JPH09227998A - Cold rolled steel sheet for color picture tube color separating electrode structural body and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a cold rolled steel sheet excellent in cold strength, high temp. strength, high temp. creep strength, etching properties or the like required for a color separating electrode structural body incorporated into a color picture tube. SOLUTION: This cold rolled steel sheet has a compsn. contg. 0.001 to 0.03% C, 0.05 to 1.5% Mn and 0.001 to 0.01% Mg and furthermore contg., at need, one or >= two kinds among 0.005 to 0.5% Mo, 0.005 to 0.5% W, <=0.5% Cr and <=0.5% Ni and/or one or >= two kinds among <=0.015% N, 0.0002 to 0.005% B, 0.005 to 0.09% Zr and 0.005 to 0.12% Sn. A continuously cast slab is subjected to hot rolling so as to regulate the finishing temp. to 850 to 950 deg.C and the coiling temp. to 450 to 700 deg.C, is pickled, is thereafter subjected to intermediate cold rolling, is next subjected to continuous annealing so as to regulate the annealing temp. to 620 to 900 deg.C and the average cooling rate in tie temp. range of 600 to 350 deg.C to >=5 deg.C/sec and moreover subjected to final cold rolling to produce into a prescribed thickness. The final cold rolling is executed in such a manner that the rolling ratio is regulated to 30 to 90% and the steel sheet temp. at the time of the cold rolling to 50 to 250 deg.C.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cold rolled steel sheet used as a color selection electrode assembly incorporated in a color picture tube and a method for producing the same.

[0002]

2. Description of the Related Art A color picture tube has a color selection electrode structure for converting an electron beam emitted from an electron gun into an image, and the color selection electrode structure is supported by a frame. By irradiating a specific phosphor screen with an electron beam, a desired color tone is developed. Further, the inside is covered with a magnetic shield material in order to prevent deflection of the electron beam due to the geomagnetism.
In the color selection electrode assembly, a slit through which an electron beam passes is formed in a sloping shape by etching. This color selection electrode assembly is pulled up by the repulsive force generated in the frame by seam welding or spot welding to the frame which is opposed to the upper and lower sides and the left and right sides of the frame-shaped frame which is pressed inward, and then the pressure is released. . The stretched color selection electrode structure is then blackened. In the blackening treatment, conditions of heating to 450 to 480 ° C. for 20 to 30 minutes are usually adopted. The blackening treatment prevents generation of heat radiation, generation of secondary electrons, generation of rust, etc., and forms an oxide film with good adhesion on the surface of the steel sheet.

The color selection electrode assembly has a plate thickness of 0.08-0.
A 25 mm cold rolled steel plate is usually used, but it is required to have various properties such as etching property, black film delamination resistance, pulling tension (small creep deformation during blackening treatment) and magnetic properties. Steel plates have been proposed. For example, in order to secure the tension for tensioning without impairing the etching property, a steel sheet in which N is added to a low carbon steel as a base (Japanese Patent Laid-Open No. Sho 6-62).
No. 2-249339), steel plates containing Cr, Mo, N (JP-A-5-311330), Mn, W, N.
Steel sheet to which i and N are added (JP-A-5-31127), Mn, W and Ni together with Nb, V, Ti, Zr and T
Steel plate with a and B added (JP-A-5-311331), Mn, N and W, Ni, and further Nb, V, Ti and Z
Steel sheet with r, Ta, B added (Japanese Patent Laid-Open No. 5-311332)
Publication).

[0004]

However, recent color picture tubes tend to be large-sized and have high definition, and there is a demand for a cold rolled steel sheet for a color selection electrode assembly which exhibits a higher tension. Further, since demagnetization is required, it is also required to have magnetic characteristics with low coercive force. The tension for tension is determined by the high temperature strength and creep deformation at the blackening treatment temperature. However, if the strength during blackening is increased,
Magnetic properties deteriorate. For this reason, there is a limit to improving the tension of tension because it imparts a predetermined magnetic property, and the demands for large-sized and high-definition color picture tubes are not currently satisfied. The present invention has been devised to solve such a problem. By improving the magnetic properties by adding Mg, and improving the high temperature strength and creep resistance by adding Mn, Mo, W and the like. , Magnetic properties,
It is an object of the present invention to provide a cold-rolled steel sheet for a color selection electrode assembly, which has good etching properties, peeling resistance of a blackening film, and tension.

