JP7266910B1 - Seal structure with metal contact - Google Patents

Abstract

An object of the present invention is to provide a seal structure using a metal contact that can satisfactorily seal an object to be sealed even under a relatively severe use environment. SOLUTION: The seal structure by the metal contact according to the present invention is a seal structure by the metal contact in which metals are brought into contact with each other to seal a sealing target between a sealing target presence side and a sealing target non-existing side along a partition direction. It is characterized in that at least one surface of the seal portion 1 where metal contacts each other is subjected to a softening treatment along the partition direction so as to soften below the hardness of the base material. In the present invention, the depth from the surface to be softened is 400-50 μm, and the hardness Hv of the surface is in the range of 150-200. [Selection drawing] Fig. 1

Description

The present invention relates to a seal structure for sealing (sealing) a fluid (gas or liquid) or powder to be sealed with a metal contact.

Japanese Patent Laid-Open Publication No. 2002-100000, for example, discloses a metal contact sealing structure for sealing at least one of fluid (gas or liquid) and powder.

As shown in FIG. 6A, by tightening the fastening nut 74 to the male screw 75, the fastening nut 74 moves the contact surface of the flared portion 72 of the pipe 71 to the contact surface of the tapered portion 73. , the metals are brought into contact with each other to form a seal portion 1 that seals the fluid to be sealed.

JP 2008-309295 A

Fluid leakage may occur in such a conventional metal contact seal structure, but when we observe the part where the leakage occurs, it is found that the leakage is from the part where the contact is missing due to the flatness and surface roughness of the surface. was confirmed.

FIG. 5(A) shows the site where the missing contact was confirmed. In the drawing, the center in the vertical direction is the seal portion 1 , the upper side of the seal portion 1 is the seal portion upstream (gas upstream) 2 , and the lower side of the seal portion 1 is the seal portion downstream (gas downstream) 3 . Here, when there is no leak to be sealed, the sealing portion upstream (gas upstream) 2 corresponds to the sealing target presence side, and the sealing portion downstream (gas downstream) 3 corresponds to the sealing target non-existing side.

From FIG. 5(A), it can be seen that the contact surfaces (strike surfaces) 5 of the sealing portions 1 of the facing joints 10 and 20 (see FIG. 5(B)) are not attrited, and the contact surfaces are separated from each other with a slight gap (sealing). It can be confirmed that there is a passage connecting the upstream portion 2 and the downstream portion 3 of the sealing portion, that is, a loose portion 4 .
FIG. 5(B) is a view of the contact surface (strike surface) 5 and the gap (strike free portion) 4 of the facing joints 10 and 20 viewed from the AA direction of FIG. 5(A).

Here, as a method of sealing fluid leakage from such microscopic gaps, for example, a soft rubber or resin (liquid gasket, etc.) is applied to the surface, and when it collapses, the gap is closed and sealing performance is improved. There is a way to raise it.
However, the method cannot be used in a high-pressure environment, a high-temperature environment, a corrosive environment, or the like. In addition, there is also a fact that when the contact surface moves due to microvibration or the like, it peels off and stops functioning.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a metal contact sealing structure that can satisfactorily seal a sealing object even under a relatively severe use environment.

For this reason, the seal structure using metal contacts according to the present invention is
A sealing structure using metal contacts that seals a sealing target along a partition direction between a sealing target presence side and a sealing target non-existing side by bringing metals into contact with each other at the joints that face each other,
A predetermined region of several tens of μm to several mm in the direction perpendicular to the partition direction on at least one surface of the seal portion, which is a part of the joint portion and where the metals are in contact with each other, is irradiated with a laser, thereby It is characterized in that a softening treatment is applied to a depth of 400 to 50 μm from the surface in a linear or band-like manner so as to soften the hardness of the base material of the joint portion .
In addition, the seal structure by the metal contact according to the present invention is
A seal structure using metal contacts that seals between a sealing target presence side and a sealing target non-existing side along a partition direction by bringing metals into contact with each other,
A softening treatment for softening at least one surface of a seal portion where metals are in contact with each other along the partition direction to a degree lower than the hardness of the base material, wherein the softened portion is streak-like in the partition direction. And, it is characterized in that it is applied so as to be arranged in a plurality in a direction intersecting with the partition direction.

The present invention can be characterized in that the hardness Hv of the surface to be softened is in the range of 150-200.

