JPH0827520A - Method for manufacturing TV support frame material - Google Patents

Abstract

(57) [Summary] [Objective] To provide a method for manufacturing a mask frame material for a TV CRT, which has high productivity, material uniformity, and high magnetic properties, at low cost. [Structure] C: 0.010% or less by weight ratio, Mn:
0.3% or less, P: less than 0.03%, S: less than 0.01%, O: 0.010% or less, N: 0.0050% or less,
B: steel containing 0.0050% or less, the balance being Fe and unavoidable impurities, hot-rolled, cold-rolled, and then recrystallized in a continuous annealing furnace; The steel of the composition is heated at a temperature of 1100 ° C. to 1180 ° C., finish-rolled at a temperature of 800 ° C.-880 ° C., further wound at a temperature of 700 ° C.-780 ° C., then cold-rolled, and continuously annealed. A method for manufacturing a support frame material for TV, which is annealed in a furnace at a temperature of 800 ° C to 850 ° C.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a support frame material, which is one of the magnetic shield materials for color TV cathode ray tubes.

[0002]

2. Description of the Related Art Generally, the basic structure of a color TV picture tube is composed of an electron gun and a photosensitive surface for converting an electron beam into an image, and further, a magnetic shield material for preventing the electron beam from being deflected by the earth's magnetism covers the inside. . The characteristics required for these magnetic shield materials are geomagnetism (about 0.3 Oe)
High magnetic permeability in the magnetic field of. Further, it is also required that the coercive force (Hc) for improving the demagnetization characteristic be small. As described above, the cold-rolled steel sheet generally used for the TV support frame is required to have a very high level.

Therefore, since the cold-rolled steel sheet used for the TV support frame does not contain Si, the iron loss value is inferior,
It is widely used in household electric appliances because of its good magnetic permeability and its low price. Precipitates such as Al ₂ O ₃ clusters, MnS and AlN, and B-based inclusions are important factors that influence the magnetic properties of cold-rolled steel sheets used for TV support frames. That is, fine MnS and AlN that are precipitated in the hot rolling step, and B-type inclusions that are precipitated during rolling hinder the growth of crystal grains in the final annealing step after finish rolling and significantly deteriorate the magnetic properties. .

In order to remove the above-mentioned adverse effects of the components in the steel, it is effective to remove them in the stage of steel melting, and the present steelmaking technology does not cause any particular problem in melting. The cold-rolled steel sheet used for the TV support frame has a large sheet thickness of 1.2 to 1.6 mm and cannot be annealed in the conventional continuous annealing furnace. For example, as disclosed in JP-A-2-61029, the sheet thickness is By decarburizing and annealing steel having a thickness as small as 0.10 to 0.25 mm and having a C content of 0.05% or less, the C content is set to 0.005% or less and the crystal grains are increased to secure magnetic properties. It is disclosed that the magnetic permeability is determined only by the grain size of the material and the residual strain, rather than the composition of the components. In addition, ISIJ Vol. 3 (1990)-
1838 discloses a product manufactured by decarburization annealing in an open coil annealing furnace.

[0005]

As described above, in the conventional process, a thin steel plate is used in the steel making process, hot process, cold process, electric cleaning line, decarburization annealing, temper rolling and winding process. However, this conventional manufacturing process is not economically advantageous because the process is long and there are many handling defects when passing through each process. In addition, there is a problem that the thick steel plate has not been clarified. In order to solve such a problem, the present invention uses high-purity steel and continuously anneals thick steel plates as compared with conventional steel plates,
Furthermore, by controlling the processing conditions such as the appropriate hot heating temperature, cold rolling condition and continuous annealing temperature condition, the high productivity and the uniformity of material properties that continuous annealing possesses, and good magnetic properties can be obtained. It is to provide a method of manufacturing a steel sheet having characteristics.

[0006]

Means for Solving the Problems That is, according to the present invention, impurities that impede the magnetic properties of a cold rolled steel sheet used for a TV support frame are reduced as much as possible, and a high temperature is obtained in a continuous annealing furnace which is a cold rolled steel sheet production line. By annealing,
It is a method for manufacturing a material for a color TV support frame having magnetic properties equal to or better than those of a conventional cold-rolled steel plate for a TV support frame by decarburization annealing. The gist of the invention is (1) by weight, C: 0.010% or less, Mn: 0.3
% Or less, P: less than 0.03%, S: less than 0.01%,
O: 0.010% or less, N: 0.0050% or less, B:
Steel for containing 0.0050% or less, the balance of which is Fe and unavoidable impurities, is hot-rolled, followed by cold rolling, and then recrystallization annealing in a continuous annealing furnace. Method of manufacturing support frame material.

