JP2590626B2 - Fe-Ni alloy cold rolled sheet excellent in cleanliness and etching piercing properties and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention can be used as a shadow mask material for high-definition TV, which has no defects at the time of etching perforation, and has a low coefficient of thermal expansion, cleanliness and etching perforation. The present invention relates to an excellent Fe-Ni alloy cold rolled sheet and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, Fe-Ni alloy plates have been mainly used as materials for electronic parts. For example, 42w
t. % Of nickel is used as an IC lead frame material because of its excellent electrical conductivity, heat resistance, bending workability, plating adhesion and solderability. Furthermore, the thermal expansion coefficient is very small, 36 wt. % Of nickel is used as a shadow mask material for a color television or a container material for storing a low-temperature liquid.

[0003] F as a high definition TV shadow mask material
The cold rolled e-Ni alloy sheet is required to have no defect at the time of etching perforation and to have a low coefficient of thermal expansion.
The following Fe-Ni-based alloy cold-rolled sheets have been proposed as Fe-Ni-based alloy cold-rolled sheets as shadow mask materials for TVs.

A Fe—Ni-based alloy cold-rolled sheet disclosed in Japanese Patent Application Laid-Open No. Sho 62-161,936 having excellent surface properties during cold rolling and essentially consisting of: nickel: 30 to 45 wt. . %, Manganese: 0.3 to 1.0 wt. %, Silicon: 0.1 to 0.3 wt. %, Aluminum: 0.0004 to 0.0020 wt. %,
And the remaining iron and unavoidable impurities, provided that the non-metallic inclusions as the unavoidable impurities are Al ₂ O ₃ − shown in FIG.
In the MnO—SiO ₂ ternary phase diagram, point 1: Al ₂ O ₃ : 4 wt. %, MnO: 58 wt. %, SiO ₂ : 38 wt. %, Point 2: Al ₂ O ₃ : 5 wt. %, MnO: 49 wt. %, SiO ₂ : 46 wt. %, Point 3: Al ₂ O ₃ : 23 wt. %, MnO: 23 wt. %, SiO ₂ : 54 wt. %, Point 4: Al ₂ O ₃ : 27 wt. %, MnO: 31 wt. %, SiO ₂ : 42 wt. % And point 5: Al ₂ O ₃ : 17 wt. %, MnO: 54 wt. %, SiO ₂ : 29 wt. %, In a region surrounded by a line that sequentially connects (hereinafter, referred to as “prior art”).

[0005]

The above-mentioned prior art has the following problems. That is, in the Al ₂ O ₃ —MnO—SiO ₂ system ternary phase diagram shown in FIG. 1, the nonmetallic inclusions in the region surrounded by the line connecting points 1, 2, 3, 4, and 5 in sequence. Due to the composition, the non-metallic inclusions have the lowest temperature of 1,2
It is composed of a composition in a region close to spessartite, surrounded by a liquidus temperature line of 00 ° C. As a result, the non-metallic inclusions have a low melting point and a large deformability, and
The total amount is large. When the particle size of the non-metallic inclusions is large, or the content of the compound having a low melting point is large, the alloy ingot is hot-rolled, when cold-rolled to prepare a cold-rolled sheet,
Non-metallic inclusions in the cold-rolled sheet are deformed linearly, which causes defects at the time of etching perforation.

[0006] Accordingly, Fe which can be used as a shadow mask material of a high definition TV, has no defect at the time of etching perforation, has a low coefficient of thermal expansion, and is excellent in cleanliness and etching perforation properties. Although a cold rolled Ni-based alloy sheet is required, such a cold rolled alloy sheet and a method for producing the same have not been proposed yet.

Accordingly, it is an object of the present invention to provide a shadow mask material for a high definition TV, which has no defect at the time of etching perforation, has a low coefficient of thermal expansion, and is excellent in cleanliness and etching perforation. Fe-Ni
An object of the present invention is to provide a cold rolled system alloy sheet and a method for producing the same.

[0008]

SUMMARY OF THE INVENTION From the above-mentioned viewpoints, the present inventors have found that a defect can not be generated at the time of etching perforation, which can be used as a shadow mask material of a high definition TV.
Then, intensive studies were conducted to develop a Fe-Ni-based alloy cold-rolled sheet having a low coefficient of thermal expansion, excellent in cleanliness and etching piercing properties, and a method for producing the same. As a result, the following findings were obtained.

[0009] 30 to 45 wt. % Of a dephosphorized and decarburized Fe-Ni-based molten alloy containing nickel in the range of 20 to 40 wt. % In a MgO-CaO-based refractory ladle containing CaO in the range of 0.1% by weight, and adding the aluminum to the Fe-Ni-based molten alloy thus prepared and adding the aluminum to the Fe-Ni.
The molten alloy is placed in the ladle with the following Ca
_{O-Al 2} O 3 -MgO slag: CaO and _Al 2 _O 3: _57wt. % Or more, provided that the ratio of CaO / (CaO + Al ₂ O ₃ ) is 0.45
As described above, MgO: 25 wt. % Or less, SiO ₂ : 15 wt. % Or less, and an oxide of a metal having a lower oxygen affinity than silicon: 3w
t. % Or less to deoxidize the Fe-Ni-based molten alloy, thereby reducing the amount of dissolved oxygen in the molten alloy and absorbing the oxides generated in the molten alloy into the slag.

As a result, the total amount of nonmetallic inclusions present in the Fe—Ni-based alloy cold-rolled sheet is 0.0
02 wt. % Or less. In other words, as the amount of dissolved oxygen in the molten alloy decreases, during solidification of the molten alloy, not only does the total amount of nonmetallic inclusions that precipitate decrease, but also a low-melting-point suspension that serves as precipitation nuclei. , The growth of the particle size of the nonmetallic inclusions is suppressed.

