U.S. patent application number 10/536355 was filed with the patent office on 2006-06-29 for cold rolled steel sheet for gasket material, method for production thereof and gasket material produced by the method.
This patent application is currently assigned to TOYO KOHAN CO. LTD.. Invention is credited to Shinichi Aoki, Hiroyasu Itoh, Satoshi Oh, Toshiyuki Ueda.
Application Number | 20060137167 10/536355 |
Document ID | / |
Family ID | 32473652 |
Filed Date | 2006-06-29 |
United States Patent
Application |
20060137167 |
Kind Code |
A1 |
Ueda; Toshiyuki ; et
al. |
June 29, 2006 |
Cold rolled steel sheet for gasket material, method for production
thereof and gasket material produced by the method
Abstract
A cold rolled steel sheet for a gasket material, characterized
in that it has a chemical composition, in wt %: C: 0.08 to 0.60%,
Si: 1.0 to 3.0%, Mn: 0.5 to 3.0%, P.ltoreq.0.06%, S;.ltoreq.0.06%,
Al: .ltoreq.0.1%, N: 0.0010 to 0.0150%, and the balance: Fe and
inevitable impurities: and a method for producing the steel sheet.
The cold collect steel sheet for a gasket material can provide a
good balance between bead formability and spring characteristics,
together with excellent gas sealing property, and can be produced
at a low cost, and thus can be used for producing a gasket being
suitably used at openings such as those for cooling water and a
lubricating oil and a bolt hole.
Inventors: |
Ueda; Toshiyuki;
(Kudamatsu-shi, JP) ; Itoh; Hiroyasu;
(Kudamatsu-shi, JP) ; Oh; Satoshi; (Kudamatsu-shi,
JP) ; Aoki; Shinichi; (Kudamatsu-shi, JP) |
Correspondence
Address: |
BROWDY AND NEIMARK, P.L.L.C.;624 NINTH STREET, NW
SUITE 300
WASHINGTON
DC
20001-5303
US
|
Assignee: |
TOYO KOHAN CO. LTD.
2-12, Yonbancho Chiyoda-ku
Tokyo
JP
102-8447
|
Family ID: |
32473652 |
Appl. No.: |
10/536355 |
Filed: |
October 10, 2003 |
PCT Filed: |
October 10, 2003 |
PCT NO: |
PCT/JP03/13001 |
371 Date: |
November 9, 2005 |
Current U.S.
Class: |
29/527.1 ;
148/648; 29/505; 428/638 |
Current CPC
Class: |
C21D 8/1266 20130101;
Y10T 428/12653 20150115; C21D 8/0236 20130101; C21D 8/1277
20130101; C21D 8/0268 20130101; Y10T 29/49908 20150115; Y10T
29/4998 20150115; C22C 38/04 20130101; C22C 38/02 20130101 |
Class at
Publication: |
029/527.1 ;
148/648; 428/638; 029/505 |
International
Class: |
B32B 15/18 20060101
B32B015/18; B21B 1/46 20060101 B21B001/46 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 29, 2002 |
JP |
2002-347344 |
Feb 24, 2003 |
JP |
2003-45421 |
Claims
1. A cold rolled steel sheet for a gasket material characterized by
comprising, on the weight % base, from 0.08 to 0.60% of C, from 1.0
to 3.0% of Si, from 0.5 to 3.0% of Mn, 0.06% or more of P, 0.06% or
less of S, 0.1% or less of Al, from 0.0010 to 0.0150% of N and the
balance of Fe and inevitable impurities.
2. A method of producing a cold rolled steel plate for a gasket
material, characterized by hot rolling a continuously cast piece
comprising, on the weight % base, from 0.08 to 0.60% of C, from 1.0
to 3.0% of Si, from 0.5 to 3.0% of Mn, 0.06% or more of P, 0.06% or
less of S, 0.1% or less of Al, from 0.0010 to 0.0150% of N and the
balance of Fe and inevitable impurities, conducting pickling,
applying cold rolling at a draft of from 50 to 90%.
