JP3362399B2 - 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 TVs, has no defects during etching perforation, and has a low coefficient of thermal expansion, cleanliness and etching perforability. The present invention relates to an excellent cold-rolled Fe-Ni alloy sheet and a method for manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, Fe-Ni alloy sheets have been mainly used as materials for electronic parts. For example, a Fe-Ni alloy plate containing 42 wt.% Nickel is excellent in electrical conductivity, heat resistance, bending workability, plating adhesion and solderability, so it is used as an IC lead frame material. It is used. Furthermore, Fe-Ni alloy plate containing 36 wt.% Nickel, which has a very low coefficient of thermal expansion, is used as a shadow mask material for color televisions or as a material for containers for storing low temperature liquids. .

Fe-N as a shadow mask material for high definition TV
The i-based alloy cold-rolled sheet is required to have no defects during etching perforation and have a low coefficient of thermal expansion. The following Fe-Ni alloy cold-rolled sheet has been proposed as a Fe-Ni alloy cold-rolled sheet as a shadow mask material for TVs.

As disclosed in JP-A-62-161936,
Excellent surface quality during cold rolling, consisting essentially of
Fe-Ni alloy cold rolled sheet: 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 rest,
In the Al ₂ O ₃ -Mn0-SiO ₂ ternary phase diagram shown in FIG. 6, iron and unavoidable impurities, but the non-metallic inclusions as the unavoidable impurities are 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 the region surrounded by the line connecting them in sequence. (Hereinafter referred to as "prior art").

[0005]

SUMMARY OF THE INVENTION The above-mentioned prior art is
It includes the following problems. That is, the non-metallic inclusions are
In the Al ₂ O ₃ -MnO-SiO ₂ system ternary phase diagram shown in FIG. 6, the composition is in a region surrounded by a line connecting points 1, 2, 3, 4 and 5 sequentially. Due to
The non-metallic inclusions consist of the composition in the region near the spessatite surrounded by the coldest liquidus temperature line of 1200 ° C. As a result, the nonmetallic inclusions have a low melting point, a large deformability, and a large total amount. If the grain size of non-metallic inclusions is large, or if the content of compounds with a low melting point is large, the alloy ingot is hot-rolled,
When cold-rolled sheet is prepared by cold rolling, non-metallic inclusions in the cold-rolled sheet are linearly deformed, and as a result, defects are generated during etching perforation.

As a result, Fe, which can be used as a shadow mask material for high-definition TV, has no defects during etching perforation, has a low coefficient of thermal expansion, and is excellent in cleanability and etching perforation. -Ni-based alloy cold-rolled sheet is required, but such alloy cold-rolled sheet and its manufacturing method have not been proposed yet.

Therefore, an object of the present invention is that it can be used as a shadow mask material for high-definition TV, has no defects during etching perforation, and has a low coefficient of thermal expansion.
An object of the present invention is to provide an Fe—Ni based alloy cold rolled sheet excellent in cleanliness and etching perforation and a method for producing the same.

[0008]

From the above-mentioned viewpoints, the present inventors can use it as a shadow mask material for high-definition TVs, have no defects during etching perforation, and have a low coefficient of thermal expansion. In order to develop a Fe-Ni alloy cold-rolled sheet excellent in cleanliness and etching piercing property and a manufacturing method thereof, intensive studies were conducted. As a result, the following findings were obtained.

A dephosphorized and decarburized Fe-Ni based molten alloy containing nickel in the range of 30 to 45 wt.
To 40 wt.% CaO in the MgO-CaO refractory ladle, aluminum and titanium were added to the Fe-Ni molten alloy thus prepared, and aluminum and titanium were added. In the ladle, the Fe-Ni-based molten alloy prepared as described above was formed into CaO-Al ₂ O ₃ -Ti
0 ₂ -MgO slag: CaO and Al ₂ O ₃ : 57 wt.% Or more, Ti0 ₂ : 30 wt.% Or less, but the ratio of CaO / (CaO + Al ₂ O ₃ + Ti0 ₂ ) is 0.7 or more, MgO: 25 wt.% Or less, SiO ₂ : 15 wt.% Or less, and an oxide of a metal having a weaker oxygen affinity than silicon: 3 wt.% Or less to deoxidize the Fe-Ni molten alloy. By doing so, the amount of dissolved oxygen in the molten alloy is reduced, and the oxide generated in the molten alloy is absorbed by the slag.

As a result, the total amount of nonmetallic inclusions present in the Fe-Ni alloy cold-rolled sheet was 0.002 wt.% In terms of oxygen.
It becomes the following. In other words, as the amount of dissolved oxygen in the molten alloy decreases, not only the total amount of non-metallic inclusions that precipitate during solidification of the molten alloy decreases, but also a low melting point suspension that becomes precipitation nuclei. Is not present, the growth of the particle size of non-metallic inclusions is suppressed. The non-metallic inclusions present in the Fe-Ni alloy cold-rolled sheet are mainly composed of titanium oxide and have a particle size of 6 μm or less.

