JPH04191352A - Gasket material for internal combustion engine excellent in settling resistance - Google Patents

Abstract

PURPOSE:To obtain a gasket material for internal combustion engine having a dual-phase structure of austenite and strain induced martensite and excellent in settling resistance, strength, formability, and corrosion resistance by regulating the components in an Ni-Cr-Cu alloy steel having a specific composition. CONSTITUTION:As a gasket material for internal combustion engine particularly excellent in settling resistance, a steel material prepared by applying temper rolling to an alloy steel having a composition which contains, by weight, <0.10% C, >1.0-3.0% Si, <3.0% Mn, 4.0-10.0% Ni, 12.0-20.0% Cr, 0.5-3.0% Cu, <0.20% N, and <0.008% S and in which (C+N)<0.10% is satisfied and the value of M represented by equation I is regulated to 30-100 or to an alloy steel having a composition which further contains <3.0% Mo and 0.1-1.0% of one or more elements among Ti, Nb, and V and in which the value of M represented by equation II is regulated to 30-100 is used. Further, this steel material has a dual-phase structure having <=60vol.% strain induced martensite phase in an austenite phase. This steel material has >=5% elongation, and the gasket material having >=175kg/mm<2> tensile strength can be obtained by means of ageing treatment after forming into the prescribed shape.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a material for a gasket for an internal combustion engine that has excellent resistance to settling. In particular, the gasket material of the present invention is suitable for metal gaskets for engines of automobiles, motorcycles, etc. because it has excellent properties such as high strength, moldability, heat resistance, and corrosion resistance in addition to resistance to set.

[Conventional technology]

One of the parts that makes up an internal combustion engine (hereinafter referred to as an engine) is a gasket that is installed at a joint. This gasket has the properties necessary to maintain the airtightness of the joint surfaces.
It must be maintained under the high temperatures, high pressures, and high vibrations characteristic of engines, and over long periods of repeated temperature and pressure changes. Conventionally, materials such as asbestos have been commonly used as materials for engine gaskets due to their heat resistance. However, metal gaskets are increasingly being used in response to the recent trend toward higher engine performance and non-asbestos regulations. Materials for metal gaskets include work-hardened metastable austenitic stainless steel, such as 5US, which can easily achieve high strength through cold rolling.
301 series steel is mainly used. One way to use it is to form a bead on a thin plate having a desired shape and having a thickness of about 0.1 to 0.4 mm.

It is common to install this on the joint surfaces around the combustion chamber, water grooves, and oil grooves, and use the high surface pressure generated when the beats are tightened to seal out gas, water, and oil.

[The problem that the invention attempts to solve]

Metal gaskets used in engine cylinder heads require particularly good gas sealing properties because they are under high pressure during compression during the engine cycle. For this reason, it is necessary to increase the height of the bead molding to increase the surface pressure, and -1- the material strength must also be sufficiently strong. The stainless steel that can handle this is 5US301 series steel (SUS
301.304. Examples include TYpe301L) and 5US631.

However, in order to obtain high strength, 5tlS301 series steel requires intense cold working, which reduces formability and causes problems such as cracking at the machined R part during bead forming. . Furthermore, when the strength is lowered to improve moldability, it is necessary to increase the bead molding height in order to increase the sealing performance by increasing the two-face pressure. At that time, if the bead forming height is increased, microcracks are likely to occur in the bead shoulder R section (inner R section, outer mR section) (and cracks may occur starting from these microcracks during use).

There was a problem that the seal resistance deteriorated. For this reason, measures such as lowering the bead height and constructing a structure in which many layers are stacked have to be taken, resulting in complicated assembly work.

Even so, in view of the material properties, both the fatigue resistance and the fatigue properties were not satisfactory.