The non-metallic inclusions present in the Fe—Ni alloy cold rolled sheet are as shown in the ternary phase diagram of CaO—Al ₂ O ₃ —MgO shown in FIG. %, Al ₂ O ₃ : 39.2 wt. %, MgO: 0 wt. %. Point 2: CaO: 55.3 wt. %, Al ₂ O ₃ : 38.5 wt. %, MgO: 6.2 wt. %. Point 3: CaO: 36.9 wt. %, Al ₂ O ₃ : 52.3 wt. %, MgO: 10.8 wt. %. Point 4: CaO: 31.6 wt. %, Al ₂ O ₃ : 64.6 wt. %, MgO: 3.8 wt. %. And Point 5: CaO: 32.7 wt. %, Al ₂ O ₃ : 67.3 wt. %, MgO: 0 wt. %. In the region other than the region surrounded by the line connecting the 1600 in order, ie, 1600 specified by the liquidus line at 1600 ° C.
Since the composition is in the range of the melting point of not less than ° C., the particle diameter of the nonmetallic inclusion becomes 6 μm or less.

The present invention has been made based on the above-mentioned findings, and the Fe—Ni-based alloy cold-rolled sheet excellent in cleanliness and etching piercing property of the present invention essentially consists of the following. I have. Nickel: 30 to 45 wt. %, Aluminum: 0.003 to 0.030 wt. %, Manganese: 1.0 wt. %, Silicon : 0.4 wt. % Or less, chromium : 0.1 wt. % Or less, carbon : 0.005 wt. % Or less, nitrogen : 0.005 wt. % Or less, sulfur : 0.005 wt. % Or less, phosphorus : 0.010 wt. %, Oxygen : 0.002 wt. % Or less, and non-metallic inclusions : 0.002 wt. % Or less, the non-metallic inclusions contained is formed of a composition having the following particle size 6 [mu] m, and, the composition, Ca
Contains at least one of O, Al ₂ O ₃ and MgO.

The method for producing a cold-rolled Fe—Ni alloy according to the present invention, which is excellent in cleanliness and etching piercing properties, comprises the following steps. 30 to 45 wt. % Of a Fe-Ni-based molten alloy containing nickel in the range of 20 to 40 wt. % In a ladle made of MgO-CaO-based refractory containing CaO in the range of
Aluminum is added to the Fe-Ni-based molten alloy thus prepared, and the Fe-N to which aluminum is added is added.
In the ladle, the i-type molten alloy is mixed with C
_{aO-Al 2} O 3 -MgO slag: CaO and _Al 2 _O 3: _57wt. % Or more, where the ratio of CaO / (CaO + Al ₂ O ₃ ) is 0.4
5 or more, MgO: 25 wt. % Or less, SiO ₂ : 15 wt. % Or less, and an oxide of a metal having a lower oxygen affinity than silicon: 3w
t. % To deoxidize the Fe-Ni-based molten alloy and solidify the deoxidized Fe-Ni-based molten alloy.
Cold-rolled to have a particle size of 6 μm or less, and 0.002 wt. % Of an Fe-Ni-based alloy cold rolled sheet containing a total amount of non-metallic inclusions of not more than%.

The chemical composition of the Fe—Ni alloy cold rolled sheet excellent in cleanliness and etching piercing property of the present invention is as follows:
The reason for limiting to the above range will be described below. (1) Nickel: Nickel is a component that has a large effect on the coefficient of thermal expansion of an Fe—Ni-based alloy plate. Nickel content between 30 and 4
5 wt. %, The coefficient of thermal expansion of the alloy plate is small.
However, if the nickel content is 30 wt. %, The coefficient of thermal expansion of the alloy plate becomes high. On the other hand, when the nickel content is 45 wt. %, The coefficient of thermal expansion of the alloy increases. When a cold-rolled Fe—Ni-based alloy having a high coefficient of thermal expansion is used as a shadow mask material, it causes color shift. Therefore, the nickel content is between 30 and 4
5 wt. It should be limited to the range of%. Note that, as the nickel raw material, Incon Nickel (trade name of nickel manufactured by International Corporation) and electrolytic nickel are usually used. To reduce the cost, Tonimet containing cobalt (trade name of nickel manufactured by Tokyo Nickel Co., Ltd.) may be used. At this time, 1 wt. % Or less of cobalt, but there is no problem if the content of nickel is within the above range.

(2) Manganese: Manganese has the function of improving the hot workability of an Fe—Ni alloy plate. However, when the manganese content is 1.0 wt. %, The hardness of the alloy plate becomes excessively high and is not suitable as a shadow mask material. Therefore, the manganese content is 1.0 wt. % .

(3) Aluminum: Aluminum is a component that affects the amount of nonmetallic inclusions in the Fe-Ni-based alloy plate and the size of the particle size. Aluminum content from 0.003 to 0.03w
t. %, Small and small amounts of non-metallic inclusions are formed in the alloy sheet. However, when the content of aluminum is 0.003 wt. %, A large amount of non-metallic inclusions having a large particle size, a low melting point, and a high malleability are generated in the cold-rolled sheet in a linear form. As a result, a defect occurs when the alloy plate is etched. On the other hand, the content of aluminum is 0.03w
t. %, The blackening property of the alloy plate is reduced. Therefore, the content of aluminum is 0.003 to 0.0.
30 wt. It should be limited to the range of%.

(4) Silicon: Silicon is one of the impurities that are inevitably mixed into the Fe—Ni alloy. The smaller the silicon content, the better. However, it is difficult from the viewpoint of economy to significantly reduce the silicon content on an industrial scale. However, when the silicon content is 0.4 wt. %,
At the time of etching perforation of the Fe-Ni-based alloy plate, the etchant is contaminated to lower the productivity. Therefore, the content of silicon is 0.4 wt. %.

(5) Chromium: Chromium is one of the impurities unavoidably mixed into the Fe-Ni alloy. The smaller the chromium content, the better. However, it is difficult from the viewpoint of economic efficiency to significantly reduce the chromium content on an industrial scale. However,
Chromium content is 0.1 wt. %, Fe-N
The etching perforation speed of the i-based alloy plate becomes slow, the productivity decreases, and the coefficient of thermal expansion of the alloy plate increases,
Color shift occurs. Therefore, the content of chromium is 0.1 w
t. %.