[0005]

The cold rolled steel sheet for a color picture tube color selection electrode assembly of the present invention has the following object.
C: 0.001 to 0.03% by weight, Mn: 0.05 to
1.5% by weight and Mg: 0.0001 to 0.01% by weight
And the balance substantially has a composition of Fe. This cold-rolled steel sheet further has Mo: 0.005-0.5
% By weight, W: 0.005-0.5% by weight, Cr: 0.5
1% or more of Ni: 0.5% by weight or less, and / or N: 0.015% by weight or less, B: 0.0
002-0.005% by weight, Zr: 0.005-0.0
9% by weight, Sn: 0.005 to 0.1% by weight, and one or more types may be included.

The components contained in the cold-rolled steel sheet as deoxidizing agents and unavoidable impurities are Si: 0.09 wt% or less, P: 0.
04 wt% or less, S: 0.02 wt% or less, Cu: 0.
09 wt% or less, Al: 0.04 wt% or less, O: 0.
01 wt% or less, Ti: 0.01 wt% or less, Nb:
It is preferable to regulate to 0.01% by weight or less and V: 0.01% by weight or less. This cold-rolled steel sheet is obtained by subjecting a continuous cast slab having the above-mentioned composition to hot rolling at a finishing temperature of 850 to 950 ° C and a winding temperature of 450 to 700 ° C, pickling, and then performing intermediate cold rolling, and then annealing. Final cold rolling, which is produced by continuously annealing at an average cooling rate of 5 ° C / sec or more in a temperature of 620 to 900 ° C and a temperature range of 600 to 350 ° C, and further making a predetermined plate thickness in the final cold rolling, Rolling rate 30-
It is preferably performed under the conditions of 90% and a steel plate temperature during cold rolling of 50 to 250 ° C.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The inventors of the present invention have variously investigated and examined the strength and magnetic properties of a cold-rolled low-carbon steel sheet subjected to blackening treatment, and as a result, improved magnetic properties when ultra-low-carbon steel contains Mg. It was found that the high temperature strength and the creep characteristics are improved by the addition of Mn, Mo, W and the like. Further, when the age hardening effect of C and N is expressed in the final cold rolling step, the age hardening effect is added to the improvement of hardness and strength by rolling, so that the hardness and strength are good even at a relatively low rolling reduction. A good steel plate is obtained, and deterioration of magnetic properties is prevented. Based on such knowledge, by adjusting the components under the conditions described above, it is possible to obtain a color selection electrode assembly satisfying all of the magnetic characteristics, etching properties, black film peeling resistance, and tension. Clarified. These properties are
When the continuous annealing with a high cooling rate is performed as the intermediate annealing and the final cold rolling is performed at the steel sheet temperature of 50 ° C. or more, the further improvement is achieved.

The alloy components and contents contained in the cold rolled steel sheet of the present invention will be described below. C: 0.001 to 0.03% by weight It is an alloy component that has the effect of increasing the high temperature strength and improving the tension by making it in a solid solution state after annealing. Such an effect becomes remarkable when the content of C is 0.001% by weight or more. However, when a large amount of C exceeding 0.03% by weight is contained, the amount of precipitated carbide increases and the etching property deteriorates. Mn: 0.05 to 1.5% by weight Mn is a component necessary as a deoxidizer and is an impurity S.
It is fixed as S and exhibits an effect of suppressing hot embrittlement. Such an effect becomes remarkable when the Mn content is 0.05% by weight or more. Mn also has the effect of improving the strength related to the tensile tension, but even if it is contained in an amount of more than 1.5% by weight, the effect corresponding to the increase in the amount cannot be obtained, and rather the formability and weldability deteriorate. .

Mg: 0.0001 to 0.01% by weight It functions as a deoxidizing agent and effectively acts to improve the magnetic properties after blackening treatment. In order to obtain such an effect, it is necessary to contain 0.0001% by weight or more of Mg. However, even if Mg is contained in an amount of more than 0.01% by weight, the improvement in the magnetic characteristics, which is in proportion to the increase in the amount, cannot be seen, and the peeling resistance of the blackened film deteriorates. Mo: 0.005 to 0.5% by weight An alloy component added as necessary, which improves the resistance to annealing and softening, and increases the high-temperature strength as fine precipitates such as MoC and improves the tensile tension. Present. Such an effect becomes remarkable when Mo is contained by 0.005% by weight or more. However, since it is an expensive element and causes an increase in steel material cost, the upper limit of the Mo content is set to 0.
Regulated to 5% by weight.