3. A method of producing a cold rolled steel plate for a gasket
material, characterized by hot rolling a continuously cast piece
comprising, on the weight % base, from 0.08 to 0.60% of C, from 1.0
to of 3.0% Si, from 0.5 to 3.0% of Mn, 0.06% or more of P, 0.06% or
less of S, 0.1% or less of Al, from 0.0010 to 0.0150% of N and the
balance of Fe and inevitable impurities, conducting pickling,
applying cold rolling at a draft of from 50 to 90%, and further
applying Zn or Ni plating on the surface.
4. A method of producing a cold rolled steel plate for a gasket
material, characterized by hot rolling a continuously cast piece
comprising, on the weight % base, from 0.08 to 0.60% of C, from 1.0
to 3.0% of Si, from 0.5 to 3.0% of Mn, 0.06% or more of P, 0.06% or
less of S, 0.1% or less of Al, from 0.0010 to 0.0150% of N and the
balance of Fe and inevitable impurities, conducting pickling,
applying cold rolling at a draft of from 50 to 90%, applying
annealing at 630 to 870.degree. C. or higher by continuous
annealing or at 500 to 750.degree. C. or higher by batchwise
annealing and, subsequently, applying secondary rolling at a draft
of 30% or more.
5. A method of producing a cold rolled steel plate for a gasket
material, characterized by hot rolling a continuously cast piece
comprising, on the weight % base, from 0.08 to 0.60% of C, from 1.0
to 3.0% of Si, from 0.5 to 3.0% of Mn, 0.06% or more of P, 0.06% or
less of S, 0.1% or less of Al, from 0.0010 to 0.0150% of N and the
balance of Fe and inevitable impurities, conducting pickling,
applying cold rolling at a draft of from 50 to 90%, applying
annealing at 630 to 870.degree. C. or higher by continuous
annealing or at 500 to 750.degree. C. or higher by batchwise
annealing and, subsequently, applying secondary rolling at a draft
of 7% or less.
6. A method of producing a cold rolled steel plate for a gasket
material, characterized by hot rolling a continuously cast piece
comprising, on the weight % base, from 0.08 to 0.60% of C, from 1.0
to 3.0% of Si, from 0.5 to 3.0% of Mn, 0.06% or more of P, 0.06% or
less of S, 0.1% or less of Al, from 0.0010 to 0.0150% of N and the
balance of Fe and inevitable impurities, conducting pickling,
applying a cold rolling at a draft of from 50 to 90%, applying
annealing at 630 to 870.degree. C. or higher by continuous
annealing or at 500 to 750.degree. C. or higher by batchwise
annealing, subsequently, applying secondary rolling at a draft of
30% or more and, further, applying Zn or Ni plating on the
surface.
7. A method of producing a cold rolled steel plate for a gasket
material, characterized by hot rolling a continuously cast piece
comprising, on the weight % base, from 0.08 to 0.60% of C, from 1.0
to 3.0% of Si, from 0.5 to 3.0% of Mn, 0.06% or more of P, 0.06% or
less of S, 0.1% or less of Al, from 0.0010 to 0.0150% of N and the
balance of Fe and inevitable impurities, conducting pickling,
applying cold rolling at a draft of from 50 to 90%, applying
annealing at 630 to 870.degree. C. or higher by continuous
annealing or at 500 to 750.degree. C. or higher by batch annealing,
subsequently, applying secondary rolling at a draft of 7% or less
and, further, applying Zn or Ni plating on the surface.
8. A gasket material produced by using the cold rolled steel sheet
for a gasket material according to claim 1.
9. A gasket material produced by using the cold rolled steel sheet
for a gasket material according to claim 2.
10. A gasket material produced by using the cold rolled steel sheet
for a gasket material according to claim 3.
11. A gasket material produced by using the cold rolled steel sheet
for a gasket material according to claim 4.
12. A gasket material produced by using the cold rolled steel sheet
for a gasket material according to claim 5.
13. A gasket material produced by using the cold rolled steel sheet
for a gasket material according to claim 6.
14. A gasket material produced by using the cold rolled steel sheet
for a gasket material according to claim 7.
Description
TECHNICAL FIELD
[0001] The present invention concerns a cold rolled steel sheet for
a gasket material used as a sealing material for each of opening
portions including cylinders in internal combustion engines, a
method for producing thereof and a gasket material produced by the
method.