Further, in the present invention, when the metal is medium carbon steel or high carbon steel, the carbon contained in the metal is oxidized by laser heating in an air atmosphere for a short period of time to decarburize. It can be characterized by applying a softening treatment.

According to the present invention, it is possible to provide a sealing structure using metal contacts that can satisfactorily seal the object to be sealed even under a relatively severe use environment.

(A) is a cross-sectional view when the seal portion (contact surface) of the joint (joint portion) of the metal contact according to the present embodiment is softened by laser (cross-sectional view seen from direction B in FIG. 5A). , and (B) is an example of an image of a cross section taken when the seal portion (contact surface) of the joint (joint portion) of the metal contact according to the above embodiment is actually softened by laser, and (C ) is a graph in which the horizontal axis represents the depth X from the surface and the vertical axis represents the hardness Hv. (A) is a cross-sectional view when the seal portion (contact surface) of the joint (joint portion) of the metal contact according to the above embodiment is softened by laser after decarburization, and (B) is a cross-sectional view of the above embodiment. FIG. 4 is a cross-sectional view when the entire seal portion (contact surface) of the joint (joint portion) by the metal contact is not softened but softened in a streaky shape. (A) is a cross-sectional view when a plurality of rows of grooves (circumferential grooves) are dug in the sealing portion (contact surface) of the joint (joint portion) of the metal contact according to the above embodiment, and a plurality of rows of mountains having a trapezoidal cross section are formed. , (B) is an image taken from the outside of an example of the surface of the seal portion (contact surface) 1 having a trapezoidal uneven shape in (A), and (C) is an image taken at the time of tightening (at the time of tightening). FIG. 10 is a diagram for explaining a phenomenon that as the load increases and the deformation progresses, the contact area increases, so that the top of the mountain is less likely to collapse and does not collapse more than a predetermined amount. (A) is a diagram explaining that the load becomes constant when the peak is crushed to a predetermined degree (for example, about 50%), and (B) is at least two or more peaks within the actual hit width Z. It is the image which image|photographed from the outside an example of the surface of the seal|sticker part (contact surface) at the time of forming so that it may exist. (A) is a view showing a portion where a loose contact has been confirmed, and (B) is a view of the loose contact portion of the facing joint viewed from the AA direction of (A). (A) is a cross-sectional view showing an example of a metal joint to which the structure of the sealing portion (contact surface) of the joint according to the above embodiment can be applied, and (B) is a cross-sectional view showing another example of the same metal joint; It is a diagram.

An embodiment according to the present invention will be described below with reference to the accompanying drawings. It should be noted that the present invention is not limited by the embodiments described below.

A metal contact seal structure according to an embodiment of the present invention can be used to seal at least one of a fluid such as gas or liquid or powder (hereinafter simply referred to as a fluid). For example, it can be applied to various things such as metal joints of passages (pipes, etc.) for water, fuel, oil, refrigerants for air conditioners, and other fluids, and metal contact seals for high-pressure gas pipes such as CNG, LPG, and hydrogen. is.

As mentioned above, as an example of a method of sealing fluid leaks from microscopic gaps, there is a method of applying soft rubber or resin to the contact surfaces and crushing the rubber to bring the gaps into close contact.

However, such methods using rubber or resin cannot be used in high-pressure, high-temperature, or corrosive environments. There is a fact that it will be lost.

As another method, a copper or aluminum washer (gasket) (thickness 1 to 0.5 mm) is sandwiched between the joints to fasten the joint. There is a way to prevent it from doing so.

With such a method, the gap can be filled and sealed immediately after fastening, but if a large load is applied to the joint after that, the soft washer will be plastically deformed (set), loosening the fastening (the surface pressure of the contact surface will decrease), There is a problem that a gap is generated in the part (seal part) and leakage occurs.

For this reason, the present inventors have conducted various studies and experimental studies, and as a result, have found that the relatively severe usage environment that could not be solved by the above-described conventional methods could not be solved without using a resin gasket or a soft metal gasket. We have found a new seal structure for metal contacts that can effectively suppress fluid leakage even at the bottom.

The seal structure using a metal contact in the present invention is based on the idea that the seal performance is enhanced by increasing the actual contact area of the seal portion (contact surface).

More specifically, the sealing structure of the metal contact according to the present invention softens only the extreme surface of the contact surface of the joint so that it is easily crushed to prevent the formation of gaps, or softens the extreme surface of the contact surface of the joint. It is based on the idea of making the shape of the body easy to be crushed so as not to create a gap.

