JP2006148500A - Manufacturing method of inner shielding material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inner shielding material manufacturing method preventing troubles in passing a material sheet through a plating line, and uniformizing plating quality without damaging its magnetic property as an inner shielding material. <P>SOLUTION: In the manufacturing method for inner shielding material which is plated on its surface and is used for magnetic shielding for cathode-ray tubes, a steel tape of low carbon steel or ultra low carbon steel is cold rolled, the steepness of this steel tape is adjusted to 0.3% or less by temper rolling after that, then continuous annealing is carried out, and subsequently this steel tape is plated on its surface. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing a TV inner shield material whose surface is plated.

  An inner shield material used for a TV cathode ray tube is used as a magnetic shield material for preventing geomagnetic drift, and as its characteristics, it needs to have a high non-historical permeability. Therefore, the TV inner shield material needs to be sufficiently recrystallized by annealing. Moreover, Cr, Ni, etc. are plated on the surface for rust prevention. When manufacturing such a TV inner shield material, recrystallization annealing is performed by batch type box annealing or continuous annealing.

  In the case of box annealing, the TV inner shield material has a thin plate thickness, so that seizure of the steel plates during annealing, so-called adhesion may occur. In view of this, Japanese Patent Laid-Open No. 6-36702 (Patent Document 1) proposes a technique of performing annealing by adjusting the surface roughness of a steel sheet within a predetermined range in order to prevent adhesion in box annealing. On the other hand, in the case of continuous annealing, there is no need for adjusting the surface roughness to a predetermined range because the adhesion of the steel sheet during annealing does not occur in principle.

  In the production of a general cold-rolled steel sheet, temper rolling with an elongation of about 1.0 to 2.0% is usually performed after annealing. However, in the manufacture of the TV inner shield material, the magnetic properties are reduced when the temper rolling is performed after annealing, so that the magnetic permeability decreases. Therefore, the TV inner shield material is a product that is annealed, that is, not subjected to temper rolling.

For example, in the technique described in JP-A-10-168551 (Patent Document 2), after recrystallizing the average crystal grain size to 3 to 20 μm by continuous annealing, Cr or Ni plating is performed without temper rolling. Techniques that are applied to produce products have been proposed.
JP-A-6-36702 Japanese Patent Laid-Open No. 10-168551

  The inner shield material targeted by the invention described in Patent Document 2 is a product obtained by plating. Generally, a steel strip passed through a plating line is annealed and temper-rolled, and the shape at the time of passing is good. Therefore, the plating line is designed on the assumption that the shape of the steel strip to be passed is good.

  However, in the technique described in Patent Document 2, since temper rolling is omitted, the shape of the steel strip that passes through the plating line remains cold-rolled, and the shape of the steel strip is not necessarily good. There is. For this reason, when the steel strip is passed through the plating line, a trouble in passing the steel strip is liable to occur due to the defective shape of the steel strip, and the uniformity of the plating quality is further reduced.

  Further, the inner shield material is required to have a high plate thickness accuracy in addition to a high rolling reduction, and it is necessary to make the plate thickness uniform. However, when trying to equalize the plateau thickness and plate thickness, the shape of the steel strip after cold rolling generally deteriorates. For this reason, it is easy for trouble to pass through the plating line. Furthermore, when high-speed threading in a continuous annealing line is required from the viewpoint of efficiency, running may become unstable, leading to the occurrence of steel strip drawing in the furnace, and even accidents such as fracture.

  For these problems, measures such as improvement of the shape of the plate at the time of cold rolling are required, but this is not disclosed in the prior art of Patent Document 2.

  Moreover, although the technique of the said patent document 1 is demonstrated about control of surface roughness, about the shape of a steel plate, only the shape after annealing is touched. In this technique, if the plate is passed through the plating line after annealing, the shape is deteriorated because it is soft, so the plate is passed through the plating line before annealing. Therefore, this technique cannot be applied to a manufacturing method of passing through a plating line after annealing.

  Furthermore, in the technique described in Patent Document 2, a method for adjusting the crystal grain size is mainly described, and the shape of the steel sheet is not mentioned at all. Therefore, based on this technology, it is difficult to cope with the trouble of passing through the plating line and the problem of unstable running at the time of CAL high-speed passing.

  Further, in general, in the steel strip after the cold rolling, rolling oil unevenness (remaining pit pattern of the rolling oil on the surface of the steel plate), traces of residual scale due to pickling failure, and the like are generated. Such poor surface properties of the steel sheet with a particular pattern that occur during cold rolling are alleviated by subsequent temper rolling, but these techniques that do not perform temper rolling avoid such problems. I can't.

  Accordingly, the present invention provides a method for manufacturing an inner shield material that can prevent the occurrence of plate-passing troubles in the plating line and make the plating quality uniform without impairing the magnetic properties of the inner shield material. The purpose is to do.

The above problems are solved by the following invention.
[1] In a method for producing an inner shield material having a plated surface used for a magnetic shield of a cathode ray tube, a steel strip of low carbon steel or ultra low carbon steel is cold-rolled and then subjected to temper rolling. A method for producing an inner shield material, characterized in that the steepness of a steel strip is adjusted to 0.3% or less, followed by continuous annealing, and then plating the surface of the steel strip.

  The present invention is characterized in that the steepness of the steel strip after cold rolling is adjusted by temper rolling. In this way, by adjusting the steepness, which is the shape of the steel strip, within a predetermined range, it is possible to pass through the plating line without causing a plate passing trouble. Moreover, by adjusting the steepness before the continuous annealing, the shape of the steel strip can be improved without impairing the magnetic properties as the inner shield material.