The present invention was made on the basis of the above-mentioned findings, and the Fe-Ni alloy cold-rolled sheet excellent in cleanliness and etching perforation of the present invention essentially consists of the following. There is. Nickel: 30 to 45 wt.%, Manganese: 0.1 to 1.0 wt.%, And the balance of iron and impurities, but including titanium as impurities.
The content is 0.6 wt.% Or less, and the content of each of the inevitable impurities of silicon, chromium, carbon, nitrogen, sulfur, phosphorus, oxygen, aluminum and non-metal inclusions is 0.4 wt.% For silicon. Below, 0.1 wt.% Or less for chromium, 0.005 wt.% Or less for carbon, 0.005 wt.% Or less for nitrogen, 0.005 wt.% Or less for sulfur, 0.010 wt.% For phosphorus. Below, 0.002 wt.% Or less for oxygen, 0.030 wt.% Or less for aluminum, and 0.002 wt.% For non-metallic inclusions converted to oxygen.
The non-metallic inclusions consist of the following, and are characterized in that they mainly consist of titanium oxide.

The method of manufacturing a cold-rolled Fe-Ni alloy sheet excellent in cleanliness and etching perforation according to the present invention comprises the following steps. A dephosphorized and decarburized Fe-Ni based molten alloy containing nickel in an amount in the range of 30 to 45 wt.% Was prepared, containing MgO in an amount in the range of 20 to 40 wt.%, MgO- In a ladle made of CaO-based refractory, aluminum and titanium were added to the Fe-Ni molten alloy thus prepared, and the Fe-Ni-based molten alloy added with aluminum and titanium was placed in the ladle. In, the CaO-Al ₂ O ₃ -Ti0 ₂ -MgO slag consisting of: CaO and Al ₂ O ₃ : 57 wt.% Or more, Ti0 ₂ : 30 wt.% Or less, but CaO / (CaO + Al ₂ O The ratio of ₃ + Ti0 ₂ ) reacts with 0.7 or more, MgO: 25 wt.% Or less, SiO ₂ : 15 wt.% Or less, and an oxide of a metal having a weaker oxygen affinity than silicon: 3 wt.% Or less. Then, the Fe-Ni based molten alloy is deoxidized, the deoxidized Fe-Ni based molten alloy is cast into an ingot, and the ingot is slab-rolled, hot-rolled, Te, and cold rolling, with a particle size of 6μm or less, and, Fe-N containing in terms of oxygen 0.002 wt.% Or less of the amount of nonmetallic inclusions
Manufacture cold rolled i-based alloy.

The reason why the chemical composition of the Fe-Ni alloy cold-rolled sheet excellent in cleanliness and etching perforation of the present invention is limited to the above-mentioned range will be described below. (1) Nickel: Nickel is a component that greatly affects the coefficient of thermal expansion of the Fe—Ni alloy plate. When the nickel content is in the range of 30 to 45 wt.%, The coefficient of thermal expansion of the alloy plate is small. However, if the nickel content is less than 30 wt.%, The coefficient of thermal expansion of the alloy plate will be high. On the other hand, even if the nickel content exceeds 45 wt.%, The coefficient of thermal expansion of the alloy increases. When a cold rolled Fe-Ni alloy plate having a high coefficient of thermal expansion is used as a shadow mask material, it causes color misregistration. Therefore, the nickel content should be limited to the range of 30 to 45 wt.%. As a raw material of nickel, incone nickel (trade name of nickel manufactured by International Co., Ltd.) and electrolytic nickel are usually used. In order to reduce the cost, Tonimet containing cobalt (trade name of nickel manufactured by Tokyo Nickel Co.) may be used. At this time, although the amount of cobalt is less than 1 wt.%,
There is no problem if the nickel content is within the above range.

(2) Manganese: Manganese has the function of improving the hot workability of the Fe-Ni alloy plate. However, if the manganese content is less than 0.1 wt.%, The desired effects cannot be obtained in the above-mentioned actions. On the other hand, when the manganese content exceeds 1.0 wt.%, The hardness of the alloy plate becomes excessively high, which makes it unsuitable as a shadow mask material. Therefore, the manganese content should be limited to the range of 0.1 to 1.0 wt.%.

(3) Silicon: Silicon is one of the impurities that are inevitably mixed in the Fe-Ni alloy. The smaller the silicon content, the more preferable, but it is difficult to reduce the silicon content significantly on an industrial scale from the economical point of view. However, if the silicon content is
If it exceeds 0.4 wt.%, The etching solution becomes dirty during the perforation of the Fe-Ni alloy plate for etching, which lowers the productivity. Therefore, the content of silicon should be limited to 0.4 wt.% Or less.

(4) Chromium: Chromium is one of the impurities inevitably mixed in the Fe-Ni alloy. The lower the chromium content, the more preferable, but it is difficult to reduce the chromium content significantly on an industrial scale from the economical point of view. However, when the content of chromium exceeds 0.1 wt.%, The etching perforation rate of the Fe-Ni alloy plate becomes slow, the productivity is lowered, and the thermal expansion coefficient of the alloy plate becomes high, which causes Misalignment occurs. Therefore, the chromium content should be limited to 0.1 wt.% Or less.

(5) Titanium Titanium is positively added as a deoxidizer in the Fe-Ni alloy.
Suppresses non-metallic inclusions from linear deformation during rolling
After deoxidation, the smaller the amount, the better the impurities.
However, it is difficult to significantly reduce the titanium content on an industrial scale from the economical point of view. However, when the content of titanium exceeds 0.6 wt.%, The blackening property of the alloy plate is deteriorated, and the titanium oxide film is formed, so that the etching performance is deteriorated. Therefore, the titanium content should be limited to 0.6 wt.% Or less, more preferably 0.1 wt.% Or less.

