JP3093091B2 - Manufacturing method of metal gasket - Google Patents

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.
It relates to a method of manufacturing, and more particularly toughness, a method for manufacturing <br/> thin metal gasket having both heat resistance and durability.

[0002]

2. Description of the Related Art Usually, a cylinder head gasket is interposed between a cylinder block and a cylinder head of an engine. The cylinder head gasket hermetically seals a combustion chamber of the engine so that gas is discharged from the combustion chamber to the outside. To prevent leakage. Recently, as the cylinder head gasket, a metal gasket obtained by laminating metal plates having a thickness of 0.05 to 1.0 mm is mainly used. The 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. In general, a stopper plate having a stopper portion formed by turning the peripheral portion of the portion and forming a stopper portion, and a spacer plate appropriately laminated in the middle are generally used.

[0003] 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 tensile strength as a material thereof. Spring steel is used. On the other hand, the stopper plate is a stopper formed at the periphery of the opening to prevent the entire compression of the annular bead, prevent the occurrence of cracks and settling, improve the durability, and enhance the reliability of the sealing performance. However, since the stopper portion is formed by folding, the elongation of the material is about 2%.
It is necessary to use a material that is sufficiently larger than 0% and has excellent bending workability, and SUS304-based general materials are mainly used.

In recent years, there has been an increasing demand for a thinner metal gasket from the viewpoint of improving the combustion efficiency of an engine.
There is a limit in 01 series spring steel and SUS304 series general materials. For example, a conventional bead plate has a thickness of 0.2 to 0.2.
Although a 5 mm one is used, if it is made thinner than that, not only the strength of the annular bead is lowered and a sufficient surface pressure cannot be obtained, but also cracks occur at the bead outside R portion during bead forming, and the bead shoulders are formed. Micro cracks occur in the R portion, and the sealing performance is reduced. The stopper plate has a thickness of 0.05 in the case of a grommet structure in which another metal plate, for example, a flat portion at the periphery of the opening of the bead plate is inserted between the substrate and the stopper portion formed by folding. Although it is possible to use one having a thickness of about 0.15 mm, in the case of a goby-folded structure in which the substrate and the stopper portion are closely attached, the radius of curvature of the bent portion becomes small, and cracks occur at this portion and the durability is impaired. In this case, it was a problem.

[0005] These problems can be improved to some extent by using comparative steel (steel having the chemical composition shown in Table 1). Incidentally, the comparative steel is a high-hardness stainless steel not specified in JIS.
Although the proof stress and the tensile strength are superior to the general type 04 material and the elongation is slightly inferior, the material of the stopper plate is superior to the general SUS304 type material. In the cold-rolled state, the comparative steel is superior in proof strength and tensile strength to SUS301 spring steel, so that the bead plate can be replaced with SUS301 spring steel as a material for the bead plate, but the elongation is extremely small. Therefore, the problem of bead crack generation remains. On the other hand, SUS630 or SUS631, which is a precipitation hardening stainless steel, is also considered as a material for the metal gasket.
As specified in S, -73 ±
Since a heat treatment step of keeping the temperature at 6 ° C. for 8 hours is required, the heat treatment is extremely troublesome and costly.

[0006] A high silicon toughness steel disclosed in Japanese Patent Publication No. 46-9536 has been known. This high silicon toughness steel has a C content of 0.05% or less and a Si content of 3.5 to 6%.
%, Mn 5% or less, Ni 3 to 9%, Cr 6 to 15% and the balance Fe, and the sum of the contents of Ni and Mn is twice the Si content, and the Cr content is 2.5 times the Si content. The A ₃ transformation point is lowered to 750 ° C. or lower by adjusting the doubling as a target, and the crystal is refined to provide rich toughness equivalent to twice 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 Silicolloy Industrial Co., Ltd., the present applicant.

Japanese Patent Publication No. 47-23056 discloses that a solution treatment is performed, and then aging is performed at 500 ° C., whereby a Vickers hardness of 5 is obtained without practically causing deformation.
An aging high silicon steel that hardens to more than 00 is disclosed.
This aging high silicon steel has a C content of 0.05% or less, and Si4-7.
%, 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 C 1% or less respectively.
u, Co alone or in combination, the balance being Fe, the sum of the contents of Ni and Mn is twice the content of Si,
The content of r is adjusted to be three times the content of Si. Hereinafter, this aging high silicon steel is referred to as "Silicolloy C".
Called.