On the other hand, 5US631 steel has higher ductility in the cold rolled state than 5US301 series steel, and high strength can be obtained through aging treatment, so it is somewhat advantageous in terms of forming processing compared to 5LIS301 series steel. However, this steel contains At as a precipitation strengthening element with a high affinity for oxygen and nitrogen.
Since 75 to 1.5% is added, alumina-based nonmetallic inclusions are formed during steel manufacturing, and agglomerated AIN inclusions are formed during casting, which may cause the surface of the product to become rough. In many cases, ductility and toughness are impaired. For this reason, during use as a gasket, fatigue cracks occur starting from this, and sealing resistance deteriorates in a short period of time.

[Means for solving problems]

The above problem regarding metal gaskets for engines is
The problem can be practically solved if we develop a stainless steel that has excellent moldability, develops high strength through aging treatment after molding, and has excellent wear resistance and fatigue strength. As a result of repeated testing and research aimed at this purpose, the inventors of the present invention have found that this problem can be solved if the steel components are regulated extremely strictly and within a specific content range, and the structure is appropriately adjusted. Knew.

That is, the present invention provides a metal gasket material for engines that solves the above problems.

In weight%.

C: 0.10% or less Si: More than 1.0% to less than 3.0%.

Mn: 3.0% or less (preferably less than 0.5%).

Ni: 4.0~io, o%.

Cr: 12.0-20.0%.

Cu: 0.5-3.0%.

N: 0.20% or less (preferably 0.06-0.1
5%).

S・0.008% or less (preferably 0.003% or less)
.

Total of C and N: 0.10% or more.

Even more in some cases.

Mo: 3.0% or less.

One or more of Ti, Nb, and V = 0.1 to 1.0%.

and M = 330- (480X C%)-(2XSi%
)-(IOXMn%) (14XNi%)-(5,
7xCr%) - (5XMo%) (14XCu%)
- M value according to the formula (320X N%) or 30 or more 100
C, Si, °Mn, Ni, C within the following ranges
A complex phase in which the amounts of r, Mo, Cu, and N are adjusted, and the remainder consists of Fe and unavoidable impurities, and a deformation-induced martensitic phase of 60% by volume or less is generated in the austenite phase. Has an organization. The present invention provides an engine gasket material with excellent wear resistance.

After the gasket material of the present invention is molded into the desired gasket shape (after bead processing), it is aged to 175%.
It exhibits a tensile strength of over 100 kg/mm.

It has an elongation of 5% or more before molding and an elongation of 3% or more even after one aging treatment.

The gasket material of the present invention is designed to have a strict balance of component composition and microstructure control as described above, and is a plate material that exhibits a metastable austenite phase in a solution treatment state.
By subjecting this plate material to mild temper rolling, the deformation-induced martensite content of 60% by volume or less (preferably 30% to 30% by volume)
60% by volume), thereby developing its properties.

[Effect]

First, an overview of the effects and content ranges of each alloying element employed in the present invention will be individually explained.

C is an austenite-forming element and has an extremely active effect on suppressing δ ferrite generated at high temperatures and strengthening the deformation-induced martensitic phase induced by cold working. but,
If the C content is increased, carbides will precipitate at the grain boundaries, causing intergranular corrosion resistance and a decrease in ductility, so the C content is set to 0.10% or less.

Mn is an element that controls the stability of the austenite phase, and its utilization is considered in balance with other elements. In the present invention, the Mn content can be utilized up to 3.0%. However, the formation of M n S reduces ductility, especially when high strength is achieved. Therefore, especially when high strength and ductility are important, it is preferable that the Mn content is less than 0.15%.

N1 is an essential component for obtaining an austenitic phase at high and room temperatures. In the case of the material of the present invention, it exhibits a metastable austenite phase at room temperature after solution treatment, and a martensitic phase is induced during cold working. If the Ni content is lower than 4.0%, a large amount of δ ferrite phase will be formed at high temperatures, and it will be difficult for the alloy to become an austenite phase or a metastable state at room temperature. On the other hand, if Ni exceeds 10%, it becomes difficult to induce a martensitic phase during cold working. Therefore, the amount of Nl is 4
．． 0 to 100%.

