JPH09137220A - Iron-nickel alloy sheet for electronic member and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce an Fe-Ni alloy sheet for electronic member having superior press formability and etching characteristic by establishing the hot rolled plate heat treatment conditions improved in yield and hardly causing duplex grain structure. SOLUTION: At the time of producing an Fe-Ni alloy sheet for electronic member, having a composition consisting of, by mass, 34-50% Ni, <=0.3% Si, <=0.5% Mn, <=0.05% Al, and the balance Fe with inevitable impurities, a hot rolled plate after hot rolling is annealed at a temp. between the recrystallization temp. and 800 deg.C for >=1hr, subjected to a repetition of cold rolling and annealing at least once, and then finished to the prescribed sheet thickness.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a shadow mask, I
The present invention relates to a Fe—Ni alloy thin plate for electronic members, which is a material for a C lead frame, a magnetic head, and the like, and a method for manufacturing the same.

[0002]

2. Description of the Related Art Fe-Ni alloy thin plates are used for shadow masks, IC lead frames required as electronic members for their low thermal expansion, and magnetic heads because of their high magnetic permeability. For example, when the Fe-Ni alloy thin plate is used as a shadow mask, the Fe-Ni alloy thin plate having a predetermined plate thickness and plate width is formed with a hole for passing an electron beam by photoetching and then annealed. Then, a step of press-molding into a curved shape to match the shape of the cathode ray tube is taken. After obtaining the curved surface shape, the surface is subjected to blackening treatment and finally assembled as a shadow mask.

This Fe-Ni alloy thin plate has a high strength and a small elastic coefficient as compared with the conventional aluminum-killed steel, so that the press formability is very poor. Therefore, there is a problem that even if annealing is performed before the press forming, it cannot be formed into a shape suitable for the shape of the cathode ray tube in the subsequent press forming step.

As a method for improving the press formability of such Fe-Ni alloy thin plate, Japanese Patent Laid-Open Nos. 6-57383 and 6-57384 propose the following method. That is, a hot rolled plate that has undergone the hot rolling process has a temperature of 810 ° C to 890 ° C.
Heat treatment is performed at ℃, and the reduction ratio in cold rolling is 81 to 94.
%, And the reduction ratio in finish cold rolling is set to 16 to 29% to prevent the annealed Fe-Ni alloy thin plate before press forming from having a mixed grain structure and further Fe-
The degree of integration of the crystal plane on the surface of the Ni-based alloy thin plate is {331} to 3
5% or less, {210} is 16% or less, {211} is 20
%, The press formability is improved.

[0005]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
The methods described in Japanese Patent Laid-Open No. 3-57384 and Japanese Patent Laid-Open No. 6-57384 are
It is effective as one method for improving the press formability of the e-Ni alloy thin plate. JP-A-6-57383 and JP-A-6-57384, the method described in JP-A-6-57384, in reducing the mixed grain structure, the rolling reduction in the cold rolling after the heat treatment of the hot rolled plate within a predetermined range. Although it is especially important to keep the content inside, it is not possible to completely remove the mixed-grained structure from the structure having the mixed-grained structure, because the mixed-grained structure cannot be completely removed even by repeating cold rolling and annealing. However, the unevenness of the etching property or the press formability still occurs. In view of the above problems, it is an object of the present invention to provide an Fe—Ni alloy thin plate for electronic members, which has excellent press formability and etching properties, and a method for manufacturing the same.

[0006]

Means for Solving the Problems The present inventors have found that Fe for electronic members has excellent etching properties and press formability.
-As a result of studying a method for obtaining a Ni-based alloy thin plate, it is necessary to eliminate the mixed grain structure and form a sized structure by subjecting the hot rolled plate after hot rolling to a temperature lower than the conventional temperature of 800 ° C or lower. It was found that, as a result, unevenness in etching property and press formability can be sufficiently eliminated.

