JPH07243530A - Metal gasket - Google Patents

Abstract

PURPOSE:To achieve an innovated characteristic of metal gasket using a material based on a high-silicon content stainless steel of eduction hardening type which was developed for structural use but has not been used as a material for metal gasket. CONSTITUTION:A specified shape is formed from a thin sheet of high-silicon two-phase stainless steel of eduction hardening type consisting of 0.05wt.% carbon, 3-6wt.% silicon. no more than 5wt.% manganese, 5-10wt.% nickel, 6-12wt.% chromium (not including 12), 0.2-1wt.% molybdenum, 0.5-3wt.% copper, and iron as remainder, followed by age hardening, and the steel plate(s) 9, 10 thus formed is/are laid either solely or in a plurality of layers.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal gasket interposed between an engine cylinder block and a cylinder head, and more particularly to a thin metal gasket having both toughness, heat resistance and durability.

[0002]

2. Description of the Related Art Normally, a cylinder head gasket is interposed between a cylinder block and a cylinder head of an engine, and the cylinder head gasket seals a combustion chamber of the engine in an airtight manner so that gas is discharged from the combustion chamber to the outside. To prevent it from leaking. Recently, as the cylinder head gasket, a metal gasket in which metal plates having a thickness of 0.05 to 1.0 mm are laminated has become mainstream. This metal gasket has an opening formed at a position corresponding to the cylinder bore, and a bead plate having an annular bead formed along the outer periphery of the opening, and an opening formed at a position corresponding to the cylinder bore. It is common to have a structure in which a stopper plate having a stopper part formed by folding back the peripheral part of the part and a spacer plate are appropriately laminated in the middle.

Here, since the bead plate secures the sealing property by the surface pressure of the annular bead, it is necessary to use a spring material having a large proof stress and a large tensile strength as its material. Spring steel is used. On the other hand, the stopper plate is a stopper portion formed at the peripheral portion of the opening to prevent the annular bead from being fully compressed to prevent cracks and settling, improve durability, and enhance reliability of sealing performance. However, since the stopper is formed by folding it back, the material has a stretch of about 2
It is necessary to use a material sufficiently larger than 0% and excellent in bending workability, and SUS304 general material is mainly used.

In recent years, the demand for thinner metal gaskets has been increasing from the viewpoint of improving the combustion efficiency of the engine.
There is a limit in 01 type spring steel and SUS304 type general material. For example, a conventional bead plate has a thickness of 0.2 to 0.2.
Although the thickness of 5 mm is used, if the thickness is made thinner than that, the strength of the annular bead will be reduced and sufficient surface pressure will not be obtained, and cracks will occur in the R part on the outside of the bead during bead molding, and the bead shoulders Micro-cracks are generated in the R part and the sealing property is deteriorated. In addition, the stopper plate has a grommet structure in which another metal plate, for example, a flat part around the opening of the bead plate is inserted between the substrate and the stopper part formed by folding back, and the stopper plate has a thickness of 0.05. It is possible to use a board having a length of up to 0.15 mm, but with a goby-folding structure in which the substrate and the stopper are in close contact with each other, the radius of curvature of the bent part becomes small and cracks occur at this part, impairing durability. , In this case it was a problem.

To some extent, these problems can be improved by using a comparative steel (a steel having the chemical composition shown in Table 1). By the way, the comparative steel is a high-hardness stainless steel not specified in JIS, and in the state of solution heat treatment, SUS3
It is superior to the 04 type general material in yield strength and tensile strength and slightly inferior in elongation, but it is superior to the SUS304 type general material as the material of the stopper plate. Further, since the comparative steel is superior in proof strength and tensile strength to the SUS301 series spring steel in the cold rolled state, it can be replaced with the SUS301 series spring steel as the material of the bead plate, but the elongation is extremely small. Therefore, the problem of bead cracking remains. On the other hand, as a material for the metal gasket, SUS630 or SUS631 which is precipitation hardening type stainless steel is also considered, but this stainless steel has a JI
As specified by S, the standard dimension is -73 ±
Since a heat treatment step of holding the temperature at 6 ° C. for 8 hours is required, the heat treatment requires a great deal of time and cost.