Cr is an essential component for maintaining corrosion resistance. At least 12.0% Cr is required to impart the intended corrosion resistance. However, since Cr is also a ferrite-forming element, if the temperature is too high, a large amount of δ ferrite phase will be formed at high temperatures. Therefore, in order to suppress the δ ferrite phase, austenite forming elements (C, N, Ni, Mn, Cu
If you add a large amount of austenite-forming elements, the austenite phase at room temperature will become stable, instead of becoming the metastable monostenite phase, and the cold After processing.

Even if an aging treatment is performed later, it will not be possible to obtain sufficiently high strength. Because of this, the upper limit of Cr is 20
96.

Cu provides a characteristic effect of hardening the material through interaction with 81 during aging treatment.

If it is too small, the effect will be small, and if it is too large, hot workability will be inhibited and cracks will occur. For this purpose, the Cu content is set in the range of 0.5 to 3.0%.

Sl serves to induce the martensite phase by cold working and to strengthen the martensite.

In addition to Cu, it is also important for hardening through aging treatment. In order to exhibit such an effect, at least 1.0% or more of 81 is required. However, if the content is too high, it promotes the formation of the δ ferrite phase and the effect is small compared to the amount added, so the upper limit is set at 3.0%.

N is an austenite-forming element as well.

It is an extremely effective element for hardening the austenite and martensite phases, and a large amount may cause blowholes during casting, so the content should be 0.20% or less.

S coexists with Mn to produce MnS, resulting in a decrease in ductility, so S is set to 0.00% or less.

For this MnS thin plate that particularly affects the ductility 7 fatigue properties and in the high strength region, it is preferable that Mn and S are as low as possible, the amount of Mn is less than 0.5%, and the amount of Sl is 0.003%.
The following is appropriate.

MO increases the base hardness of the steel and also increases the hardness after aging treatment, so it acts effectively in obtaining high strength. However, since it is a ferrite former, if it is added in a large amount, the δ ferrite phase will crystallize, which may even cause a decrease in strength, so the upper limit is set at 3.0%.

Note that, as described above, C and N exhibit similar effects and are compatible with each other. For the reasons mentioned above, each upper limit must be regulated individually, or the total amount must be 0.10% or more in order to fully exhibit the effects intended by the present invention.

T i, N b, and V act to increase the hardness after aging treatment and to obtain high strength. In order to exhibit this effect, it is necessary to add 0.1% or more of one or more of these elements. However, if more than necessary is added, a large amount of nonmetallic inclusions will be produced, leading to a decrease in fatigue strength and deterioration of surface cleanliness, so the upper limit should be set at 1.0%.

Regarding M value: 30 or more and 100 or less.

C, Si, Mn, Ni, Cr, Mo, Cu and N are contained in the above ranges, or M according to the following formula (1)
Each component is adjusted so that the value is 30 or more and 100 or less.

M = 330- (480X Cu) (2XSi
%)-(IOXMn%)-(14XNi%)-(5,7
xCr%)-(5xMo%)-(14Xcu%)-(
320X N%) (1) The constants of each component in formula (1) were confirmed in a laboratory during the development of the material of the present invention. This M value is an index of austenite stability, and in order to obtain the intended high strength after cold rolling or aging treatment when this M value is less than 30, it is necessary to increase the strength by 70% or more at room temperature during cold rolling. This reduces the ductility of the material, which requires additional processing.
Heat formability as an engine gasket is reduced. Therefore, the M value needs to be 30 or more. Also M value is 1
If it exceeds 00, it will be difficult to obtain an austenite phase in the solution treatment state, and it will be difficult to achieve the characteristic of the material of the present invention, which is a two-phase structure of austenite and martensite phases.

Therefore, it is necessary to set the M value to 30 or more and 100 or less, and an important means for achieving the purpose of the present invention is to strictly adjust the amount of each component so that it falls within this M value range. .