[0008] This siliconloy C is the same as the siliconloy A described above.
1, the contents of Si, Ni and Cr were increased, and Mo, W, V and Co, and Cu and Ti were newly added.
And Al have been added to enhance age hardening characteristics, and have been developed for wear resistance with high hardness. Accordingly, since it is expensive as a whole because a large amount of expensive elements are used as compared with the above-mentioned Silicolloy A1, it is currently used only in limited products with high added value.

In addition, the above-mentioned silicoalloy 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.
That is, a precipitation hardening type high silicon stainless steel having both toughness and corrosion resistance (JP-B-57-17070) has been developed. This precipitation hardening type high silicon stainless steel is C0.
05% or less, Si 2 to 4%, Mn 2% or less, Mo0.2
~ 1%, Cu0.5 ~ 3%, Ni5 ~ 10%, Cr8 ~
13% with the balance being Fe, twice the Cr content and Si
The sum of the contents was 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 The above-mentioned Silicolloy A1
A2 and A2 are mainly used for structural purposes, and are inexpensive and versatile as compared with Silicolloy C, but are inferior to Silicolloy C in terms of hardness. However, Silicoroy A2 is a special precipitation hardening heat treatment for its steel type, but by performing a simpler heat treatment than the precipitation hardening heat treatment of SUS630 or SUS631, it is necessary to provide optimal mechanical properties as a material for a metal gasket. I found it.

In view of the above situation, the present invention seeks to solve the problem by depositing a general-purpose and inexpensive material developed for structural purposes, but not conventionally used as a material for metal gaskets. Another object of the present invention is to provide a method of manufacturing a metal gasket that employs a new material based on hardened high-silicon stainless steel (Silicolloy A2), has toughness, heat resistance, and durability, and can respond to thinning. .

[0012]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides, in weight percent, 0.05% or less of carbon, 3% to 6% of silicon, 5% or less of manganese, ~ 1
0% nickel and 6-12% (excluding 12%)
Chromium, 0.2-1% molybdenum, and 0.5-3
% And a balance of iron, the metal gasket is formed by processing a thin plate of a precipitation hardening type high silicon duplex stainless steel into a predetermined shape, and then hardening by age hardening, singly or by laminating a plurality of plates. Was constructed.

Specifically, the metal gasket of the present invention
The production method is as follows : the precipitation hardening type high silicon duplex stainless steel sheet is rapidly cooled while being maintained at a temperature of 900 to 1000 ° C. for a predetermined time, and then cooled at a temperature of 600 to 700 ° C. for a predetermined time; The steel sheet is processed into a predetermined shape while being rapidly cooled by heating to a solution heat temperature of 1150 ° C.
Manufacture a component plate with an annular bead and a stopper.
After that, the component plate is age-hardened at a temperature of 420 to 520 ° C. for at least one minute per 1 mm of its thickness .

The thickness of the component plate is set to 0.05 to
More preferably, it is set to 0.15 mm, and a stopper plate is formed on one component plate by turning the periphery of the opening provided therein, and an annular bead is formed along the outer periphery of the stopper unit. This is an example.

[0015]

The method of manufacturing a metal gasket of the present invention having the above-mentioned contents is a precipitation hardening type high silicon duplex stainless steel, that is, 0.05% or less of carbon and 3 to 6% of silicon.
5% or less manganese, 5-10% nickel, 6-
12% (excluding 12%) chromium and 0.2-1
% Of molybdenum, 0.5 to 3% of copper, and the balance of iron, is processed into a predetermined shape into a thin plate of a high-hardness duplex stainless steel, and hardened in a relatively short time by a special age hardening treatment. After that, the component plate formed by age hardening,
A metal gasket is formed singly or by laminating a plurality of the metal gaskets.
(0 to 520 ° C.) at the same time, toughness, heat resistance, and durability that enable continuous use for a long time at a high temperature.

The reason for using each element and the reason for its mixing ratio are described in detail in the above-mentioned Japanese Patent Publication No. Sho 57-17070. In the present invention, in particular, chromium is used for the purpose of reducing the cost of the material. 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 small as possible. The metal gasket of the present invention uses the precipitation hardening type high silicon duplex stainless steel having the above-mentioned compounding ratio, so that the component plate can have a thickness of 0.05-0.
Even when it is as thin as 15 mm, it has mechanical strength and toughness, heat resistance and durability, and by age hardening, its properties are improved and hardness is increased, and relatively elongation after age hardening is relatively high. Since it is large, cracks do not occur in the bead and the stopper portion, and have ideal sealing properties.