(6) Carbon: Carbon is one of the impurities inevitably mixed in the Fe-Ni alloy. The carbon content is
The smaller the amount, the more preferable, but it is difficult to significantly reduce the carbon content on an industrial scale from the economical point of view.
However, if the carbon content exceeds 0.005 wt.%, Fe
-A large amount of iron carbide is generated in the Ni-based alloy plate, which hinders the etching piercing of the alloy plate and causes piercing defects. Further, if the carbon content exceeds 0.005 wt.%, The press formability of the alloy sheet will deteriorate. Therefore, the carbon content is 0.
It should be limited to 005 wt.% Or less.

(7) Nitrogen: Nitrogen is one of the impurities inevitably mixed in the Fe-Ni alloy. The nitrogen content is
The smaller the amount, the more preferable, but it is difficult to significantly reduce the nitrogen content on an industrial scale from the economical point of view.
However, when the nitrogen content exceeds 0.005 wt.%, A large amount of metal nitride is generated in the alloy plate, which hinders the etching perforation property of the alloy plate and causes perforation defects. Therefore, the nitrogen content should be limited to 0.005 wt.% Or less.

(8) Sulfur: Sulfur is one of the impurities unavoidably mixed in the Fe-Ni alloy. The sulfur content is
The smaller the amount, the more preferable, but it is difficult from the economical point of view to significantly reduce the sulfur content on an industrial scale.
However, when the sulfur content exceeds 0.005 wt.%, Fe
-A large amount of sulfide-based non-metallic inclusions are generated in the Ni-based alloy sheet, which hinders the etching and piercing properties of the alloy sheet and causes piercing defects. Therefore, the sulfur content should be limited to 0.005 wt.% Or less.

(9) Phosphorus: Phosphorus is one of the impurities inevitably mixed in the Fe-Ni alloy. The smaller the phosphorus content, the more preferable, but it is difficult to reduce the phosphorus content significantly on an industrial scale from the economical point of view. However, when the phosphorus content exceeds 0.010 wt.%, The hot workability of the Fe-Ni alloy plate deteriorates significantly. Therefore, the phosphorus content should be limited to 0.010 wt.% Or less.

(10) Oxygen: Oxygen is one of the impurities unavoidably mixed in the Fe-Ni alloy. The oxygen content is
The smaller the amount, the more preferable, but it is difficult from the economical point of view to greatly reduce the oxygen content on an industrial scale.
However, if the oxygen content exceeds 0.002 wt.%, A large amount of oxide-based non-metallic inclusions are generated in the alloy, which hinders the etching perforation property of the alloy sheet and causes perforation defects. Therefore, the oxygen content should be limited to 0.002 wt.% Or less.

(11) Aluminum: Aluminum is Fe
-It is one of the impurities that are inevitably mixed in the Ni-based alloy. The smaller the aluminum content, the more preferable, but it is difficult to reduce the aluminum content significantly on an industrial scale from the economical point of view. However, if the amount of aluminum exceeds 0.030 wt.%, The blackening processability of the alloy sheet will deteriorate. Therefore, the content of aluminum is 0.03
It should be limited to 0 wt.% Or less.

(12) Non-metallic inclusions: Non-metallic inclusions positively add titanium to the Fe-Ni alloy plate.
It is one of the impurities that are inevitably generated when added . The non-metallic inclusions are mainly composed of titanium oxide and are components that have a great influence on the etching perforability of the Fe-Ni alloy plate. When the content of the non-metallic inclusions in the alloy plate in terms of oxygen exceeds 0.002 wt.%, The etching perforation property of the alloy plate is obstructed, which causes a perforation defect. Therefore, the content of non-metallic inclusions should be limited to 0.002 wt.% Or less in terms of oxygen.

Next, according to the present invention, when refining a molten Fe-Ni alloy in a ladle, a ladle made of MgO-CaO refractory containing CaO in an amount in the range of 20 to 40 wt.%. The reason for using is described below. (1) If the content of CaO in the refractory is less than 20 wt.%, The penetration depth of the slag into the refractory becomes large and the refractory deteriorates. On the other hand, when the content of CaO exceeds 40 wt.%, The melting point of the refractory material becomes low, the degree of melting loss (worn ratio) becomes large, and it becomes impossible to slag the molten alloy at a high temperature for a long time. Therefore, the content of CaO in the refractory is 20 to 40 wt.%.
Should be limited to within the range.

The above will be described in detail with reference to FIG. In FIG. 2, “●” 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 broken line indicates the degree of erosion. A curve is shown. In FIG. 2, the vertical axis represents the infiltration depth, and
Indicates the degree of erosion. The horizontal axis shows the contents of MgO and CaO. That is, the upper scale on the horizontal axis is Mg from 0 to 100 wt.%.
O content, and its lower scale is from 100
The CaO content of 0 wt.% Is shown. Therefore, the horizontal axis shows that the total amount of MgO and CaO is always 100 wt.%. For example, when the MgO content is 100 wt.%, C
The content of aO is 0 wt.%, and the content of MgO is
At 20 wt.%, The CaO content is 80 wt.%. As is clear from Fig. 2, the content of CaO is 20 to 40 wt.%.
Within the range, both the infiltration depth of the slag and the melting degree of the refractory material are small.

(2) Since the ladle made of 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, ladle made of MgO-CaO refractory should be used.