In addition to these ingredients, AI, which is commonly used as a deoxidizing agent,
Ca or REM (rare earth element), which is commonly used as a desulfurization agent, and B (0.01% or less), which has an effect of improving hot workability, can be contained as necessary, or they are unavoidably mixed. It may contain impurities. However, A
If I is required to have high strength and high fatigue strength, it should not be used, or it should be used in an amount that does not form non-metallic inclusions in the steel. Note that, if the properties are comparable to those of conventional steel, there is no particular problem even if AI is included in the composition of the steel of the present invention.

The material of the present invention whose alloy components are adjusted to the above-mentioned range of chemical composition values exhibits a substantially austenitic structure in the solution treatment state (at room temperature after solution treatment). If temper rolling is performed from this state, the target strength level and amount of martensite can be achieved. Is the temper rolling rate appropriately selected depending on the stability of the austenite phase?

As shown in the examples below, the target martensite content of 60% by volume or less, substantially 30 to 60% by volume, is achieved with a lower temper rolling rate than that of conventional materials.

The thus obtained material of the present invention has high ductility in the temper-rolled state and even higher strength after aging treatment. Since it has the moldability and high strength required for this, it ensures high sealing performance, and it also has very excellent fatigue strength and fatigue resistance, so it can maintain an extremely long seal life. The excellent fatigue strength and fatigue resistance will be shown in the examples below, or can be explained approximately as follows.

The composition of the material of the present invention is designed to suppress the formation of nonmetallic inclusions such as nitrides as much as possible.

Therefore, the fatigue life is also improved. In addition, we discovered that the resistance to settling is significantly controlled by the amount of martensite.
In terms of components, a moderate amount of C+N and the addition of Si generate a denser martensite phase with light processing, and the addition of Cu increases the strength increase due to aging treatment, keeping the temper rolling rate low. Without improving the forming processability, the amount of martensite after temper rolling was reduced to 60% or less by volume, and the required high strength was maintained while at the same time, the settling resistance was improved.

In this way, the gasket material of the present invention.

After strictly balancing the component composition as described above, the austenite phase is formed in the solution treatment state, and this is converted into austenite having substantially 30 to 60 volume % of the martensite phase in the temper rolling (cold rolling) state. As a two-phase structure of phase and martensitic phase, it has 9 strength,
Excellent ductility.

Furthermore, an engine gasket material has been obtained which has high strength through aging treatment and has excellent moldability and set resistance.

Especially in the present invention.

(a) If Si exceeds 1.0%, which contributes to the refinement and strengthening of the martensitic phase induced by cold working, 3
．． The martensitic phase induced by mild cold working (temper rolling) is reduced to less than 0%, which is higher than that of conventional materials, and the total content of C and N, which are the strengthening elements of the martensitic phase, is made to be more than 0.10%. Strengthened with Si, C, and N.

The material has excellent formability, strength, and ductility in the cold-worked state.

(b) For 1-age hardening, by adding Cu, which interacts with Sl and does not cause the formation of non-metallic inclusions, even higher strength and ductility can be achieved after 1-age aging treatment. point.

(By utilizing the interaction between Cu and Si as the C1 reinforcing element, it is possible to avoid the addition of reinforcing elements that generate non-metallic inclusions such as nitrides as in conventional materials, and to improve the surface texture. This has also improved fatigue properties.

(C) Settling resistance or tensile strength and full tensile strength 1
-Knowing that the amount of martensite is affected by the amount of martensite produced by cold working,
Improved fatigue resistance while maintaining high strength.

(d) Furthermore, by adding necessary amounts of Ti, Nb, and V, even higher strength can be developed after aging treatment.

It comprehensively provides characteristic effects in etc.,
As a result, it has been possible to create a high-strength metal gasket material for engines that has formability, fatigue resistance, and fatigue properties that have been difficult to achieve with conventional steels.

Examples are given below to specifically illustrate the characteristics of the material of the present invention.