  FIG. 1 shows an example of the state of occurrence of plate drawing in the relationship between the steepness of the sheet steel strip in the plating line and the line tension. Here, the plate diaphragm refers to a situation in which, when there is a shape defect (medium extension / ear wave) of a sheet steel strip, the shape defect portion buckles due to line tension, and the steel strip is wrinkled or cracked. Say.

Generally, the line tension in the plating line is about 1.0 to 2.0 kg / mm ² per unit area. In this case, it can be seen from FIG. 1 that the occurrence of plate drawing can be prevented if the steepness of the steel strip passing through is set to 0.3% or less.

  Here, although the steel strip is distorted by temper rolling, it can be eliminated by recrystallization by continuous annealing. Moreover, the surface defect which generate | occur | produced in the case of cold rolling can also be reduced by performing temper rolling. As a result, it is possible to prevent the occurrence of plate troubles in the plating line and make the plating quality uniform.

  In addition, the said low carbon steel or extremely low carbon steel refers to what contains 0.001 to 0.08% of C by mass%.

  According to the present invention, the steel strip after the cold rolling of the inner shield material is temper-rolled and the steepness is adjusted, so that the plate can be passed through the plating line without causing troubles. Further, since the temper rolling is performed before the continuous annealing, the shape of the steel strip can be improved without impairing the magnetic properties as the inner shield material.

  In carrying out the invention, it can be manufactured under the same conditions as in the normal manufacturing method of the inner shield material until cold rolling.

  A steel strip after normal cold rolling may have a steepness λ of about 1% or more, and there is a risk that a plate line trouble may occur in this state. Therefore, temper rolling is performed so that the steepness is within 0.3% as described above.

When the steepness is kept within the above range, the conditions for temper rolling are different from the conditions for steel strip after normal annealing (hereinafter referred to as “annealed plate”), and the elongation, rolling load and line tension are annealed. A considerably lower level (rolling load of 0.5 T / mm or less, tension of 15 kg / mm ² or less) is sufficient.

  If the temper rolling is a facility capable of processing a normal annealed sheet, the inner shield material according to the present invention can be processed, but the condition of the temper rolling needs to be significantly changed. Regarding the condition of temper rolling, the load and tension are usually adjusted to obtain the target elongation rate and transfer rate, but in the present invention, the load and tension are adjusted to adjust the steepness. Therefore, the value of the expansion rate is not particularly limited as long as the shape can be corrected. In this case, the expansion rate may be about 0.3 to 0.5% in the present invention, while the normal target expansion rate is about 1 to 3%. It is difficult to make the elongation ratio higher than that, because the steel strip after cold rolling is hard and difficult.

  Since the load during temper rolling is set from the viewpoint of steepness, it may be lower than the load during temper rolling of a normal annealed sheet. Also, from the viewpoint of shape improvement, it is advantageous that shape adjustment is easier when the load is low.

  Note that the transfer rate of the surface roughness greatly depends on the load, and the transfer rate becomes low by reducing the load. Therefore, it is desirable to set the surface roughness of the roll taking this into consideration.

  Thus, the temper rolling after the cold rolling of the inner shield material aims at shape correction. As a result, temper rolling is comparatively lighter from the viewpoint of load, tension and the like than a normal annealing plate, and the equipment can be downsized. Further, if the facilities are the same, the line speed can be increased, so that it can be controlled in accordance with the sheet passing speed of the continuous annealing line, and high efficiency can be achieved.

  In mass%, C: 0.01 to 0.06%, Si: 0.03% or less, Mn: 0.10 to 0.05%, P: 0.02% or less, S: 0.01 to 0.00. 025%, N: 0.0035% or less, thin steel plate with a steepness of λ = 1.0% after cold rolling is subjected to temper rolling before annealing, and then annealed Went. The temper rolling was carried out using a two-stand temper rolling mill. Table 1 shows the conditions for temper rolling. In addition, as a comparative example 1, the case of the normal tinplate which gave temper rolling after annealing is shown.

  The steepness of the thin steel plate after temper rolling was measured. The measurement results are also shown in Table 1. The shape necessary for charging the plating line has a steepness λ ≦ 0.3%.

  From this table, it can be seen that, in the example of the present invention, a steepness λ of 0.3% or less is obtained at a rolling load of 1/2 to 1/3 as compared with Comparative Example 1. Moreover, the mill exit side tension may be less than 1/2, and the load capacity of the temper rolling mill, the tension of the exit side equipment, etc., may be less than half of the equipment capacity compared to normal tin temper rolling equipment. Recognize. Furthermore, it can be seen that Comparative Example 1 in which temper rolling was performed after annealing did not obtain the desired magnetic properties, whereas the inventive examples obtained good magnetic properties.

  Next, the thin steel plate thus obtained was passed through a plating line. Table 2 shows the plate passing speed in the plating line at that time. In addition, as the comparative example 2, the case where temper rolling is not performed is also shown. Note that the steepness λ when the temper rolling was not performed was about 1.0%.

  From this table, compared with Comparative Example 2 in which temper rolling is not performed, in the present invention example, the shape is good, so that it is possible to prevent the trouble of threading, and the speed of threading of the plating line is three times faster. You can see that Further, in Comparative Example 2 in which temper rolling was not performed, pattern-like surface defects generated during cold rolling were observed after plating, but in the present invention example, the surface properties were also good.

It is a figure which shows an example of the sheet | seat drawing generation | occurrence | production situation in the relationship between the steepness of the sheet steel strip in a plating line, and line tension.

Claims (1)

  In a method for producing an inner shield material with a plated surface used for a magnetic shield of a cathode ray tube, after cold rolling a steel strip of low carbon steel or extremely low carbon steel, the steel strip is subjected to temper rolling. A method for producing an inner shield material, characterized in that the steepness is adjusted to 0.3% or less, followed by continuous annealing, and then plating the surface of the steel strip.

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