JPH11158548A - Hot rolled steel sheet for shrink band of tv cathode-ray tube and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a hot rolled steel sheet for a shrink band in which the reduction of the cost is attained, high strength and magnetic properties are reconciled and the use of a large amt. of iron scrap which is the need of the time is made possible. SOLUTION: This steel sheet is the one having a compsn. contg., by weight, <=0.01% C, 1 to 4% Si, 0.1 to 3% Mn, <=0.3% P, <=0.02% S, 0.001 to 2% Sol.Al, <=0.006% N, <=0.01% Ti, <=0.01% V, <=0.01% Nb, 0.005 to 0.5% Cu, 0.001 to 0.3% Sn, 0.005 to 2% Ni, 0.004 to 0.2% Cr, <=0.3% Mo and <=0.01% B, satisfying Al2 O3 /(Al2 O3 +CaO+MnO+SiO2 )>=0.1, and the balance Fe with inevitable impurities, in which the average grain size is regulated to 20 to 300 μm, distortion equivalent to skinpass rolling is regulated to 0.1 to 2.0%, and the sheet thickness is regulated to 0.8 to 1.7 mm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot-rolled steel sheet for a TV CRT shrink band, and more particularly to a hot-rolled steel sheet which can consume a large amount of iron scrap and has excellent magnetic properties and strength.

[0002]

2. Description of the Related Art The basic structure of a color cathode ray tube comprises an electron gun and a phosphor screen for converting an electron beam into an image. Further, a magnetic shield material, a shadow mask or an aperture grill which prevents the electron beam from being deflected by geomagnetism,
The frame material that supports them covers the inside, but the outside is covered with an explosion-proof band. Since this explosion-proof band is often used for shrink fitting, it is also called a shrink band. Recently, there is a strong demand for the sharpness of the screen for TVs having a large size and high definition, and still images for personal computers, etc. Therefore, shrink bands are required to have magnetic shielding properties in addition to the conventional high strength. The magnetic shielding property is usually discussed in terms of the low magnetic permeability of the terrestrial magnetism of the DC magnetization characteristic. Often evaluated in.

Conventionally, a cold-rolled steel sheet having a thickness of 1.0 to 2.0 mm, which is obtained by plating a cold-rolled steel sheet obtained by cold-rolling and annealing a hot-rolled steel sheet, has been used for the shrink band.
This steel sheet was slit into a width of about 50 to 200 mm, heated to a temperature of about 500 to 800 ° C. through processing such as bending, mounted on the outer peripheral portion of a cathode ray tube, and shrink-fitted. Although the steel sheet had a tensile strength of about 30 to 50 kgf / mm ² (yield point: 20 to 30 kgf / mm ² ), the steel sheet should be thinned (0.8 to 1.7 m
m) When the thickness is reduced, the rigidity is impaired. Therefore, it is necessary to increase the yield point. However, when a high-tensile steel plate is used, the magnetic properties are impaired, and there is a contradiction that the magnetic shielding property is deteriorated.

[0004]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention specifically aims at reducing costs with hot-rolled steel sheets,
Provided is a hot-rolled steel sheet for a shrink band, which can achieve both high strength and magnetic properties and can use a large amount of iron scrap, which has been demanded by the times.

[0005]

The gist of the present invention is as follows. (1) A hot-rolled steel sheet having a corrosion-resistant coating on its surface and used for a shrink band of a TV cathode-ray tube.
C ≦ 0.01%, Si: 1-4%, Mn: 0.1-3%, P ≦ 0.3%, S ≦ 0.02%, Sol.Al: 0.001-2%, N ≦ 0.006%, Ti ≦ 0.01%, V ≦ 0.01%, Nb ≦ 0.01%, Cu: 0.005 to 0.5%, Sn: 0.001 to 0.3%, Ni: 0.005 to 2%, Cr: 0.004 to 0.2%, Mo ≦ 0.3%, B ≦ 0.01%, Al ₂ O ₃ / (Al ₂ O ₃ + CaO + MnO + SiO ₂ ) ≧ 0. 1, the balance being Fe and unavoidable impurities, an average crystal grain size of 20 to 300 μm, a strain equivalent to skin pass rolling of 0.1 to 2.0%, and a sheet thickness of 0.8 to 2.0%.
A hot-rolled steel sheet for a TV CRT shrink band, which is 1.7 mm.