〔Example〕

Materials of the present invention E1 to 9 containing chemical component values (wt%) shown in Table 1 in iron. Conventional materials (A, B) and comparative materials (a-
C) is melted by a conventional method, hot rolled, and then cold rolled,
After annealing and pickling, the plate thickness after final temper rolling is 0.25m.
mt, and samples were taken from these. Table 2 shows the rolling ratio of the final skin pass rolling (cold rolling) of each material.

For each sample, the amount of martensite (α° amount) induced by cold rolling was measured, as well as the tensile strength, elongation, and bendability. The results are shown in Table 2. 2. As shown in Figure 4, sample 3 is punched and bent using a die 1 with a 90° recess and a punch 2 with a radius of 0.2 mm at the tip. It was evaluated based on the following criteria.

In addition, each material after final skin pass rolling was subjected to aging treatment at 400°C for 1 hour, and the tensile strength after 1 hour aging treatment.

Elongation and ΔTS were measured. ΔTS is the difference in tensile strength before and after aging treatment. The results are also listed in Table 2.

Furthermore, in order to investigate the fatigue resistance properties of metal gasket materials, the heat residual rate of each aged material was measured. In this test, a bead shape is placed on the plate (500 mm on a flat plate).
A test piece was prepared by drilling a hole of approximately 1.0 mm in diameter and applying heat to the outer circumference of the hole (Fig. 5fa).
As shown in FIG.
5b, and tighten the load fluctuation flanges 5a and 5b as shown in Fig. 5(b), measure the beat height when this tightening and releasing amplitude is repeated 100 times, and calculate the beat survival rate (%). was calculated using the following formula.

Original bead height The results are also shown in Table 2.

Moreover, FIG. 1 shows the relationship between this bead residual rate and the amount of martensite. In Fig. 1, ○ marks are inventive materials, ・ marks are comparative examples (martensite content exceeds the range defined by the present invention), Δ marks are conventional materials, outside the specified range).

From the results in Table 2 and Figure 1, we can see the following two things.

El~9 of the present invention material exhibits a heat survival rate of 50% or more after one aging treatment. On the other hand, both the comparative example and the conventional material are lower than the present invention material. I want to do it 1
It can be seen that the material of the present invention has excellent resistance to settling. Although the conventional material B has a martensite content of 40%, which is the same as that of the material of the present invention, it shows a low bead survival rate. This is because, as will be discussed later, in conventional materials, if the amount of martensite is kept low, the ATS due to aging treatment will not increase as in the materials of the present invention.

Does the material of the present invention have excellent fatigue resistance as described above?

The reason for this is thought to be that the addition of Sl makes it easier to generate finer, harder martensite, and moderate work hardening occurs in the portions that are significantly deformed during the solidity test. This also corresponds to the fact that, as seen in FIG. 1, if the amount of martensite is 60% or less, that is, if the untransformed austenite phase remains 40% or more, it has excellent resistance to set. In other words, the part that receives the untransformed austenite phase or the thick Ct shape undergoes work hardening and increases the resistance to set.

Figure 2 shows that the amount of martensite is lower (○
By making two types of rolled materials, one with a martensite content of 519% and the other with a high martensite content (marked with a martensite content of 65%), and changing the aging treatment conditions when aging these two types of materials respectively. This figure shows the relationship between tensile strength and heat survival rate when the above-mentioned fatigue test was conducted on these two types of materials with varying strength levels. Figure 2 also shows measured values for some of the conventional materials and comparative materials.

From the results in Figure 2, even if the material (E4) has the same chemical composition value, a material with a low amount of martensite (○ mark 51%) and a material with a high martensite content (・mark 65%) are compared.