Further, a high silicon toughness steel disclosed in Japanese Patent Publication No. 46-9536 is conventionally known. This high silicon toughness steel has C0.05% or less, Si3.5-6
%, Mn 5% or less, Ni 3 to 9%, Cr 6 to 15%, and the balance Fe, the sum of the contents of Ni and Mn is twice the Si content, and the content of Cr is 2.5 of the Si content. The A ₃ transformation point is lowered to 750 ° C. or lower by adjusting the double to the target, and the crystal is refined to give abundant toughness equivalent to double that of other tough special steels. Hereinafter, this high silicon toughness steel is referred to as "Silicolloy A1". "Silicolloy" is a trade name of high silicon stainless steel manufactured by Nippon Silycoloy Industries, Ltd., which is the applicant of the present invention.

[0007] Further, Japanese Patent Publication No. 47-23056 discloses that a solution treatment is applied, and then aging is performed at 500 ° C., so that Vickers hardness of 5 is obtained without substantially causing deformation.
Aged high silicon steel that hardens to 00 or above is disclosed.
This aging high silicon steel has C0.05% or less, Si4 to 7
%, Mn 3% or less, Ni 6-16%, Cr 12-20
%, V 4% or less, each 1% or less Ti, Al and each 4% or less Mo, W or each 1% or less C
u, Co alone or in combination, with the balance Fe, the sum of the contents of Ni and Mn being twice the content of Si, C
The content of r is adjusted with a target of 3 times the content of Si. Hereafter, this aging high silicon steel is referred to as "Silicolloy C".
Called.

This silicoloy C is the aforementioned silicoloy A.
1, the content of Si, Ni and Cr is increased, and Mo, W, V and Co, and Cu and Ti are newly added.
And Al are added to enhance the age-hardening property, and are developed for wear resistance with high hardness. Therefore, as compared with the above-mentioned silicoloy A1, since a large amount of expensive elements are used, the cost is high as a whole, so that it is currently used only in limited products with high added value.

In addition, the above-mentioned silicoloy A1 is improved to have a mixed state of a martensite phase and an austenite phase at room temperature, and desirable properties derived from both of them,
That is, a precipitation hardening type high silicon stainless steel (Japanese Patent Publication No. 57-17070) having both toughness and corrosion resistance has also been developed. This precipitation hardening high silicon stainless steel has a C0.
05% or less, Si2-4%, Mn2% or less, Mo0.2
~ 1%, Cu 0.5 ~ 3%, Ni 5 ~ 10%, Cr 8 ~
Consists of 13% and the balance Fe, twice the Cr content and Si
The sum of the contents is adjusted to 20 to 30%. Hereinafter, this precipitation hardening type high silicon stainless steel is referred to as "Silicolloy A2".

[0010]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
Although A2 and A2 are mainly used for structural purposes and are cheaper and more versatile than Silicolloy C, they are inferior to Silicolloy C in terms of hardness. However, Silicolloy A2, which is a special precipitation hardening heat treatment for the steel type, is provided with optimum mechanical properties as a material of the metal gasket by performing a simpler heat treatment than the precipitation hardening heat treatment of SUS630 or SUS631. I found it.

In view of the above-mentioned situation, the present invention is intended to solve the problems that are general-purpose and inexpensive developed for structural purposes, but were not conventionally used as a material for metal gaskets. It is a point to provide a metal gasket which is newly made of a material based on a hardening type high silicon stainless steel (Silicolloy A2) and has toughness, heat resistance and durability, and which can be made thinner.

[0012]

In order to solve the above-mentioned problems, the present invention provides, in weight%, 0.05% or less of carbon, 3 to 6% of silicon, 5% or less of manganese, and 5% or less. ~ 1
0% nickel and 6-12% (excluding 12%)
Chromium, 0.2-1% molybdenum, 0.5-3
% Of copper and the balance of iron, a precipitation hardening type high silicon duplex stainless steel thin plate is processed into a predetermined shape and then age hardened. Configured.

Here, the precipitation hardening high silicon duplex stainless steel sheet is maintained at a temperature of 900 to 1000 ° C. for a predetermined time to be rapidly cooled, and then maintained at a temperature of 600 to 700 ° C. for a predetermined time to be cooled, and then, A component plate is processed and formed from the steel sheet in a state of being heated to a solution temperature of 950 to 1150 ° C. and rapidly cooled, and the component plate is maintained at a temperature of 420 to 520 ° C. for at least 1 minute per 1 mm of its thickness. It is a preferred embodiment to be age hardened.

Then, the thickness of the constituent plate is 0.05 to
It is more preferable that the length is set to 0.15 mm, and that a stopper portion is formed by folding back the peripheral edge of the opening provided in the one component plate, and an annular bead is formed along the outer periphery of the stopper portion. This is an example.