(2) A TV having a corrosion-resistant coating on its surface
A method for producing a hot-rolled steel sheet for use in a CRT shrink band, wherein, by weight%, C ≦ 0.01%, Si: 1-4%, Mn: 0.1-3%, P ≦ 0.3%, S ≦ 0.02%, Sol.Al: 0.001-2%, N ≦ 0.006%, Ti ≦ 0.01%, V ≦ 0.01%, Nb ≦ 0.01%, Cu: 0. 005-0.5%, Sn: 0.001-0.3%, Ni: 0.005-2%, Cr: 0.004-0.2%, Mo ≦ 0.3%, B ≦ 0.01 %, Al ₂ O ₃ / (Al ₂ O ₃ + CaO + MnO + SiO ₂ ) ≧ 0.1, the balance being a slab composed of Fe and unavoidable impurities, which is subjected to hot rolling at a finishing temperature of 900 ° C. or more by hot rolling. 8
To 1.7 mm, after finishing hot rolling, without water injection for 1 to 7 seconds to obtain a hot-rolled coil having an average crystal grain size of 20 to 300 μm, and then reducing the hot-rolled coil by 0.1 to 2.0%. A method for producing a hot rolled steel sheet for a TV CRT shrink band, wherein skin pass rolling is performed at a reduction rate.

(3) A TV having a corrosion-resistant coating on its surface
A method for producing a hot-rolled steel sheet for use in a CRT shrink band, wherein the slab according to (2) has a thickness of 0.8.
Hot-rolled to ~ 1.7mm, and finished hot-rolled steel sheet 70
A hot-rolled coil having an average crystal grain size of 20 to 300 μm was obtained by self-annealing at a winding temperature of 0 to 900 ° C.
A method for producing a hot-rolled steel sheet for a TV CRT shrink band, wherein the hot-rolled coil is then subjected to skin pass rolling at a rolling reduction of 0.1 to 2.0%.

(4) A TV having a corrosion-resistant coating on its surface
A method for producing a hot-rolled steel sheet for use in a CRT shrink band, wherein the slab according to (2) has a thickness of 0.8.
Hot-rolled to ~ 1.7mm, 60
The average grain size is 2
A method for producing a hot-rolled steel sheet for a TV CRT shrink band, comprising obtaining a hot-rolled coil having a thickness of 0 to 300 µm, and then subjecting the hot-rolled coil to skin pass rolling at a rolling reduction of 0.1 to 2.0%.

(5) A TV having a corrosion-resistant coating on its surface
A hot-rolled steel sheet used for a CRT shrink band, wherein, by weight%, C ≦ 0.01%, Si: 1-4%, Mn: 0.1-3%, P ≦ 0.3%, S ≦ 0. 0.02%, Sol.Al: 0.001-2%, N ≦ 0.006%, Ti ≦ 0.01%, V ≦ 0.01%, Nb ≦ 0.01%, Cu: 0.005-0 0.5%, Sn: 0.001 to 0.3%, Ni: 0.005 to 2%, Cr: 0.004 to 0.2%, Mo ≦ 0.3%, B ≦ 0.01%, Al ₂ O ₃ / (Al ₂ O ₃ + CaO + MnO + SiO ₂ ) ≧ 0.1, the balance being Fe and unavoidable impurities, the average crystal grain size is 10 to 300 μm, and the plate thickness is 0.8 to 1.7.
mm hot rolled steel sheet for TV CRT shrink bands.