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

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

The second heat treatment step is performed at 950 to 1150
The solution is heated to a solution temperature of about 10 ° C., preferably about 1050 ° C., and then rapidly cooled (water-cooled). The time required for this heating is sufficient until the steel material rises 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,
Elongation is 48%. Surface hardness and elongation in this state are most suitable for processing such as pressing and bending,
Therefore, processing with high accuracy and excellent surface finish can be performed.

In the third heat treatment step, the steel material has a thickness of 1 mm.
Age hardening is carried out at a temperature of 420 to 520 ° C., preferably 460 to 480 ° C. for at least one minute per time. The time spent in the third heat treatment step is about 10 seconds when the thickness of the steel material is, for example, 0.1 mm, and the steel material can be sufficiently age-hardened. After the 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-described first heat treatment step and second heat treatment step, and then subjected to squeezing and bending into a predetermined product shape by a press forming step. Finally, a third heat treatment step is performed. Accordingly, 1000, which causes thermal deformation in the steel material,
After the first heat treatment step and the second heat treatment step accompanied by a heat treatment at a high temperature close to 0 ° C., and since the steel material is processed with a Vickers hardness HV of about 245 to 320 as a surface hardness, processing is performed. Easy, 500 ° C after its processing
Since the third heat treatment step involving a low-temperature heat treatment is performed as the heat treatment at a low degree, the thermal deformation of the workpiece is extremely small, and the workpiece has high precision and high hardness (the hardness is 490 to 68 in Vickers hardness HV).
0) The metal gasket can be provided. Here, it should be noted that SUS630 or SUS63 conventionally known as precipitation hardening stainless steel is used.
The supercooling heat treatment step of maintaining the temperature at -73 ± 6 ° C. for 8 hours as in the precipitation hardening heat treatment 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 large elongation. The stopper can be formed by turning the periphery of the provided opening, and an annular bead can be formed along the outer periphery of the stopper, whereby the metal gasket can be made thin.

[0023]

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.
) Is 0.05% by weight
Carbon, 3-6% silicon, 5% manganese, 5-10% nickel, 6-12% (12%
% Of chromium, 0.2 to 1% of molybdenum,
It is composed of 0.5 to 3% of copper and the balance iron.

In the precipitation hardening type high-silicon duplex stainless steel, the content of silicon is first specified to be 3 to 6% from a practical point of view. The carbon content is specified to be 0.05% or less, which can sufficiently be achieved in a normal steel making process, because an increase in carbon content causes not only a decrease in toughness but also a reduction in corrosion resistance. Manganese does not significantly contribute to the hardening of precipitation hardening stainless steel, but contributes to refinement of the structure and increase in hardness. Therefore, the amount of manganese is slightly increased from the normal specification range of stainless steel of 2% to 5% or less. Stipulated. Molybdenum and copper are added for the purpose of increasing corrosion resistance. However, since molybdenum is an expensive and strong ferrite-forming element, its use is restricted to 1% or less. Copper also acts as a precipitation hardening element and also as an austenite forming element, and its ferrite suppressing action is about 1/3 of molybdenum's ferrite forming action. It is set at a certain 3% or less. Further, copper significantly impairs hot workability due to the increased amount thereof, so the upper limit is kept at 3%. In addition, the lower limit of molybdenum and copper, in order to ensure corrosion resistance,
It is specified as 0.2% molybdenum and 0.5% copper.

In the above composition ranges of carbon, manganese, copper and molybdenum, the content of nickel is reduced to 5 in order to maintain the characteristics of the precipitation hardening type high silicon duplex stainless steel and to minimize the material cost. The content is set to 6 to 12% (excluding 12%) while setting to 10% to 10%. Here, the reason why the content of chromium is excluded from 12% is that the content of chromium in the above-mentioned siliconcolloy C is 12 to 20%, and the material cost is reduced as compared with siliconolloy C.