W: 0.005-0.5% by weight This is an alloy component added as necessary, and improves the resistance to annealing and softening, enhances the high temperature strength as fine precipitates such as WC, and raises the tensile tension. Has an improving effect. Such an effect becomes remarkable when W is contained in an amount of 0.005% by weight or more. However, since it is an expensive element and causes an increase in steel material cost, the upper limit of the W content is regulated to 0.5% by weight. Cr: 0.5% by weight or less An alloy component added as necessary, which enhances high temperature strength and tensile tension. However, when a large amount of Cr exceeding 0.5% by weight is contained, the etching property and the blackening property deteriorate. Ni: 0.5 wt% or less It is an alloy component added as necessary, and has an effect of enhancing high temperature strength. However, when a large amount of Ni exceeding 0.5% by weight is contained, the etching property and the blackening film property are deteriorated.

N: 0.015% by weight or less This is an alloy component added as necessary, and has the action of increasing strength and improving tensile tension by keeping it in a solid solution state after annealing. However, when a large amount of N exceeding 0.015% by weight is contained, surface defects are likely to occur. B: 0.0002 to 0.005% by weight It is an alloy component added as necessary, and has the effect of strengthening the crystal grain boundaries and improving the rolling property. In addition, the crystal grains are made finer to increase the high temperature strength and improve the tensile tension.
Such an effect becomes remarkable when B is contained in an amount of 0.0002% by weight or more. However, since it has the effect of fixing N as BN, if a large amount of B exceeding 0.005 wt% is contained, the effect of N at high temperature strength improvement is lost.

Zr: 0.005 to 0.09% by weight It is an alloy component added as required, and is effective as a deoxidizing agent with very little deterioration of magnetic properties. The deoxidizing effect becomes remarkable when the content of Zr is 0.005% by weight or more. However, when a large amount of Zr exceeding 0.09% by weight is contained, the effect of preventing deterioration of magnetic properties is saturated. Sn: 0.005 to 0.1% by weight It is an alloy component added as necessary, and has the effect of increasing high temperature strength and improving tension. Such an effect becomes remarkable when 0.005 wt% or more of Sn is contained. However, if the Sn content exceeds 0.12% by weight,
Cold rollability is impaired.

In addition to the alloy components listed above, there are unavoidable impurities derived from deoxidizing agents, raw materials and the like. The unavoidable impurities are preferably as small as possible, and the upper limit of each impurity is regulated as follows. Si: 0.09 wt% or less Silicate-based inclusions are generated, which adversely affects the etching property and deteriorates the blackening film property. Such adverse effects are suppressed by setting the upper limit of the Si content to 0.09% by weight. P: 0.04 wt% or less Since it is likely to segregate at grain boundaries, which lowers the strength and adversely affects etching properties, the upper limit of the P content is restricted to 0.04 wt%. S: 0.02 wt% or less The inclusions such as MnS are formed, and the strength, corrosion resistance, etching property, etc. are impaired. Therefore, the upper limit of the S content is 0.0
It was regulated to 2% by weight.

Cu: 0.09 wt% or less Hot workability is deteriorated, and surface defects are likely to occur during hot rolling. Further, the blackened film is also easily peeled off. Therefore, in the present invention, the upper limit of the Cu content is restricted to 0.09% by weight. Al: 0.04 wt% or less Although it is an element effective as a deoxidizer, it easily causes surface defects and deteriorates the blackening film property. Further, it has a function of fixing N as AlN, which impairs the strength improving effect of N. Therefore, in the present invention, the upper limit of the Al content is 0.04.
Restricted to weight percent. O: 0.01% by weight or less Basically, it is a harmful element. When the O content is high, oxide-based inclusions increase, which causes deterioration of etching properties and surface defects. Therefore, in the present invention, the upper limit of the O content is regulated to 0.01% by weight. Ti, Nb, V: 0.01% by weight or less All bind to C and N to form carbonitrides and fix C and N. Therefore, even if it is age hardened, the increase in strength cannot be expected due to C and N. Therefore, in the present invention, the upper limits of these elements are restricted to 0.01% by weight.