Next, according to the present invention, when refining the Fe-Ni system molten alloy in the ladle, the following Ca is used.
O-Al ₂ O ₃ -Ti0 ₂ -MgO slag: CaO and Al ₂ O ₃ : 57 wt.% Or more, Ti0 ₂ : 30 wt.% Or less, but CaO / (CaO + Al ₂ O ₃ + Ti0 ₂ ) The reason for using a ratio of 0.7 or more, MgO: 25 wt.% Or less, SiO ₂ : 15 wt.% Or less, and a metal oxide having a weaker oxygen affinity than silicon: 3 wt or less will be described below.

(1) The ratio of CaO / (CaO + Al ₂ O ₃ + Ti0 ₂ ) is 0.7.
If it is less than 0.5, the activity of Al ₂ O ₃ and Ti0 _{2 in} the slag exceeds 0.5. When the activities of Al ₂ O ₃ and Ti0 _{2 in} the slag exceed 0.5, the deoxidizing power of Al and Ti decreases when the amounts of Al and Ti are constant. Therefore, the ratio of CaO / (CaO + Al ₂ O ₃ + Ti 0 ₂ ) should be limited to 0.7 or more.

The above description will be described in detail with reference to FIG. _{3, CaO-Al 2 O 3 -Ti0} 2 -MgO system Al ₂ O ₃ in the slag,
Each activity of Ti0 ₂ and CaO and CaO / (CaO + Al ₂ O ₃ + Ti
3 is a graph showing the relationship between the ratio of 0 ₂ ). The vertical axis is Al
Each activity of ₂ O ₃ , Ti0 ₂ and CaO (a _Al2O3 , a _Tio2 a
nd a _CaO ), and the horizontal axis is CaO / (CaO + Al ₂
The ratio of O ₃ + Ti 0 ₂ ) is shown. Furthermore, FIG. 3 shows three commonly known isosteres of Al ₂ O ₃ , TiO ₂ and CaO. As is clear from Fig. 3, CaO / (CaO + Al ₂ O ₃ + Ti0
The ratio of _2), with 0.7 or more, in any of the Al ₂ O _3, Ti0 ₂ of Tokatsu amount line, activity of Al ₂ O ₃ and Ti0 ₂ is suppressed below 0.5. As a result, the ratio of _{CaO / (CaO + Al 2 O} 3 + Ti0 2) is, at least 0.7 can be deoxidizing strength aluminum and titanium obtain strong slag.

(2) The content of MgO in the slag is 25 wt.
When it exceeds%, the melting point of the slag rises and the Fe-N of the slag increases.
The reaction with the i-type molten alloy is reduced. Therefore, the MgO content should be limited to 25 wt.% Or less.

(3) The content of SiO _{2 in} the slag is 15 wt.%
When it exceeds, the activity of SiO _{2 in} the slag (a _{SiO 2} ) increases,
Then, the amount of oxygen in the Fe-Ni-based molten alloy increases due to SiO ₂ . As a result, the oxygen content present in the Fe-Ni alloy cold-rolled sheet exceeds 0.0020 wt.%. Therefore, the content of SiO ₂ should be limited to 15 wt.% Or less.

(4) When the total amount of metal oxides having a weaker oxygen affinity than Si in the slag exceeds 3 wt.%, The oxygen content present in the Fe-Ni alloy cold-rolled sheet becomes 0.
0020wt.% Over. Therefore, the total amount of oxides of metals having a weaker oxygen affinity than silicon should be limited to 3 wt.% Or less, and more desirably 1.5 wt.% Or less.

Further, by deoxidizing the Fe-Ni molten alloy using the above-mentioned slag, Fe-N excellent in cleanability is obtained.
The reason why the i-based alloy cold rolled sheet can be obtained will be described in detail with reference to FIG. Fig. 4 shows the aluminum used for deoxidation when the deoxidation reached equilibrium with aluminum, silicon or titanium in a Fe-Ni based molten alloy containing 36 wt.% Nickel at a temperature of 1,550 ° C. It is a graph which shows the relationship between the dissolved amount of silicon or titanium in a molten alloy, and the dissolved amount of oxygen in a molten alloy.

In FIG. 4, the vertical axis represents the dissolved amount of oxygen in the molten alloy, and the horizontal axis represents the dissolved amount of aluminum, silicon or titanium in the molten alloy. Further, in FIG. 4, the diagonal solid line indicates the Al ₂ O ₃ isoactivity line, and the diagonal dashed line indicates the SiO ₂ isoactivity line. Further, in FIG. 4, “C” indicates the dissolved amount of silicon, aluminum or titanium and the dissolved amount of oxygen in the molten alloy of the present invention obtained by deoxidizing the molten alloy using the above-mentioned slag of the present invention, And "A (A ₁ , A ₂ )"
And each of "B" do not use the slag of the present invention,
The amounts of dissolved silicon, aluminum or titanium and the amount of dissolved oxygen in the molten alloy deoxidized by the method (hereinafter referred to as "comparison deoxidizing method") No. 1 or 2 outside the scope of the present invention are shown.

As is clear from FIG. 4, 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, titanium and the above-mentioned slag, the respective activities in equilibrium a _Al2O3 , a _Tio2 and a _SiO2 are reduced, and The oxygen concentration in the state is lower and stable. Thus, non-metallic inclusions consisting of oxides in the molten alloy are adsorbed by the slag and removed. As a result, the molten alloy can be cleaned and a very small amount of non-metallic inclusions having an extremely fine grain size can be distributed in the molten alloy.