[0015]

The metal gasket of the present invention having the above-mentioned content is a precipitation hardening type high silicon duplex stainless steel, that is,
05% or less carbon, 3 to 6% silicon, 5% or less manganese, 5 to 10% nickel, 6 to 12% (excluding 12%) chromium, and 0.2 to 1 % Molybdenum, 0.5 to 3% copper, and the balance iron, a thin plate of precipitation hardening high silicon duplex stainless steel is processed into a predetermined shape,
It is cured in a relatively short time by a special age hardening treatment,
After that, the component plate formed by age-hardening is a metal gasket composed of a single plate or a plurality of laminated plates.
The metal gasket has an age hardening temperature (420 to 520).
It has toughness, heat resistance and durability that enable continuous use for a long time at a high temperature up to (.degree. C.).

Here, the reason for using each element and the reason for the mixing ratio thereof are described in detail in the above-mentioned Japanese Patent Publication No. 57-17070, but in the present invention, chromium is used especially for the purpose of reducing the cost of the material. The upper limit of the content of is set to 12% or less (however, 12% is not included). Needless to say, it is preferable to set the content of other elements other than iron as low as possible. The metal gasket of the present invention uses the precipitation hardening type high-silicon duplex stainless steel in the above-mentioned compounding ratio to make the constituent plate 0.05 to 0.
It has mechanical strength, toughness, heat resistance, and durability even when thinned to 15 mm, and by age hardening, those properties are improved and hardness is increased, and the elongation after age hardening is relatively high. Since it is large, no cracks occur in the bead or stopper, and it has an ideal sealing property.

However, generally, there is a drawback that the processing becomes difficult when the hardness of the material becomes high, but for this problem, it is fortunate that the steel material used in the present invention is a precipitation hardening type. That is, for the contradictory properties that the hardness is high and the workability is excellent, three-step heat treatment is sequentially performed in a specific temperature range by the experience accumulated by the present inventor and repeated experiments. It was found that the problem can be solved by performing press work or bending work during. That is, as shown in FIG. 1, first, in a steelmaking process of a base material, the above precipitation hardening high silicon duplex stainless steel ingot is rolled or cast to form a steel material having a shape close to a final part, and then a raw steel is produced. A first heat treatment step of refining, a second heat treatment step of forming a supersaturated solid solution which is a source of age hardening (solution treatment), and processing into a predetermined shape to produce a component plate having an annular bead and a stoper portion. The press forming step and the third heat treatment step of age hardening are performed thereafter.

The first heat treatment step is 900 to 1000.
C., preferably 950.degree. C., for a predetermined time (at least 10 minutes per cm thickness of steel), followed by oil phase quenching, then 600-700.degree. C., preferably 65.
After maintaining at 0 ° C. for a predetermined time (at least 1.5 hours per 1 cm of steel thickness), vapor phase cooling (air cooling) is performed to temper the steel material. Note that the temperature does not necessarily have to be limited to the above values, because there is a fluctuation of about ± 5% due to a measurement error of the temperature measuring device and a temperature setting error of the heating device. The same applies to the temperature value described later.

In the second heat treatment step, 950 to 1150
The solution is heated to a solutionizing temperature of ℃, preferably around 1050 ℃, and then rapidly cooled (water cooled). The time required for this heating is sufficient to raise the temperature of the steel material to a substantially uniform temperature inside. By this second heat treatment step, the surface hardness of the steel material is 245 to 320 in Vickers hardness HV,
The growth reaches 48%. The surface hardness and elongation in this state are most suitable for press working, bending, etc.,
Therefore, it is possible to perform processing with high accuracy and excellent surface finish.

In the third heat treatment step, the thickness of the steel material is 1 mm.
Therefore, it is aged for at least 1 minute or more and maintained at a temperature of 420 to 520 ° C., preferably 460 to 480 ° C. for age hardening. With respect to the time spent in the third heat treatment step, if the thickness of the steel material is, for example, 0.1 mm, the steel material can be sufficiently age-hardened in about 10 seconds. Then, after this third heat treatment step, the surface hardness increases to 490 to 680 in Vickers hardness HV.

As described above, the precipitation hardening type high-silicon duplex stainless steel material is subjected to the above-mentioned first heat treatment step and the second heat treatment step, and then subjected to the stress processing and bending processing into a predetermined product shape by the press molding process, Finally, the third heat treatment step is performed. Therefore, 1000 which causes thermal deformation in the steel material
After the first heat treatment step and the second heat treatment step accompanied by heat treatment at a high temperature close to ℃, and further, the surface hardness of the steel material is processed in a hardness state of about 245 to 320 in Vickers hardness HV, Easy and 500 ° C after its processing
Since the third heat treatment step accompanied by a low temperature heat treatment is performed as a moderate heat treatment, thermal deformation of the work piece is extremely small, and high precision and high hardness (hardness is 490 to 68 in Vickers hardness HV).
The metal gasket of 0) can be provided. Here, it should be noted that SUS630 or SUS63, which is conventionally known as precipitation hardening stainless steel, is used.
The point is that the supercooling heat treatment step of holding at −73 ± 6 ° C. for 8 hours as in the precipitation hardening heat treatment of 1 is completely unnecessary.