(6) Carbon: Carbon is one of the impurities that are inevitably mixed into the Fe—Ni alloy. The smaller the carbon content, the better. However, it is difficult from the viewpoint of economy to greatly reduce the carbon content on an industrial scale. However, if the carbon content is 0.005 wt. %, A large amount of iron carbide is generated in the Fe-Ni-based alloy plate, which hinders the etching piercing property of the alloy plate and causes puncturing defects. Further, when the carbon content is 0.005 wt. %, The press formability of the alloy sheet is reduced. Therefore, the carbon content is
0.005 wt. %.

(7) Nitrogen: Nitrogen is one of the impurities unavoidably mixed into the Fe—Ni alloy. The nitrogen content is preferably as small as possible, but it is difficult from the viewpoint of economy to greatly reduce the nitrogen content on an industrial scale. However, if the nitrogen content is 0.005 wt. %, A large amount of metal nitride is generated in the alloy plate, which inhibits the etching piercing property of the alloy plate and causes a pitting defect. Therefore, the nitrogen content is 0.005 wt. %.

(8) Sulfur: Sulfur is one of the impurities unavoidably mixed into the Fe-Ni alloy. The sulfur content is preferably as small as possible, but it is difficult from the viewpoint of economy to greatly reduce the sulfur content on an industrial scale. However, if the sulfur content is 0.005 wt. %, A large amount of sulfide-based nonmetallic inclusions are generated in the Fe-Ni-based alloy plate, which hinders the etching piercing property of the alloy plate and causes puncturing defects. Therefore, the sulfur content is 0.005 wt. %
It should be limited to:

(9) Phosphorus: Phosphorus is one of the impurities that are inevitably mixed into the Fe—Ni alloy. The smaller the phosphorus content, the better. However, it is difficult from the viewpoint of economy to greatly reduce the phosphorus content on an industrial scale. However, if the phosphorus content is 0.010 wt. %, The hot workability of the Fe—Ni-based alloy sheet is significantly deteriorated. Therefore, the phosphorus content is
0.010 wt. %.

(10) Oxygen: Oxygen is one of the impurities unavoidably mixed into the Fe—Ni alloy. The oxygen content is preferably as small as possible, but it is difficult from the viewpoint of economy to greatly reduce the oxygen content on an industrial scale. However, if the oxygen content is 0.002 wt. %, A large amount of oxide-based nonmetallic inclusions are formed in the alloy, which hinders the etching piercing property of the alloy plate and causes piercing defects. Therefore, the oxygen content is 0.002 wt. %.

(11) Non-metallic inclusions: Non-metallic inclusions are mainly composed of calcium oxide (Ca
O), aluminum oxide _(Al 2 _{O 3)} and has become of magnesium oxide (MgO), exerts a great influence on the etching perforation of the Fe-Ni alloy plate. The content of nonmetallic inclusions in the alloy plate is 0.002 in terms of oxygen.
wt. %, It inhibits the etching piercing property of the alloy plate and causes a puncturing defect. Therefore, the content of nonmetallic inclusions is 0.002 wt. %.

The non-metallic inclusion is CaO-Al shown in FIG.
_{In the 2} O ₃ -MgO ternary phase diagram, point 1,
1,600 ° C., which is specified by a liquidus line at 1600 ° C. (ie, a thick solid line in FIG. 2) in a region other than a region surrounded by lines sequentially connecting 2, 3, 4, and 5 When the composition in the above melting point region is used, the particle size of the nonmetallic inclusion becomes 6 μm or less, and the Fe—Ni alloy cold rolled sheet shows excellent etching piercing property. Therefore, the nonmetallic inclusions are points 1, 2, 3, 4, and 5 in the ternary phase diagram of CaO—Al ₂ O ₃ —MgO shown in FIG.
Should be composed of the composition in a region other than the region surrounded by the line connecting

Next, according to the present invention, when refining an Fe—Ni-based molten alloy in a ladle,
0 wt. % MgO-C containing CaO in the range of
The reason for using an aO-based refractory ladle will be described below. (1) The content of CaO in the refractory is 20 wt. %, The penetration depth of the slag into the refractory (penetrat)
ion depth) increases, and the refractory deteriorates. On the other hand, when the content of CaO is 40 wt. %, The melting point of the refractory decreases and the degree of erosion (warn r) increases.
atio), making it impossible to slag refine the molten alloy at high temperatures for long periods of time. Therefore, the content of CaO in the refractory is 20 to 40 wt.
It should be limited to the range of%.

The above is described in detail with reference to FIG. In FIG. 4, “●” indicates the infiltration depth of the slag, the solid line indicates the infiltration depth curve, “「 ”indicates the degree of erosion of the refractory, and the dashed line indicates the degree of erosion. The curve is shown. In FIG. 4, the vertical axis is the infiltration depth, and
Indicates the degree of erosion. The horizontal axis indicates the content of MgO and CaO. That is, the upper scale of the horizontal axis is 0 to 100 watts.
t. % MgO content and the lower scale is from 100 to 0 wt. % CaO content. Therefore, the horizontal axis indicates that the total amount of MgO and CaO is always 100%.
wt. %. For example, when the content of MgO is 100 wt. %, The content of CaO is 0 w
t. % And the content of MgO is 20 wt. %
, The content of CaO is 80 wt. %. FIG.
As is clear from FIG.
wt. %, The infiltration depth of the slag and the degree of erosion of the refractory are both small.

(2) Since the ladle made of the MgO—CaO refractory has a low content of oxides such as Fe ₂ O ₃ , SiO ₂ and Cr ₂ O ₃ which are sources of alloy oxides, the molten alloy The oxygen concentration in the inside can be kept low to prevent silicon and chromium pickup. Therefore, MgO
Ladles made of CaO-based refractories should be used.

Next, according to the present invention, when refining a Fe—Ni-based molten alloy in a ladle, the following CaO—Al ₂ O ₃ —MgO-based slag: CaO and Al ₂ O ₃ : 57 wt. % Or more, provided that the ratio of CaO / (CaO + Al ₂ O ₃ ) is 0.45
As described above, MgO: 25 wt. % Or less, SiO ₂ : 15 wt. % Or less, and an oxide of a metal having a lower oxygen affinity than silicon: 3w
The reason for using the following is described below.