BACKGROUND ART
[0002] Various gaskets including a cylinder head gasket have been
used being concerned with an automobile engine. As the material for
the gasket, asbestos have been used so far but non-asbestos
materials have been sought in order to cope with environmental
problems, improvement for the performance of engines, etc.
[0003] As the substitute material for asbestos, those using aramid
fibers or graphite and put to composite fabrication with soft steel
sheets have been used. Further, as those quite different from the
existent gasket structure, stainless steels coated with rubber
coating materials have also been used.
[0004] Heretofore, as a casing of using a cold rolled steel sheet
for the gasket material, JP-A No. Hei 9-194935, for example,
discloses a method of heating to a recrystallization temperature or
higher followed by quenching. In this case, because of quenching,
warps occur in the cold rolled steel sheet after quenching to
result in a problem in view of the flatness.
[0005] Further, JP-A No. 2000-109957 discloses an example of
providing a stainless steel sheet. However, since the stainless
steel sheet is expensive, this is not economical.
[0006] However, since those of using the aramid fibers or graphite
or stainless steels coated with rubber coating materials require
composite fabrication with other materials, they involve a problem
of increasing the cost.
[0007] FIG. 3 is a schematic cross sectional view showing the
manner of using a gasket material in an application use for springs
requiring spring property and application use of fabrication
requiring fabricability. As shown in FIG. 3, a gasket material 41
interposed between a cylinder 43 and a cylinder head 44 is formed
with a bead portion 42 for improving the sealability. Accordingly,
the characteristics as the gasket material 41 requiring the spring
property include bead fabricability and the spring property. The
bead fabricability and the spring property are properties contrary
to each other in a metallurgical point of view.
[0008] Generally, for improving the fabricability, it is preferred
to soften a steel material, whereas it is preferred to harden the
steel material in order to improve the spring property.
[0009] Accordingly, it is an object of the present invention to
provide a cold rolled steel sheet for a gasket material having
excellent gas sealing property which is inexpensive and while has
good balance between the bead fabricability and the spring
property, as well as a method of producing the same.
[0010] Further, it is another object of the present invention to
provide a gasket. material having particularly excellent spring
property required for the sealing performance for the opening of
the cylinder, well conforming also with various kinds of openings
such as an opening for cooling water, an opening for lubricant and
a bolt hole, and also capable of obtaining good sealing performance
with preferred spring property.
DISCLOSURE OF THE INVENTION
[0011] For attaining the foregoing object, a cold rolled steel
sheet for a gasket material according to claim 1 is characterized
by comprising, on the weight % base, from 0.08 to 0.60% of C, from
1.0 to 3.0% of Si, from 0.5 to 3.0% of Mn, 0.06% or more of P,
0.06% or less of S, 0.1% or less of Al, from 0.0010 to 0.0150% of N
and the balance of Fe and inevitable impurities. According to this,
the cold rolled steel sheet for a gasket material of the invention
is inexpensive, and having excellent gas sealing property with good
balance between the bead fabricability and the spring property.
Further, the cold rolled steel sheet for a gasket material
according to the invention is inexpensive and has a gas sealing
property with excellent bendability capable of being bent by
180.degree. C.
[0012] A method of producing a cold rolled steel plate for a gasket
material according to claim 2 is characterized by hot rolling a
continuously cast piece comprising on the weight % base, from 0.08
to 0.60% of C, from 1.0 to 3.0% of Si, from 0.5 to 3.0% of Mn,
0.06% or more of P, 0.06% or less of S, 0.1% or less of Al, from
0.0010 to 0.0150% of N and the balance of Fe and inevitable
impurities, conducting pickling, applying cold rolling at a draft
of from 50 to 90%.
[0013] A method of producing a cold rolled steel plate for a gasket
material according to claim 3 is characterized by hot rolling a
continuously cast piece comprising, on the weight % base, from 0.08
to 0.60% of C, from 1.0 to of 3.0% Si, from 0.5 to 3.0% of Mn,
0.06% or more of P, 0.06% or less of S, 0.1% or less of Al, from
0.0010 to 0.0150% of N and the balance of Fe and inevitable
impurities, conducting pickling, applying cold rolling at a draft
of from 50 to 90%, and further applying Zn or Ni plating on the
surface.
