JPS608287B2 - Manufacturing method for shadow mask materials - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a shadow mask material (meaning a material before blackening treatment) for a color television cathode ray tube.

Conventionally, shadow masks have been manufactured by the process shown in the left-hand line of FIG.

First, the material manufacturer cold-rolls and anneales a low-carbon hot-rolled steel plate using the usual method, then applies a cold reduction rate of 40% or more to a thickness of 0.
After cold rolling to a desired sheet thickness on the second side or less and correcting the shape, the sheet is shipped as a coiled cold rolled steel sheet for shadow masks. In this case, the product hardness is usually Hvloo or higher. This is a necessary characteristic from the viewpoint of threading workability in the next process, the photoetching line. Next, at the photo-etching manufacturer, after pre-processing the material coil such as degreasing, a photosensitive liquid (resist) is applied to both sides, and a reference pattern with a predetermined dot shape and slot shape is tightly attached to both sides. Expose to ultraviolet light and develop.

Development is carried out using hot water spray to form dots or slots of a predetermined shape, and then burning is carried out at about 150° C. for about 5 minutes to heat and harden the remaining photoresist film.
Next, it is etched with a ferric chloride solution to make holes of a predetermined size, and after removing the remaining photoresist film, it is cut into a predetermined size and shipped as a product. At this time, the horizontal type and Vertuca type are used for the threading method of the material coil.
There is type l. Among these, the Veucal type is threaded so that the coil edges are on the upper and lower surfaces, as shown in FIG.
This has the advantage of not causing surface imperfections caused by the surface of the material coming into contact with the loaf table, as in the case of the horizontal type, but on the other hand, there is a risk that the coil edge may be damaged or deformed, causing problems in threading work. be.

For this reason, a soft material has poor shape retention for the raw material coil, and as mentioned above, a hard material is supplied. Next, at the brown can maker, the photo-etched shadow mask material is annealed to give it deformability that allows it to be pressed.

In addition, since stretcher strain occurs during press forming when a hardened steel plate has a large elongation at yield point, a plater is applied to prevent stretcher strain. Furthermore, the provision of a stain also has the meaning of correcting the shape of the sintered anchor material. The shadow mask material subjected to the sintering and leveling process in this manner is then formed into a shadow mask by press working, and a finished product is obtained after a Fe304 film is formed on the surface by blackening and anti-corrosion treatment. The conventional process as described above has the following drawbacks. The first is that the yield point elongation that has been eliminated by the shibeller will recover again if not pressed within a short period of time, resulting in stretch strain, and the second is that Akatsuki Anchor is carried out in the state of a cut plate, so it is impossible to do so. The third problem is that the hole pattern of the mask is distorted because the scorching and leveling are performed after photo-etching and drilling.

Therefore, there is a desire to develop a method for producing a material for a shadow mask that eliminates the above-mentioned drawbacks, and several proposals have been made regarding this. For example, in Japanese Patent Publication No. 52-44868, a material made of a rolled low carbon steel plate is competitively annealed at a temperature higher than the recrystallization temperature, and the cold-annealed steel plate has a rolling reduction of 0.5 to 15%.
A method for manufacturing a shadow mask has been proposed, which comprises skin-pass rolling the steel plate to a predetermined thickness, then perforating the steel plate and press-molding the same. Although this method eliminates the above-mentioned drawbacks because a moth dulling and skin pass are performed before photo-etching and perforation, this method also has several drawbacks and cannot be said to be a perfect method for producing a shadow mask.

In other words, this method involves skin pass rolling (reduction rate 0) after annealing.
．． 5 to 15%), but it does not take into account the recovery of the yield point elongation by burning (15,000 or more x 5 minutes) in the subsequent photo-etching process. That is, the yield point elongation that disappeared due to skin pass rolling is recovered by the burning that heats and hardens the photoresist film (strain aging phenomenon), and there is a possibility that stretcher strain may occur during subsequent press working. Figure 3 shows low carbon rimmed steel (C; 0.08%, S
i; 0.01%, Mn; 0.28%, P; 0.016%
, S; 0.010%) was cold rolled (thickness: 0.2), hammered (550 qo x 10 minutes), and then cold rolled at a reduction rate of 1.5 to 30%. The mechanical test values are shown after rolling and burning treatment at 320° C. for 5 minutes.