(1) CaO / (CaO + Al ₂ O ₃ )
Is less than 0.45, the activity of Al ₂ O _{3 in} the slag exceeds 0.5. The activity of Al ₂ O ₃ in the slag is 0.
If it exceeds 5, the deoxidizing power of aluminum when the amount of aluminum is kept constant decreases. Therefore, CaO / (C
The ratio of (aO + Al ₂ O ₃ ) should be limited to 0.45 or more.

The above will be described in detail with reference to FIG. FIG. 5 shows the activity of each of Al ₂ O ₃ and CaO in CaO—Al ₂ O ₃ —MgO based slag and CaO / (Ca
₃ is a graph showing the relationship between the ratio (O + Al ₂ O ₃ ). The vertical axis indicates the activity (a) of each of Al ₂ O ₃ and CaO.
_Al2O3 and a _CaO) indicates, and the horizontal axis represents the ratio of _{CaO / (CaO + Al 2 O} 3). Further, FIG. 5 shows _three commonly known isoactivity lines for Al ₂ O ₃ and CaO. As is clear from FIG. 5, when the ratio of CaO / (CaO + Al ₂ O ₃ ) is 0.45 or more, the Al activity of any of the Al ₂ O ₃ is not affected.
Activity of ₂ O _{3 (a Al2O3)} is suppressed below 0.5. As a result, when the ratio of CaO / (CaO + Al ₂ O ₃ ) is 0.45 or more, it is possible to obtain a slag in which aluminum has a strong deoxidizing power.

(2) The content of MgO in the slag is 25
wt. %, The melting point of the slag increases, and the reaction of the slag with the Fe-Ni-based molten alloy decreases. Therefore,
The content of MgO is 25 wt. %.

(3) The content of SiO _{2 in} the slag is 1
5 wt. %, The activity of SiO _{2 in} the slag (a
_SIO2) rises and the amount of oxygen in the Fe-Ni-based molten alloy is increased by SiO _2. As a result, F
The oxygen content in the cold rolled e-Ni alloy sheet is 0.0
020 wt. %. Therefore, the content of SiO ₂ is 15 wt. %.

(4) The total amount of oxides of metals having a lower oxygen affinity than Si in the slag is 3 wt. %, The oxygen content in the Fe-Ni alloy cold-rolled sheet is 0.0020 wt. %. Therefore, the total amount of metal oxides having a lower oxygen affinity than silicon is 3
wt. % Or less, and more desirably 1.5 w
t. %.

Further, the Fe-N
The reason why the Fe-Ni-based alloy cold rolled sheet excellent in cleanliness can be obtained by deoxidizing the i-type molten alloy will be described in detail with reference to FIG. FIG. 6 shows a 36 wt. % Of a Fe-Ni-based molten alloy containing 2.5% nickel, when aluminum or silicon reaches an equilibrium state of deoxidation, the dissolved amount of aluminum or silicon used for deoxidation in the molten alloy, and 4 is a graph showing the relationship between the amount of oxygen dissolved in an alloy.

In FIG. 6, the vertical axis indicates the dissolved amount of oxygen in the molten alloy, and the horizontal axis indicates the dissolved amount of aluminum or silicon in the molten alloy. Further, in FIG. 6, the solid oblique line indicates the isoactivity line of Al ₂ O ₃ , and the oblique dashed line indicates the isoactivity line of SiO ₂ . Further, in FIG. 6, “C” indicates the dissolved amount of silicon or aluminum and the dissolved amount of oxygen in the molten alloy of the present invention obtained by deoxidizing the molten alloy using the above-described slag of the present invention, and “ Each of “A (A ₁ , A ₂ )” and “B” is a method not using the slag of the present invention, which is outside the scope of the present invention (hereinafter referred to as “comparative deoxidation method”) N
o. 2 shows the dissolved amount of silicon or aluminum and the dissolved amount of oxygen in the molten alloy deoxidized by 1 or 2.

As is clear from FIG. 6, the molten alloy of the present invention has a small amount of dissolved oxygen. That is, by vigorously stirring the molten alloy in the presence of a sufficient amount of aluminum and the above-mentioned slag, the respective activities a _Al2O3 and a _SiO2 in the equilibrium state are reduced, and the oxygen concentration in the equilibrium state is reduced. Stabilizes lower.
Thus, non-metallic inclusions consisting of oxides in the molten alloy are adsorbed and removed by the slag. As a result, the molten alloy can be cleaned, and a small amount of nonmetallic inclusions having a high melting point and a very small particle size can be distributed in the molten alloy.

[0038] In slabbing of Fe-Ni-based alloy ingot, the pressure under rate was 70% or more, and, the rolling temperature, it is preferably in the range of 1,250 ° C. from 1,150. The reason is as follows. (1) when pressure under ratio is 70% or more, if the time of blooming
This has the effect of crushing the nonmetallic inclusions in the gold and making the particle size of the nonmetallic inclusions in the cold rolled sheet extremely small. Therefore, it should limit the pressure under rate of 70% or more. (2) When the rolling temperature is lower than 1,150 ° C., it is difficult to perform the bulk rolling. On the other hand, when the rolling temperature is higher than 1,250 ° C., the deformation resistance of the matrix metal becomes small, and non-metallic inclusions are reduced. Crushing becomes difficult. Therefore, the rolling temperature should be limited to the range from 1,150 to 1,250 ° C.

[0039]

Next, the present invention will be described in detail with reference to Examples, in which the Fe-Ni-based alloy cold rolled sheet excellent in cleanliness and etching piercing property and the method for producing the same are compared with Comparative Examples outside the scope of the present invention. This will be described in more detail. Using the raw materials shown in Table 1, an Fe—Ni-based alloy cold-rolled sheet was prepared by the following manufacturing steps.

1. 1. Refining using a converter 2. Refining using VAD (Vacuum-Electric-Degassing) equipment including: Dephosphorizing refining Nickel melting 3. Refining using VOD (omission of vacuum-oxygen-decarburization) equipment Acid decarburization Vacuum decarburization Slag deoxidation Lumps 5. Bulk rolling 6. Hot rolling 7. Cold rolling

[0041]

[Table 1]

FIG. 7 shows a refining process using the above-described VAD and VOD equipment. That is, in a 250-t top-blowing converter equipped with a bottom plug for blowing gas for stirring, refined hot metal is refined to obtain molten steel that has not been deoxidized,
This was then transferred into a 250 t ladle. Next, of the 250 t of molten steel obtained in this way, 20 t
From the ladle to the 50 ton ladle was stored. The component composition of the molten steel was as follows.