[0014] A method of producing a cold rolled steel plate for a gasket
material according to claim 4 is characterized by hot rolling a
continuously cast piece comprising, on the weight % base, from 0.08
to 0.60% of C, from 1.0 to 3.0% of Si, from 0.5 to 3.0% of Mn,
0.06% or more of P, 0.06% or less of S, 0.1% or less of Al, from
0.0010 to 0.0150% of N and the balance of Fe and inevitable
impurities, conducting pickling, applying cold rolling at a draft
of from 50 to 90%, applying annealing at 630 to 870.degree. C. or
higher by continuous annealing or at 500 to 750.degree. C. or
higher by batchwise annealing and, subsequently, applying secondary
rolling at a draft of 30% or more.
[0015] A method of producing a cold rolled steel plate for a gasket
material according to claim 5 is characterized by hot rolling a
continuously cast piece comprising, on the weight % base, from 0.08
to 0.60% of C, from 1.0 to 3.0% of Si, from 0.5 to 3.0% of Mn,
0.06% or more of P, 0.06% or less of S, 0.1% or less of Al, from
0.0010 to 0.0150% of N and the balance of Fe and inevitable
impurities, conducting pickling, applying cold rolling at a draft
of from 50 to 90%, applying annealing at 630 to 870.degree. C. or
higher by continuous annealing or at 500 to 750.degree. C. or
higher by batchwise annealing and, subsequently, applying secondary
rolling at a draft of 7% or less.
[0016] A method of producing a cold rolled steel plate for a gasket
material according to claim 6 is characterized by hot rolling a
continuously cast piece comprising, on the weight % base, from 0.08
to 0.60% of C, from 1.0 to 3.0% of Si, from 0.5 to 3.0% of Mn,
0.06% or more of P, 0.06% or less of S, 0.1% or less of Al, from
0.0010 to 0.0150% of N and the balance of Fe andinevitable
impurities, conducting pickling, applying a cold rolling at a draft
of from 50 to 90%, applying annealing at 630 to 870.degree. C. or
higher by continuous annealing or at 500 to 750.degree. C. or
higher by batchwise annealing, subsequently, applying secondary
rolling at a draft of 30% or more and, further, applying Zn or Ni
plating on the surface.
[0017] A method of producing a cold rolled steel plate for a gasket
material according to claim 7 is characterized by hot rolling a
continuously cast piece comprising, on the weight % base, from 0.08
to 0.60% of C, from 1.0 to 3.0% of Si, from 0.5 to 3.0% of Mn,
0.06% or more of P, 0.06% or less of S, 0.1% or less of Al, from
0.0010 to 0.0150% of N and the balance of Fe and inevitable
impurities, conducting pickling, applying cold rolling at a draft
of from 50 to 90%, applying annealing at 630 to 870.degree. C. or
higher by continuous annealing or at 500 to 750.degree. C. or
higher by batch annealing, subsequently, applying secondary rolling
at a draft of 7% or less and, further, applying Zn or Ni plating on
the surface.
[0018] In the present invention, according to claims 2 to 4 and 6,
a cold rolled steel sheet for a gasket material which is
inexpensive and has excellent gas sealing property with good
balance between the bead fabricability and the spring property can
be produced.
[0019] According to the present invention in claims 2, 3, 5 and 7,
a cold rolled steel sheet for a gasket material which is
inexpensive and having gas sealing property of excellent
bendability can be produced.
[0020] A gasket material according to claim 8 is produced by using
the cold rolled steel sheet for a gasket material according to
claim 1.
[0021] A gasket material according to claim 9 is produced by using
the cold rolled steel sheet for a gasket material according to any
one of claim 2 to 7.
[0022] Thus, the gasket material of the present invention is
particularly preferred in view of the spring property which is
necessary as the sealing performance for the cylinder opening, well
conforms also to various types of openings such as the opening for
cooling water, the opening for lubricant and bolt holes, and can
provide sealing performance with good spring property.
[0023] It is necessary that the gasket material has a strength of
1000 MPa or more, preferably, 1200 MPa or more in view of the
tensile strength according to JIS No. 5 (tensile strength:
hereinafter referred to as "T. S."). Further, it is necessary that
the gasket material has an elongation of 3% or more (total
elongation: hereinafter referred to as "T. EL."), more preferably,
5% or more for the fabrication of the bead portion as described
above.