For details,
As <Method 1>, as shown in FIG. is softened using a laser (annealed). 1(A) is a cross-sectional view of the vicinity of the seal portion (contact surface) 1 viewed from the direction B in FIG. 5(A).
Here, the partitioning direction according to the present invention is a direction that substantially coincides with the extending direction of the seal portion 1 that separates the sealing target side and the sealing target non-existing side, and is substantially the plane of FIG. 1(A). The sealing portion 1 is formed in a linear or band shape extending in the orthogonal direction and extending in the partition direction (also in FIGS. 2A, 2B, and 3A). as well).

FIG. 1(B) shows an example of a cross-sectional image taken when the seal portion (contact surface) 1 of the joint (joint portion) 10 by metal contact is actually softened by laser. The material can be stainless steel (SUS304, SUS316, etc.), but low-carbon stainless steel (SUS304L, SUS316L, etc.) is more suitable because it is difficult to harden and easily softened.

FIG. 1C shows a diagram in which the horizontal axis represents the depth X from the surface and the vertical axis represents the hardness Hv. The hardness of the base material before softening is about 350 Hv, and the target is Hv=250 or less after softening. Actually, Hv was about 150 to 230 at the depth (X) from the surface, for example, in the range of 400 to 50 μm. With such a range, for example, when this structure was used for a sealing portion by a metal contact of a metal joint for high-pressure liquid fuel (light oil, gasoline, etc.) of several thousand bars, leakage did not occur.
However, the above is just an example, and other than "the depth (X) from the surface, for example, in the range of 400 to 50 μm, Hv = about 150 to 200", depending on the material of the base material and the specification change of laser processing, It is possible to change the depth from the surface or change the hardness (e.g. softer or harder), for example, "depth from the surface (X), e.g., in the range of 500 μm or less, Hv = 250 or less", or "Hv = 190 or less in the range of 300 µm or less in depth (X) from the surface", or "Hv = 190 or less in the range of 250 µm or less in depth (X) from the surface and Hv=170 or less". Furthermore, it is also possible to set Hv to 150 or less or 170 or less in the range of "depth (X) from the surface, for example, 500 μm or less".

By applying the softening treatment, in a joint (joint) 10 (or 20) using a metal contact, when the seal portions (contact surfaces) 1 of the joint face each other and are tightened (at the time of fastening), the soft portion is softened. It can be deformed by 200 to 50 μm to fill the gap and improve the sealing performance.

In addition, after tightening (fastening), since no soft portion remains, there is no further deformation and fastening is not loosened. In other words, even if a large load is applied to the joint, it will not undergo any further plastic deformation, so it is possible to suppress settling (a decrease in the surface pressure of the contact surface) over a long period of time. It is possible to solve the problem that a gap is generated in the (seal portion) and leakage occurs.

Fastening is not limited to fastening by screwing or the like, but includes fastening by a clamp or the like.
Further, the softening depth and hardness can be appropriately adjusted according to the material of the joint portion of the joint, the usage environment, and the like.

Here, the softening treatment (annealing treatment) in the present embodiment can be performed as follows using, for example, a laser device.
<Laser softening treatment (annealing treatment) method>
A seal portion (contact surface) 1 of a metal contact of a joint, which is an object to be processed, is irradiated with laser to soften only the surface (FIG. 1(A)).

Specifically, for example, the workpiece is rotated using a rotating jig or the like, and the laser beam is irradiated while gradually moving along the width direction Y of the seal portion 1 over one to a plurality of turns. Annealing is performed on the entire area in the width direction Y or a predetermined area.
It should be noted that the object to be processed can be applied to a metal joint using a metal contact seal or the like.

Examples of target materials include SUS materials (stainless steel materials) and steel materials with a base material hardness of about 250 to 400 HV, but are not limited to these and can be applied as long as they are metal materials that can be annealed. be.

The width (softened width) Y (the width of the softened layer formed in the seal portion 1) to be softened by annealing can be about several tens of μm to several mm. Also, the softening depth X can be about 50 to 700 μm.
The softened width Y can be the same width as the seal portion 1 , or can be a width narrower than the width of the seal portion 1 or a width wider than the width of the seal portion 1 .