(6) A TV having a corrosion-resistant coating on its surface
A method for producing a hot-rolled steel sheet for use in a CRT shrink band, wherein, by weight%, C ≦ 0.01%, Si: 1-4%, Mn: 0.1-3%, P ≦ 0.3%, S ≦ 0.02%, Sol.Al: 0.001-2%, N ≦ 0.006%, Ti ≦ 0.01%, V ≦ 0.01%, Nb ≦ 0.01%, Cu: 0. 005-0.5%, Sn: 0.001-0.3%, Ni: 0.005-2%, Cr: 0.004-0.2%, Mo ≦ 0.3%, B ≦ 0.01 %, Al ₂ O ₃ / (Al ₂ O ₃ + CaO + MnO + SiO ₂ ) ≧ 0.1, and the rest has a thickness of 0.5 to 2.0 mm by hot rolling a slab composed of Fe and unavoidable impurities. A hot-rolled coil was manufactured, and after performing skin pass rolling at a rolling reduction of 2.0% or less, or without performing skin pass rolling, 6 0
~ 1100 ° C continuous annealing to make the average grain size 10 ~
A method for producing a hot-rolled steel sheet for a TV CRT shrink band, wherein the thickness is 300 μm.

There are three points of the present invention. one,
Active use of solid solution strengthening elements such as Si, Mn, P, and Al to obtain high strength. The second is the inclusion Al
It has been discovered that the ratio of ₃ % by weight of ₂ O to other inclusions is very important in improving coercivity. The third point is that it has clarified the effects and effects on the trump element and has paved the way for mass consumption of scrap.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
First, the reasons for limiting the component composition will be described. The amount of C is
0.01% or less. If the amount of C is large, magnetic aging occurs, and the coercive force deteriorates during use.

Si is limited to 1-4%. Si is indispensable because it is an inexpensive element for increasing the strength of a steel sheet.
However, if it is less than 1%, the strength of the steel sheet is unsatisfactory, and if it exceeds 4%, it may become brittle and break during processing into a shrink band. Therefore, the Si content is set to 1% or more and 4% or less.

[0014] The amount of Mn is 0.1 to 3%. Mn is important for controlling the precipitation size of sulfide, and at the same time,
It is effective to increase the strength of the steel sheet. However, if it is less than 0.1%, MnS precipitates finely and deteriorates the coercive force. On the other hand, if it exceeds 3%, the product becomes a quenched structure and becomes brittle, and may be broken during processing into a shrink band. Therefore, the Mn content is set to 0.1% or more and 3% or less.

[0015] The P content is 0.3% or less. P is an element effective in increasing the strength of the steel sheet, but if it is too large, a work crack due to segregation occurs, so the P content is set to 0.3% or less.

The amount of S is set to 0.02% or less. S forms sulfides and deteriorates the coercive force, so that 0.02%
The following is assumed.

The amount of Sol. Al is set to 0.001 to 2% or less. Sol.Al is also an element effective in increasing the strength of the steel sheet.
% Or less. Further, if the content is less than 0.001%, the Al
Avoid the use of ₂ O ₃ -based oxides, which reduce the coercive force. Therefore, the amount of Sol. Al is set to 0.001% or more and 2% or less. In addition, Sol.Al is a so-called Soluble Al amount that is soluble in an acid in Al.

The amount of N is limited to 0.006% or less. N
Is excessively large, causing blisters called “blisters” on the steel sheet surface.

The amount of Ti is set to 0.01% or less. Ti
Forms carbides and nitrides and deteriorates the coercive force.

V is limited to 0.01% or less. V also forms carbides and nitrides and deteriorates the coercive force.
01% or less.

Nb is limited to 0.01% or less. Nb
Also form carbides and nitrides and degrade the coercive force,
0.01% or less.