(2) C: 0.010% or less by weight,
Mn: 0.3% or less, P: less than 0.03%, S: 0.0
Less than 1%, O: 0.010% or less, N: 0.0050%
Hereinafter, steel containing B: 0.0050% or less, with the balance being Fe and inevitable impurities, is 1100 ° C to 1180 ° C.
Heating at a temperature of 800 ° C, finish rolling at a temperature of 800 ° C to 880 ° C, winding at a temperature of 700 ° C to 780 ° C, then cold rolling, and 800 ° C to 8 ° C in a continuous annealing furnace.
A method of manufacturing a TV support frame material is characterized by annealing at a temperature of 50 ° C.

[0008]

The present invention will be described in detail below. First,
The reasons for limiting the component composition of the present invention will be described. C: 0.
Since the C element is an interstitial element and its presence distorts the crystal lattice and hinders the movement of the domain wall, the upper limit is set to 0.010%. When a material having better magnetic properties is required, it is more effective to reduce the C content to 0.0050% or less by performing vacuum degassing treatment. The reason why Mn is 0.3% or less is that Mn in excess of this amount inhibits the coarsening of crystal grains during recrystallization annealing.

S: 0.01% or less has a very strong correlation between S and magnetic characteristics as shown in FIGS. 1 to 3, and when the crystal grain size is small, the magnetic characteristics are Since it tends to deteriorate, the S amount needs to be 0.01% or less. That is, FIG. 1 is a diagram showing the relationship between the S amount and the coercive force. As shown in this figure, in order to reduce the coercive force to 1.5 Oe or less, the amount of S needs to be 0.01% or less. FIG. 2 is a diagram showing the relationship between the S content and the relative magnetic permeability. As shown in this figure, the relative magnetic permeability is 550
In order to obtain emμ, the S amount needs to be 0.01% or less. Further, FIG. 3 is a diagram showing the relationship between the amount of S and the maximum magnetic permeability, and from this figure, it is shown that the amount of S is 0.01% or less in order to obtain the maximum magnetic permeability of 2700 μmax or more.

O: 0.010% or less is because when O is large, oxides such as Al ₂ O ₃ are large and the crystal grain size is small. This is shown in FIG. Zunachi, Figure 4
FIG. 4 is a diagram showing the relationship between the O content and the grain size number. As shown in this figure, in order to obtain large crystal grains having a grain size number of 7.5 or less, the O amount needs to be 0.012% or less, preferably 0.010%. . FIG. 5 is a diagram showing the relationship between the amount of O and the coercive force. From this figure, the amount of O must be 0.010% in order to reduce the coercive force to 1.5 Oe or less. FIG. 6 is a diagram showing the relationship between the O content and the relative magnetic permeability. According to this figure, the O content is 0.010% or less in order to obtain the relative magnetic permeability of 550 emμ. FIG. 7 is a diagram showing the relationship between the O content and the maximum magnetic permeability.
This indicates that the O content needs to be 0.010% or less in order to obtain the maximum magnetic permeability of 2700 μmax or more.
B: 0.0050% or less is to remove the harmful effect of N, which is an interstitial element, by combining with N and precipitating as BN during hot rolling. Usually, B is preferably around B / N = 1.0.

Further, the slab heating temperature is set to 1100 to 11
The temperature of 80 ° C. was set to the Al ₂ precipitated during continuous casting.
This is because O ₃ and MnS are not redissolved. Further, the hot rolling finishing temperature is 800 to 880 ° C. and the winding temperature is 700 to 780 ° C. in order to obtain a texture having good magnetic properties and to increase the crystal grain size of the hot rolled sheet. Is. The annealing temperature of the continuous annealing is set to a temperature of 800 to 900 ° C. The predetermined crystal grain size cannot be obtained at 800 ° C. or lower, and magnetic properties are poor. On the other hand, if the annealing temperature exceeds 900 ° C., the γ region is annealed, and the crystal grain size becomes small. This relationship is shown in FIG. That is, FIG.
FIG. 4 is a diagram showing a relationship between an annealing temperature and a grain size number. From this figure, at 800 ° C. or lower, the grain size becomes 7.5 or more, indicating that the grain size is small. In addition, elements other than the above-mentioned components are Fe and unavoidable impurity elements.