[0043]

The above-mentioned 20 ton of molten steel was mixed with 57.2 wt.
% MgO, 38.4 wt. % CaO, 1.6 wt.
% SiO ₂ and 0.2 wt. % Of Al ₂ O ₃ was poured into another 20 t ladle using a magnesia chromite brick with a rotary nozzle. The ladle was then placed in a VAD (vacuum-arc-degas) facility, where the molten steel was dephosphorized. As described above, by using the molten steel that has not been deoxidized, nitrogen is prevented from being absorbed into the molten steel. Next, after removing the slag, while heating the molten steel in the ladle to a temperature of 1600 ° C. or more by a three-phase electrode heating device under reduced pressure, the pure nickel ingot and the nickel alloy ingot are It was charged in a ladle and dissolved.

Degree of vacuum: 200 to 600 Torr, Flow rate of bottom blown argon gas: 0.5 to 1.5 Nl / min. t, input timing of the slag agent: VAD refining immediately before the start, the composition of the slag agent: burnt lime 15Kg / T, fluorite 4Kg / T.

After dissolution of the nickel, the thus obtained Fe—Ni-based molten alloy in the ladle, which has now been increased to about 30 t, is heated to 1,700 ° C. or more, more preferably 1 , 750 ° C or higher. Degree of vacuum: 200 to 400 Torr, Flow rate of bottom blown argon gas: 0.5 to 1.5 Nl / min. t, Slag-making agent input: None.

At this stage, the results of examining the contents of carbon and nickel in the Fe-Ni-based molten alloy were as follows.

By the above-mentioned heating after dissolution of nickel,
Heating after refining using the following VOD (vacuum-oxygen-decarburization) equipment was unnecessary. Next, the ladle is VO
It was moved to the D facility, where the Fe-Ni-based molten alloy was decarburized. Decarburization of the molten alloy consisted of decarburization performed while blowing oxygen with a top blow lance (hereinafter, referred to as "acid decarburization by top blow lance") and vacuum decarburization under reduced pressure.

First, acid decarburization using an upper blowing lance was performed under the following conditions. Degree of vacuum: 100 Torr or less, Flow rate of bottom blown argon: 1.0 to 2.0 Nl / min. t, Flow rate of top-blown oxygen gas: 8 to 20 Nm ³ / min. t, acid supply amount: 2 to 5 Nm ³ / t, distance between lance and molten alloy surface: 700 to 900 mm, slag-making agent input: none.

Thus, the oxygen-enriched Fe—N
By promoting a carbon-oxygen reaction while stirring the i-type molten alloy with a bottom-blown argon gas, the carbon content is 0.005 wt. The molten alloy was decarburized under reduced pressure until it decreased to less than 10%. In addition, at the end of the above-mentioned acid blowing decarburization by the top blowing lance, the ladle is
Transferred to an OD facility, and added nickel into the molten alloy to fine-tune the nickel component in the molten alloy; and
The temperature of the molten alloy was adjusted to about 1,750 ° C. The contents of nickel, carbon and nitrogen in the molten alloy at this stage were as follows.

[0051]

Next, vacuum decarburization under reduced pressure treatment
The test was performed under the following conditions. Degree of vacuum: 1 Torr or less, Flow rate of bottom blown argon gas: 1.5 to 2.5 Nl / min. t, slag agent dispenser: none, vacuum decarburization at the start of molten alloy temperature: 1,745 ° C. As a result, its carbon content, 0.0009Wt. %, The Fe—Ni-based molten alloy could be decarburized.

Next, in the VOD facility,
During Fe-Ni-based molten alloy was added deoxidizing agents and slag agents, such as aluminum, and, with vigorous stirring a molten alloy by the bottom blown argon gas, in the following conditions, between the molten alloy and slag The molten alloy was deoxidized by the reaction (hereinafter, referred to as “the deoxidizing method of the present invention”).

Degree of vacuum: 1 Torr or less, flow rate of bottom blown argon: 0.5 to 2.5 Nl / min. t, slag agent and introduction of deoxidizing agent (2 times) the composition of the first-dosing slag agent: burnt lime: 30 Kg / t, fluorite: 5Kg / t, the composition of an acid acceptor: Aluminum: 10 Kg / t , Ferrosilicon: 2 Kg / t, Input time: Immediately before the start of deoxidizing and refining, 2nd input Additive composition: Fine adjuster for molten alloy components, Input time: Middle of deoxidizing and refining.

After adding a deoxidizer to the molten alloy, the slag
In the Fe-Ni-based molten alloy during the process of deoxidation by Sol. The Al content was as follows.

CaO-Al ₂ O ₃ reacted with molten alloy
-The MgO-based slag consisted of: (A) Component composition (wt.%) (B) CaO / (CaO + Al ₂ O ₃ ) ratio: 0.72 (c) Total content of oxides of metals having a lower oxygen affinity than Si (that is, T.Fe + MnO + Cr ₂ O ₃ ): 1.4 wt . %

The results of the above-described deoxidation refining of the Fe-Ni-based molten alloy in the VOD facility were as follows. Si content in molten alloy: 0.3 wt. % Or less, the estimated value of the activity of _{SiO 2 (a SiO2): 0.001~0.005} , content SolAl in molten alloy: 0.005~0.030wt. %, Activity of _Al 2 _{O 3} estimates of _{(a Al2O3):} 0.1 ~0.3, estimate the concentration of equilibrium oxygen: 1 ppm, and, T. in the molten alloy Actual content of oxygen: 10 to 50 ppm.

Furthermore, the deoxidation of the molten alloy by the reaction between the Fe—Ni-based molten alloy and the slag was performed under a high degree of vacuum while strongly stirring the molten alloy. Was prevented. The deoxidation of the Fe-Ni-based molten alloy by slag was performed without applying arc heating to prevent carbon pickup.