Cu should be 0.005 to 0.5%. C
u is an element mixed from, for example, a motor copper wire in scrap car scrap from an automobile, but is less than 0.005% in a conventional blast furnace iron-based component system. On the other hand, in the present invention, the content is 0.005% or more, but is set to 0.5% or less because Cu alone or Cu sulfide sometimes deteriorates the coercive force. In the case of the present invention using Cu, Si ≧
1% is a precondition. If Cu is contained in the component system of Si <1%, a flaw called Cu scab occurs on the entire surface of the steel sheet, and there is no problem even if Cu is contained in the component system of Si ≧ 1%. Was. The reason is unclear at present, but it is presumed to be related to the generation of a liquid phase in hot rolling.

Sn is set to 0.001 to 0.3%. S
n is an element mixed from tin can for food cans, etc., and was conventionally less than 0.001%. On the other hand, in the present invention, the content is 0.001% or more, but Sn is made 0.3% or less because Sn makes sulfide finer and deteriorates the coercive force.

Ni is set to 0.005 to 2%. Ni
Is an element mixed from stainless steel or the like, which has conventionally been less than 0.005%. On the other hand, in the present invention, 0.1.
005% or more. Impact on Ni quality 2
%, But no problem occurred in this range, so the Ni content was determined to be 2% or less.

[0025] Cr is limited to 0.004 to 0.2%. Cr is also an element mixed from stainless steel or the like, but it has conventionally been less than 0.004%. On the other hand, in the present invention, the content is 0.004% or more, but if Cr is excessively increased, the coercive force is deteriorated.

Mo is set to 0.3% or less. As the amount of Mo increases, the coercive force deteriorates. This limit is 0.3%.

B is set to 0.01% or less. B is 0.
If it exceeds 01%, cracks occur in the slab. Therefore B
Is controlled to 0.01% or less.

Also, Al ₂ O ₃ / (Al ₂ O ₃ + CaO
+ MnO + SiO ₂ ) ≧ 0.1. Al ₂ O ₃ /
The value of (Al ₂ O ₃ + CaO + MnO + SiO ₂ ) greatly affects the coercive force. If this value is reduced to less than 0.1, the coercive force is deteriorated. Al ₂ O
₃ / (Al ₂ O ₃ + CaO + MnO + SiO ₂ ) ≧ 0.
As an effective means for controlling to 1, it is a known method, but after decarburization in a steelmaking vacuum degassing apparatus, when adding a component element, prior to deoxidation with Al, Mn of
There are a method of adding a deoxidizing agent such as Si, and a method of adding 0.001% or more as a Sol.Al amount.

Next, the manufacturing process of the present invention will be described. A molten steel satisfying the above conditions is continuously cast to produce a slab, which is hot-rolled to 0.8 to 1.7 mm. The thickness of the hot-rolled steel sheet is set at 0.
8 mm is the limit. Since the thickness of the hot-rolled steel sheet is thin, it is impossible to flatten the shape of the steel sheet even with the current hot-rolling equipment operation technology. The slab heating temperature before hot rolling is 9
50-1400 degreeC is preferable.

In this finishing hot rolling,
The grain size can be adjusted by using the method of No. 61644, that is, the technique of steel sheet self-annealing by high-temperature finishing + no water injection. In this case, it is preferable that the finishing temperature is set to 900 ° C. or higher and that no water is injected for 1 to 7 seconds after the finish rolling. If the finishing temperature is lower than 900 ° C., the crystal grain size becomes small, and the coercive force of the steel sheet cannot be sufficiently reduced. In addition, even if the non-water injection time after finish rolling is less than 1 second, the crystal grain size becomes small and the coercive force of the steel sheet cannot be sufficiently reduced, and if it is 7 seconds or more, the pickling property of the steel sheet deteriorates. 7 seconds.