Further, the precipitation hardening type high silicon duplex stainless steel used in the present invention is excellent in proof stress and tensile strength and has a large elongation. It is possible to bend the peripheral edge of the provided opening to form a stopper portion and form an annular bead along the outer periphery of the stopper portion, whereby the metal gasket can be made thin.

[0023]

EXAMPLES Next, the details of the present invention will be further described based on examples. Precipitation hardening type high silicon duplex stainless steel (hereinafter referred to as "Silicolloy G") suitable for the metal gasket used in the present invention.
The chemical composition of) is 0.05% by weight.
The following carbon, 3 to 6% silicon, 5% or less manganese, 5 to 10% nickel, and 6 to 12% (however, 12
%) And 0.2 to 1% molybdenum,
It is composed of 0.5 to 3% copper and the balance iron.

In the precipitation hardening type high silicon duplex stainless steel, the content of silicon is specified to be 3 to 6% from the practical viewpoint. The carbon content not only causes a decrease in toughness due to its increase, but also a decrease in corrosion resistance. Therefore, the carbon content is specified to be 0.05% or less, which can be sufficiently achieved in a normal steelmaking process. Manganese does not contribute much to the hardening of the precipitation hardening stainless steel, but it contributes to the refinement of the structure and the increase of the hardness. Therefore, the manganese is slightly increased from the usual specification range of 2% for stainless steel to 5% or less. Stipulated in. Molybdenum and copper are added for the purpose of increasing the corrosion resistance, but since molybdenum is an expensive and strong ferrite-forming element, its use is limited to 1% or less. Copper acts as a precipitation hardening element and also as an austenite forming element, and its ferrite suppressing action is about 1/3 of the ferrite forming action of molybdenum. It is set to be less than 3%. Further, since the amount of copper significantly impairs the hot workability due to the increase in the amount, the upper limit value is suppressed to 3%. Furthermore, the lower limits of molybdenum and copper are to ensure corrosion resistance,
It is specified as 0.2% molybdenum and 0.5% copper.

In the above composition range of carbon, manganese, copper and molybdenum, the nickel content is set to 5 for the purpose of keeping the characteristics of the precipitation hardening type high silicon duplex stainless steel and minimizing the material cost. The content of chromium is regulated to 6 to 12% (excluding 12%) while being set to 10%. Here, the reason for excluding 12% in the content of chromium is that the content of chromium in the above-mentioned silicoloy C is 12 to 20% and the material cost is reduced as compared with silicoloy C.

Next, the results of actually manufacturing a sample and examining each mechanical property after heat treatment will be described. The sample of the present invention has carbon: 0.01%, silicon:
4.0%, manganese: 4.0%, nickel: 6.0%,
Chromium: 6.0%, molybdenum: 0.3% and copper: 0.
A steel plate having a composition of 6% and the balance iron was manufactured, hot-rolled at a rolling ratio of about 30%, and further cold-rolled while being stretched (steel making process of the base metal). First, the above-mentioned sample was maintained at a temperature of 920 ° C. for a predetermined time, followed by quenching in an oil phase, and then maintained at a temperature of 660 ° C. for a predetermined time,
It was air-cooled and tempered (first heat treatment step). Then 1050
After heating to a temperature of ˜1100 ° C., the oil phase was rapidly cooled for solution treatment (second heat treatment step). Finally, after maintaining the temperature of 480 ° C. for a predetermined time to age-harden, it was cooled (3rd
Heat treatment process).

Table 1 shows a sample of precipitation hardening type high silicon duplex stainless steel (Silycolloy G) used in the present invention and SUS6 which is a precipitation hardening type stainless steel prominent as a comparative material.
No. 31, SUS304A and SUS301H used as materials for conventional metal gaskets, and representative chemical compositions of comparative steels that are considered for use as metal gaskets, and Table 2 shows the mechanical properties of each steel type. Shows the result of measurement after heat treatment in the table.