[0059]

Next, after finishing the treatment in the VAD equipment and the VOD equipment, Fe-Ni under the following conditions was carried out by the under-pour ingot-making method using a 7t or 5t mold of the upper type.
A molten alloy was cast into an ingot. (1) Injection flow temperature: 1,490 to 1,525 ° C, (2) Pouring speed: 150 to 190 mm / min, (3) Sealing condition: Cover and surround the ladle nozzle and the injection pipe, Then, argon gas was supplied at 130 Nm ³ / Hr.
Supplied at the rate of

Since the injection flow was completely sealed from the atmosphere by argon gas, the oxygen concentration in the cover was 0.1% or less after 2 minutes from the start of casting.
As a result, re-oxidation of the molten alloy or nitrogen absorption into the molten alloy due to entrainment of air could be prevented.

The composition of the Fe—Ni-based molten alloy sampled from the injection flow was as follows.

In order to examine the cleanliness of the ingot of the alloy thus prepared, non-metallic inclusions in the solidified mass of the runner portion of the subnote ingot were subjected to SEM (scanning electron microscope).
The results of the analysis are shown in Table 2 and FIG.

[0064]

In the solidified mass of the runner portion of the underpoured ingot, Sol. The contents of Al, nitrogen and oxygen were as follows.

As is clear from Table 2 and FIG. 3, the test piece No. of the solidified block in the runner of the Fe—Ni alloy ingot of the present invention was used. Each of the compositions of the nonmetallic inclusions in the ternary phase diagram of CaO—Al ₂ O ₃ —MgO shown in FIG. 3 was identified by the liquidus temperature of 1,600 ° C. The value was in the range of the melting point of 600 ° C. or higher.

Next, the ingot thus prepared was subjected to a rolling reduction of 70% or more and from 1,150 to 1,150.
Slab rolling at a temperature in the range of 250 ° C .;
Through a series of steps consisting of slab surface care, hot rolling, descaling, cold rolling, annealing, cold rolling and strain relief heat treatment, the Fe— of the present invention having a thickness of 0.15 mm as shown in Table 3 was obtained. Specimen of a Ni-based alloy cold rolled sheet (hereinafter, referred to as
"This is referred to as a specimen of the present invention." 1 was prepared.

The test piece of the present invention No. The manganese, silicon, sulfur, nitrogen and oxygen contents of No. 1 were as follows.

Further, the test sample No. The distribution of manganese, silicon, sulfur, nitrogen and oxygen at the top end and bottom end of Sample No. 1 was determined as follows.

The test piece of the present invention No. It can be seen that manganese, silicon, sulfur, nitrogen and oxygen in 1 are extremely uniformly distributed at a practical level. Further, the specimen No. The component composition of 1 was as follows:

In the same manner as described above, Table 3
The test sample No. 2 and No. Prepare 3
Was.

Next, for comparison, deoxidation refining was carried out under reduced pressure using silicon and manganese without using slag (hereinafter referred to as “deoxidation method N for comparison”).
o. 1)), a cold rolled Fe—Ni-based alloy sheet having a thickness of 0.15 mm, which is also shown in Table 3, and is out of the range of the present invention is provided by the same steps as those of the present invention described above. Specimen (hereinafter referred to as “comparative specimen”) No. 4
And 5 were prepared.

Comparative deoxidation method No. According to No. 1, non-metallic inclusions consisting of oxides in deoxidation refining are mainly A
l ₂ O _3, and consists of MnO and SiO _2, and its composition is shown in Figure 1, is in the region of space over Sataito and lower its melting point, and, Shin property exhibition in the hot rolling Was high.

The comparative deoxidation method No. The results of deoxidation refining in No. 1 were as follows. Si content in molten alloy: 0.1 to 0.3 wt. %, The estimated value of the activity of _{SiO 2 (a SiO2): 0.1~0.2} , Sol in the molten alloy. Al content: 0.0004 to 0.0020 w t. %, Activity of _Al 2 _{O 3} estimates of _{(a Al2O3): 0.15~0.25,} estimated concentration of equilibrium oxygen: 10 to 15 ppm, and T. in the molten alloy Actual oxygen content: 25-35 ppm.

Further, for comparison, deoxidizing and refining was performed under reduced pressure using aluminum without using slag (hereinafter referred to as “comparative deoxidizing method No. 2”). By the same process as in the above-described present invention, a specimen of a Fe—Ni-based alloy cold-rolled sheet having a thickness of 0.15 mm and out of the range of the present invention, which is also shown in Table 3, No.) 6 and 7 were prepared. Comparative deoxidation method No. According to No. 2, non-metallic inclusions composed of oxides in deoxidation refining are mainly made of Al
_It consisted of ₂ O ₃ and had a high melting point and low ductility in hot rolling.

The comparative deoxidation method No. The result of the deoxidation refining in No. 2 was as follows. Si content in molten alloy: 0.1 to 0.3 wt. %, The estimated value of the activity of _{SiO 2 (a SiO2): 0.1~0.2} , Sol in the molten alloy. Al content: 0.005 to 0.030 wt. %, Activity of _Al 2 _{O 3} estimates of _{(a Al2O3):} 1, estimated concentration of equilibrium oxygen: 3 ppm, and T. in the molten alloy Actual oxygen content: 15-20 ppm.

[0077]

[Table 3]

As is evident from Table 3, T.D. 0 content was determined according to the test sample No. of the present invention. 1, 2 and 3
, And then the comparative sample No. Nos. 6 and 7 are followed by this, and the comparative specimen Nos. In 4 and 5 , there were many. That is, as is clear from FIG. 6, in the deoxidation method of the present invention, the comparative deoxidation method No. 1 was used.
1 and 2, the concentration of equilibrium oxygen was reduced, and the effect of adsorptive removal of suspended inclusions by slag resulted in T. Oxygen content is low.

Next, the thus-prepared specimen No. 1 of the present invention was prepared. Nos. 1 to 3 and the comparative sample Nos. In each of 4 to 7 , the area of 60 mm ² in the thickness section in the longitudinal direction was observed with a microscope of 800 times, and the width and length of the nonmetallic inclusions present in the area were measured. At that time, the nonmetallic inclusions were classified as follows according to the shape and size, and the number of nonmetallic inclusions existing per 1 mm ² was measured. (A) Nonmetallic inclusions having a length / width ratio of 3 or less (hereinafter, referred to as
(B) Non-metallic inclusions having a length / width ratio of more than 3 (hereinafter referred to as "linear non-metallic inclusions"). Table 4 shows the results.