In place of the above-described technique of steel plate self-annealing by high-temperature finishing and no water injection, self-coil annealing may be performed at a high winding temperature after hot rolling. Such a self-coil annealing technique is disclosed, for example, in Japanese Patent Publication No. 57-43.
No. 132, that is, a winding temperature of 700 to 9
There is a method of performing self-annealing at 00 ° C. Winding temperature is 70
If the temperature is lower than 0 ° C, the crystal grain size becomes small and the coercive force of the steel sheet cannot be sufficiently increased. If the temperature exceeds 900 ° C, the pickling property of the steel sheet deteriorates. As a specific operation for carrying out this method, for example, a coil wound by hot rolling is placed in a heat retaining cover, and heated for several minutes to several tens of hours. This heat retaining cover may be heated by electricity, gas, or the like, and the atmosphere is preferably a non-oxidizing atmosphere such as nitrogen or hydrogen in order to improve the pickling property of the steel sheet. In order to improve the pickling property of the steel sheet, it is also possible to perform rapid cooling such as putting in a water bucket without gradually cooling the steel sheet.

Furthermore, it is of course possible to forcibly anneal the hot-rolled coil instead of the above-described method of performing the self-annealing during the hot rolling. In this case, the normal 600 to 1100
It is good to anneal at a temperature of ° C. In the case of continuous annealing, the soaking may be performed with a soaking time of several seconds or more, and in the case of batch annealing, the soaking may be performed with a soaking time of several minutes or more. On the other hand, if the annealing temperature is less than 600 ° C., the coercive force of the steel sheet cannot be sufficiently reduced,
If the temperature exceeds 1100 ° C., the heating cost increases, so the annealing temperature is set to 600 to 1100 ° C.

Here, in the case of batch annealing, warpage in the longitudinal direction, which is referred to as curling (also referred to as a coil set), and deformation flaws at the lower part of the coil are likely to occur. Therefore, the shape should be corrected with a skin pass or a leveler. Is desirable. In the case of skin pass rolling, shape correction can be performed at a rolling reduction of 2% or less, and in the case of using a leveler, shape correction can be performed without stretching a steel sheet.

In the case of continuous annealing, the shape of the steel sheet is corrected while the steel sheet is stretched by a hearth roll during annealing, so that skin pass rolling and leveling for the correction are usually unnecessary. However, when the coil shape after hot rolling has severe elongation, elongation, etc., the shape can be corrected by performing skin pass rolling of 2% or less before or after continuous annealing.

Here, in the case of a process in which a hot-rolled sheet is skin-pass rolled and then subjected to continuous annealing, strain-induced grain growth (Strai
n Induced Grain Boundary Migration) tends to form huge crystal grains (more than 500 μm) on the surface layer. If the crystal grain exceeds 300 μm, a cracking problem occurs during processing into a shrink band. Therefore, the temperature and time of continuous annealing should be strictly controlled so that the average crystal grain size is 300 μm or less. Further, when the rolling reduction of skin pass rolling is more than 2%, the above coarse grain growth is likely to occur.
The rolling reduction of skin pass rolling is 2% or less. When skin pass rolling is not performed after continuous annealing, the coercive force of the steel sheet can be sufficiently reduced if the average crystal grain size is 10 μm or more. Further, the cooling rate of continuous annealing slightly affects the coercive force of the steel sheet, and the slow cooling is more advantageous in reducing the coercive force. For this reason, slow cooling at 150 ° C./s or less is preferable.

These methods of self-annealing or external heat annealing may be used alone or in combination.

The average crystal grain size of the steel sheet after these treatments is as follows:
When skin pass rolling is performed later, 20 to 300 μm
Must be. If the thickness is less than 20 μm, the coercive force of the steel sheet cannot be sufficiently reduced, whereas if it exceeds 300 μm, brittle cracks may occur during processing into a shrink band, and the product is not a commercial product.

When skin pass rolling is not performed later, that is, when the recrystallization / grain growth and shape correction are performed by continuous annealing, the average crystal grain size is set to 10 to 300 μm. 10 μm
If it is less than 300 μm, the coercive force of the steel sheet cannot be sufficiently reduced.
If it exceeds m, brittle cracks as described above may occur. In addition, this average crystal grain size is obtained by measuring the light microscope structure of the cross section of the steel sheet in the thickness direction and averaging it.

