KR900008792B1 - Making method of shadowmask - Google Patents

Abstract

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Description

Method of manufacturing shadow mask material

1 is a graph showing the relationship between the S content of various shadow masks and the central segregation of MnS.

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method for producing a shadow mask material which is very excellent in etching air permeability for use in shadow masks for color television and color displays and in which no transmissive stains occur even after press molding.

Conventional low-carbon rim cold rolled steel has been used as a shadow mask material for CRTs such as color televisions and color displays. When annealing is performed at low temperature to prevent adhesion between the flat plate masks, the crystal grains of the rim steel become small, and the deformation does not sufficiently enter even if the leveler is applied before press molding. There were defects such as a tendency for stretcher strain due to yield point extension. Since this strainer strain deforms the hole edges and causes color spots, it must be prevented to satisfy the performance of the shadow mask.

In addition, in the rim steel, when the annealing at high temperature causes crystal grains to coarsen and deform the edges of the holes, which are also thin during the press molding of the shadow mask, in order to prevent these problems, The fluctuations in the conditions of the change and the final annealing must be strictly limited.

In order to improve such a defect, the low carbon Al-kilted cold rolled steel with C content below 0.005% is used recently.

In recent years, however, the shadow mask is gradually being highly precisely refined, and it is necessary to precisely drill more holes in the cold rolled steel sheet having a sheet thickness of about 0.1 mm. Moreover, as another trend of improvement of a color-brown tube, what is called the FS tube which made the square tube front screen screen a square, and flattened is increasing. In order to increase the amount of information and to more faithfully reproduce the image by square-shaped and flattening the front surface, the shadow mask used in this FS tube is thermally expanded to reduce eye fatigue caused by external reflection of the viewer. In order to suppress the occurrence of color deviation caused by the doping phenomenon caused by the film, a cold rolled steel sheet having a plate thickness of about 0.2-0.3 mm is used.

With such high precision refinement of shadow masks and an increase in FS pipes, it has become impossible to say that satisfactory use of low-carbon Al-kilted cold rolled steel sheets, which have not been a problem in the past, is satisfactory.

The first shadow mask manufacturing process involves degreasing a cold rolled steel sheet, applying a resist, seizing the pattern, and etching and forming a flat plate mask with a solution mainly made of ferric chloride, and after etching After the annealing of the flat plate mask, it is press-molded into a predetermined shape, and a process of forming a black oxide film on the surface of the shadow mask by heat treatment again, but in the etching and drilling process, the center segregation is mainly performed by MnS. Since segregates preferentially corrode from the base, there is a problem that a hole-shaped bond occurs in the etching wall surface of the portion, so that a so-called transmission stain is generated. This is because the area to be etched is greatly increased in comparison with the recent high-precision refinement of the shadow mask, and thus the probability of defects is increased even in the case of using a material having a level that is not a problem in the past.

Luckily, even when no transmission stain was generated in the etching drilling process, the transmission stain occurred after press molding in the process of annealing the flat plate mask of the next step and pressing the mold into a predetermined shape. In detail, it was found that segregation due to central segregation mainly exists in MnS, and elongation characteristics of the region having this central segregation and the clean region without segregation at the center are slightly different. As a result, a slight but aberration occurred in the hole shape, and therefore, it was found that a transmission stain occurred. This phenomenon is also a problem that is increasing because the shadow shape of the shadow mask is changed due to the recent increase in the FS tube, and this problem has not been known in the past.

In view of such a situation, the present inventors have attempted to improve the conventional low carbon Al-kilted steel, in particular, to reduce segregation mainly based on MnS, and it is known that C is 0.060% or less and Mn is 0.05- by weight. 0.50%, S is 0.007% or less, SolAl is 0.010-0.080%, N is 0.0100% or less, and the remainder is dissolved in iron and inevitable by degassing and converter outside the furnace. It is made of steel slab in ordinary ingot or continuous casting, and this steel slab is hot rolled or cold rolled, and then decarbonized in a decarbonized annealing furnace until C is 0.004% or less, and then re-cold rolled. It is to provide a method for producing a shadow mask material characterized in that the plate thickness to 0.3mm or less.