Next, the result of examining the mechanical properties after actually preparing a sample and performing heat treatment will be described. The sample of the present invention has a carbon content of 0.01% and a silicon content of 0.01%.
4.0%, manganese: 4.0%, nickel: 6.0%,
Chromium: 6.0%, Molybdenum: 0.3% and Copper: 0.1%.
A steel sheet having a composition of 6% and the balance of iron was manufactured, hot-rolled at a rolling ratio of about 30%, and further rolled while being stretched in a cold state (steel making process of base metal). First, the above-mentioned sample was maintained at a temperature of 920 ° C. for a predetermined time, then rapidly cooled in an oil phase, and then maintained at a temperature of 660 ° C. for a predetermined time.
Air-cooled and tempered (first heat treatment step). Next, 1050
After heating to a temperature of １1100 ° C., the oil phase was quenched and solution-treated (second heat treatment step). Lastly, after maintaining at a temperature of 480 ° C. for a predetermined time to age harden, it was cooled (third time).
Heat treatment step).

Table 1 shows a sample of a precipitation hardening type high silicon duplex stainless steel (Silicolloy G) used in the present invention and SUS6 which is a well-known precipitation hardening type stainless steel as a comparative material.
31 and SUS304A and SUS301H used as conventional materials for metal gaskets, and representative chemical compositions of comparative steels considered for use in metal gaskets. Table 2 shows mechanical properties of each steel type. Shows the results measured after the heat treatment in the table.

[0028]

[Table 1]

[0029]

[Table 2]

Here, in the silicon alloy G according to the present invention 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 this comparison result, the silicon alloy G according to the present invention has the proof stress and tensile strength required as a component plate of a metal gasket,
SUS30 used as a material for conventional bead boards
It has an elongation of 20% or more necessary 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 simultaneously form the annular bead and the stopper by turning the peripheral portion of the opening on one component plate constituting the metal gasket, thereby reducing the number of component plates and reducing the number of component plates. It is possible to reduce the thickness of the gasket.

Further, the heat treatment for precipitation hardening of silicoalloy G according to the present invention does not involve a low-temperature treatment at 0 ° C. or lower, so that SU
The heat treatment is so simple that it is incomparable with S631. In addition, SUS631 has sufficient mechanical properties after precipitation hardening, such as proof stress, tensile strength and hardness, but its elongation is as small as 6%. Therefore, it is repeatedly hit by the vertical vibration of the cylinder head when the engine is driven. Also, if the cylinder block and the cylinder head are repeatedly deformed in the lateral direction due to the difference in the coefficient of thermal expansion, cracks may occur and durability may be reduced. In addition, the comparative steel has satisfactory strength, tensile strength, and hardness after cold rolling, but has the same problem of a smaller elongation.

Next, the steel making process and the press forming process of the base material will be explained a little. Regarding the steelmaking process of the base metal,
In the past, pure iron with extremely low carbon content was difficult to obtain, so it was manufactured by vacuum melting in order to limit the contamination of carbon in the steelmaking process. It is no longer necessary to use a furnace. As a result, the steelmaking process has been greatly simplified, and steelmaking by rolling, forging or casting has become possible. Further, precision casting by the lost wax method or the like is possible, and precision parts can be manufactured. In addition, since the press forming is performed in a state in which the hardness after the first and second heat treatment steps is relatively low (Vickers hardness HV 245 to 320), press forming and bending are performed in the same manner as ordinary stainless steel. Needless to say, cutting and grinding can be easily performed by a general-purpose machine tool such as a lathe, a drilling machine, and a milling machine.

Therefore, on the premise that the above-mentioned heat treatment is performed, a component plate of a 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 obtained by the manufacturing method of the present invention will be described. FIG. 2 is an exploded sectional view of a main part of an engine showing a typical embodiment of the present invention. The 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 on which the metal gasket 1 according to the present invention is mounted 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 lubrication oil hole are formed, and a piston 5 is provided in the cylinder bore 4. A cylinder head 3 is disposed above the cylinder block 2, a combustion chamber 6 is formed by the cylinder bore 4, the piston 5, and the cylinder head 3, and a combustion chamber is provided between the cylinder block 2 and the cylinder head 3. The metal gasket 1 is interposed to prevent gas from leaking out of the cylinder bore 6 and to prevent cooling water or the like from entering the cylinder bore 4 from a water hole or an oil hole.

Each cylinder head 3 has a combustion chamber 6
, An intake port and an exhaust port (both not shown) are opened, and an intake valve 7 is disposed in the intake port.
An exhaust valve 8 is disposed in the exhaust port, and both valves 7 and 8 are opened and closed by a valve operating mechanism (not shown) provided on the upper part of the cylinder head 3.