In the present invention, a steel having the above-mentioned components is hot-rolled, and then cold-rolled twice including annealing to produce a cold-rolled steel sheet. Hot rolling conditions: finishing temperature 850 to 950 ° C, winding temperature 4
Since the crystal grains are refined by hot rolling at 50 to 700 ° C., the finishing temperature just above the Ar ₃ transformation point is basically used, but a temperature range of 850 to 950 ° C. is allowed. If the finishing temperature does not reach 850 ° C., rolling occurs in the α phase region, and if it exceeds 950 ° C., rolling occurs in the high temperature γ phase region. In any case, the crystal grains become coarse. On the other hand, if the winding temperature does not reach 450 ° C., the plate shape becomes poor, and if the winding temperature exceeds 700 ° C., it becomes difficult to obtain a high strength material and the pickling property becomes poor. In the intermediate cold rolling, the rolling conditions are not particularly limited, but it is preferable to set the cold rolling ratio to 30% or more in order to suppress the coarsening of the crystal grains after the annealing in the next step.

Continuous annealing: an annealing temperature of 620 to 900 ° C., an average cooling rate of 5 ° C./sec or more in a temperature range of 600 to 350 ° C. An annealing temperature at the time of continuous annealing is 620 ° C. or more in order to complete recrystallization. There is a need. At an annealing temperature that does not reach 620 ° C., unrecrystallized grains remain, it becomes difficult to secure the plate shape in the final cold rolling, and the residual stress of the obtained cold-rolled steel sheet tends to be uneven. However, if the annealing temperature exceeds 900 ° C., surface defects are likely to occur in the continuous annealing line, which causes coarsening of crystal grains. In the cooling process of continuous annealing, in order to maintain C and N in a solid solution state,
It is necessary to cool the temperature range of 600 to 350 ° C at an average cooling rate of 5 ° C / sec or more.

Final cold rolling: rolling rate 30 to 90%, steel plate temperature during cold rolling 50 to 250 ° C. In use as a color selection electrode assembly, a hard steel plate is required from the viewpoint of etching workability. Further, since the strengthening by cold rolling is succeeded to the high temperature strength during the blackening treatment, it is necessary to carry out the final cold rolling at a rolling rate of 30% or more.
However, if the rolling ratio exceeds 90%, the coercive force becomes large, and the effect of improving hardness and hardness is saturated. In addition, the load on the cold rolling mill becomes too large, and the productivity decreases. When the age-hardening action of solid solution C and N is exhibited in the final cold rolling, the strength can be significantly increased. For that purpose, it is necessary to make the steel plate temperature 50 ° C. or higher in the final cold rolling step with a cold rolling rate of 30% or higher. However, at a steel sheet temperature exceeding 250 ° C., not only the hardening of C and N is saturated, but also rolling oil burning or temper color is generated on the surface of the steel sheet, which lowers the commercial value. As the cold rolling rate is set higher, the magnetic characteristics are deteriorated as the material becomes harder. However, in the present invention, age hardening is added to the improvement of hardness and strength, so that a steel sheet having the same strength can be obtained even at a low cold rolling rate, so that the magnetic properties are also good.

[0018]

【Example】

Example 1: A steel slab having the composition shown in Table 1 was hot-rolled into a hot-rolled sheet having a thickness of 2.0 mm, pickled, subjected to intermediate cold rolling and continuous annealing, and finally cooled. Sheet thickness 0.15 by hot rolling
mm cold rolled steel sheet was manufactured. The manufacturing conditions are shown in Table 2.

[0019]

[0020]

From each cold-rolled steel sheet obtained, a No. 5 test piece of JIS Z2201 was cut out in a direction orthogonal to the rolling direction, and a tensile test at room temperature in accordance with JIS Z2241 and at 450 ° C. in accordance with JIS Z2271. Was subjected to a tensile test. Also, a constant tension of 294 N / mm ² was applied to a 30 mm × 550 mm test piece at 450 ° C.
A tensile tension test was carried out to measure the stress reduction rate after the lapse of minutes. In this test, if the stress reduction rate is 7.5% or less, it is judged that the tensile strength required for the color selection electrode structure is satisfied. Further, an aqueous ferric chloride solution was sprayed onto the surface of the test piece, the material was etched in a slit shape along a direction orthogonal to the rolling direction, and the etching surface was observed to evaluate the etching property.