As is clear from this figure, the recovery of the elongation at yield point after the burning process becomes smaller as the reduction rate of cold rolling increases;
Furthermore, even at a cold reduction rate of 15%, the yield point elongation of 1.0% has been recovered, and generally the stretcher strain is 1.0%.
Judging from the fact that it is said that if there is an elongation at the yield point of % or more, this method
The method described in No. 8) cannot prevent stretcher strain from occurring during pressing. Furthermore, with this method, the material hardness during photoetching is low (material hardness Hv 93 at a cold rolling rate of 1.5%), making it difficult to adopt the VeMcal type sheet threading method described above (it is said that about 100 Hv or more is required). ). For this reason, it is necessary to adopt a horizontal type threading method, but in this case, the surface of the material comes into contact with the roller table, and this, combined with the low hardness of the material, tends to cause surface roughness on the surface of the material. The inventors of the present invention have conducted various studies to overcome these drawbacks, and have found that the following method has good sheet-threading workability, no stretcher strain occurs during pressing, and no problems in press formability. They have also developed a method for producing shadow mask materials, thereby successfully improving the conventional shadow mask manufacturing process. That is, C; 0.03 to 0
．． A hot-rolled steel sheet made of low carbon rimmed steel with 10% S and 0.014% S is first cold rolled through the normal process and decarburized to 0.005% C in an open coil bowl blunt furnace. After phosphorus dulling,
Subsequently, secondary cold rolling is performed, non-decarburization annealing is performed at a temperature above the recrystallization temperature and below 600 oo, and further cold rolling is performed at a cold rolling reduction rate of 10% or above2.
To obtain a steel strip for a shadow mask with a desired thickness by cold rolling at 5% or less, in addition, as shown in the right line of Fig. 1, after etching and perforation, a scale anchor and stainer process is omitted, and this is immediately pressed to produce a shadow mask material. This steel strip for shadow masks has improved stretcher strain resistance and press workability of the material by reducing the C content through decarburization and increasing the rolling reduction ratio after purification. The characteristic requirements of the present invention will be described in detail below.

First, the present invention has C; 0.03 to 0.10%, Smi 0.01%.
The first requirement is that the material be made of 4% low carbon rimmed steel.

The steel type was limited to rimmed steel because rimmed steel has a clean rim layer and has fewer surface defects caused by inclusions like killed steel. Also C: 0.03-0.10%
This is because if the C content is higher than this, the rimming action (CO generation) during ingot making of the rimmed steel will become weaker, the clean rim layer will become thinner, and the time required for decarburization in the next step of decarburization, the decarburization hammer, will be longer. This is because if the C content is lower than this, the amount of 02% in the steel will increase and the amount of oxide inclusions will become so large that it impairs the accuracy of drilling during photoetching.
Furthermore, the S% is 0.014%.
This is because, if the amount exceeds 1, the amount of sulfide-based inclusions becomes large enough to impair the accuracy of drilling during photo-etching. Next, the cold-rolled steel sheet that has been primarily cold-rolled through a normal process is decarburized and annealed to 0.005% C in an open coil annealing furnace in a wet hydrogen atmosphere.

The second requirement of the present invention is to decarburize the C content to 0.005% or less using this decarburizing hammer. In other words, in the production of shadow mask materials that are subjected to press processing without performing a hammer or leveler after photo-etching perforation, which is the object of the present invention, stretcher strain occurs during press processing in order to recover the yield point elongation by the burning process during photo-etching. (reduction of strain aging). In general, the strain aging phenomenon is caused by the presence of interstitial solid solution elements such as C and N.
), C is the main cause. Therefore, from the viewpoint of the burning treatment temperature, reducing C% is an effective means. To be more specific according to the test example, FIG. 4 shows C;0.
．． 04%, Si; 0.01%, Mn; 0.30%, P;
0.016%, S; 0.010% low carbon rimmed steel was first cold-rolled to a thickness of 0.6 mm in a normal process, and then heated in a hot hydrogen atmosphere (275%, fog) in an open-coil moth blunt furnace. The specimens were annealed with phosphorus for various times at a temperature of +50 pm and the C content was varied, and then secondarily spread on a willow board with a thickness of 0.18 at 550°C x 10
FIG. 2 is a diagram showing the relationship between yield point elongation and C content after 4.0% skin pass rolling and 320 qo×5 minute high-temperature aging treatment. . As is clear from this Figure 4, as the C content decreases, the yield point elongation rises once and peaks around C: 0.02%, then gradually decreases and remains almost constant below C: 0.005%. shows the value of In this way, C; 0.00
The reason why the yield point elongation becomes constant at 5% or less is considered to be that strain aging due to solid solution C becomes almost negligible at C; 0.005% or less. This makes C% 0.0
This is the reason why it was limited to 0.5% or less. Note that C; 0.02%
The reason why the yield point elongation peaks near this area is because the solid solute C%, which is the direct cause of strain aging, reaches its maximum in this area (
If the C% is less than this, the absolute amount of C% is small, so the solid lacquer C% is also small.On the other hand, if the C% is higher than this, the C coexists with carbide and hardened C, and the solid solution C% decreases. do).
In addition, in the state of 0.005% CS, there are no carbides, which eliminates the cause of defects during photo-etching, and the fracture limit shifts to the stronger processing side during press processing. After decarburizing annealing to CS 0.005% in this way, it is then subjected to secondary cold rolling, non-decarburized sintering is performed at a temperature above the recrystallization temperature and below 600 qo, and further with a cold rolling reduction of 10% or above and 25%
The third requirement of the present invention is to perform cold rolling to obtain the desired thickness.