In the slabbing of the Fe-Ni alloy ingot, the rolling ratio is 70% or more, and the rolling temperature is 1,
It is desirable that the temperature is within the range of 150 to 1,250 ℃. The reason is as follows. (1) When the rolling ratio is 70% or more, the structure of the alloy and the non-metallic inclusions in the alloy during slabbing are crushed, and the grain size of the non-metallic inclusions in the cold-rolled sheet is made extremely fine. effective. Therefore, the rolling rate should be limited to 70% or more. (2) If the rolling temperature is less than 1,150 ° C, slabbing is difficult, while if the rolling temperature is more than 1,250 ° C, the deformation resistance of the matrix metal becomes small, making it difficult to crush nonmetallic inclusions. Become. Therefore, the rolling temperature is 1,
It should be limited to the range of 150 to 1,250 ° C.

[0038]

EXAMPLES Next, the Fe-Ni alloy cold-rolled sheet excellent in cleanliness and etching piercing property of the present invention and the method for producing the same will be compared with Comparative Examples outside the scope of the present invention by the Examples. Further details will be described. Fe-Ni alloy cold-rolled sheets were prepared by the following manufacturing process using the raw materials shown in Table 1.

[0039]

[Table 1]

1. Refining using a converter 2. 2. Refining dephosphorization refining nickel melting using VAD (vacuum-electric arc-degassing omitted) equipment including: Refining and sending acid decarburization vacuum decarburization slag deoxidation using VOD (vacuum-oxygen-decarburization omitted) equipment 4. Ingot 5. Slab rolling 6. Hot rolling 7. Cold rolling

The process of refining using the VAD and VOD equipment described above is shown in FIG. That is, in a 250t upper blowing converter equipped with a bottom plug for blowing a stirring gas, dephosphorized hot metal is refined to obtain undeoxidized molten steel, which is then transferred to a 250t ladle. did. Then, of the 250 tons of molten steel thus obtained, 20 tons were put into a 250 tons to 50 tons ladle. The composition of the molten steel was as follows.

[0042]

The above-mentioned 20 ton of molten steel was mixed with 57.2 wt.% Of MgO.
, 38.4 wt.% CaO, 1.6 wt.% SiO ₂ and 0.2 wt.%
It was poured by a rotary nozzle into another 20-ton ladle using a magnesia-dolomite brick made of Al ₂ O _{3 of} . The ladle was then placed in a VAD (vacuum-arc-degas) facility, where the molten steel was dephosphorized. Thus, the use of undeoxidized molten steel prevented absorption of nitrogen into the molten steel. Then, after removing the slag, while heating the molten steel in the ladle to a temperature of 1,600 ° C or higher with a three-phase electrode heating device under reduced pressure, the pure nickel lump and the nickel alloy lump are ladle under the following conditions. It was charged inside and melted.

Degree of vacuum: 200-600 Torr, flow rate of bottom-blown argon gas: 0.5-1.5 Nl / min.t, timing of introducing slag agent: just before the start of VAD refining, composition of slag agent: calcined lime 15 Kg / T, fluorite
4 Kg / T.

After melting of nickel, the Fe-Ni-based molten alloy thus obtained in the ladle, which is now increased to about 30 tons, is heated to 1,700 ° C. or higher, more preferably 1,
Heated to a temperature above 750 ° C. Vacuum degree: 200 to 400 Torr, Bottom blown argon gas flow rate: 0.5 to 1.5 Nl / min.t, Slag injection agent: None.

The results of investigating the carbon and nickel contents in the Fe-Ni system molten alloy at this stage were as follows.

By the above-mentioned heating after melting of nickel,
No heating was required after the completion of refining using the following VOD (vacuum-oxygen-decarburization) equipment. Then, the ladle is VO
It moved to the D equipment and decarburized the Fe-Ni system molten alloy here. Decarburization of the molten alloy consisted of decarburization performed while blowing oxygen with an upper blowing lance (hereinafter referred to as "acid feeding decarburization with an upper blowing lance"), and vacuum decarburization under reduced pressure.

First, acid-feeding decarburization with an upper blowing lance was carried out 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: 0.8 to 1.2 Nm ³ /min.t
, Amount of acid fed: 2 to 5 Nm ³ / t, Distance between lance and molten alloy surface: 700 to 900 mm, Charge of slag agent: None.

In this way, the Fe-Ni-based molten alloy enriched with oxygen is stirred by the bottom-blown argon gas while promoting the carbon-oxygen reaction, so that the carbon content is 0.005 wt.%. The molten alloy was decarburized under reduced pressure until it decreased below. In addition, at the end of the above-mentioned acid-feeding decarburization by the upper blowing lance, the ladle is again moved to the VOD facility, and nickel is added to the molten alloy to finely adjust 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.

[0050]

Next, vacuum decarburization under reduced pressure treatment
It was carried out 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, Addition of slag agent: None, Temperature of molten alloy at the start of vacuum decarburization: 1,745 ℃ As a result, decarburize Fe-Ni molten alloy until its carbon content decreases to 0.0009 wt.% or less. We were able to.

Next, in the VOD facility,
Add deoxidizing agent and slag agent such as titanium alloy and aluminum to Fe-Ni molten alloy, and stir the molten alloy with bottom-blown argon gas under the following conditions. By the reaction between
The molten alloy was deoxidized (hereinafter referred to as "the deoxidation method of the present invention").