[0080]

[Table 4]

As shown in Table 4, the test sample No. 1
The number of nonmetallic inclusions in was as follows. Number of spherical nonmetallic inclusions: less than 3 μm in width: 8; 3 μm to less than 6 μm in width: 1; Number of linear nonmetallic inclusions: less than 3 μm in width: 1; 3 μm or more in width: None.

That is, the specimen No. In 1,
It was found that most of the nonmetallic inclusions consisted of spherical nonmetallic inclusions of 3 μm or less, and thus the particle size of the nonmetallic inclusions was extremely small. The above description is based on the test piece No. 1 of the present invention. The same was true for 2 and 3 .

On the other hand, the comparative sample No. The number of nonmetallic inclusions in No. 4 was as follows. Number of spherical nonmetallic inclusions: less than 3 μm in width: 8; width of 3 μm to less than 6 μm: 1; number of linear nonmetallic inclusions: less than 3 μm in width: 20;

That is, the comparative sample No. In 4 ,
It was found that a large number of linear nonmetallic inclusions were present, and thus the particle diameter of the nonmetallic inclusions was large. The above-mentioned results are shown in Comparative Sample No. The same was true for No. 5 .

Further, the comparative specimen No. The number of nonmetallic inclusions in 7 was as follows. Number of spherical nonmetallic inclusions: width less than 3 μm: 11, width 3 μm to less than 6 μm: 6, width 6 μm to less than 14 μm: 1 piece, number of linear nonmetallic inclusions: less than 3 μm width 1, more than 3 μm width None.

That is, the comparative specimen No. In 7 ,
The specimen No. of the present invention. Compared to 1-3, spherical nonmetal inclusions the number was often. The above-mentioned results are shown in Comparative Sample No.
The same was true for No. 6 .

As described above, the comparative sample No. 4 to
In all 7, the number of nonmetallic inclusions was large and / or the particle size of the nonmetallic inclusions was large. As a result, Fe
-Impaired the etching piercing property of the Ni-based alloy cold-rolled sheet. On the other hand, the specimen No. In Nos . 1 to 3 , the number of nonmetallic inclusions was small, and the particle size was small. As a result, the Fe—Ni-based alloy cold rolled sheet was excellent in etching piercing property.

Next, the specimen No. 1 of the present invention described above was used. 1 to
3 and the comparative specimen No. For 4 to 7 , etching perforations having a pitch of 135 to 280 μm in diameter were actually performed, and the results were examined. When each specimen subjected to the etching perforation was observed with a microscope, the etching perforation defect was as shown in FIG.
It could be classified into four types (B), (C) and (D). The results are shown in Table 4.

The test piece of the present invention No. In No. 1, there was no occurrence rate of defective etching perforation. As mentioned above,
Due to the small number of non-metallic inclusions and their small particle size, the specimen No. 1
Was found to be excellent in etching piercing property. The specimen No. of the present invention. Also in 2 and 3 , (C)
Type and (D) type defects occurred.
It was evident that the amount was extremely small, and the etching piercing property was excellent.

On the other hand, the comparative sample No. In 4 ,
The state of occurrence of defective etching perforation was as follows. (A) mold failure rate: 0.04%, (B) mold failure rate: 0.03%, (C) mold failure rate: 2.35%, and (D) mold failure rate Rate: 2.54%,

As is clear from the above, the comparison
Specimen No.4, Defective etching perforation
The rate was high. That is, as described above, the linear non-metallic
Due to the large number of specimens, the comparative specimen No.4
Is clearly inferior in etching piercing property.
Was. The above-mentioned results are shown in Comparative Sample No.5About
And so on.

Further, the comparative sample No. In 7 ,
The state of occurrence of defective etching perforation was as follows. (A) mold failure rate: 0.15%, (B) mold failure rate: 0.05%, (C) mold failure rate: 0.82%, and (D) mold failure rate Rate: 0.01%.

As is clear from the above description, the comparative sample No. 7 , the test piece of the present invention No. 7 1 to
In comparison with No. 3 , the rate of occurrence of defective etching perforation was higher. That is, as described above, due to the large number of spherical nonmetallic inclusions, the comparative sample No. 7 was inferior to the etching piercing property. The above-mentioned results are shown in Comparative Sample No. The same was true for No. 6 .

[0094]

As described above in detail, according to the present invention, it can be used as a shadow mask of a high definition TV, does not generate defects at the time of etching perforation, and has a low coefficient of thermal expansion, cleanliness and F with excellent etching piercing property
An e-Ni-based alloy cold-rolled sheet and a method for producing the same can be provided, and an industrially useful effect can be obtained.

[Brief description of the drawings]

FIG. 1 shows the composition range of nonmetallic inclusions present in a conventional Fe—Ni alloy cold-rolled sheet, showing Al ₂ O ₃ —MnO—S.
FIG. 3 is a diagram of an iO ₂ ternary system.

FIG. 2 shows CaO—Al ₂ O ₃ showing the composition range of nonmetallic inclusions present in the Fe—Ni alloy cold rolled sheet of the present invention.
-It is a MgO ternary phase diagram.

FIG. 3 is a graph showing the composition of non-metallic inclusions present in a cold rolled Fe—Ni alloy sheet according to an embodiment of the present invention.
FIG. 3 is a ternary phase diagram of —Al ₂ O ₃ —MgO.

FIG. 4 shows a MgO—CaO refractory composed of a ladle;
It is a graph which shows the relationship between CaO content, the degree of erosion of the refractory, and the infiltration depth of the slag in the refractory.

FIG. 5 Al in CaO—Al ₂ O ₃ —MgO based slag
The activity of each of ₂ O ₃ and CaO, and CaO / (CaO
+ Al ₂ O ₃ ).

6: 36 wt. At a temperature of 1,550 ° C. FIG. % Of an Fe—Ni-based molten alloy containing
Dissolved silicon level in "deoxidation equilibrium" state, or
3 is a graph showing the relationship between dissolved aluminum levels in an “Al-deoxidation equilibrium” state and equilibrium dissolved oxygen levels.