That is, the manufacturing method of the present invention uses Ni: 3
4 to 50 mass%, Si: 0.3 mass% or less, M
n: 0.5 mass% or less, Al: 0.05 mass%
In the production of an Fe-Ni alloy thin plate for electronic members, which contains the following and the balance is Fe and inevitable impurities, the hot-rolled sheet after hot rolling has a recrystallization temperature or higher and a temperature of 800 ° C or lower for 1 hour or longer. Of the Fe-Ni-based alloy thin plate for an electronic member, which is improved in the etching property and the press formability by finishing the predetermined plate thickness by repeating at least one cold rolling and annealing thereafter. .

Preferably, in order to suppress the generation of a mixed grain structure and regulate the grain size of the crystal grains, the temperature rising rate in the heat treatment of the hot rolled plate is 1000 ° C./hr. The cooling rate is 100 ° C./hr. The following is assumed. In addition, the so-called pinning effect of suppressing the growth of crystal grains can be effectively used by growing inclusions in the structure by heat treatment. Preferably 80% or more of the inclusions in the tissue is 0.1μ
It has a particle size of m or more.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION One of the greatest features of the present invention is that the recrystallization temperature of a hot-rolled sheet is used as a means for establishing a manufacturing method in which it is difficult to generate a mixed grain structure that adversely affects etching properties and press formability. As described above, the heat treatment is performed at a low temperature of 800 ° C. or lower. The cause of the mixed grain structure is considered as follows. The diffusion of inclusions proceeds more easily in the crystal grain boundaries than in the crystal grains, and the difference between the two is remarkable when the temperature is low. However, the higher the temperature, the smaller the difference between the two.
When a heating temperature of 810 ° C. or higher is applied to the hot rolled plate as described in JP-A-6-57383 and JP-A-6-57384, many inclusions are distributed in the crystal grains.

As a result, the so-called pinning effect, in which the inclusions are gathered at the crystal grain boundaries and the movement of the crystal grain boundaries is suppressed, becomes small, and the crystal grains tend to become coarse. Further, when the heat treatment is performed at a high temperature, the driving force of the crystal grain boundary is large, the crystal grain boundary moves relatively freely, the growth of the crystal grain progresses too much, and the crystal grain tends to become coarse. Due to such a cause, a mixed grain structure is formed. That is, when the heat treatment is performed on the hot rolled plate at a temperature higher than 800 ° C., the driving force of the crystal grain boundaries is large, and therefore the pinning action of the crystal grain boundaries can be maintained depending on the grain size of the inclusions. Some things can't be done.

As described above, a portion where the crystal grains grow largely due to the grain size of inclusions and a portion where the growth is suppressed and the crystal grains generated by the primary recrystallization are maintained are mixed,
As a result, the mixed grain structure cannot be eliminated. Once the structure has such a mixed-grain structure, the mixed-grain structure cannot be completely removed even after repeated cold rolling and annealing, which adversely affects the etching property and the press formability. Cause.

On the other hand, in order for the pinning effect to work effectively, it is necessary to grow the inclusions to an appropriate size and disperse the inclusions sparsely. For this reason, the heat treatment temperature is higher than the recrystallization temperature. It is necessary to. Therefore, the temperature of the heat treatment in the present invention is specified to be not lower than the recrystallization temperature and not higher than 800 ° C. The temperature is preferably 650 ° C. to 800 ° C. In addition, performing heat treatment at a low temperature of 800 ° C. or less also suppresses the amount of oxide film formed on the material surface during heat treatment to a small amount, which leads to an improvement in the yield of the material, and therefore from the viewpoint of industrial productivity. It is valid.

The temperature rising rate in the heat treatment is 1000 ° C. /
hr. The following is preferred. If heating is performed at a faster rate than this, the crystal grains often grow large before the inclusions grow to have a grain size sufficiently exhibiting the pinning effect, that is, 0.1 μm or more and dispersed, A portion where the crystal grains grow largely and a portion where the grain boundary pinning action works and the growth of the crystal grains is suppressed appear, resulting in a mixed grain structure.