[0024] Further, in addition to the application use for springs
requiring the spring property, the gasket material also includes a
fabrication application use requiring bending fabrication as shown
in FIG. 4. In this case, it is necessary that the strength is 500
MPa or more, preferably, 600 MPa or more as the T. S. according to
JIS No. 5 piece and requires 15% or more and, preferably, 20% or
more of T. EL.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] FIG. 1 is a schematic view showing an evaluation method for
the fabricability of a gasket.
[0026] FIG. 2 is a schematic view showing a test method for
evaluation of the spring property.
[0027] FIG. 3 is a schematic cross sectional view showing the mode
of using a gasket material for spring application.
[0028] FIG. 4 is a schematic cross sectional view showing the mode
of using the gasket material applied with a vending
fabrication.
BEST MODE FOR PRACTICING THE INVENTION
[0029] Preferred embodiments of the present invention are to be
described in details.
Steel Ingredients of a Cold Rolled Steel Sheet for a Gasket
Material as a Starting Plate
[0030] The steel ingredients in the cold rolled steel sheet for a
gasket material according to the present invention comprises, on
the weight % base, from 0.008 to 0.60% of C, from 1.0 to 3.0% of
Si, from 0.5 to 3.0% of Mn, 0.06% or more of P, 0.06% or less of S,
0.1% or less of Al, from 0.0010 to 0.0150% of N and the balance of
Fe and inevitable impurities.
[0031] C is preferably 0.08% by weight or more in order to provide
a high degree of fineness to a cold rolled steel sheet for a gasket
material. On the other hand, in a case where the ingredient C
exceeds 0.60% by weight, the precipitation amount of carbides
increases to deteriorate the fabricability of the cold rolled steel
sheet for the gasket material and, at the same time, causes
lowering of the productivity such as increase of the load for cold
rolling, deterioration of the shape, inhibition for sheet passing
in a continuous annealing step, etc. Accordingly, the upper limit
value for the ingredient C is defined as 0.60% by weight in the
invention.
[0032] Since Mn is an essential ingredient for preventing
embrittlement under red heating during hot rolling due to impurity
S and, at the same time, providing high fineness to the cold rolled
steel sheet for the gasket material like C described above, the Mn
ingredient is defined as 0.5% by weight or more. However, also in
the same manner as C, if it is excessive, it causes lowering of the
productivity such as increase of the load for cold rolling,
occurrence of crack during slab rolling, deterioration of the shape
and inhibition for sheet passing in a continuous annealing step,
etc., so that the upper limit value is defined as 3.0% by
weight.
[0033] Since P is a crystal grain refining ingredient and also it
improves the strength of the cold rolled steel sheet for the
gasket, it is added at a predetermined ratio but, on the other
hand, it hinders the corrosion resistance. In a case where P
exceeds 0.06% by weight, the corrosion resistance, particularly,
pit resistance is remarkably deteriorated for the application use
of the invention, so that the upper limit value is defined as 0.06%
by weight.
[0034] S is an impurity ingredient causing embrittleness under red
heating during hot rolling and it is desirably as less as possible.
However, since intrusion from iron ores, etc. can not be prevented
completely and desulfurization during the step is difficult, it may
inevitably remain to some extent. Since the embrittleness under red
heating due to small amount of remained S can be moderated with Mn,
the upper limit value for the S ingredient is defined as 0.06% by
weight.
[0035] Al is added in a steel bath as a deoxidant upon steel
making. However, if it is 0.10% by weight or more, excess Al reacts
with an oxidation suppressor and oxygen in a casting mold powder
used as an anti-scorching agent to a casting die in the continuous
casting during continuous casting to hinder the intended powder
effect. Accordingly, the amount of Al is controlled to 0.10% by
weight or less.
[0036] N, like C and Mn, provides a high fineness to the cold
rolled steel sheet for the gasket. While this is an essential
ingredient for improving the proof stress, reduction to less than
0.01% by weight results in the difficulty in view of steel making.