Next, in order to demonstrate this invention further more concretely, the reason for limitation of a component and manufacturing conditions are demonstrated. C: When the amount of C in the cold rolled sheet is large, iron carbide is formed, and this carbide impairs etching perforation. In addition, when the flat plate mask is annealed after the shadow mask is annealed, non-molding (generation of the strainer strain) occurs in press forming unless the solid solution C is reduced. In order to satisfy both of these requirements, the upper limit of the C content of the cold rolled Al-kilted steel sheet needs to be 0.004%. If the C content is within this range, the amount of solid solution C is also small enough, so there is no problem. In order to effectively lower the C content to this level in the decarbonization furnace, the C content in the steelmaking step needs to be 0.060% or less.

7할 필요가 있다. 그러나, Mn은 0.50%를 초과하면 섀도우마스크로서는 너무 딱딱하게 되어 평판마스크의 성형성을 손상한다. 따라서, Mn의 성분범위는 0.05-0.50%로 한다. S : 강속의 S를 저감하는 것은 직접 MnS의 중심편석의 저감과 관계가 있다. 에칭천공이나 프레스성형에서 문제가 되는 MnS의 중심편석을 착안하였을 경우, 제1도에 도시한 바와 같이 그 효과는 0.007%이하로 나타난다.From the above, C of a cold rolled steel sheet shall be 0.004% or less, and C before a hot rolled steel sheet shall be 0.060% or less. Mn: Mn is useful for improving the strength of steel without deteriorating various properties of shadow mask besides the purpose of deoxidation. In addition, the role of Mn is to combine with the S in the river to prevent the heat fragility of the steel. Therefore, Mn is required at least 0.05%, and Mn (%) / S (%) in the weight ratio of Mn and S

7 need to be. However, when Mn exceeds 0.50%, it becomes too hard as a shadow mask, and damages the formability of a flat plate mask. Therefore, the component range of Mn is made 0.05-0.50%. S: Reducing the velocity S is directly related to the reduction of central segregation of MnS. In the case of focusing on the central segregation of MnS, which is a problem in etching drilling and press molding, the effect is less than 0.007% as shown in FIG.

In addition, in the case of ingot casting in continuous casting, the use of electromagnetic stirring can further improve the effect. SolAl: In addition to reducing the amount of inclusions by deoxidizing the steel, it is necessary to contain Al as SolAl (acid soluble Al) in order to fix solid solution N with AlN and to prevent strainer strain during press molding. However, when it contains a large amount, it worsens.

0.010% or more is required at the point of deoxidation, and the upper limit is 0.080% at the point of ductility. N: Since N increases yield point extension | strength and causes a stretcher strain, it is preferable that it is as little as possible. However, in the case of excessive reduction, the cost is high, so in the present invention, it is made 0.0100% or less.

Prior to melting the steel of such composition, the molten iron is desulfurized out of the furnace by desulfurization to 0.007% or less. After that, it melts in a converter and removes steel after composition. Although the casting may use a conventional ingot method, casting with the electronic stirring using a continuous casting can obtain the thing of the good quality with less central segregation of MnS. At this time, if the S content of the molten iron desulfurized outside the furnace does not sufficiently drop, the efficiency in the converter is poor, and it is difficult to melt the steel of the target S content.

In order to regulate S to 0.007% or less, it is desirable to ensure the final finish rolling start temperature in the hot rolling step to 1000 ° C or more.

