuously for one year or more, there is no need to replace it.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION According to the present invention, specific gravity is about 2 g /
cc, the coefficient of thermal expansion is 2.0 × 10 ⁻⁶ / ° C. or less;
Carbon fiber and carbon other than carbon fiber, which do not substantially cause distortion even by thermal itinerary repeatedly exposed to high temperatures exceeding 00 ° C. for a long time, are obtained by impregnating metallic silicon with carbon and silicon carbide. A brazing jig made of metal silicon, or a composite material composed of carbon and silicon carbide,
It is manufactured from the composite material described in detail below. As this composite material, a C / C composite is used as a basic skeleton, and in a state surrounding the basic skeleton, a Si-SiC-based composite material in which a matrix made of a Si-SiC-based material is formed, and a matrix made of a SiC-based material Is formed on the SiC-based composite material. Here, it is said that the material does not substantially cause distortion even by thermal itinerary such as repeatedly exposed to a high temperature exceeding 600 ° C. for 45 days or more.
Even if you repeatedly put it in and out of the brazing kiln,
It means that the flatness of the plate surface does not show a fluctuation exceeding ± 0.1 mm.

[0007] In the present specification, the C / C composite is a powdery binder that acts as a matrix of a bundle of carbon fibers, and pitch and coke that become free carbon to the bundle of carbon fibers after firing. And further, if necessary, by containing a phenol resin powder or the like, thereby preparing a carbon fiber bundle, forming a flexible film made of a plastic such as a thermoplastic resin around the carbon fiber bundle, To obtain a preformed yarn as a functional intermediate material. This preformed yarn is disclosed in
After forming a sheet or a woven fabric by the method described in JP-A-0639, laminating a required amount, and then molding by hot pressing, or a fired body obtained by firing this molded body, Say.

As a C / C composite used as a basic material, carbon fibers having a diameter of about 10 μm are usually bundled to form a fiber bundle (yarn) by bundling hundreds to tens of thousands of carbon fibers.
This fiber bundle is coated with a thermoplastic resin to obtain a flexible thread-like intermediate material, which is formed into a sheet by the method described in Japanese Patent Application Laid-Open No. 2-80639. Alternatively, a preformed body (fiber preform) having a predetermined shape is formed by arranging in a three-dimensional direction to form a unidirectional sheet (UD sheet) or various cloths, or by laminating the sheets or cloths. It is only necessary to use a material obtained by baking a film of a thermoplastic resin or the like made of an organic substance formed on the outer periphery of the fiber bundle of the preform and removing the film by carbonization. In this specification, the description of Japanese Patent Application Laid-Open No. 2-80639 is cited for reference. In the C / C composite used in the present invention, the carbon component other than the carbon fiber in the yarn is preferably a carbon powder, particularly preferably a graphitized carbon powder.

In the present invention, the composite material composed of carbon, silicon carbide, and metallic silicon is sometimes referred to by the name of a Si—SiC-based composite material.
Wt% carbon, 1 wt% to 10 wt% silicon, 10 wt%
And 50% by weight of silicon carbide, and at least yarns containing at least a bundle of carbon fibers and a carbon component other than carbon fibers are three-dimensionally combined while being oriented in the layer direction so as not to be separated from each other. An integrated yarn assembly, comprising a matrix made of a Si-SiC-based material filled between the adjacent yarns in the yarn assembly, and having a dynamic friction coefficient of 0.05 to 0.6. , 0.
A composite material having a controlled porosity of 5% to 10%. This material can be manufactured by the method disclosed in Japanese Patent Application No. 10-267402 filed on Sep. 4, 1998. Therefore, Japanese Patent Application No. 10-26740.
The contents of Issue 2 are quoted here.

[0010] Here, the Si-SiC-based material is a typical material including several different phases from a silicon phase composed of silicon remaining in an unreacted state to almost pure silicon carbide. Is composed of a silicon phase and a silicon carbide phase.
It refers to one that can include an iC coexisting phase. Therefore, Si-Si
The C-based material is, as described above, in the Si-SiC series,
It is a general term for materials contained in the range of 0 mol% to 50 mol% as the concentration of carbon. In the Si-SiC-based composite material according to the present invention, the matrix portion is formed of the Si-SiC-based material.