It can be seen that even if the strength is the same, the amount of martensite is low or the heat survival rate is high. On the other hand, the heat survival rate is also affected by the tensile strength, and it can be seen that even if the amount of full tensile strength is small, if the strength level is too low, the heat survival rate will be low. For example, in order to ensure a heat survival rate of 50% or more, it is necessary to have a tensile strength of 175 kg/mm2 or more when the amount of martensite is 60% or less. Although conventional material B has a martensite content of 40%, its strength level is low and its heat survival rate is also low. In other words, it can be seen that the key to achieving resistance to fatigue as a metal gasket is to reduce the amount of martensite and develop sufficient tensile strength. Comparative material a has a chemical component value that is within the range specified by the present invention or has a low M value as specified by the present invention, and therefore martensitic transformation due to rolling occurs and the present invention material ( The beet survival rate is lower than that in (marked with ○).

Figure 3 shows the amount of change ΔT in tensile strength due to aging when aging treatment is performed for 400'CX 1 hour among the results in Table 2.
This shows the relationship between S and the amount of martensite, and ○
The marks are for the present invention materials El to 9, and the marks are for Comparative Examples E4 and E5 whose component compositions are within the range specified by the present invention or whose martensite content is greater than that specified by the present invention. Also, the mouth mark and the △ mark correspond to the conventional material and comparative material in FIGS. 1 and 2.

From Fig. 3, 1) both the inventive materials (OEITEI~9) and the comparative examples (marked E4~5), although variations occur due to changes in the amount of Sl and Cu, 2) due to the increase in the amount of martensite, the A
I understand that TS will be higher. In other words, it is recognized that the degree of strengthening ΔTS due to 9-aging is influenced by the amount of martensite. However, even within the component range of the present invention, if the M value is low, the amount of martensite will be less than 30%, and the ATS
suddenly decreases (kuchi-in comparison material a). In other words, if the 1M value is low and strong working is required, the working will cause a decrease in ductility, resulting in not only poor formability but also no strength after aging. Therefore, it can be seen that it is important to set the M value to 30 or more from this point of view.

As mentioned above, in terms of ductility or formability, as is clear from the results in Table 2, materials that have the component composition specified in the present invention and have a martensite content of 60% or less cannot be subjected to aging treatment. It has excellent formability as it has an elongation of more than 5% before and no cracking occurred even in a 90 degree bending test with a tip RO of 2mm, and even after aging it has an elongation of more than 3% and is ductile. It has excellent properties and high strength. In contrast, when trying to obtain high strength after aging with conventional materials, the elongation and ductility before aging decrease. That is, if heat molding is attempted, cracks will occur.

On the other hand, even if each component is within the range specified by the present invention, if the M value is low like comparative steel a, it is necessary to obtain high strength after one aging by Δ
Since the TS is low (for example, Fig. 3), it is necessary to increase the cold rolling to increase the strength before aging. Therefore, in the cold rolled state, the ductility and bendability decrease, making it difficult to form the metal gasket. On the other hand, if the M value is too high, too much martensite will be generated in the light machining area.
Like Comparative Steel d, the ductility, formability, and resistance to set-off are also reduced, and the object of the present invention cannot be achieved. I want to do it 2
In order to advantageously achieve the object of the present invention, the M value is an extremely important index, and it is important to adjust the amounts of each component so that the M value is in the range of 30 to 100. It is also an important requirement that the amount of deformation-induced martensite be 60% or less by appropriately adjusting the final rolling rate.

〔effect〕

As shown in the above examples, it is clear that the material of the present invention has the properties required for engine gaskets, and provides a novel engine gasket material. In particular, the material of the present invention has a greater increase in strength by one aging than conventional metal gasket materials such as 5OS301, so the temper rolling rate before aging treatment can be lowered. Therefore, it has excellent moldability and can be formed into a high bead without causing processing cracks. Additionally, it has excellent resistance to settling, which is a property not available with conventional materials.

As a result, when used as a metal gasket, it has excellent sealing resistance, and while conventionally many layers were used, one or two layers can be used, and the effect is great. In addition, there is no particular difference in the production of the two inventive materials from the conventional materials, and since there is no difference in cost from the conventional materials, it is possible to provide an excellent engine gasket material at a low cost.