[0028]

[Table 1]

[0029]

[Table 2]

Here, in the silicoloy G according to the present invention shown in Table 2, the upper solution heat treatment corresponds to the first heat treatment step, and the lower precipitation hardening heat treatment corresponds to the second and third heat treatment steps. Therefore, the mechanical properties in the lower stage are measured values after the first to third heat treatment steps. As can be seen from the comparison result, the silicoloy G according to the present invention has the proof stress and the tensile strength required as the constituent plate of the metal gasket,
SUS30 used as a material for conventional bead boards
It is comparable to 1H, and has an elongation of 20% or more required for bending workability even after age hardening, and is comparable to SUS304A used as a material for a conventional stopper plate. In other words, it is possible to fold the annular bead and the peripheral edge of the opening to form the stopper part at the same time on one component plate that constitutes the metal gasket, thereby reducing the number of component plates and reducing the metal plate. It is possible to reduce the thickness of the gasket.

In addition, since the precipitation hardening heat treatment of silicoloy G according to the present invention does not perform a low temperature treatment of 0 ° C. or lower, SU
The heat treatment is so simple that it cannot be compared with S631. In addition, SUS631 has sufficient mechanical strength, tensile strength, and hardness in terms of mechanical properties after precipitation hardening, but its elongation is small at 6%, so it is repeatedly hit by vertical vibration of the cylinder head when the engine is driven. Or, if the cylinder block and the cylinder head are repeatedly deformed in the lateral direction due to the difference in coefficient of thermal expansion, cracks may occur and durability may be deteriorated. Further, the comparative steel is also satisfactory in yield strength, tensile strength and hardness after cold rolling, but has a smaller elongation and has the same problem.

Next, the steelmaking process and press forming process of the base material will be briefly described. Regarding the steelmaking process of the base material,
Conventionally, it was difficult to obtain pure iron with an extremely low carbon content, so it was manufactured by vacuum melting to limit the mixing of carbon in the steelmaking process, but in recent years it has become easier to obtain pure iron, so vacuum melting No need to use a furnace. As a result, the steel making process has been remarkably simplified, and it has become possible to make steel by rolling, forging or casting. Furthermore, precision casting by the lost wax method or the like is possible, and precision parts can be manufactured. Further, since press working is performed in a state where the hardness after passing through the first and second heat treatment steps is relatively low (Vickers hardness HV245 to 320), press working and bending work are performed in the same manner as ordinary stainless steel. Of course, a general-purpose machine tool such as a lathe, a drilling machine, a milling machine and the like can easily perform cutting and grinding.

Therefore, on the premise that the above-mentioned heat treatment is applied, the constituent plate of the metal gasket is manufactured by using the precipitation hardening type high silicon duplex stainless steel (Silicolloy G) having the above composition.

Next, specific examples of the metal gasket of the present invention will be described. FIG. 2 shows an exploded cross-sectional view of an essential part of an engine showing a typical embodiment of the present invention. Metal gasket 1 (cylinder head gasket) of this embodiment
Is interposed between the cylinder block 2 and the cylinder head 3.

First, the structure of an engine equipped with the metal gasket 1 of the present invention will be briefly described. The cylinder block 2 has a structure in which a cylinder bore 4, a cooling water hole (not shown), and a lubricating oil hole are formed.
A piston 5 is arranged in the cylinder bore 4.
A cylinder head 3 is arranged above the cylinder block 2, and a combustion chamber 6 is formed by the cylinder bore 4, the piston 5 and the cylinder head 3.
Between the cylinder head 3 and the cylinder head 3, a metal gasket is provided to prevent gas from leaking from the combustion chamber 6 to the outside and to prevent cooling water or the like from entering the cylinder bore 4 through a water hole or an oil hole. 1 is installed.

The cylinder head 3 is provided with each combustion chamber 6
, An intake port and an exhaust port, both of which are not shown, are opened, and an intake valve 7 is arranged in the intake port.
An exhaust valve 8 is arranged in the exhaust port, and both valves 7 and 8 are opened and closed by a valve mechanism (not shown) provided on the upper portion of the cylinder head 3.