Further, this Si—SiC-based composite material
Preferably, the matrix has a gradient composition in which the silicon content increases as the distance from the yarn surface increases. In the Si-SiC-based composite material, preferably, the yarn aggregate made of carbon fibers is composed of a plurality of yarn arrays, and each yarn array is formed by bundling a specific number of carbon fibers. The yarns are formed by two-dimensionally arranging the obtained yarns substantially in parallel, and a yarn aggregate is formed by stacking the respective yarn arrays. Thereby, Si-Si
The C-based composite material has a laminated structure in which a plurality of yarn arrays are laminated in a specific direction.

FIG. 1 is a schematic perspective view for explaining the concept of the yarn aggregate, and FIG.
FIG. 2B is a cross-sectional view taken along the line IIa, and FIG.
It is Ib line sectional drawing. The skeleton of the Si—SiC-based composite material 7 is constituted by the yarn aggregate 6. The yarn aggregate 6 includes the yarn arrays 1A, 1B, 1C, 1D, 1
E and 1F are vertically stacked. In each yarn array, the yarns 3 are two-dimensionally arranged, and the longitudinal directions of the yarns are substantially parallel. The longitudinal direction of each yarn in each vertically arranged yarn array is orthogonal. That is, each yarn array 1A, 1C, 1E
The longitudinal direction of each yarn 2A is parallel to each other and orthogonal to the longitudinal direction of each yarn 2B of each yarn array 1B, 1D, and 1F. Each yarn is made of carbon fiber,
The fiber bundle 3 is made of a carbon component other than carbon fibers.
The yarn assembly 6 having a three-dimensional lattice shape is formed by stacking the yarn arrays. Each yarn is crushed during a pressure forming process as described below, and has a substantially elliptical shape.

In each of the yarn arrays 1A, 1C, and 1E, a matrix 8A is provided between adjacent yarns.
And each matrix 8A extends along and parallel to the surface of the yarn 2A. In each of the yarn arrays 1B, 1D, and 1F, the gap between adjacent yarns is filled with a matrix 8B, and each matrix 8B extends along the surface of the yarn 2B and parallel thereto. In this example, the matrices 8A and 8B are respectively composed of silicon carbide phases 4A and 4B covering the surface of each yarn.
And Si-SiC-based material phases 5A and 5B having a lower carbon content than silicon carbide phases 4A and 4B. Silicon may be partially contained in the silicon carbide phase. In this example, silicon carbide phases 4A and 4B are also generated between yarns 2A and 2B that are vertically adjacent to each other.

Each of the matrices 8A and 8B is elongated, preferably linear, along the surface of the yarn, respectively, and each of the matrices 8A and 8B is orthogonal to one another. Then, the matrix 8A in the yarn arrays 1A, 1C, and 1E and the yarn array 1 orthogonal to the matrix 8A
The matrix 8B in B, 1D, and 1F is continuous at the gap between the yarns 2A and 2B, respectively. As a result, the matrices 8A and 8B form a three-dimensional lattice as a whole.

In the present invention, the composite material composed of carbon and silicon carbide is composed of silicon carbide, carbon fiber, and a carbon component other than carbon fiber, sometimes referred to as a SiC-based composite material. SiC-C having a structure composed of a skeleton and a matrix formed around the skeleton
/ C composite composite material, wherein at least 50% of silicon carbide is β-type, the skeleton is formed of carbon fiber and carbon components other than carbon fiber, and silicon carbide is present in a part of the skeleton. The matrix may be formed of silicon carbide, the matrix and the skeleton may be integrally formed, and the composite material may have a porosity of 0.5% to 5% and a double porosity. A composite material having a distribution of the average pore diameter of the mold.