FIG. 7 is a process flow diagram showing an example of a process for refining an Fe—Ni-based molten alloy according to the present invention in a ladle.

FIG. 8A is a schematic explanatory view showing a state of a defect generated at the time of etching perforation of an Fe—Ni-based alloy plate.

FIG. 8B is a schematic explanatory view showing a state of a defect generated at the time of etching perforation of the Fe—Ni-based alloy plate.

FIG. 8C is a schematic explanatory view showing a state of a defect generated at the time of etching perforation of the Fe—Ni-based alloy plate.

FIG. 8D is a schematic explanatory view showing a state of a defect generated at the time of etching perforation of the Fe—Ni-based alloy plate.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tomoyoshi Ohkita 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Inside Nippon Kokan Co., Ltd. (72) Yoshiki Kikuchi 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Japan Inside Kokan Co., Ltd. (72) Inventor Hidetoshi Matsuno 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Japan Kokan Co., Ltd. (56) References JP-A-58-130215 (JP, A) JP-A-61-143558 ( JP, A)

Claims (8)

(57) [Claims] (1) Nickel: 30 to 45 wt. %, Aluminum: 0.003 to 0.030 wt. %, Manganese: 1.0 wt. % Or less , silicon : 0.4 wt. % Or less, chromium : 0.1 wt. % Or less, carbon : 0.005 wt. % Or less, nitrogen : 0.005 wt. % Or less, sulfur : 0.005 wt. % Or less, phosphorus : 0.010 wt. %, Oxygen : 0.002 wt. % Or less, and non-metallic inclusions : 0.002 wt. % Or less, containing the non-metallic inclusions is formed of a composition having the following particle size 6 [mu] m, and, the composition, CaO, Al
Characterized in that it contains at least one of ₂ O ₃ and MgO, detergency and etching perforation excellent in Fe-Ni-based alloy cold-rolled sheet. 2. Nickel: 30 to 45 wt. %, Aluminum: 0.003 to 0.030 wt. %, Manganese: 1.0 wt. % Or less , silicon : 0.4 wt. % Or less, chromium : 0.1 wt. % Or less, carbon : 0.005 wt. % Or less, nitrogen : 0.005 wt. % Or less, sulfur : 0.005 wt. % Or less, phosphorus : 0.010 wt. %, Oxygen : 0.002 wt. % Or less, and non-metallic inclusions : 0.002 wt. % Or less, and the non-metallic inclusions have a melting point of 1600 ° C. or more specified by a liquidus line of 1600 ° C. in a ternary phase diagram of CaO—Al ₂ O ₃ —MgO. 6 μm in the area of
Cleanliness and etching perforations, comprising a composition having the following particle size, wherein said composition contains at least one of CaO, Al ₂ O ₃ and MgO Fe-Ni-based alloy cold rolled sheet with excellent heat resistance. 3. The method according to claim 1, wherein the weight is 30 to 45 wt. % Of a Fe-Ni-based molten alloy containing nickel in the range of 20 to 40 wt. % In a ladle made of a MgO-CaO-based refractory containing CaO in the range of 0.1% by weight, and adding the aluminum to the Fe-Ni-based molten alloy thus prepared; System molten alloy,
Wherein in the ladle, _CaO-Al 2 O 3 -MgO slag consisting of the following: CaO and _Al 2 _O 3: _57wt. % Or more, provided that the ratio of CaO / (CaO + Al ₂ O ₃ ) is 0.45
As described above, MgO: 25 wt. % Or less, SiO2: 15 wt. % Or less, and the total amount of oxides of metals having a lower oxygen affinity than silicon: 3 wt. % Or less, thereby deoxidizing the Fe-Ni-based molten alloy, solidifying the deoxidized Fe-Ni-based molten alloy, and then cooling.
Cold rolling has a particle size of 6 μm or less and 0.002 wt. % Fe-Ni-based alloy cold rolled sheet containing non-metallic inclusions in a total amount of not more than 0.3%, which is excellent in cleanability and etching piercing property.
-A method for producing a cold rolled Ni-based alloy sheet. 4. 30 to 45 wt. % Of dephosphorized and decarburized Fe-Ni-based molten alloy containing nickel in the range of 20 to 40 wt. % In a ladle made of a MgO-CaO-based refractory containing CaO in the range of 0.1% by weight, and adding the aluminum to the Fe-Ni-based molten alloy thus prepared; System molten alloy,
In the ladle, _CaO-Al 2 _{O 3} consisting of the following
-MgO slag: CaO and _Al 2 _O 3: _57wt. % Or more, provided that the ratio of CaO / (CaO + Al ₂ O ₃ ) is 0.45
As described above, MgO: 25 wt. % Or less, SiO ₂ : 15 wt. % Or less, and the total amount of oxides of metals having a lower oxygen affinity than silicon: 3 wt. % Or less, thereby deoxidizing the Fe-Ni-based molten alloy, casting the deoxidized Fe-Ni-based molten alloy into an ingot, and subjecting the ingot to slab rolling and hot rolling. And cold-rolled to a particle size of 6 μm or less and 0.002 wt. % Fe-Ni-based alloy cold rolled sheet containing non-metallic inclusions in a total amount of not more than 0.3%, which is excellent in cleanability and etching piercing property.
-A method for producing a cold rolled Ni-based alloy sheet. The total amount of 5. The oxide of the metal in the slag is 1.5 wt. % Or less.
The method described in. The preparation according to claim 6, wherein the Fe-Ni-based molten alloy is to refine the molten steel in the converter furnace and the molten steel, within the ladle of a reduced pressure of 600 Torr or less, and dephosphorization, melted 5. A method according to claim 3 or claim 4 comprising adding nickel and decarburizing. The deoxidation wherein said Fe-Ni-based molten alloy is carried out in said ladle under reduced pressure below 1 Torr, the method according to claim 3 or 4. The blooming rolling wherein said ingot 70
The method according to any one of claims 4 to 7 , wherein the method is carried out at a reduction ratio of at least% and a temperature in the range of 1,150 to 1,250 ° C.