On the other hand, addition in excess of 0.0150% by weight
remarkably lowers the yield of ferro nitrides added during steel
making lacks in stability and also remarkably deteriorates the
anisotropy during press molding. Further, since this results in
cracks at the surface of a continuous cast piece to form casting
defects, the range for the N ingredient is defined in the invention
as from 0.001 to 0.0150% by weight. More preferably, it is defined
as from 0.0021 to 0.0150%.
[0037] Si provides a main feature of the invention. Si has a
significant solid solubilization strengthening performance in the
steel and it is an effective element for obtaining a spring
property. Accordingly, it is necessary by 1.0% by weight or more.
Further, while more content is preferred in view of strengthening
the material, since increase of load in the cold rolling and
deterioration of the shape are caused when it exceeds 3.0% by
weight, the upper limit value is defined as 3.0% by weight.
Hot Rolling
[0038] The heating temperature for the steel piece in the hot
rolling step is not specified in the present invention but it is
preferably 1100.degree. C. or higher in view of positive
decomposition and solid-solubilization of N and stable insurance of
the hot finishing rolling temperature. Since the crystal tissue in
a hot steel sheet gives a grain mixture and grain growth failing to
obtain an aimed strength in a case where the hot rolling finishing
temperature is below the Ar3 point, the hot rolling finishing
temperature is preferably Ar3 point or higher. The take-up
temperature is defined as 450.degree. C. to 650.degree. C.
450.degree. C. is defined as the lower limit while considering the
quality stability in the lateral direction and the longitudinal
direction of the coil during hot rolling. Further, in a case where
the take-up temperature exceeds 650.degree. C., since the crystal
grain size increases during hot rolling and continuous annealing
thereby causing failure during fabrication of gasket beads, the
take-up temperature is preferably 650.degree. C. or lower.
[0039] The steel sheet subjected to hot rolling with the ingredient
system as described above is cold rolled, and the cold draft is an
important strength factor together with the ingredients in the
invention and it is conducted at 50 to 90% in order to obtain an
aimed strength.
[0040] As described above, the material applied with cold rolling
at 50 to 90% is degreased in a cleaning step and then applied with
continuous annealing at 630 to 870.degree. C. or higher and,
preferably, at 680 to 870.degree. C. Alternatively, batchwise
annealing is applied at 500 to750.degree. C. or, preferably, 600 to
750.degree. C. The annealing time may be within such a range as the
material is recrystallized.
[0041] In the case of use for the spring application, secondary
cold rolling is applied at a draft of 30% or more, preferably, 60%
or more to introduce strains. Subsequently, surface roughness is
optionally applied by temper rolling.
[0042] On the other hand, in a case of use for the fabrication
application with excellent bending property, a secondary rolling at
a draft of 7% or less or temper rolling is applied after annealing.
Subsequently, the surface roughness is applied optionally by temper
rolling.
[0043] Then, the cold rolled steel sheet for the gasket material
according to the invention prepared as described above includes
sheet-like and coil-like steel sheets, steel foils, or those formed
by applying a surface treatment to the steel sheets described
above. Particularly, electrolytic chromate treated steel sheets
having a two-layered structure comprising a lower layer of a
metallic chromium and an upper layer of chromium hydrate oxide, or
extremely thin tin-plated steel sheets, nickel plated steel sheets,
zinc plated steel sheets and those formed by applying a surface
treatment with chromium hydrate oxide, or a surface treatment
having a two-layered structure comprising an upper layer of
chromium hydrate oxide and a lower layer of a metallic chromium
layer to the plated steel sheets described above are excellent in
view of the corrosion resistance.
EXAMPLE
[0044] For examples of the invention and comparative examples,
steel ingredients and manufacturing conditions such as a draft are
shown in Table 1 and the results of evaluation for the
characteristics thereof are shown in Table 2.
[0045] In view of Table 1 and Table 2, specimens Nos. 1 to 10 as
the examples can be used for the spring application of high
strength and showing high spring property, while specimens Nos. 11
to 13 can be used for fabrication of excellent bendability. In
Table 2, specimens Nos. 1 to 10 used for spring application are
indicated by symbols "O" in the columns for the spring evaluation
and bead fabrication and favorable therefor, the bendability is
indicated by ".times." to which they can not be applied. Further,
while the specimen Nos. 11 to 13 used for fabrication application
are indicated by ".times." in the column for the spring property
and are not applicable to the spring application, they are
indicated by "O" in the column for bending fabricability and show
good bendability.