In addition, the intergranular diffusion of inclusions increased at high temperatures, but it decreased when the temperature decreased, and diffusion proceeded more easily at the crystal grain boundaries at low temperatures. As a result, it is possible to introduce a pinning effect in which the movement of the crystal grain boundaries is suppressed by the inclusion of the inclusions in the crystal grain boundaries during the cooling process. The cooling rate is 100 ° C./hr. The following is desirable. If cooling at a faster rate than this, the pinning effect does not work sufficiently because the inclusions do not have enough time to diffuse into the crystal grain boundaries, and there are cases in which there is a portion where the movement of the crystal grain boundaries is relatively easy. is there. In this case, local growth of crystal grains may occur during annealing after cold rolling, resulting in a mixed grain structure.

Since the heat treatment according to the present invention is carried out at a low temperature of 800 ° C. or lower, the holding time of the heat treatment is set to 1 hour or longer in order to sufficiently grow the inclusions and move the grain boundaries. Desirably, holding for 5 hours or more is more effective. Further, by growing 80% or more of the inclusions in the structure to a grain size of 0.1 μm or more, the portion where the crystal grains grow locally can be reduced, and the pinning effect can be uniformly introduced. Generation of a mixed grain structure can be suppressed, and a Fe—Ni based alloy thin plate for an electronic member having sufficiently excellent press formability and etching property can be obtained.

Next, the reasons for limiting the components of the present invention will be described. Ni was 34 to 50 mass%. If Ni is out of this range, the thermal expansion coefficient of the Fe—Ni alloy thin plate itself becomes too large, and it cannot be used as a shadow mask material or a lead frame material that requires low thermal expansion. S
i, Mn or Al can be added as a deoxidizing agent in the refining process.

Si is 0.3 mass%, and Al is 0.
If added in excess of 05 mass%, workability is adversely affected. Therefore, Si is 0.3 mass% or less, A
1 was 0.05 mass% or less. Mn is also added as a deoxidizing agent, but its effect does not change much even if it is added in excess of 0.5 mass%, so it was set to 0.5 mass% or less. Si, Mn, or Al is an element added for the purpose of deoxidizing molten steel in the refining process, and as a result, is an element remaining in the material. Therefore, Si,
Mn or Al may be reduced to the impurity level content.

[0018]

The present invention as described above will be described in more detail with reference to the following examples. First, the inventors of the present invention conducted an electric furnace to produce an alloy A (36Ni-F) having the composition shown in Table 1.
e) and B (42Ni-Fe) ingots were melted. After caring for each of the ingots in Table 1, slab rolling, surface scratch removal, and hot rolling were performed. The obtained hot-rolled sheet had A (36Ni-Fe) in Table 2 and B (42Ni-).
For Fe), heat treatment was performed under the conditions shown in Table 3.
By observing the crystal structure of the heat-treated strip with an optical microscope, the distribution of the crystal grain size was examined, and the results are shown in Tables 2 and 3. The heating rate in the heat treatment is 20
0 ° C./hr. , The cooling rate is 20 ° C./hr. And

[0019]

[Table 1]

Next, the heat-treated strip is cold-rolled (reduction of 50%), and subsequently A (36Ni-Fe) is added.
At 1000 ° C. for B (42Ni-Fe) 1100
Each for 10 min. Was annealed. After that, finish cold rolling (reduction of 10%), and finally strain relief annealing (580 ° C. × 5 min.) Are performed to obtain a plate thickness of 0.25 mm.
The Fe-Ni type alloy thin plate of was obtained. The distribution of the crystal grain size was investigated by observing the crystal structure of the obtained Fe-Ni alloy thin plate with an optical microscope. The results are also shown in Tables 2 and 3.

[0021]

[Table 2]

[0022]

[Table 3]

First, looking at the band material obtained by the heat treatment, when the heat treatment temperature of the hot-rolled plate is 850 ° C., it is found that the temperature is large between the maximum grain size and the minimum grain size of the crystal. While the difference of 33 μm occurs, when the heat treatment temperature of the hot rolled plate is 800 ° C. or less, the difference in crystal grain size is about 18 μm at the maximum, and the crystal grains are sized. I understand. Especially the heat treatment temperature is from 650 ° C to 8
In the case where the temperature is between 00 ° C., even if the difference in crystal grain diameter is large, it is about 10 μm, which shows the effect of the heat treatment of the present invention.