In the skin pass rolling, the rolling reduction is 0.1 to 2.
0%. When the rolling reduction is increased, the coercive force is significantly deteriorated, and the strength is increased. If it is less than 0.1%, the shape is not sufficiently corrected, and if it exceeds 2.0%, the coercive force is deteriorated, so that the rolling reduction is 0.1 to 2.0%. Note that pickling may be performed before skin pass rolling, or the pickling may be omitted. In addition, the reduction rate of the product can be easily measured by, for example, measuring the half-value width using X-rays.

Next, after pickling, a corrosion-resistant film is formed on the surface of the steel sheet. As the corrosion-resistant coating, for example, Zn plating and those disclosed in Japanese Patent Publication No. 6-2389 can be used. In this method, a chromate treatment is performed on the Zn-Ni plating, and then a silica / water glass / organic mixed coating is applied and baked.

[0041]

EXAMPLES Example 1 Molten steel containing the chemical components shown in Table 1 was melted in vacuum to form a steel ingot. Al ₂ O ₃ / (Al ₂ O
_{The value of (3} + CaO + MnO + SiO ₂ ) was controlled by controlling the order of alloy addition to the molten steel, that is, the timing of adding Al before or after deoxidation with Si or Mn, or after deoxidation. The heating was performed at 1250 ° C., the finishing temperature was 850 ° C., and the thickness was 1.2 mm.

At a winding temperature of 730 ° C., the film was inserted into a heat insulating furnace, kept for 15 minutes, and then cooled with water. Then 0.5
% Skin pass rolling, pickling and then Zn plating 20
g / m ² and then chromate treatment (90 mg / m ²
m ² ), and a mixed aqueous solution of silica, water glass and polyethylene was applied and dried to form a film having a thickness of 1.7 g / m ² . Epstein sample (30mm
× 300 mm), and the coercive force was measured with a maximum magnetizing force of 10 Oe (Oersted) according to JIS C 2550 for DC magnetic characteristics in the same manner as for a non-oriented electrical steel sheet. The yield point was measured on a sample in the rolling direction in a No. 5 tensile test. Table 1 was obtained by measuring the crystal grain size. Note that the meaning of the Al ₂ O ₃ ratio in Table 1 is Al ₂ O ₃ / (Al ₂ O ₃ + CaO), which is a weight ratio obtained by chemical analysis.
+ MnO + SiO ₂ ).

[0043]

[Table 1]

As shown in Table 1, those satisfying the component range of the present invention can satisfy both the excellent coercive force (≦ 2.3 Oe) and the excellent yield point (≧ 31 kg / mm ² ). Was. Example 2 C: 0.002%, Si: 2.
11%, Mn: 0.12%, P: 0.02%, S: 0.
001%, Sol. Al: 0.25%, N: 0.001%,
B: 0.0001%, Ti: 0.001%, V: 0.0
02%, Nb: 0.003%, Cu: 0.05%, S
n: 0.006%, Ni: 0.025%, Cr: 0.0
3%, Mo: 0.003, Al ₂ O ₃ / (Al ₂ O ₃ +
A slab consisting of CaO + MnO + SiO ₂ ) = 0.26 and the balance substantially consisting of iron was heated at 1200 ° C.
Thick hot coils were produced. The finishing temperature in the hot rolling was changed as shown in Table 2, and after the steel plate passed through the final finishing stand, no water was injected on the hot run table for 2.5 seconds, and then water was injected and wound at 660 ° C. Then
After changing the rolling reduction of the skin pass rolling, pickling was performed, and the same coating as in Example 1 was applied. .