0.010% 이하의 강에서는 열간압연공정에서 생성하는 스케일의 밀착성이 향상하여 마무리압연스탠드 입구쪽에서 디스케일링 불량이 발생하기 때문에, 침식스케일 등의 표면결합을 일으키는 원인이 되기 때문이다.This is S

This is because, in the steel of 0.010% or less, the adhesion of the scale produced in the hot rolling process is improved and descaling defects are generated at the inlet of the finish rolling stand, which causes surface bonding such as erosion scale.

It is also an effective means for improving the descaling property by securing the temperature at the finish rolling inlet and increasing the scale thickness by taking enough time from the end of rough rolling to the start of finish rolling.

The band of the steel hot-rolled under the above conditions is subjected to open coil decarbonization annealing through a cold rolling process, so that the amount of C is 0.004% or less.

After decarbonization annealing, it is preferable to carry out a rough rolling or a roller leveler, and to re-cold-roll for the next process. By re-cold rolling, the thickness required by the shadow mask maker should be 0.3 mm or less.

The Al-kilted cold rolled steel sheet produced in this way is excellent in etching permeability, and can be processed uniformly even in press molding, and the shadow mask material which does not generate a permeable stain is obtained.

FIG. 1 shows the relationship between the S content of various shadow mask materials and the MnS central segregation. In the figure, the number of MnS center segregation refers to 30 arbitrary cross sections of rolled rectangular cross sections (plate thickness × 600 mm width) of various shadow mask materials, which are inspected after etching these sections in ferric chloride solution and having a size of 20 μ or more. It is a measure of the number of groups. As apparent from FIG. 1, the S content correlates with the central segregation of MnS, which is the cause of permeation, and when the S content is 0.007% or less, the amount of MnS segregation of 20 mu or more is 0, but exceeds 0.007%. It can be seen that the amount of increase rapidly.

In this way, the S content is closely related to the generation of transmissive stains, and the critical condition of 0.007% or less has an important meaning in the high-precision shadow mask.

Next, the operation and effect of the present invention will be described with reference to Examples and Comparative Examples of the present invention.

The test material was first molten iron out of the furnace until the S content was less than 0.010% as CaO, and then molten in all the arcs, and then sintered by continuous casting. C after casting was in the range of 0.005-0.008%.

This steel strip was made into a thin steel plate of 0.25 mm in the process of hot rolling, pickling, cold rolling, decarbon annealing, temper rolling, and re-cold rolling.

The components of this cold rolled steel are shown in the first table.

After the cold rolled steel was degreased, a flat mask was prepared in a process consisting of resist coating, exposure, development, etching, and resist removal to investigate the occurrence of transmissive stains. In addition, the good thing without the generation of a permeable stain was press-molded by FS pipe | tube through the annealing in the decarburization atmosphere for 10 minutes at 750 degreeC, and the occurrence state of the permeable stain in the press molding process was investigated. The results are listed in the first table, but No. In the case of 1-5, permeation stain did not occur even after etching punching and after press molding, and a good result was obtained.

No. Since 6 and 7 had a large amount of S, perforated stains parallel to the rolling direction were generated after etching and drilling. No. In Fig. 8, no significant stain was generated after the etching, but the press molding also caused a parallel stain in the rolling direction.

As is apparent from the above, the shadow mask obtained by the manufacturing method of the present invention has little occurrence of a transmission stain after etching punching and a transmission stain after press molding, and a good shadow mask material can be obtained. At present, further progress in high-precision refinement of the color CRT has a remarkable effect of providing a very excellent shadow mask material according to the present invention.

[Table 1]

Claims (1)

By weight% C is less than 0.060%, Mn is less than 0.05-050% S is less than 0.007%, SolAl is less than 0.010-0.080%, N is less than 0.0100%, and the rest of the steel consisting of iron and unavoidable impurities in desulfurization and converter The steel slab in ordinary ingot or continuous casting, and then hot-rolled and cold-rolled the steel slab, decarbonized in a decarbonized annealing furnace until C is 0.004% or less, and then re-cold rolled. A method of manufacturing a shadow mask material, characterized in that the thickness is 0.3 mm or less.

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