[Brief explanation of drawings]

Figure 1 shows 7 inventive materials El to 9 (marked with ○) and comparative examples E4 to 5.
(・mark), conventional material A-B (△ mark) and comparative material a-C (
The amount of martensite at the mouth) and after aging treatment (400°C
1 hour) and the beet survival rate (solid test results). Figure 2 shows two examples of the invention material E4, one with a low martensite content (O mark 51%) and one with a high martensite content (・mark 65%).
The relationship between the tensile strength and the beat survival rate was compared with 2 conventional materials and some comparative materials when the strength level was changed by making different rolled materials and changing the aging treatment conditions of these two materials. Figure shown. FIG. 3 is a diagram showing the relationship between the amount of change ΔTS in tensile strength and the amount of martensite due to two-time aging. Fig. 4 is a schematic cross section showing the test condition of the thrust bending test Fig. 5f
at is a schematic cross-sectional view showing the state before load application in the fatigue resistance test. Fig. 5 (bl is a schematic cross-sectional view showing the load state of the sagging resistance test. 1. Dice. 2. Punch. 5a, 5b. Load fluctuation flange.

Claims (7)

[Claims] (1) In weight%, C: 0.10% or less, Si: more than 1.0% to 3.0% or less, Mn: 3.0% or less, Ni: 4.0 to 10.0%, Cr: 12 .0-20.0%. Cu: 0.5 to 3.0%, N: 0.20% or less, S: 0.008% or less, total of C and N: 0.10% or more, and M = 330-(480 ×C%)-(2×Si%)-(1
0xMn%) - (14xNi%) - (5.7xCr%)
The amounts of C, Si, Mn, Ni, Cr, Cu, and N are adjusted so that the M value according to the formula - (14 × Cu%) - (320 × N%) is in the range of 30 to 100, A gasket for an internal combustion engine that has a component composition in which the remainder is Fe and unavoidable impurities, and has a multi-phase structure in which 60% by volume or less of a deformation-induced martensite phase is formed in an austenite phase, and has excellent settling resistance. Materials for use. (2) In weight%, C: 0.10% or less, Si: more than 1.0% to 3.0% or less, Mn: 3.0% or less. Ni: 4.0 to 10.0%. Cr: 12.0-20.0%, Cu: 0.5-3.0%, N: 0.20% or less, S: 0.008% or less, Total of C and N: 0.10% or more, Furthermore, it contains Mo: 3.0% or less, one or more of Ti, Nb, and V: 0.1 to 1.0%, and M=330-(480×C%)-(2×Si%) −(1
0xMn%) - (14xNi%) - (5.7xCr%)
−(5×Mo%)−(14×Cu%)−(320×N%
) The amounts of C, Si, Mn, Ni, Cr, Mo, Cu, and N are adjusted so that the M value according to the formula is in the range of 30 to 100, and the remainder is Fe and inevitable impurities. with 60% by volume in the austenite phase
A material for gaskets for internal combustion engines that has a multi-phase structure in which the following deformation-induced martensitic phase is formed and has excellent resistance to settling. (3) Mn: less than 0.5%, S: 0.003% or less, N
The gasket material according to claim 1 or 2, wherein: 0.06 to 0.15%. (4) The gasket material according to claim 1, 2 or 3, wherein the strain-induced martensitic phase is produced by temper rolling a plate material having an austenitic structure. (5) The gasket material according to claim 1, 2, 3, or 4, wherein the deformation-induced martensitic phase is generated in a range of 30 to 60% by volume. (6) Claims 1, 2, 3, wherein the gasket material has an elongation of 5% or more before aging treatment, and a tensile strength of 175 kg/mm^2 or more and an elongation of 3% or more after aging treatment.
The gasket material according to 4 or 5. (7) The gasket material according to claim 1, 2, 3, 4, 5, or 6, wherein the gasket material is subjected to an aging treatment after being molded into a desired shape.