[0012]

【Example】

Example 1 A slab prepared by adjusting the components shown in Table 1 at the steelmaking stage was used.
Heating at 160 ° C, finishing temperature: 860 ° C, winding temperature:
A hot rolled steel sheet (sheet thickness 4.0 mm) wound at 750 ° C. was cold-rolled (sheet thickness 1.2 mm), and then annealed at an annealing temperature of 850 ° C. in a continuous annealing furnace. Table 2 shows the electromagnetic characteristics of this material
Shown in As shown in Table 2, it is understood that the magnetic properties of the steel of the present invention, which has a very small chemical composition due to the high purification, are remarkably improved as compared with the conventional unadjusted composition materials.

[0013]

[Table 1]

[0014]

[Table 2]

Example 2 As in Example 1, a slab adjusted to have the composition shown in Table 3 was heated at 1160 ° C. in the steelmaking stage, and the finishing temperature was 85.
Using hot rolled steel sheet wound at 0 ° C and winding temperature: 730 ° C,
Cold rolling is performed, and then the annealing temperature is 750 to 750 in a continuous annealing furnace.
Annealing was performed by changing the temperature to 900 ° C. The electromagnetic characteristics of this material are shown in Table 4. As shown in Table 4, as the annealing temperature in the continuous annealing furnace becomes higher, the grain size number of the material becomes smaller (the grain size becomes larger) and the magnetic permeability, which is an important characteristic value of the magnetic shield material, becomes higher. . As described above, in the present invention, the magnetic properties of the steel of the present invention are higher than those of the conventional unadjusted components by refining the steel, controlling the hot rolling process conditions, and increasing the continuous annealing temperature. , Much improved.

[0016]

[Table 3]

[0017]

[Table 4]

[0018]

As described above, according to the present invention, a mask frame material for a TV CRT having high productivity, material uniformity, and high magnetic properties can be manufactured at low cost. It provides an excellent way of doing it.

[Brief description of drawings]

FIG. 1 is a diagram showing a relationship between an S content and a coercive force,

FIG. 2 is a diagram showing a relationship between an S content and a relative magnetic permeability,

FIG. 3 is a diagram showing a relationship between the S content and the maximum magnetic permeability,

FIG. 4 is a diagram showing the relationship between O content and crystal grain size number;

FIG. 5 is a diagram showing the relationship between the O content and the coercive force,

FIG. 6 is a diagram showing the relationship between the O content and the relative permeability,

FIG. 7 is a diagram showing the relationship between the O content and the maximum magnetic permeability,

FIG. 8 is a diagram showing a relationship between an annealing temperature and a grain size number.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Hiroyuki Homma Hiroyuki Honma 1 Kimitsu, Kimitsu-shi, Chiba Inside Nippon Steel Corporation (72) Inventor Takeshi Kubota 1-1, Hibahata-cho, Tobata-ku, Kitakyushu, Fukuoka Inside Nippon Steel Co., Ltd. Yawata Works

Claims (2)

[Claims] 1. By weight ratio, C: 0.010% or less Mn: 0.3% or less P: less than 0.03% S: less than 0.01% O: 0.010% or less N: 0.0050% The following B: 0.0050% or less is contained, and the balance is Fe and inevitable impurities. Steel is hot-rolled, cold-rolled, and then recrystallized in a continuous annealing furnace. Manufacturing method of TV support frame material. 2. By weight ratio, C: 0.010% or less Mn: 0.3% or less P: less than 0.03% S: less than 0.01% O: 0.010% or less N: 0.0050% The following B: 0.0050% or less is contained, and the balance of Fe and inevitable impurities is heated to a temperature of 1100 ° C to 1180 ° C, and a temperature of 800 ° C to
Finish rolling is performed at a temperature of 880 ° C, and then 700 ° C ~
A method for producing a support frame material for TV, comprising winding at 780 ° C., then cold rolling, and annealing in a continuous annealing furnace at a temperature of 800 ° C. to 850 ° C.