Then, the metal gasket 1 of the first embodiment
2 and 3 have a structure in which two component plates are laminated, and are referred to as a first component plate 9 and a second component plate 10 from the cylinder block 2 side for convenience. 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 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
Reference numeral 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 the opening 13 at a position corresponding to the opening 11. In addition, the stopper 13 having a grommet structure is formed by folding a peripheral portion of the opening 13 downward so as to wrap a flat portion inside the annular bead 12 of the first component plate 9. With this stopper portion 14,
When the metal gasket 1 is assembled between the cylinder block 2 and the cylinder head 3, the entire compression of the annular bead 12 is prevented, and the sealing performance is secured by the surface pressure due to the resilience of the annular bead 12. Here, the first component plate 9 has a thickness of 0.2
mm, using a thin plate having a thickness of 0.1 mm for the second component plate 10,
When 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 0.43 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 periphery 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 has an annular bead 16 protruding 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 of a thin plate having a thickness of 5 to 0.15 mm, and the peripheral edge of the opening 11 is folded upward in a goby fold to form a stopper portion 15, and the first component plate 9 extends downward along the outer periphery of the stopper portion 15. The second component plate 10 has an annular bead 16 projecting downward along the outer periphery of the opening 13 at a position corresponding to the annular bead 12 so as to be in close contact with each other. It is formed. In this case, by reducing the thickness of the component plates, the spring property of the beads 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 them in the same position, and a sufficient surface pressure is secured to enhance the 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 0.1 mm.
33 mm.

FIG. 6 shows a fourth 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 of a thin plate having a thickness of 5 to 0.15 mm. The first component plate 9 has an annular bead 12 protruding downward along the outer periphery of the opening 11. The stopper portion 14 is formed by folding the portion downward in a goby fold, and an annular bead 16 is formed along the outer periphery of the stopper portion 14 at a position corresponding to the annular bead 12 so as to protrude downward 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 a 3 mm coating layer 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, 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 first component plate 9 is formed by folding the peripheral edge of the opening 11 downward in a goby fold to form a stopper portion 15 and, along the outer periphery of the stopper portion 15, The second component plate 10 has an annular bead 16 projecting downward along the outer periphery of the opening 13 at a position corresponding to the annular bead 12 so as to be in close contact with each other. It is 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 a 3 mm coating layer 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, 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 of an annular bead 12 projecting upward along the outer periphery of the opening 11, and the second component plate 10 is formed of a thin plate having a thickness of 5 to 0.15 mm. The stopper portion 14 is formed by folding the portion downward in a goby-fold shape, and the annular portion protruding downward so that the top portions abut against each other at positions corresponding to the annular beads 12 along the outer periphery of the stopper portion 14 and come into contact with the annular bead 12. A 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. The first component plate 9 is formed by folding the peripheral edge of the opening 11 downward in a goby fold to form a stopper portion 15 and, along the outer periphery of the stopper portion 15, The second component plate 10 protrudes upward along the outer periphery of the opening 13 at a position corresponding to the annular bead 12 so that the tops are opposite to each other. An annular 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, the distance between the cylinder block 2 and the cylinder head 3 is reduced. When assembled, 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 component plate is made of a single veneer, and the component plate 17 has an opening 18 at a position corresponding to the cylinder bore 4. The stopper 18 is formed by folding the peripheral edge of the opening 18 upward in a goby-like manner, and an annular bead 20 protruding downward along the outer periphery of the stopper 19 is formed. The reinforcing bead 21 is formed by extending the distal end portion of the stopper portion 19 to approximately the center of the annular bead 20 and bending along the upper surface of the annular bead 20. The 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 thickness of the component plate 17 is 0.1 m.
When a thin plate having a thickness 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 and step beads provided around the openings are omitted, but these are provided as usual. I have. Further, in the present embodiment, the metal gasket 1 having two or one component plate has been exemplified. However, the metal gasket 1 may be formed by using three or more component plates. In view of the demand for thinning, it is preferable to make the constituent plates as thin and small as possible, and it is more preferable that all the constituent plates have a thickness of 0.05 to 0.15 mm.