[0045]

[Table 2]

As shown in Table 2, those having a finishing temperature, a crystal grain size and a skin pass rolling reduction within the range of the present invention were excellent in both magnetism and strength. In addition, the experiment No. which omitted skin pass rolling. In the case of No. 6, the shape was poor.

Example 3 C: 0.006% by weight
%, Si: 1.2%, Mn: 1.5%, P: 0.13
%, S: 0.015%, Sol. Al: 0.73%, N:
0.003%, B: 0.0001%, Ti: 0.002
%, V: 0.003%, Nb: 0.005%, Cu:
0.18%, Sn: 0.033%, Ni: 0.048
%, Cr: 0.07%, Mo: 0.068%, Al ₂ O
₃ / (Al ₂ O ₃ + CaO + MnO + SiO ₂ ) = 0.
69, a slab consisting essentially of iron at 1180 ° C.
At a finishing temperature of 830 ° C and a winding temperature of 570 ° C.
A hot coil having a thickness of 1.4 mm was manufactured at a temperature of ° C. Next, the rolling reduction of skin pass rolling and the temperature of continuous annealing were changed. The soaking time was 2 minutes, the atmosphere was nitrogen, and the cooling was 42 ° C./s by mist cooling. Next, Z was washed with acid in Example 1.
Magnetic properties, mechanical properties, and crystal grain sizes were measured in the same manner as in Example 1 with a plating film in which n was changed to Zn-Ni (15% Ni), and Table 3 was obtained.

[0048]

[Table 3]

As shown in the table, those having the same reduction ratio, temperature and crystal grain size in the range of the present invention exhibited excellent coercive force and strength, but those out of the range of the present invention could satisfy both. I could not do it. In addition, all the steel plate shapes of the products were good. In addition, No. In the experimental material No. 9, cracks occurred in the bending process to the shrink band, but there was no problem at all for the other materials.

[0050]

As described above, according to the present invention, the cost can be reduced by using a hot-rolled steel sheet, and both high strength and magnetic characteristics can be achieved.
In addition, a hot rolled steel sheet for a shrink band capable of using a large amount of iron scrap, which has been demanded by the times, can be provided.

Claims (6)