[0053] Degree of vacuum: 1 Torr or less, Bottom-blown argon flow rate: 0.5-2.5 Nl / min.t, Add slag and deoxidizer (twice) First time input Composition of slag agent: Roasted lime: 30 Kg / t, Fluorite: 5 Kg / t, Deoxidizer composition: Aluminum: 10 Kg / t, Ferrosilicon: 2 Kg / t, Ferrotitanium: 8 Kg / t, Input time: Just before the start of deoxidation refining, Second input Additive composition: Molten alloy component fine adjuster, Input period: Mid-term deoxidation refining.

Before deoxidizing the molten alloy with slag,
The contents of titanium, silicon and Sol.Al in the Fe-Ni based molten alloy were as follows.

CaO-Al ₂ O reacted with molten alloy as described above
₃ -Ti0 ₂ -MgO system slag, consisted of the following. (a) Component composition (b) CaO / (CaO + Al ₂ O ₃ + Ti0 ₂ ) ratio: 0.58 (c) Total content of oxides of metals having a weaker oxygen affinity than Si (that is, T.Fe + MnO + Cr ₂ O ₃ ): 0.9 wt.%

The results of the above-described deoxidation refining of the Fe-Ni system molten alloy in the VOD facility were as follows. Si content in molten alloy: 0.1-0.3 wt.
%, The estimated value of the activity of _{SiO 2 (a SiO2): 0.001} ~0.005, the content of Ti in the molten alloy: 0.1 to 0.6 w
t.%, estimated value of TiO ₂ activity (a _TiO2 ): 10 ^-2 to 10 ^-8 , estimated concentration of equilibrium oxygen: 1 to 2 ppm,
And the actual content of T. oxygen in the molten alloy: 7 to 14 ppm.

Further, the above-mentioned deoxidation of the molten alloy by the reaction between the Fe-Ni system molten alloy and the slag was carried out under a high vacuum degree while vigorously stirring the molten alloy. It was possible to prevent the absorption of nitrogen into the interior. The above-mentioned deoxidation of the Fe-Ni-based molten alloy by slag was performed without applying arc heating in order to prevent carbon pickup.

The composition of the Fe—Ni based molten alloy at this time was as follows.

Then, after finishing the treatment in the VAD facility and the VOD facility, a Fe-Ni type molten alloy was cast into an ingot by the downward pouring ingot method using an upper wide type 7t or 5t mold under the following conditions. did. (1) Injection flow temperature: 1,490 to 1,525 ℃, (2) Casting speed: 150 to 190mm / min, (3) Seal condition: Enclose the space between the ladle nozzle and the injection pipe, and Argon gas was supplied at a rate of 130 Nm ³ / Hr.

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

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

As a result of SEM (scanning electron microscope) analysis of the non-metallic inclusions in the solidified mass of the runner portion of the ingot thus prepared, the non-metallic inclusions consisted of titanium oxide. . And Sol. In the solidified mass of the runner part.
The contents of Al, nitrogen and oxygen were as follows.

Next, the thus prepared ingot was slab-rolled at a rolling reduction of 70% or more and at a temperature in the range of 1,150 to 1,250 ° C., and then slab surface care, hot rolling and de-sizing were performed. Scale, cold rolling, annealing,
The Fe of the present invention having a thickness of 0.15 mm, shown in Table 3, was obtained by a series of steps consisting of cold rolling and strain relief heat treatment.
-Ni-based alloy cold-rolled sheet specimens (hereinafter referred to as "specimens of the present invention") Nos. 1 to 3 were prepared.

[0064]

[Table 3]

The component composition of Sample No. 1 of the present invention was as follows:

Further, the results of examining the distribution states of manganese, silicon, sulfur, nitrogen and oxygen at the top end and the bottom end of the sample No. 1 of the present invention were as follows. From the above, it can be seen that manganese, silicon, sulfur, nitrogen and oxygen in Sample No. 1 of the present invention are extremely uniformly distributed at a practical level.

Next, for comparison, deoxidation refining was carried out under reduced pressure without using slag and with silicon and manganese (hereinafter referred to as “comparative deoxidation method N”).
o.1 ”), the Fe-Ni alloy cold-rolled sheet outside the scope of the present invention having a thickness of 0.15 mm shown in Table 3 by the same steps as in the present invention described above. Specimens (hereinafter referred to as "comparative specimens") Nos. 1 and 2 were prepared.

According to the comparative deoxidizing method No. 1, non-metallic inclusions composed of oxides in deoxidizing refining are mainly Al ₂ O 3.
₃ , consisting of MnO and SiO ₂ and its composition lies in the region of spesser-tight, shown in FIG.
The melting point was low and the malleability was high in hot rolling.

The results of deoxidation refining in the above-mentioned comparative deoxidation method No. 1 were as follows. Si content in the molten alloy:. 0.1 ~0.3 wt%, the estimated value of the activity of _{SiO 2 (a SiO2): 0.1} ~0.3, the content of Sol.Al in molten alloy: .0004 to .0020 w
. t%, the estimated value of the activity of _{Al 2 O 3 (a Al2O3)} : 0.10~0.20, estimated concentration of the equilibrium oxygen: 10 to 15 ppm, and actual content of T. oxygen in the molten alloy: 25-35 ppm.