Examples of specifications of laser processing equipment (apparatus) include the following.
The types of lasers can be carbon dioxide lasers, semiconductor lasers, fiber lasers, disk lasers, YAG lasers, and the like.

Oscillation method: continuous wave (CW), pulse oscillation, etc. Laser wavelength: about 300 to 1500 nm Laser output: several hundred watts Power density: 10 to 300 W/mm ²
Processing speed: several hundred mm/min
Condensing shape: circular, rectangular, etc.

As a specific type of laser processing equipment, for example, the LDF series manufactured by LASERLINE can be used.

In the case of medium-carbon steel (e.g., S53C) and high-carbon steel (e.g., S55C/SK), which are difficult to soften, the carbon contained in the metal is removed by laser heating in an air atmosphere for a short period of time. Oxidize and decarburize. This is done by utilizing the fact that the oxidation rate of carbon is faster than that of iron.
In this case, some oxides of iron are formed and are removed with a laser.
After that, the softening treatment of (1) above is performed (see FIG. 2A).
However, the decarburization treatment performed before the softening treatment is not limited to laser heating as described above, and can be performed using an electric furnace or the like.

As <Method 2>, if the tightening load (fastening load) is large and the load during actual operation is large, the entire contact surface should not be softened, and should be streaked in the direction of the partition (if the outer periphery of the contact surface is circular, or spiral stripes), and softened so that a plurality of them are lined up in a direction intersecting the partition direction. That is, as shown in FIG. 2B, a softened portion 30 (width a=approximately 0.2 mm to 1 mm) and a non-softened portion 40 (width b=approximately 0.5 mm to 3 mm) are formed on the surface of the seal portion 1. exist alternately. Further, the depth from the surface of the softened portion 30 can be made equivalent to the depth X in FIG. 1(A).

The process heats with a laser that can focus energy.
This processing can be carried out by adjusting the output of the laser processing apparatus used in (1) above.

In addition, when the outer periphery of the seal portion (contact surface) 1 is circular, in the case of softening in an annular (endless) streak, rotate the work using a rotating jig or the like so that the starting point and the end point are aligned. is irradiated with a laser to form one circular stripe, and then the irradiation position of the laser is moved along the Y direction to form another circular stripe in order, resulting in a plurality of rows (or stripes) of A streaky softened portion can be formed. In addition, when the outer periphery of the seal portion (contact surface) 1 is circular, in the case of softening it into a spiral streak, the laser irradiation position is moved along the Y direction while rotating the workpiece using a rotating jig or the like. By moving gradually, it is possible to form continuous helical streaks (male threaded streaks) on the outer circumference of the seal portion (contact surface) 1 .

As <Method 3>, the shape of the sealing portion (contact surface) of the joining portion of the joint is easily crushed to prevent the formation of a gap.
Specifically, as shown in FIG. 3(A), a plurality of rows (or rows) of grooves (grooves extending in the partition direction) 50 are dug in the seal portion (contact surface) 1, and a mountain (convex) having a trapezoidal cross section is formed. 60 are formed in a plurality of rows in a direction intersecting the direction in which the grooves 50 extend (partitioning direction), that is, the surface of the seal portion (contact surface) 1 is made uneven with protrusions having a trapezoidal cross section. FIG. 3B is an image of an example of the surface of the seal portion (contact surface) 1 having an uneven shape with a convex portion having a trapezoidal cross section. The cross section here is a cross section cut along a plane substantially perpendicular to the extending direction of the groove 50 or the peak (projection) 60 .

The pitch P of the grooves 50 (ridges 60) can be set to about 45 μm to 600 μm, and the depth from the surface of the grooves 50 can be set to be equivalent to the depth X in FIG. 1(A). Further, the upper base d of the trapezoidal cross section of the peak 60 can be about 10 μm to 100 μm, the lower base D can be about 15 μm to 500 μm, and the inclination angle θ can be about 10 to 85°. The cross-sectional trapezoidal shape of the peak 60 is such that the upper base d is shorter than the lower base D. As shown in FIG. That is, in the present embodiment, the peak (convex portion) 60 having a continuous trapezoidal cross-sectional shape with the side on the surface side of the seal portion 1 as the upper base and the side on the bottom side of the groove 50 as the longer lower base is formed in the partition direction. A plurality of rows (or rows) were formed in a direction intersecting with the .
This trapezoidal shape makes it easier for the crest to collapse during tightening (fastening). As the tightening load (fastening load) increases and deformation progresses, the contact area increases, making it difficult for the top of the crest to collapse, and it will not collapse beyond a predetermined level (Fig. 3(C)).