[0046] On the other hand, specimens Nos. 14 to 31 as comparative
examples do not satisfy the characteristics for the spring property
for the bead fabricability and can not be applied to the spring
application (symbol ".times." is indicated the column for the
spring property or the bead fabricability in Table 2). Further, the
bendability is poor in each of the cases being indicated by
".times.". TABLE-US-00001 TABLE 1 Steel ingredient, rolled down
ratio and annealing condition Primary Continuous Secondary Specimen
Example or Comparative Chemical ingredient (wt %) rolling annealing
Batchwise annealing rolling No. Example C Si Mn P Al N (draft %)
temperature temperature (8 hrs.) (draft %) 1 Example 1 0.09 1.5 2.5
0.030 0.031 0.0050 70% 820.degree. C. -- 52% 2 Example 2 0.15 2.8
1.7 0.010 0.062 0.0032 70% 820.degree. C. -- 40% 3 Example 3 0.13
2.0 2.1 0.021 0.044 0.0028 70% 820.degree. C. -- 65% 4 Example 4
0.58 1.1 0.6 0.008 0.005 0.0061 70% 820.degree. C. -- 70% 5 Example
5 0.35 1.1 0.8 0.052 0.052 0.0041 70% 820.degree. C. -- 65% 6
Example 6 0.09 1.5 2.5 0.030 0.031 0.0050 70% 800.degree. C. -- 65%
7 Example 7 0.15 2.8 1.7 0.010 0.062 0.0032 70% 800.degree. C. --
65% 8 Example 8 0.13 1.0 2.1 0.021 0.044 0.0028 70% 830.degree. C.
-- 65% 9 Example 9 0.58 1.1 0.6 0.008 0.005 0.0061 70% 830.degree.
C. -- 65% 10 Example 10 0.35 1.1 0.8 0.052 0.052 0.0041 70%
830.degree. C. -- 65% 11 Example 11 0.09 1.5 2.5 0.030 0.031 0.0050
70% 720.degree. C. -- none 12 Example 12 0.15 2.8 1.7 0.010 0.062
0.0032 70% 670.degree. C. -- none 13 Example 13 0.13 2.0 2.1 0.021
0.044 0.0028 70% -- 630.degree. C. none 14 Comparative Example 1
0.04 1.5 1.7 0.011 0.061 0.0029 70% 830.degree. C. -- 65% 15
Comparative Example 2 0.15 0.8 1.8 0.021 0.049 0.0054 70%
830.degree. C. -- 65% 16 Comparative Example 3 0.72 1.8 1.7 0.008
0.022 0.0033 70% 830.degree. C. -- 65% 17 Comparative Example 4
0.16 3.2 1.2 0.014 0.012 0.0011 70% 830.degree. C. -- 65% 18
Comparative Example 5 0.28 1.1 3.3 0.015 0.007 0.0024 70%
830.degree. C. -- 65% 19 Comparative Example 6 0.22 2.1 0.3 0.020
0.082 0.0110 70% 830.degree. C. -- 65% 20 Comparative Example 7
0.09 1.5 2.5 0.030 0.032 0.0050 70% 600.degree. C. -- 65% 21
Comparative Example 8 0.13 2.0 2.1 0.021 0.044 0.0028 70% --
490.degree. C. none 22 Comparative Example 9 0.15 0.8 1.8 0.021
0.049 0.0054 70% 800.degree. C. -- 15% 23 Comparative Example 10
0.72 1.8 1.7 0.008 0.022 0.0033 70% 800.degree. C. -- 20%
[0047] TABLE-US-00002 TABLE 2 Result for the Evaluation of
Characteristic Example or Specimen Comparative T. S. T. EL. Spring
Bead No. Example (MPa) (%) property fabricability Bendability 1
Example 1 1,080 5.2% .smallcircle. .smallcircle. x 2 Example 2
1,180 5.0% .smallcircle. .smallcircle. x 3 Example 3 1,145 5.1%
.smallcircle. .smallcircle. x 4 Example 4 1,250 3.9% .smallcircle.