Further, for comparison, except that deoxidation refining was carried out under reduced pressure using aluminum without using slag (hereinafter referred to as "comparison deoxidation method No. 2"), By the same process as in the present invention described above, a Fe-Ni alloy cold-rolled sheet specimen having a thickness of 0.15 mm shown in Table 3 and outside the scope of the present invention (hereinafter referred to as "comparative specimen"). No. 3 and 4 were prepared. According to the comparative deoxidation method No. 2, the non-metallic inclusions made of oxides in deoxidation refining consist mainly of Al ₂ O ₃ , have a high melting point, and are expanded during hot rolling. The sex was low.

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

As is clear from Table 3, the TO content in the specimens is the lowest among the specimens 1 to 3 of the present invention, followed by the comparative specimens 3 and 4, and , For comparative specimen Nos. 1 and 2,
There were many. That is, as is clear from FIG. 4, in the deoxidizing method of the present invention, the concentration of equilibrium oxygen was lower than in the comparative deoxidizing methods Nos. 1 and 2, and the suspended inclusions by the slag were The T. oxygen content is lowered by the effect of adsorption removal of T.

Next, the test specimen of the present invention thus prepared
In each of Nos. 1 to 3 and each of the comparative specimens Nos. 1 to 4, 80 mm in the area of 60 mm ² in the longitudinal thickness section.
The width and length of the non-metallic inclusions present in the area were measured under a 0x microscope. At that time, the non-metallic inclusions were classified according to the shape and size as follows, and the number of non-metallic inclusions present per 1 mm ² was measured. (a) Nonmetallic inclusions having a length / width ratio of 3 or less (hereinafter referred to as "spherical nonmetallic inclusions"), and (b) nonmetallic inclusions having a length / width ratio of more than 3 ( "Linear non-metallic inclusions"
That). The results are shown in Table 4.

[0074]

[Table 4]

As shown in Table 4, the samples of the present invention No. 1 to No. 1
The number of non-metallic inclusions in 3 was as follows. That is, in the sample No. 1 of the present invention, there are only 6 spherical non-metallic inclusions having a width of less than 3 μm, and the sample No. 2 of the present invention
, There are 8 spherical non-metallic inclusions having a width of less than 8 μm and only one spherical non-metallic inclusion having a width of 3 μm to less than 6 μm, and in the present invention sample No. 3, the width is less than 3 μm. There were only seven spherical non-metallic inclusions of. As described above, in the sample of the present invention, only a small amount of spherical non-metallic inclusions having an extremely small particle size was present.

On the other hand, the number of non-metallic inclusions in the comparative sample No. 1 was as follows. Number of spherical nonmetallic inclusions: width less than 3 μm: 8 pieces, width 3 μm to less than 6 μm: 1 piece, number of linear nonmetallic inclusions: width less than 3 μm: 20 pieces, width 3 μm or more: 8 pieces. As described above, in the comparative sample No. 1, it was found that a large number of linear nonmetallic inclusions were present, and therefore the particle size of the nonmetallic inclusions was large. The above was the same for the comparative sample No. 2.

Further, the number of non-metallic inclusions in the comparative sample No. 3 was as follows. Number of spherical non-metallic inclusions: width less than 3 μm: 10 pieces, width 3 μm to less than 6 μm: 4 pieces, width 6 μm to less than 14 μm: 1, number of linear non-metal inclusions: width less than 3 μm 1 piece, width 3 μm or more None.

That is, in the comparative sample No. 5, the number of spherical non-metallic inclusions was larger than that in the inventive samples No. 1 to 3. The same applies to the comparative sample No. 6.

As described above, the comparative specimen Nos. 1 to 4
In each case, the number of non-metallic inclusions is large, and / or
The particle size of non-metallic inclusions was large. As a result, the etching piercing property of the Fe-Ni alloy cold rolled sheet was impaired. On the other hand, in the samples Nos. 1 to 3 of the present invention, the number of non-metallic inclusions was small and the particle size was small. As a result, the Fe-Ni alloy cold-rolled sheet was excellent in etching piercing property.

Next, the above-mentioned specimens No. 1 to 3 of the present invention,
And, for the comparative sample Nos. 1 to 4, pitch etching perforation with a diameter of 135 to 280 μm was actually performed,
I examined the results. Observation of each of the test pieces subjected to the etching perforation by a microscope revealed that the etching perforation defects showed (A), (B), (C) and
It was possible to classify into four types of (D). The result is
It is also shown in Table 4.

In the test samples Nos. 1 and 3 of the present invention, there was no occurrence rate of defective etching perforations. As described above, due to the small number of non-metallic inclusions and the small particle size, the specimen No.
It was clear that 1 and 3 were excellent in etching piercing property. Also in the sample No. 2 of the present invention, defects of type (C) and type (D) were generated, but the occurrence rate was extremely small, and it was clear that etching perforation was excellent.

On the other hand, in the comparative sample No. 1, the state of occurrence of defective etching perforations 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: 2.54%,

As is clear from the above description, the comparative sample No. 1 had a high incidence rate of defective etching perforations. That is, as described above, it was clear that the comparative sample No. 1 was inferior in the etching piercing property due to the large number of linear non-metallic inclusions. The above was the same for the comparative sample No. 2.

Further, in the comparative sample No. 3, the state of defective etching perforation was as follows. (A) Type defect rate: 0.75%, (B) Type defect rate: 0.04%, (C) Type defect rate: 0.50%, and (D) Type defect rate: 0.01%.