[0046]

According to the present invention described above, a general-purpose and inexpensive precipitation-hardened high-silicon stainless steel, which has been developed for structural use but has not been used for metal gaskets, has been used. Because the component plate was formed, due to the toughness, heat resistance and durability and excellent workability of the material, the metal gasket using the conventional SUS301-based spring steel and SUS304-based general material even if the overall thickness was reduced. It is possible to provide a metal gasket having equal or better sealing performance and durability. In addition, by processing in a state of large elongation before the precipitation hardening heat treatment, that is, in a state of easy processing comparable to SUS304 general material, an annular bead and a stopper formed by folding back in a goby shape on one component plate. Parts can be formed at the same time, and after the processing, by precipitation hardening heat treatment, it is possible to impart proof strength, tensile strength and hardness equivalent to SUS301 series spring steel, and it is possible to form a metal gasket. It can cope with ultra-thinness and has excellent sealing properties. This contributes to the improvement of the combustion efficiency of the engine. Also, even after the precipitation hardening heat treatment, the elongation is relatively large at about 20%,
Cracks hardly occur at the shoulder R portion of the annular bead and the bent portion of the stopper portion, and the durability is excellent.

In particular, by forming a component plate from a precipitation hardening type high silicon stainless steel and then subjecting it to age hardening to produce a metal gasket, thermal deformation is caused in the steel material in terms of workability and precision. After a first heat treatment step and a second heat treatment step involving a heat treatment at a high temperature of about 1000 ° C., press working and bending work are performed in a state where the surface hardness of the steel material is about 245 to 320 in Vickers hardness HV. Since it is performed, it is significantly superior to SUS301 spring steel, and after the processing, a third heat treatment step involving a low-temperature heat treatment of about 500 ° C. is performed. Hardness is also Vickers hardness H
V increases to about 490 to 680, has excellent spring properties, and a sufficient surface pressure can be secured by the annular bead. In particular, it is a noteworthy feature that it has heat resistance that allows long-term continuous use at high temperatures up to the age hardening temperature (420 to 520 ° C). Furthermore, the corrosion resistance and stress corrosion cracking resistance of solutions containing sulfuric acid, nitric acid or chloride ions have already been demonstrated, 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 the drawings]

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

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

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

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

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

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

FIG. 7 is an enlarged sectional view of a main part of a fifth embodiment of the metal gasket.

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

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

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

[Explanation of symbols]

 DESCRIPTION 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 constituent plate 10 Second constituent plate 11 Opening 12 Annular bead 13 Opening 14 Stopper part 15 Stopper part 16 Annular bead 17 Constitution plate 18 Opening 19 Stopper 20 Annular bead 21 Reinforcement bead

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Takayasu Shimizu 287-23 Shibawaki, Hara, Inagawa-cho, Kawabe-gun, Hyogo Prefecture Inside of Silicolloy Industrial Co., Ltd. (56) References JP-A-5-105989 (JP, A) JP-A-4-147946 (JP, A) JP-A-5-279802 (JP, A) JP-A-6-50434 (JP, A) JP-A-5-263940 (JP, A) JP-A-5-65959 (JP, A) JP-B-57-17070 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) F16J 15/08 C22C 38/00 302 C22C 38/44 F02F 11/00

Claims (3)

(57) [Claims] 1. In weight percent, no more than 0.05% carbon, no more than 3-6% silicon, no more than 5% manganese,
0% nickel and 6-12% (excluding 12%)
Chromium, 0.2-1% molybdenum, and 0.5-3
% Of copper and a balance of iron and a precipitation hardening type high silicon duplex stainless steel sheet at a temperature of 900 to 1000 ° C for a predetermined time.
Quenching, maintaining at a temperature of 600-700 ° C.
Maintain a fixed time and cool, then 950-1150 ° C
The steel sheet is heated to the solution temperature and rapidly cooled, and
Configuration that has an annular bead or stopper part processed into a shape
A plate is manufactured and then the component plate is
At a temperature of 420-520 ° C for at least one minute
Manufacturing method for a metal gasket age hardened, characterized in that the arrangement plate formed by singly or stacked plurality Te. 2. The thickness of the component plate is set to 0.05 to 0.15.
formed by set to mm claim 1 Symbol placement of metal gasket
Manufacturing method . To 3. A single structure plate, so as to form a stopper portion by folding back the peripheral edge of the opening portion which is provided to it by forming a annular bead along the outer periphery of the stopper portion according to claim 1 or 2 Symbol placement Manufacturing method of metal gasket.