Therefore, this SiC-based composite material uses, as a skeleton, a C / C composite in which each carbon fiber is composed of a carbon fiber bundle. Therefore, even if SiC is partially formed, Since each carbon fiber has a structure as a carbon fiber, which is maintained without being broken, the carbon fiber does not become short due to silicon carbide. Therefore, a machine having a C / C composite as a raw material is used. The main feature is that the mechanical strength is almost maintained or increases due to silicon carbide. Moreover, the yarn assembly has a composite structure in which a matrix made of a SiC-based material is formed between adjacent yarns. In this respect, it is different from the above-described Si-SiC-based composite material. In addition,
This material can be manufactured by the method disclosed in Japanese Patent Application No. 11-31979 filed on Feb. 9, 1999. Therefore, the contents of Japanese Patent Application No. 11-31979 are cited here.

In the present invention, the SiC-based material refers to a material containing silicon carbide having a different degree of bonding with carbon, and the SiC-based material is manufactured as follows. In the present invention, for C / C composite,
The metal silicon is impregnated. At this time, the metal silicon reacts with carbon atoms constituting carbon fibers in the composite and / or free carbon atoms remaining on the surface of the carbon fibers, and is partially carbonized. A partially carbonized silicon is formed between the yarns composed of the outermost surface of the C / C composite and the carbon fibers, and thus a matrix composed of silicon carbide is formed between the yarns. Is done.

In this matrix, a very small amount of silicon and carbon are bonded but may contain several different phases from a silicon carbide phase to a pure silicon carbide crystal phase. However, this matrix contains only metallic silicon below the X-ray detection limit (0.3% by weight). That is, although this matrix is typically made of a silicon carbide phase, the silicon carbide phase may include a SiC-based phase in which the content of silicon is inclined. Therefore, SiC
The term “based material” refers to a concentration of carbon of at least 0.01 mol% or more and 50 m in such SiC series.
It is a generic term for materials contained within the range up to ol%.
In order to control the carbon concentration to less than 0.01 mol%, the amount of free carbon in the C / C composite is controlled as follows:
It is not practical because strict measurement of the amount of metallic silicon to be added is required and temperature control in the final step is complicated. Therefore, theoretically, the carbon concentration is 0.001 mol
% Can be controlled.

The Si-based composite material will be further described with reference to the drawings. The skeleton of this SiC-based composite material is basically the same as that shown in FIG. FIG. 3 is a sectional view when the SiC-based composite material according to the present invention is cut along the line IIa-IIa in FIG.
FIG. 3A is a cross-sectional view taken along line IIb-IIb in FIG. The skeleton of the SiC-based composite material 17 is constituted by the yarn aggregate 16, similarly to the skeleton of the Si—SiC-based composite material 7. The yarn aggregate 16 includes the yarn arrays 11A and 11A.
B, 11C, 11D, 11E, and 11F are vertically stacked. In each yarn array, the yarns 13 are two-dimensionally arranged, and the longitudinal directions of the yarns are substantially parallel. The longitudinal direction of each yarn in each vertically arranged yarn array is orthogonal. That is, each yarn 12A of each yarn array 11A, 11C, 11E
Are parallel to each other and perpendicular to the longitudinal direction of each yarn 12B of each yarn array 11B, 11D, 11F. Each yarn is composed of a fiber bundle 13 composed of carbon fibers and carbon components other than carbon fibers. The yarn assembly 16 having a three-dimensional lattice shape is formed by stacking the yarn arrays. Each yarn is crushed during a pressing step, as described below, and is slightly oval.

Each yarn array 11A, 11C, 11E
In, the gap between adjacent yarns is filled with a matrix 18A, and each matrix 18A extends along and parallel to the surface of the yarn 12A. In each of the yarn arrangements 11B, 11D, 11F, the gap between adjacent yarns is filled with a matrix 18B, and each matrix 18B extends along the surface of the yarn 12B and parallel thereto. As shown in FIGS. 3A and 3B, the matrices 18A and 18A
B consists of a silicon carbide phase 14 covering the surface of each yarn. Part of the silicon carbide phase is the small protrusion 1
It may project to the surface as 9 or to the carbon fiber layer inside the composite member. Inside such small projections, pores (voids: 15) having a median diameter of about 100 μm are formed. In addition, since the small protrusions 19 are formed along the traces of the matrix composed of carbon components other than the carbon fibers of the raw material C / C composite, the distance between the yarns and / or
Alternatively, the density of the small projections 19 per unit area can be adjusted by appropriately selecting the interval between the yarn arrays. Silicon carbide phase 14 may be formed between adjacent yarns 12A and 12B.