Then, the metal gasket 1 of the first embodiment.
2 has a structure in which two constituent plates are laminated as shown in FIGS. 2 and 3, and for convenience sake, they are referred to as a first constituent plate 9 and a second constituent plate 10 from the cylinder block 2 side. First component plate 9
The (bead plate) is a thin plate having a thickness of 0.05 to 0.25 mm, has an opening 11 formed at a position corresponding to the cylinder bore 4, and has an annular bead 12 protruding downward along the outer periphery of the opening 11. Is formed. Also, the second component plate 1
0 (stopper plate) is a thin plate having a thickness of 0.05 to 0.15 mm, is laminated on the upper surface of the first component plate 9, and has an opening 13 having a smaller diameter than that at a position corresponding to the opening 11. Along with the formation, the peripheral portion of the opening 13 is folded back so as to wrap around the flat portion inside the annular bead 12 of the first component plate 9 to form the stopper portion 14 of the grommet structure. With this stopper portion 14,
When the metal gasket 1 is assembled between the cylinder block 2 and the cylinder head 3, the annular bead 12 is prevented from being fully compressed, and the sealability is secured by the surface pressure due to the restoring property of the annular bead 12. Here, the first component plate 9 has a thickness of 0.2.
mm, a thin plate having a thickness of 0.1 mm is used for the second component plate 10,
When a coating layer having a thickness of 0.03 mm is provided as the sealing material, the total thickness of the metal gasket 1 of this embodiment is about 0.43 mm.

FIG. 4 shows a second embodiment of the metal gasket 1, in which the first component plate 9 is formed of a thin plate having a thickness of 0.05 to 0.15 mm, and the peripheral edge of the opening 11 is goby-folded upward. The second component plate 10 is formed of a thin plate having a thickness of 0.05 to 0.25 mm, and the stopper 15 is formed by folding back in a circular shape, and the annular bead 16 protrudes downward along the outer periphery of the opening 13. Is formed. Also in this case, the first component plate 9 has a thickness of 0.1 mm, and the second component plate 10 has a thickness of 0.2 m.
When a thin plate of m is used and a coating layer having a thickness of 0.03 mm is provided as a sealing material, the total thickness of the metal gasket 1 is about 0.43 mm.

FIG. 5 shows a third embodiment of the metal gasket 1, in which both the first component plate 9 and the second component plate 10 have a thickness of 0.0.
The first component plate 9 is formed by a thin plate having a thickness of 5 to 0.15 mm, the peripheral edge of the opening 11 is folded back upward to form a stopper portion 15, and the stopper portion 15 is formed downward. The annular bead 12 is formed so as to protrude toward the second component plate 10. The second component plate 10 has an annular bead 16 protruding downward so as to be in close contact with each other along the outer periphery of the opening 13 at a position corresponding to the annular bead 12. It was formed. In this case, by reducing the thickness of the component plates, the springiness of the bead per component plate is reduced and the surface pressure is reduced, but the annular beads 12, 16 of the two component plates 9, 10 are reduced.
This is prevented by arranging at the same position, ensuring sufficient surface pressure and improving sealing performance. Here, the first component plate 9,
When a thin plate having a thickness of 0.1 mm is used as the second component plate 10 and a coating layer having a thickness of 0.03 mm is provided as a sealing material, the total thickness of the metal gasket 1 of this embodiment is about 0.
It will be 33 mm.

FIG. 6 shows a fourth embodiment of the metal gasket 1, both the first component plate 9 and the second component plate 10 having a thickness of 0.0.
It is formed by a thin plate of 5 to 0.15 mm, the first constituent plate 9 is formed with an annular bead 12 protruding downward along the outer periphery of the opening 11, and the second constituent plate 10 is the peripheral edge of the opening 13. The stopper portion 14 is formed by folding the portion downward in a goby fold shape, and an annular bead 16 protruding downward is formed along the outer periphery of the stopper portion 14 at a position corresponding to the annular bead 12 so as to be in close contact with each other. It was done. Also in this case, a thin plate having a thickness of 0.1 mm is used for both the first component plate 9 and the second component plate 10 and a thickness of 0.0
When the coating layer of 3 mm is provided, the total thickness of the metal gasket 1 is about 0.33 mm.

FIG. 7 shows a fifth embodiment of the metal gasket 1, both the first component plate 9 and the second component plate 10 having a thickness of 0.0.
The first component plate 9 is formed by a thin plate having a thickness of 5 to 0.15 mm, and the peripheral edge of the opening 11 is folded downward in a goby-folded manner to form a stopper portion 15. The stopper portion 15 is formed downward along the outer periphery of the stopper portion 15. The annular bead 12 is formed so as to protrude toward the second component plate 10. The second component plate 10 has an annular bead 16 protruding downward so as to be in close contact with each other along the outer periphery of the opening 13 at a position corresponding to the annular bead 12. It was formed. Also in this case, a thin plate having a thickness of 0.1 mm is used for both the first component plate 9 and the second component plate 10 and a thickness of 0.0
When the coating layer of 3 mm is provided, the total thickness of the metal gasket 1 is about 0.33 mm.