As is clear from the above description, in the comparative sample No. 3, the etching perforation defect occurrence rate was higher than in the inventive samples No. 1 to 3. That is,
As described above, it was clear that Comparative Specimen No. 3 was inferior in etching piercing property due to the large number of spherical non-metallic inclusions. The above was the same for the comparative sample No. 4.

[0086]

As described in detail above, according to the present invention, it can be used as a shadow mask for a high definition TV, does not cause defects during etching perforation, and has a low coefficient of thermal expansion, cleanliness and cleanliness. Fe with excellent etching perforation
It is possible to provide a -Ni-based alloy cold-rolled sheet and a method for producing the same, thus providing industrially useful effects.

[Brief description of drawings]

FIG. 1 is a process flow chart showing an example of a process for refining an Fe—Ni based molten alloy according to the present invention.

FIG. 2 is a graph showing the relationship between the CaO content in MgO-CaO refractory composed of ladle, the degree of erosion of the refractory, and the depth of slag infiltration into the refractory. is there.

FIG. 3 Al ₂ O ₃ and CaO in CaO-Al ₂ O ₃ -MgO slag
₃ is a graph showing the relationship between the activity of each of the above and the ratio of CaO / (CaO + Al ₂ O ₃ ).

[Fig. 4] Dissolved silicon level in "Si-deoxidization equilibrium" state, "Al-deoxidation equilibrium" state in a Fe-Ni-based molten alloy containing 36 wt.% Nickel at a temperature of 1,550 ° C. 3 is a graph showing the relationship between dissolved aluminum level or dissolved titanium level in “Ti-deoxidation equilibrium” state and equilibrium dissolved oxygen level.

5A to 5D are schematic explanatory views showing states of defects generated at the time of punching by etching the Fe—Ni based alloy plate.

FIG. 6 is a phase diagram of an Al ₂ O ₃ —MnO—SiO ₂ ternary system showing a composition region of nonmetallic inclusions existing in a conventional Fe—Ni alloy cold-rolled sheet.

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Masayuki Kinoshita 1-2-1 Marunouchi, Chiyoda-ku, Tokyo Nippon Steel Tube Co., Ltd. (72) Atsushi Watanabe 1-2-1 Marunouchi, Chiyoda-ku, Tokyo Nippon Steel Pipe Incorporated (72) Inventor Nakaichi Nakamoto 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nippon Kokan Co., Ltd. (56) Reference JP-A-64-25944 (JP, A) (58) Fields investigated ( Int.Cl. ⁷ , DB name) C22C 38/00

Claims (5)

(57) [Claims] 1. Nickel: 30 to 45 wt.%, Manganese: 0.1 to 1.0 wt.%, And the balance, iron and impurities, but the titanium content as impurities is 0.6 wt.% Or less,
The inevitable impurities of silicon, chromium, carbon, nitrogen, sulfur, phosphorus, oxygen, aluminum and non-metallic inclusions are 0.4 wt.% Or less for silicon and 0.1 wt.% For chromium. Below, 0.005 wt.% Or less for carbon, 0.005 wt.% Or less for nitrogen, 0.005 wt.% Or less for sulfur, 0.010 wt.% Or less for phosphorus, 0.002 wt.% For oxygen. Below, 0.030 wt.% Or less for aluminum, and 0.002 wt.% In terms of oxygen for non-metallic inclusions.
The Fe-Ni alloy cold-rolled sheet excellent in cleanliness and etching piercing properties, characterized in that the non-metallic inclusions are mainly composed of titanium oxide. 2. A dephosphorized and decarburized Fe-Ni based molten alloy containing nickel in an amount in the range of 30 to 45 wt.% And CaO in an amount in the range of 20 to 40 wt.% Is prepared. Contains MgO-Ca
In a ladle made of O 2 refractory, aluminum and titanium were added to the Fe-Ni molten alloy thus prepared, and the Fe-Ni molten alloy containing aluminum and titanium was added to the ladle. In CaO-Al ₂ O ₃ -Ti0 ₂ -MgO slag: CaO and Al ₂ O ₃ : 57 wt.% Or more, Ti0 ₂ : 30 wt.% Or less, but CaO / (CaO + Al ₂ O ₃ The ratio of + Ti0 ₂ ) is 0.7 or more, MgO: 25 wt.% Or less, SiO ₂ : 15 wt.% Or less, and the total amount of metal oxides having a weaker oxygen affinity than silicon: 3 wt.% Or less. After reacting, the Fe-Ni
The molten alloy is deoxidized, the deoxidized Fe-Ni molten alloy is cast into an ingot, and the ingot is slab-rolled, hot-rolled, and cold-rolled to obtain its grain. Cleanliness and etching, characterized in that a Fe-Ni alloy cold-rolled sheet having a diameter of 6 μm or less and containing a total amount of 0.002 wt.% Or less of non-metallic inclusions in terms of oxygen is manufactured. A method for manufacturing a cold-rolled Fe-Ni alloy sheet with excellent piercing properties. 3. The preparation of the Fe—Ni based molten alloy comprises refining molten steel in a converter and converting the molten steel into 600
The method of claim 2 comprising dephosphorizing, adding molten nickel and decarburizing in the ladle depressurized to below torr. 4. The deoxidation of the Fe—Ni based molten alloy is 1
The method according to claim 2, which is performed in the ladle whose pressure is reduced to less than or equal to torr. 5. The slabbing of the ingot is 70%
The method according to any one of claims 2 to 4, which is carried out at the rolling reduction and the temperature in the range of 1,150 to 1,250 ° C.