Each matrix 18A and 18B is elongated, preferably linear, along the surface of the yarn, respectively, and each matrix 18A and 18B is orthogonal to one another. Then, the yarn arrays 11A, 11
The matrix 18A in C and 11E and the matrix 18B in the yarn arrays 11B, 11D and 11F orthogonal thereto are continuous at the gap between the yarns 12A and 12B, respectively. As a result, matrix 1
8A and 18B form a three-dimensional lattice as a whole.

Since both of the above materials have a C / C composite as a skeleton, their specific gravity is as light as about 2 g / cc and handling is easy. The thermal expansion coefficient is 2.0 × 1
Since it is 0 ⁻⁶ / ° C. or less, it is a low thermal expansion material, and does not suffer damage due to thermal expansion even if thermal cycling is repeated. Further, both materials have a thermal conductivity of 50 W / m.
-Since it is a good thermal conductor of K or more, the temperature can be rapidly raised to a predetermined temperature during heating.

The brazing jig according to the present invention has a plate (21) shown in FIG. 4 and a plate, as schematically shown in FIG. 5, at specific positions on the plate, usually at least four positions. The support (2) is provided in the cutout (24) provided.
2) is fitted and assembled. Bottom plate (2
1) is directly connected to the column (22) with bolts and nuts. Other plates may be mounted via the spacer (23). Even if it is made of stainless steel,
Alternatively, it may be made of the same material as the plate (21). The same applies to the spacer. The shape of the notch varies depending on the material used for the support, but in the case of stainless steel, the coefficient of thermal expansion between the plate and the support differs,
It is necessary to provide a notch so as to allow some play. In the case of the same member, they may be provided in the same shape so that they can be tightly fitted. There is no particular limitation on the attachment of the spacer to the column as long as it can be mechanically fixed, and any method may be used.

[0024]

EXAMPLES Hereinafter, the present invention will be further described with reference to examples, but the present invention is not limited to these examples.

(Production Example of Plate) A carbon fiber which is aligned in one direction is impregnated with a phenol resin and has a diameter of 10%.
Approximately 10,000 carbon long fibers of μm are bundled to obtain a fiber bundle (yarn), and a yarn array (prepreg sheet) in which the yarn is shaped like a cord is arranged as shown in FIG. A laminate was obtained. The thus-obtained prepreg sheet laminate was wound around a cylindrical mold having a diameter of 18 mm, and a carbon-based adhesive was applied thereon to fix the yarns together.
After the fixation, the fixed body was released from the mold, the released columnar prepreg sheet laminate was placed in an oven, and the impregnated phenol resin was cured at 180 ° C. and normal pressure. Fired at ℃. The obtained fired body was cut and processed into an outer periphery to produce three plate plates each having an outer peripheral portion having a diameter of 540 mm, a central hole having a diameter of 18 mm, and a thickness of 4 mm. To this, Si powder having a purity of 99.9% and an average particle diameter of 1 mm was added. This was placed in a firing furnace having a furnace temperature of 1300 ° C. and a furnace pressure of 1 hPa, and argon gas of 20 NL / min was introduced into the furnace. It was held for 4 hours while flowing at a ratio. Next, the furnace pressure was raised to 1600 ° C. while the furnace pressure was maintained, and Si was impregnated. Thus, a plate plate according to the present invention comprising a Si-SiC-based composite material comprising Si, Si-C, and carbon fibers was obtained. In addition, the size of the notch provided in four places was provided with some clearance in accordance with the stainless steel column.
Using this, a stainless steel column, and a spacer, a brazing jig as shown in FIG. 5 was manufactured.

Using this jig, the aluminum product was brazed. Even after 45 days, no distortion occurred.
I was not able to admit.