FIG. 8 shows a sixth embodiment of the metal gasket 1, both the first component plate 9 and the second component plate 10 having a thickness of 0.0.
The first component plate 9 has an annular bead 12 protruding upward along the outer periphery of the opening 11, and the second component plate 10 has a peripheral edge of the opening 13. The stopper portion 14 is formed by folding the portion downward in a goby-folded shape, and the annular portion is protruded downward along the outer circumference of the stopper portion 14 at positions corresponding to the annular beads 12 so that the top portions abut against and abut against each other. The bead 16 is formed. Also in this case, when a thin plate having a thickness of 0.1 mm is used for both the first component plate 9 and the second component plate 10 and a coating layer having a thickness of 0.03 mm is provided as a sealing material,
When assembled between the cylinder block 2 and the cylinder head 3, the total thickness of the metal gasket 1 is about 0.33 mm.
Becomes

FIG. 9 shows a seventh embodiment of the metal gasket 1 in which both the first component plate 9 and the second component plate 10 have a thickness of 0.0.
The first component plate 9 is formed by a thin plate having a thickness of 5 to 0.15 mm, and the peripheral edge of the opening 11 is folded downward in a goby-folded manner to form a stopper portion 15. The stopper portion 15 is formed downward along the outer periphery of the stopper portion 15. The second component plate 10 is formed along the outer periphery of the opening 13 at a position corresponding to the annular bead 12 so that the tops thereof are opposite to each other. The annular bead 16 is formed. Also in this case, when the first constituent plate 9 and the second constituent plate 10 are both thin plates having a thickness of 0.1 mm and a coating layer having a thickness of 0.03 mm is provided as a sealing material, the gap between the cylinder block 2 and the cylinder head 3 is reduced. When assembled in, the total thickness of the metal gasket 1 is about 0.33 mm.

FIG. 10 shows an eighth embodiment of the metal gasket 1. In this embodiment, the constituent plate is a single plate, and the constituent plate 17 has an opening 18 at a position corresponding to the cylinder bore 4. And forming a stopper portion 19 by folding the peripheral portion of the opening portion 18 upward in a goby fold shape, and forming an annular bead 20 projecting downward along the outer periphery of the stopper portion 19, and The stopper bead 19 has a structure in which the tip end portion is extended to approximately the center of the annular bead 20 and is curved along the upper surface of the annular bead 20 to form the reinforcing bead 21. This reinforcing bead 21 is for reinforcing the spring property of the annular bead 20 and ensuring a sufficient surface pressure, and is formed in a state where the elongation before the precipitation hardening heat treatment is large. Here, the constituent plate 17 has a thickness of 0.1 m.
When a thin plate of m is used and a coating layer having a thickness of 0.03 mm is provided as a sealing material, the total thickness of the metal gasket 1 of this embodiment is about 0.23 mm.

In each of the embodiments of the metal gasket 1 described above, the openings corresponding to the water holes and the oil holes and the arc-shaped beads, step beads and the like provided around the openings are omitted, but they are provided as usual. There is. Further, in the present embodiment, the metal gasket 1 constituted by two or one constituent plate is exemplified, but it may be constituted by using three or more constituent plates, but the total thickness of the metal gasket 1 is From the requirement of thinning, it is preferable to make the constituent plates as thin and small as possible, and it is more preferable to set the thickness of all the constituent plates to 0.05 to 0.15 mm.

[0046]

EFFECTS OF THE INVENTION According to the present invention as described above, it is possible to use a precipitation hardening type high silicon stainless steel which has been developed for structural purposes and which is general-purpose and inexpensive, but has not been used for metal gaskets. Since the component plate is formed, due to the toughness, heat resistance and durability of the material, and excellent workability, a metal gasket using conventional SUS301 series spring steel and SUS304 series general material even if the total thickness is thin It is possible to provide a metal gasket having a sealability and durability equal to or higher than that of the metal gasket. Moreover, by processing in a state in which the elongation before the precipitation hardening heat treatment is large, that is, in a state in which it is easy to process comparable to that of SUS304 type general material, an annular bead and a stopper formed by folding back into a goby fold shape on one component plate. Can be formed at the same time, and by subjecting it to precipitation hardening heat treatment after processing, it is possible to impart proof strength, tensile strength and hardness comparable to SUS301 series spring steel. Can be used for ultra-thin products and has excellent sealing properties. This contributes to the improvement of combustion efficiency of the engine. Even after the precipitation hardening heat treatment, since the elongation is relatively large at about 20%,
Cracks are less likely to occur at the shoulder R part of the annular bead and the bent part of the stopper part, and it has excellent durability.