Next, a Fe-Ni alloy thin plate which has been heat-treated and then repeatedly cold-rolled and annealed to have a predetermined thickness will be described. The grain size difference generated between the maximum grain size and the minimum grain size of the crystal in the strip at the time of the heat treatment is hardly changed even if cold rolling and annealing are repeated thereafter.

From this, the distribution of the crystal grain size determined by the heat treatment is hardly affected by the subsequent cold rolling and annealing, so that the heat treatment results in a structure having a mixed grain structure. If so, the mixed grain structure cannot be completely removed even after repeated cold rolling and annealing. Therefore, it can be seen that the generation of the mixed grain structure is greatly influenced by the heat treatment condition of the hot rolled plate, and the heat treatment condition of the hot rolled plate according to the present invention has a great effect on the prevention of the mixed grain structure.

Next, focusing on the influence of the holding time of the heat treatment of the hot rolled plate, when the heat treatment is performed at, for example, 650 ° C., the longer the heat treatment time, the difference in the crystal grain size. Is getting smaller. From the above, it is understood that the longer the heat treatment time is, the more effective the particle size regulation is. Regarding the particle size of inclusions in the structure, for example, when heat treatment is performed at 750 ° C., the larger the number of inclusions having a particle size of 0.1 μm or more, the smaller the difference in crystal grain size. When the occupancy rate occupies 80% or more, the mixed grain structure is sufficiently eliminated to obtain a sized structure.

Further, Table 4 summarizes the relationship between the temperature rise and cooling rates in the heat treatment and the difference in crystal grain size. From this, the heating rate is 1000 ° C./hr. In the rapid heating exceeding 1, the difference in crystal grain size becomes large, and as a result, a mixed grain structure tends to be formed. Further, the cooling rate is 100 ° C./hr.
It can be seen that even in the case of rapid cooling exceeding 5 ° C., a mixed grain structure tends to similarly occur.

[0028]

[Table 4]

[0029]

As described above, in the production of the Fe-Ni alloy thin plate for electronic members, the hot-rolled plate after hot rolling is subjected to heat treatment at a temperature of recrystallization temperature or higher and 800 ° C. or lower for 1 hour or longer, The heating rate at that time was 1000 ° C./hr. Below,
Further, the cooling rate was 100 ° C./hr. After that, cold rolling and annealing are repeated at least once to finish to a predetermined plate thickness, so that the yield is good, and the generation of a mixed grain structure is suppressed, and the Fe having excellent press formability and etching property is provided. It is possible to provide a method for manufacturing a Ni-based alloy thin plate, which can greatly contribute to efficiency improvement and quality improvement in manufacturing electronic members.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication H01L 23/48 H01L 23/48 V 23/50 23/50 V

Claims (4)

[Claims] 1. Ni: 34 to 50 mass%, Si:
0.3 mass% or less, Mn: 0.5 mass% or less,
Al: containing 0.05% by mass or less, and the balance being Fe and unavoidable impurities in the production of an Fe-Ni alloy thin plate for electronic members, in a hot-rolled plate after hot rolling, at a recrystallization temperature or higher and 800 ° C or lower. At a temperature of 1 hour or more, and then cold rolling and annealing are repeated at least once to finish the sheet to a predetermined sheet thickness. 2. The heating rate in the heat treatment is 1000.degree.
/ Hr. Hereinafter, the cooling rate was 100 ° C./hr. Fe-N for electronic members according to claim 1, characterized in that
i-type alloy sheet manufacturing method. 3. 80% or more of inclusions in the tissue confirmed according to JIS G0555 are heated to 0.1 by heat treatment.
3. The method for producing a Fe—Ni alloy thin plate for electronic members according to claim 1, wherein the grain size is μm or more. 4. By heat treatment, 80% or more of the inclusions in the tissue confirmed according to JIS G0555 are 0.1% or more.
Fe for electronic member characterized by having a particle size of μm or more
-Ni-based alloy sheet.