That is, as shown in FIG. 4A, for example, when the height of the mountain is crushed to a predetermined level (for example, about 50%), the load becomes constant, so the groove 50 is used within this range. It is preferable to form a mountain 60 by extension.

For this reason, even if a large load is applied to the seal portion (contact surface) 1 of the joint, the seal portion (contact surface) 1 does not undergo any further plastic deformation. Therefore, it is possible to solve the problem that a gap is formed in the joint (sealed portion) after a long period of time and leakage occurs.

Moreover, according to method 3, it is possible to improve the sealing performance by eliminating gaps in the sealing portion (contact surface) due to crushing due to tightening, and to improve the sealing performance. , the groove 50 accommodates and dams the fluid, and functions as a so-called multi-stage labyrinth seal, thereby enhancing the sealing performance to a higher level.

As for the method for forming the groove 50, in the case of forming the annular (endless) groove 50 when the outer periphery of the seal portion (contact surface) 1 is circular, as in the case of the softened portion 30 described above, a rotary jig is used. , etc., to irradiate the laser so that the starting point and the end point coincide with each other to form one annular groove 50. Then, the laser irradiation position is moved (scanned) along the Y direction. Multiple rows (lines) of grooves 50 can be formed by sequentially forming other annular grooves 50 . Further, when the spiral groove 50 is formed when the outer periphery of the seal portion (contact surface) 1 is circular, the laser irradiation position is moved along the Y direction while rotating the workpiece using a rotating jig or the like. By gradually moving (scanning), a continuous spiral groove (male screw groove) 50 can be formed on the outer circumference of the seal portion (contact surface) 1 .

In consideration of actual product variations and variations in use (tightening force, etc.), as shown in FIG. That is, the ridges 60 can be formed at intervals smaller than the actual width Z (pitch smaller than half Z).

Here, grooving according to the present embodiment will be described.
<Groove processing>
As a processing method using a laser, as described above, fine groove processing is performed by irradiating a laser to the seal portion 1 of the joint formed by the metal contact of the object to be processed. For example, the workpiece is rotated using a rotating jig or the like, or the laser is scanned by a scanner optical system and irradiated with the laser to perform groove processing.
It should be noted that the object to be processed can be applied to a metal joint using a metal contact seal or the like.
Examples of target materials include SUS materials (stainless steel materials) and steel materials with a base material hardness of about 250 to 400 HV. is applicable.
The grooves 50 formed in the present embodiment can have a groove width of about several tens of μm, a groove pitch of about several tens of μm, and a groove depth of about several tens of μm.

Examples of specifications of laser processing equipment (apparatus) used for groove processing are as follows.
As for the type of laser, an ultrashort pulse laser can be used.
The pulse width can be about "50 fs [femtoseconds] to 950 ps [picoseconds]", and the laser wavelength can be about "200 to 1600 nm [nanometers]".
The pulse energy can be "1 μJ [microjoule] to 1 mJ [millijoule]".
Specific examples of usable laser processing equipment (apparatus) include, for example, the Monaco series manufactured by COHERENT.

As a metal joint to which the structure of the seal portion (contact surface) 1 of the joint portion 10 according to the present embodiment is applied, for example, those shown in FIGS. be done.

FIG. 6A shows a sectional view of a metal joint 70 to which the structure of the seal portion (contact surface) 1 of the joint portion 10 (20) can be applied. The metal joint 70 has a flared portion 72 in which the tip of a pipe (piping) 71 through which fluid flows is widened in a tapered shape. and a seal portion (1) of a tapered portion 73 (corresponding to the joint portion 20) having a narrowed tip that contacts the .

A fastening nut 74 through which a pipe (piping) 71 is inserted is engaged on the outside of the flared portion 72, and a female threaded portion 74A formed inside the fastening nut 74 is the outer peripheral threaded portion of a male screw 75 having a tapered portion 73. It is screwed to 75A. Therefore, when the fastening nut 74 is tightened to the male screw 75, the fastening nut 74 presses the contact surface of the flared portion 72 of the pipe (piping) 71 against the contact surface of the tapered portion 73, thereby is formed.
Various seal structures described above can be adopted for the seal portion 1 of FIG. 6(A).