[0022]

As can be seen from Table 3 showing the investigation results, the cold-rolled steel sheets of steel types 1 to 10 according to the present invention have high room temperature strength and high temperature strength and a low stress reduction rate at 450 ° C. The etching property was also good. From the above, it can be seen that the characteristics required for the color selection electrode structure are satisfied. On the other hand, the cold-rolled steel sheet of Comparative Example is inferior in one or more of room temperature strength, high temperature strength, stress reduction rate at 450 ° C., and etching property, and satisfies the required characteristics as a color selection electrode assembly. There wasn't. For example, the cold-rolled steel sheet of steel type number 11 has a large O content because it does not contain Mg, has a large coercive force,
A patter was generated on the surface of the steel sheet after etching. A lot of A
The cold-rolled steel sheets of Steel Grade Nos. 12 and 13 containing 1 showed good etchability due to the small O content, but had low room temperature strength and high temperature strength, and showed a large stress reduction rate in the creep test. The cold-rolled steel sheet with steel type number 14 is
Since it did not contain Mg, the O content was high, and since it contained a large amount of C, precipitation of Fe ₃ C was observed and a large coercive force was exhibited. After the etching, roughening of the surface of the steel sheet occurred and pit defects were also observed.

[0024]

As described above, the steel sheet for a color-selecting electrode structure of the present invention is improved in magnetic properties by adding Mg, and is strengthened and hardened in consideration of age hardening of C and N. Therefore, even if cold rolling is performed at a relatively low rolling rate in order to suppress an increase in coercive force, the characteristics required for the color selection electrode assembly are satisfied. Further, addition of Mn, Mo, W, etc. also improves high temperature strength and creep strength. In this way, the cold-rolled steel sheet according to the present invention is sufficiently compatible with applications for color picture tubes, which are becoming larger and more fine.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location H01J 9/14 H01J 9/14 G 29/07 29/07 Z

Claims (7)

[Claims] 1. C: 0.001-0.03% by weight, M
n: 0.05 to 1.5% by weight and Mg: 0.0001 to
A cold rolled steel sheet for a color picture tube color selection electrode assembly containing 0.01% by weight, and the balance being substantially Fe. 2. C: 0.001-0.03% by weight, M
n: 0.05 to 1.5% by weight and Mg: 0.0001 to
0.01% by weight and further Mo: 0.005-0.5
% By weight, W: 0.005-0.5% by weight, Cr: 0.5
A cold-rolled steel sheet for a color picture tube color selection electrode assembly, which contains one or two or more of Ni and 0.5% by weight or less, and the balance of which is substantially Fe. 3. C: 0.001-0.03% by weight, M
n: 0.05 to 1.5% by weight and Mg: 0.0001 to
0.01% by weight, N: 0.015% by weight or less, B: 0.0002 to 0.005% by weight, Zr: 0.
005 to 0.09% by weight, Sn: 0.005 to 0.1% by weight, one or two or more of them, and the balance being substantially Fe composition. Cold rolled steel sheet for color picture tube color selection electrode assembly. . 4. C: 0.001-0.03% by weight, M
n: 0.05 to 1.5% by weight and Mg: 0.0001 to
0.01% by weight and further Mo: 0.005-0.5
% By weight, W: 0.005-0.5% by weight, Cr: 0.5
1% or more of Ni: 0.5 wt% or less, N: 0.015 wt% or less, B: 0.0002 to
Color containing at least one of 0.005% by weight, Zr: 0.005 to 0.09% by weight, Sn: 0.005 to 0.1% by weight, and the balance substantially Fe. Cold rolled steel sheet for cathode ray tube color selection electrode assembly. 5. Si: 0.09% by weight or less as an element contained as a deoxidizer or an unavoidable impurity, P: 0.04
% By weight, S: 0.02% by weight or less, Cu: 0.09
Wt% or less, Al: 0.04 wt% or less, O: 0.01
Wt% or less, Ti: 0.01 wt% or less, Nb: 0.0
The cold-rolled steel sheet for a color picture tube color selection electrode assembly according to any one of claims 1 to 4, which is regulated to 1% by weight or less and V: 0.01% by weight or less. 6. A continuous casting slab having the composition according to claim 1 is subjected to hot rolling at a finishing temperature of 850 to 950 ° C. and a winding temperature of 450 to 700 ° C. Color picture tube color that is cold-rolled, then continuously annealed at an average cooling rate of 5 ° C./sec or more in an annealing temperature of 620 to 900 ° C. and a temperature range of 600 to 350 ° C., and further to a predetermined plate thickness in the final cold rolling. A method for manufacturing a cold rolled steel sheet for a selective electrode structure. 7. A cold rolled steel sheet for a color picture tube color selection electrode assembly which is subjected to final cold rolling according to claim 6 under the conditions of a rolling rate of 30 to 90% and a steel sheet temperature during cold rolling of 50 to 250 ° C. Production method.