[Claims] 1. A hot-rolled steel sheet having a surface provided with a corrosion-resistant coating and used for a TV CRT shrink band,
% By weight, C ≦ 0.01%, Si: 1-4%, Mn: 0.1-3%, P ≦ 0.3%, S ≦ 0.02%, Sol.Al: 0.001-2 %, N ≦ 0.006%, Ti ≦ 0.01%, V ≦ 0.01%, Nb ≦ 0.01%, Cu: 0.005 to 0.5%, Sn: 0.001 to 0.3 %, Ni: 0.005 to 2%, Cr: 0.004 to 0.2%, Mo ≦ 0.3%, B ≦ 0.01%, Al ₂ O ₃ / (Al ₂ O ₃ + CaO + MnO + Si
O ₂ ) ≧ 0.1, the balance being Fe and unavoidable impurities, an average crystal grain size of 20 to 300 μm, a strain equivalent to skin pass rolling of 0.1 to 2.0%, 0.8 ~
A hot-rolled steel sheet for a TV CRT shrink band, which is 1.7 mm. 2. A method for producing a hot-rolled steel sheet having a surface provided with a corrosion-resistant coating and used for a TV CRT shrink band, wherein, by weight%, C ≦ 0.01%, Si: 1-4%, Mn. : 0.1-3%, P ≦ 0.3%, S ≦ 0.02%, Sol. Al: 0.001-2%, N ≦ 0.006%, Ti ≦ 0.01%, V ≦ 0 0.01%, Nb ≦ 0.01%, Cu: 0.005 to 0.5%, Sn: 0.001 to 0.3%, Ni: 0.005 to 2%, Cr: 0.004 to 0. 2%, Mo ≦ 0.3%, B ≦ 0.01%, Al ₂ O ₃ / (Al ₂ O ₃ + CaO + MnO + Si
O ₂₎ a ≧ 0.1, the slab and the balance being Fe and unavoidable impurities, the thickness between the finishing temperature is above 900 ° C. hot rolled 0.8
To 1.7 mm, after finishing hot rolling, without water injection for 1 to 7 seconds to obtain a hot-rolled coil having an average crystal grain size of 20 to 300 μm, and then reducing the hot-rolled coil by 0.1 to 2.0%. A method for producing a hot rolled steel sheet for a TV CRT shrink band, wherein skin pass rolling is performed at a reduction rate. 3. A method for manufacturing a hot-rolled steel sheet having a surface coated with a corrosion-resistant coating and used for a TV CRT shrink band, wherein the slab according to claim 2 has a thickness of 0.8 to 1.7.
hot-rolled to a thickness of 700 to 90 mm.
The coil was self-annealed at a coiling temperature of 0 ° C. to obtain a hot-rolled coil having an average crystal grain size of 20 to 300 μm, and then subjected to skin-pass rolling at a rolling reduction of 0.1 to 2.0%. A method for producing a hot rolled steel sheet for a TV CRT shrink band. 4. A method for producing a hot-rolled steel sheet having a corrosion-resistant coating on its surface and used for a TV CRT shrink band, wherein the slab according to claim 2 has a thickness of 0.8 to 1.7.
hot-rolled to a thickness of 600 to 11 mm.
Annealed hot rolled sheet at 00 ° C to obtain an average crystal grain size of 20 to 30
A method for producing a hot-rolled steel sheet for a TV CRT shrink band, comprising obtaining a hot-rolled coil having a thickness of 0 μm, and then subjecting the hot-rolled coil to skin pass rolling at a rolling reduction of 0.1 to 2.0%. 5. A hot-rolled steel sheet having a surface provided with a corrosion-resistant coating and used for a TV CRT shrink band,
% By weight, C ≦ 0.01%, Si: 1-4%, Mn: 0.1-3%, P ≦ 0.3%, S ≦ 0.02%, Sol.Al: 0.001-2 %, N ≦ 0.006%, Ti ≦ 0.01%, V ≦ 0.01%, Nb ≦ 0.01%, Cu: 0.005 to 0.5%, Sn: 0.001 to 0.3 %, Ni: 0.005 to 2%, Cr: 0.004 to 0.2%, Mo ≦ 0.3%, B ≦ 0.01%, Al ₂ O ₃ / (Al ₂ O ₃ + CaO + MnO + Si
O ₂ ) ≧ 0.1, the balance being Fe and unavoidable impurities, the average crystal grain size is 10 to 300 μm, and the plate thickness is 0.8 to 1.7.
mm hot rolled steel sheet for TV CRT shrink bands. 6. A method for producing a hot-rolled steel sheet having a surface coated with a corrosion-resistant coating and used for a TV CRT shrink band, wherein, by weight%, C ≦ 0.01%, Si: 1-4%, Mn : 0.1-3%, P ≦ 0.3%, S ≦ 0.02%, Sol. Al: 0.001-2%, N ≦ 0.006%, Ti ≦ 0.01%, V ≦ 0 0.01%, Nb ≦ 0.01%, Cu: 0.005 to 0.5%, Sn: 0.001 to 0.3%, Ni: 0.005 to 2%, Cr: 0.004 to 0. 2%, Mo ≦ 0.3%, B ≦ 0.01%, Al ₂ O ₃ / (Al ₂ O ₃ + CaO + MnO + Si
O ₂ ) ≧ 0.1, and a slab consisting of Fe and unavoidable impurities is hot-rolled to produce a hot-rolled coil having a sheet thickness of 0.5 to 2.0 mm. % After or after skin pass rolling of not more than 600%
~ 1100 ° C continuous annealing to make the average grain size 10 ~
A method for producing a hot-rolled steel sheet for a TV CRT shrink band, wherein the thickness is 300 μm.