FIG. 6B shows a cross-sectional view of a metal joint 80 to which the structure of the seal portion (contact surface) 1 of the joint portion 10 (20) can be applied. The metal joint 80 has a tip tapered portion 82 in which the tip of a pipe (piping) 81 through which fluid flows is narrowed in a tapered shape, and the seal portion (1) on the outer surface of the tip tapered portion 82 (corresponding to the joint portion 10) , and a seal portion (1) of an inner tapered portion 83 (corresponding to the joint portion 20) that contacts the same.

A fastening nut 84 through which a pipe (piping) 81 is inserted is engaged with the outside of the tip tapered portion 82 , and a female threaded portion 84A formed inside the fastening nut 84 is formed on the outer periphery of a male screw 85 having an inner tapered portion 83 . It is screwed onto the threaded portion 85A. Therefore, when the fastening nut 84 is tightened to the male screw 85, the fastening nut 84 presses the contact surface of the tip tapered portion 82 of the pipe (piping) 81 against the contact surface of the inner tapered portion 83, thereby sealing. Part 1 is formed.
Various seal structures described above can be adopted for the seal portion 1 of FIG. 6(B).

However, the sealing structure with metal contacts according to the present embodiment is not limited to the one described above, and can be applied to sealing portions with metal contacts such as other metal joints including flange joints.

As described above, according to the sealing structure of the metal contact according to the present embodiment, only the extreme surface of the contact surface of the joint is softened and easily crushed to prevent the formation of a gap, or It is based on the idea of making the extreme surface of the contact surface into a shape that is easy to collapse so that no gaps are formed. In addition, it is possible to effectively suppress fluid leakage even under a relatively severe usage environment.

In other words, according to the present embodiment, it is possible to provide a seal structure using metal contacts that can satisfactorily seal a fluid even under a relatively severe use environment.

In addition, in the present embodiment, the seal structure according to the present embodiment is not limited to applying the seal structure according to the present embodiment to one seal portion 1 of the joint portion 10 (20). structure can be applied. In that case, both can select the same one from the above method 1, the above method 2, and the above method 3 and both can have the same seal structure, and both can select different methods and both have different seals. A structure is also possible.

In the present embodiment, the laser processing is performed by rotating the side to be processed. .

In addition, according to the laser processing equipment (apparatus) (ultrashort pulse laser) according to the present embodiment, it is possible to form complicated and fine grooves with high precision without causing burrs. High-precision and fine processing is possible even for sizes and complex shapes that cannot be formed by cutting or pressing, as well as difficult-to-process surface shapes such as tapered surfaces that are difficult to form by cutting or pressing. It is possible.

The embodiment described above is merely an example for explaining the present invention, and various modifications can be made without departing from the gist of the present invention.

1 Seal part (contact surface)
2 Seal upstream (gas upstream)
3 Downstream of seal section (downstream of gas)
4 Gap (missing part)
5 Contact surface (strike surface)
10, 20 joint (metal contact part of metal joint)

Claims (4)

A sealing structure using metal contacts that seals a sealing target along a partition direction between a sealing target presence side and a sealing target non-existing side by bringing metals into contact with each other at the joints that face each other,
A predetermined region of several tens of μm to several mm in the direction perpendicular to the partition direction on at least one surface of the seal portion, which is a part of the joint portion and where the metals are in contact with each other, is irradiated with a laser, thereby A sealing structure by metal contact, characterized in that a softening treatment is applied to a depth of 400 to 50 μm from the surface in a linear or band-like manner so as to soften the hardness of the base material of the joint portion . A seal structure using metal contacts that seals between a sealing target presence side and a sealing target non-existing side along a partition direction by bringing metals into contact with each other,
A softening treatment for softening at least one surface of a seal portion where metals are in contact with each other along the partition direction to a degree lower than the hardness of the base material, wherein the softened portion is streak-like in the partition direction. and a sealing structure by a metal contact, characterized in that a plurality of the seals are arranged in a direction crossing the partition direction. 3. The sealing structure by metal contacts according to claim 1, wherein the hardness Hv of the surface to be softened is in the range of 150-200. When the metal is medium carbon steel or high carbon steel, the carbon contained in the metal is oxidized by laser heating in an air atmosphere for a short period of time to perform decarburization, and then the softening treatment is performed. 4. The sealing structure by the metal contact according to any one of claims 1 to 3 .

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