[0027]

EFFECT OF THE INVENTION The brazing jig according to the present invention has a light specific gravity of about 2 g / cc, so that it is easy to carry it around in preparation for the brazing process and to carry it out. Since it is as high as 50 W / m · K or more, the heating energy required for brazing is little wasted in heating the brazing jig itself, so that energy can be saved as a result. it can. In addition, the thermal expansion coefficient is 2.0 × 10 ⁻⁶ / ° C. or less, and therefore, substantially no distortion is caused by thermal itinerary such as repeated exposure to a high temperature exceeding 600 ° C. for a long time. It can be used continuously for a long time, for example, one year or more.

[Brief description of the drawings]

FIG. 1 is a perspective view schematically showing a structure of a yarn assembly which is a basic structure of a composite material used for a brazing jig of the present invention.

FIG. 2A is a cross-sectional view of a Si—SiC-based composite material cut along a line IIa-IIa in FIG. 1;
FIG. 2B is a cross-sectional view of the same material taken along line IIb-IIb in FIG. 1.

FIG. 3A shows a SiC-based composite material IIa in FIG.
FIG. 2B is a cross-sectional view taken along line IIa, and FIG.
It is sectional drawing at the time of cutting | disconnecting the same material along the IIb-IIb line of FIG.

FIG. 4 is a plan view of a plate which is a part of the brazing jig according to the present invention.

FIG. 5 is a perspective view of a brazing jig according to the present invention.

[Explanation of symbols]

1A, 1B, 1C, 1D, 1E and 1F ... yarn arrangement, 2A ... yarn, 2B ... yarn, 3 ... fiber bundle (yarn), 4A ... silicon carbide phase, 4B ... silicon carbide phase, 4C ... silicon carbide phase, 5A ... Si-SiC material phase, 5B ... Si-
SiC-based material phase, 5C: Si-SiC-based material phase, 6: Yarn aggregate, 7: Fiber composite material, 8A: Matrix,
8B ... matrix, 11A, 11B, 11C, 11
D, 11E and 11F ... yarn arrangement, 12A ... yarn, 12B ... yarn, 13 ... fiber bundle (yarn), 14 ...
Silicon carbide phase, 15 ... voids, 16 ... yarn aggregate, 17 ...
Fiber composite material, 18A matrix, 18B matrix, 19 small projection, 21 plate, 22 support, 23 spacer, 24 cutout.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4G001 BA60 BA62 BA76 BA86 BB22 BB60 BB62 BB86 BC17 BC22 BC33 BC47 BC56 BD03 BD04 BD07 BE15 BE32 4G032 AA33 AA42 AA52 BA01 GA06 GA11

Claims (2)

[Claims] 1. A specific gravity of about 2 g / cc and a thermal conductivity of 50 W
/ M · K or more, the coefficient of thermal expansion is 2.0 × 10 ⁻⁶ / ° C. or less, and does not substantially cause distortion even when subjected to repeated thermal exposure to a high temperature exceeding 600 ° C. for a long time. A brazing jig made of a composite material composed of carbon, silicon carbide, and metal silicon, or carbon and silicon carbide, obtained by impregnating carbon fibers and carbon other than carbon fibers with carbon. 2. The method according to claim 1, wherein the composite material comprises 55% to 75% by weight.
Carbon, 1% to 10% silicon, 10% by weight
５０50% by weight of silicon carbide, yarns containing at least a bundle of carbon fibers and a carbon component other than carbon fibers are three-dimensionally combined while being oriented in the layer direction, and integrated so as not to be separated from each other. Yarn assembly that is
A matrix made of a Si-SiC-based material filled between the yarns adjacent to each other in the yarn aggregate; a dynamic friction coefficient of 0.05 to 0.6;
A composite material having a porosity controlled to 0%, or SiC comprising silicon carbide, carbon fiber, and a carbon component other than carbon fiber, having a structure formed of a skeleton and a matrix formed around the skeleton. A C / C composite composite, wherein at least 50% of the silicon carbide is of the β type;
The skeleton is formed of carbon fiber and a carbon component other than the carbon fiber, and silicon carbide may be present in a part of the skeleton, and the matrix is formed of silicon carbide, and the matrix and the skeleton are formed. The wax according to claim 1, wherein the wax is integrally formed with the portion, and the composite material is a composite material having a porosity of 0.5% to 5% and a distribution of two-peaked average pore diameter. Fixture jig.