.smallcircle. x 5 Example 5 1,210 4.2% .smallcircle. .smallcircle.
x 6 Example 6 1,080 8.2% .smallcircle. .smallcircle. x 7 Example 7
1,280 8.0% .smallcircle. .smallcircle. x 8 Example 8 1,220 7.2%
.smallcircle. .smallcircle. x 9 Example 9 1,320 4.2% .smallcircle.
.smallcircle. x 10 Example 10 1,290 4.9% .smallcircle.
.smallcircle. x 11 Example 11 560 25.0% x .smallcircle.
.smallcircle. 12 Example 12 595 17.0% x .smallcircle. .smallcircle.
13 Example 13 600 20.0% x .smallcircle. .smallcircle. 14 Comp.
Example 1 980 8.0% x .smallcircle. x 15 Comp. Example 2 990 8.2% x
.smallcircle. x 16 Comp. Example 3 1,320 0.8% .smallcircle. x x 17
Comp. Example 4 1,290 0.9% .smallcircle. x x 18 Comp. Example 5
1290 0.9% .smallcircle. x x 19 Comp. Example 6 940 7.8% x
.smallcircle. x 20 Comp. Example 7 1,080 0.8% x x x 21 Comp.
Example 8 1,290 0.7% .smallcircle. x x 22 Comp. Example 9 880 12.0%
x .smallcircle. x 23 Comp. Example 10 990 7.8% x .smallcircle.
x
Evaluation for Spring Property and Bead Fabricability
[0048] For bead fabricability and the spring property for the
gasket of the present invention were evaluated as described below.
At first, a steel sheet was pressed into a cross sectional shape as
shown in FIG. 1 (fabrication of flanged bead groove), to form a
bead portion of width w and height t. During bead fabrication,
those where no cracks were generated in the bead portion were
indicated by "O" and evaluated as satisfactory, whereas those where
cracks were generated were judged as failed for the bead
fabricability and evaluated as ".times.".
[0049] FIG. 2 shows a step of a compression test as a test method
for the evaluation of the spring property. In FIG. 2, (a) shows a
state of the fabricated bead portion before compression, (b) shows
a state of applying a compressive load and (c) shows the state of
removing the compressive load.
[0050] As shown in FIG. 2, a compressive load was applied from
above to the bead portion by a compression tester. After removing
the load, those in which the recovery amount (T1) exceeded 40%
relative to the compression amount (T) were regarded as
satisfactory for the spring property and indicated by "O". On the
other hand, those of 40% or less were judged as failed with the
spring property being indicated by ".times.".
[0051] Evaluation for the Bendability.
[0052] The bendability was evaluated by subjecting specimens to
180.degree. C. bending fabrication at 0T (sheet not interposed in
the bent portion) and was evaluated depending on whether cracks
occurred or not in the specimen. Those with generation of cracks
were indicated as ".times." and evaluated as failed. On the
contrary, those with no generation of cracks were indicated as "O"
and evaluated as satisfactory. Specimens showing elongation of 15%
or more were favorable in view of the bendability.
INDUSTRIAL APPLICABILITY
[0053] Since the cold rolled steel sheet for the gasket material
and the production method thereof according to the present
invention are constituted and function as described above, a cold
rolled steel sheet for the gasket material having excellent gas
sealing property while being inexpensive and with good balance
between the bead fabricability and the spring property can be
obtained.
[0054] The gasket material according to the present invention has
excellent gas sealing property both for the spring application with
good balance between the fabricability and the spring property, and
for the fabrication application being excellent in the OT
bendability, by changing the production method slightly.
[0055] Further, the gasket material applied with the surface
treatment shows excellent corrosion resistance and shows gas
sealing property for a long period of time even when it is exposed
to the state of high temperature. Further, the gasket material
according to the present invention has particularly preferred
spring property required for the sealing performance for openings
of the cylinder in the spring application and can be used suitably
also to various kinds of openings such as the opening for cooling
water, opening for lubricant and bolt holes. For the fabrication
application. Although it cannot be applied to the use for spring
application, it can be used suitably also for various kinds of
openings such as the opening for cooling water, the opening for
lubricant and bolt holes.
* * * * *