In particular, by forming a constituent plate of precipitation hardening type high silicon stainless steel, and then subjecting it to age hardening treatment to manufacture a metal gasket, thermal deformation is caused in the steel material in terms of workability and accuracy. After the first heat treatment step and the second heat treatment step accompanied by heat treatment at a high temperature close to 1000 ° C., and pressing or bending is performed in a hardness state where the surface hardness of the steel material is about 245 to 320 in Vickers hardness HV. Since it is performed, it is remarkably excellent as compared with the SUS301 series spring steel, and since the third heat treatment step involving heat treatment at a low temperature of about 500 ° C. is performed after the machining, the thermal deformation of the workpiece is extremely small and the accuracy is high. Hardness is also Vickers hardness H
V increases to about 490 to 680, has excellent spring property, and a sufficient surface pressure can be secured by the annular bead. In particular, it is a remarkable feature that it has heat resistance capable of continuous use for a long time at high temperatures up to the age hardening temperature (420 to 520 ° C.). Furthermore, the corrosion resistance and stress corrosion cracking resistance of a solution containing sulfuric acid, nitric acid or chloride ions have already been proved, and the corrosion resistance is satisfactory. Therefore, it can be said that the metal gasket using the precipitation hardening type high silicon stainless steel of the present invention is a truly ideal metal gasket.

[Brief description of drawings]

FIG. 1 is a block diagram showing a manufacturing process of a constituent plate of a metal gasket of the present invention.

FIG. 2 is an exploded sectional view of an essential part of an engine showing an example of using a metal gasket.

FIG. 3 is an enlarged sectional view of an essential part showing a first embodiment of the metal gasket of the present invention.

FIG. 4 is an enlarged sectional view of an essential part showing a second embodiment of the metal gasket of the same.

FIG. 5 is an enlarged sectional view of an essential part showing a third embodiment of the metal gasket of the same.

FIG. 6 is an enlarged sectional view of an essential part showing a fourth embodiment of the metal gasket of the same.

FIG. 7 is an enlarged sectional view of an essential part showing the fifth embodiment of the metal gasket of the same.

FIG. 8 is an enlarged sectional view of an essential part showing a sixth embodiment of the metal gasket of the same.

FIG. 9 is an enlarged sectional view of an essential part showing a seventh embodiment of the metal gasket of the same.

FIG. 10 is an enlarged sectional view of an essential part showing the eighth embodiment of the metal gasket of the same.

[Explanation of symbols]

 1 Metal Gasket 2 Cylinder Block 3 Cylinder Head 4 Cylinder Bore 5 Piston 6 Combustion Chamber 7 Intake Valve 8 Exhaust Valve 9 First Construction Plate 10 Second Construction Plate 11 Opening 12 Annular Bead 13 Opening 14 Stopper 15 Stopper 16 Annular Bead 17 Component Plates 18 Openings 19 Stoppers 20 Annular Beads 21 Reinforcing Beads

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takaaki Shimizu 287-23 Shibawaki, Inagawa, Kawabe-gun, Hyogo Prefecture

Claims (4)

[Claims] 1. In weight%, 0.05% or less of carbon, 3 to 6% of silicon, 5% or less of manganese, and 5 to 1
0% nickel and 6-12% (excluding 12%)
Chromium, 0.2-1% molybdenum, 0.5-3
% Of copper and the balance iron, a precipitation-hardening high-silicon duplex stainless steel thin plate is processed into a predetermined shape, and then age-hardened to form a single or a plurality of laminated component plates. Characteristic metal gasket. 2. The precipitation hardening high silicon duplex stainless steel sheet is maintained at a temperature of 900 to 1000 ° C. for a predetermined time to be rapidly cooled, and then maintained at a temperature of 600 to 700 ° C. for a predetermined time to be cooled, and then 950. In the state of being heated to a solutionizing temperature of ˜1150 ° C. and being rapidly cooled, a constituent plate is processed and formed from the steel plate, and the constituent plate is maintained at a temperature of 420 to 520 ° C. for at least 1 minute per 1 mm of its thickness The metal gasket according to claim 1, which is formed by age hardening. 3. The thickness of the component plate is 0.05 to 0.15.
The metal gasket according to claim 1 or 2, wherein the metal gasket has a thickness of mm. 4. A single component plate, wherein a stopper portion is formed by folding back a peripheral edge of an opening provided therein, and an annular bead is formed along an outer circumference of the stopper portion. The described metal gasket.