Among these, the non-decarburized hot hammering condition after the secondary cold rolling is carried out at a temperature above the recrystallization temperature and below 600°C because cold rolled steel sheets for shadow masks are generally ultra-thin steel sheets with a thickness of 0.2 or less. The board thickness is also extremely thin. For this reason, if the annealing temperature is set to 600 qo or more, the coil will develop chamfering and cannot be commercialized. In addition, the cold rolling reduction rate after non-decarburization is 10
The reason why it is limited to % or more and 25% or less is as follows. As shown in Figure 4, by setting C to 0.005%, the strain aging factor caused by C becomes almost negligible, but the factor caused by N still remains, and as shown in the figure, the yield point elongation is still around 1.8%. Generally, stretcher strain may occur if there is a yield point elongation of 1.0% or more, so stretcher strain cannot be prevented only by removing carbon. Figure 5 shows
Ultra-low carbon rimmed steel manufactured with the same manufacturing history as the material shown in Figure 4 was rolled between the sides at a reduction rate of 1.5 to 30% after non-decarburized sintering, and subjected to a 320x0 x 5 minute burning process. This shows the mechanical test values after the test. As is clear from this figure, as the cold rolling reduction after annealing increases, the recovery of yield point elongation by the burning process becomes smaller.

In order to suppress the recovery of the yield point elongation due to the burning process to less than 1.0% so that stretcher strain does not occur in the subsequent press working, the reduction ratio between the sashes after the anchoring is 10%.
It is necessary to do the above. This is the reason why the lower limit of the cold rolling reduction rate was set at 10%. Table 1 shows the press working results when materials having different final cold reduction ratios shown in FIG. 5 were pressed into shadow masks as they were after photoetching (including burning treatment).

Table 1 From this, it can be seen that the softer the material with a lower fold pressure ratio is, the better the press forming is, but that press forming is possible up to a cold reduction ratio of 25%.

On the other hand, when the cold rolling reduction is less than 10%, stretcher strain occurs as described above. This is the reason why the upper limit of the cold rolling reduction rate is set to 25% or less. In addition, if the rolling reduction rate is selected within the range of the method of the present invention, the hardness of the material will be Hv120-15.
It falls within the range of 2, and there is no problem with threading workability in the photo-etching process. Next, examples of the present invention will be described.

In 90 ton LD converter C: 0.06%, Si: 0.01
%, Mm; 0.31%, P; 0.016%, S; 0.0
Low carbon rimmed steel with a composition of 0.09% is melted and 6 coils of hot rolled steel sheet with a thickness of 2.5 mm are manufactured under normal manufacturing conditions.

These hot-rolled coils were manufactured to a thickness of 0.1 through the manufacturing process shown in Table 2.
A cold-rolled steel plate for shadow masks with 5 rails was manufactured and various investigations were conducted. The decarburization process was carried out in an open-coil compaction furnace under a warm hydrogen atmosphere (AX gas, dew point of 150°C). The results are summarized in Table 2. As is clear from the results in Table 2, the steel sheet produced by the method of the present invention has sufficient properties as a steel sheet for shadow masks used in the manufacturing process of immediately press-forming into shadow masks, omitting the dovetailing and leveling steps after photo etching. It can be seen that it is equipped with

On the other hand, those that do not meet the requirements of the method of the present invention are recognized to have some kind of defect, and the effectiveness of the method of the present invention is obvious. In this way, the method of the present invention completes the hammering process at the material manufacturer's stage with high efficiency and low cost, which greatly shortens the process required by conventional cathode ray tube manufacturers.From a total cost standpoint, this method is industrially extremely effective. A method for producing a useful shadow mask material is provided.

[Brief explanation of drawings]

Figure 1 is a process diagram of the conventional example (left side line) and the present invention example (right side line), Figure 2 is a schematic perspective view showing the sheet passing state and method in the photo-etching process, and Figure 3 is cold reduction. Figure 4 is a relationship diagram between C% and yield point elongation, and Figure 5 is a relationship diagram between cold reduction rate of decarburized material and test value after burning treatment. It is. Reference symbols in FIG. 2 represent the following. 1...Turntail, 2...Shadow mask material, 3...
Reference pattern, A...pretreatment and photosensitive liquid application band, B...exposure band. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] 1 A hot rolled steel sheet made of low carbon rimmed steel with C: 0.03 to 0.10% and S≦0.014% is first cold rolled through a normal process to form an open coil. C≦0.005 in annealing furnace
%, followed by secondary cold rolling, non-decarburizing annealing at a temperature above the recrystallization temperature and below 600°C, and further cold rolling at a cold rolling rate of 10% to 25% to obtain the desired result. A method for manufacturing a material for a shadow mask, which is characterized by making it thick. 2 C: 0.03 to 0.10%, S≦0.014% A hot rolled steel plate made of low carbon rimmed steel is first cold rolled through a normal process, and then C≦ in an open coil annealing furnace. 0.005
%, followed by secondary cold rolling, non-decarburizing annealing at a temperature above the recrystallization temperature and below 600°C, and then cold rolling at a rough reduction rate of 10% to 25%. 1. A method for producing a material for a shadow mask, which comprises forming a material to a desired thickness, photo-etching holes, and press-forming without annealing and leveling.