JPH04354853A - Fe-ni alloy cold rolled sheet excellent in cleanliness and etching pierceability and its production - Google Patents

Abstract

PURPOSE:To manufacture an Fe-Ni alloy cold rolled sheet usable as a shadow mask for a high bright TV, free from defects at the time of etching piercing, low in thermal expansibility and excellent in cleanliness and etching pierceability. CONSTITUTION:This sheet is constituted of, by weight, 30 to 45% Ni, 0.1 to 1.0% Mn and the balance Fe with inevitable impurities ; where the inevitable impurities are constituted of <=0.4% Si, <=0.1% Cr, <=0.6% Ti, <=0.03% Al, each <=0.005% C, N and S and <=0.010% P as well as nonmetallic inclusions by #<=0.002% expressed in terms of 0, and the nonmetallic inclusions are essentially consisting of Ti oxide.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] This invention can be used as a shadow mask material for high-definition TVs, has no defects during etching perforation, has a low coefficient of thermal expansion, and has excellent cleanliness and etching perforation properties. 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 plates have been mainly used as materials for electronic parts. For example, 42w
t. The Fe-Ni alloy plate containing % of nickel is
It is used as an IC lead frame material because it has excellent electrical conductivity, heat resistance, bending workability, plating adhesion, and soldering properties. Furthermore, the thermal expansion coefficient is very small, 36wt. Fe-Ni containing % nickel
BACKGROUND ART alloy plates are used as shadow mask materials for color televisions or as materials for containers for storing low-temperature liquids.

F as a shadow mask material for high-definition TVs
Cold-rolled e-Ni alloy sheets are required to have no defects during etching and perforation and to have a low coefficient of thermal expansion. The following Fe--Ni alloy cold-rolled sheets have been proposed as Fe--Ni alloy cold-rolled sheets for use as shadow mask materials for TVs.

[0004] A cold-rolled Fe-Ni alloy sheet having excellent surface properties during cold rolling and essentially consisting of the following is disclosed in JP-A-62-161,936: Nickel: 30 to 45 wt. ．．
%, manganese: 0.3 to 1.0 w
t. %, silicon: 0.1 to 0.3
wt. %, aluminum: 0.0004-0.002
0 wt. %, and the rest, iron and unavoidable impurities. However, the non-metallic inclusions as the unavoidable impurities are defined as point 1: Al2O3: 4 wt. %, MnO: 58 wt. %, SiO2: 38 wt. %, point 2: Al2O3: 5 wt. %, MnO: 49 wt. %, SiO2: 46 wt. %, point 3: Al2O3:23 wt. %, MnO: 23 wt. %, SiO2: 54 wt. %, point 4: Al2O3:27 wt. %, MnO: 31 wt. %, SiO2: 42 wt. %, and point 5: Al2O3:17 wt. %, MnO: 54 wt. %, SiO2: 29 wt. (hereinafter referred to as "prior art") consisting of the composition within the area surrounded by lines sequentially connecting % and .

[0005]

[Problem to be solved by the invention] The above-mentioned prior art is
It includes issues such as: That is, the nonmetallic inclusions are
In the Al2O3-MnO-SiO2 system ternary phase diagram shown in FIG. Non-metallic inclusions have the lowest temperature, 1.
It consists of a composition in a region close to spessartite, surrounded by a liquidus temperature line of 200°C. As a result, the nonmetallic inclusions have a low melting point, a high deformability, and a large total amount. The particle size of nonmetallic inclusions is large;
Alternatively, if the content of a compound with a low melting point is high, when a cold rolled sheet is prepared by hot rolling and cold rolling an alloy ingot, nonmetallic inclusions in the cold rolled sheet are deformed into linear shapes. As a result, defects may occur during etching holes.

For these reasons, Fe, which can be used as a shadow mask material for high-definition TVs, does not generate defects during etching holes, has a low coefficient of thermal expansion, and has excellent cleanliness and etching perforation properties. -Ni alloy cold-rolled sheets are required, but such cold-rolled alloy sheets and methods for producing the same have not yet been proposed.

[0007] Therefore, an object of the present invention is to provide a material that can be used as a shadow mask material for high-definition TVs, has no defects during etching perforation, has a low coefficient of thermal expansion, and has excellent cleanliness and etching perforation properties. Fe-Ni
An object of the present invention is to provide a cold-rolled alloy sheet and a method for manufacturing the same.

[0008]

[Means for Solving the Problems] From the above-mentioned viewpoints, the present inventors have discovered a method that can be used as a shadow mask material for high-definition TVs, and which does not generate defects during etching and perforation.
In order to develop a cold-rolled Fe--Ni alloy sheet with a low coefficient of thermal expansion, excellent cleanliness and etching perforability, and a method for producing the same, we conducted extensive research. As a result, we obtained the following knowledge.

[0009] 30 to 45 wt. A dephosphorized and decarburized Fe-Ni based molten alloy containing nickel in the range of 20 to 40 wt. CaO within %
Aluminum and titanium were added to the Fe-Ni molten alloy thus prepared in a ladle made of an MgO-CaO refractory containing aluminum, and the Fe-Ni molten alloy to which aluminum and titanium had been added was then heated. , in the ladle, consisting of CaO-Al2O3
- Ti02-MgO slag: CaO and Al2O3: 57 wt. % or more, T
i02: 30 wt. % or less, provided that CaO / (CaO + Al2O3 + Ti0
2) The ratio is 0.7 or more, MgO
: 25 wt. % or less, SiO2
: 15 wt. % or less, and metal oxides with a weaker oxygen affinity than silicon:
3 wt. % or less, the Fe-Ni
By deoxidizing the system molten alloy, the amount of dissolved oxygen in the molten alloy is reduced, and the oxides generated in the molten alloy are absorbed into the slag.

[0010] As a result, the total amount of nonmetallic inclusions present in the Fe-Ni alloy cold-rolled sheet was 0.0% in terms of oxygen.
002 wt. % or less. In other words, as the amount of dissolved oxygen in the molten alloy decreases, not only does the total amount of nonmetallic inclusions that precipitate during solidification of the molten alloy decrease, but also the low melting point suspended matter that becomes the precipitation nucleus decreases. does not exist, so
Growth of the particle size of nonmetallic inclusions is suppressed. Fe-Ni
The non-metallic inclusions present in the cold-rolled sheet of alloys are mainly
It is made of titanium oxide, and its particle size is 6 μm or less.

[0011] The present invention has been made based on the above-mentioned findings, and the Fe-Ni alloy cold-rolled sheet of the present invention, which has excellent cleanliness and etching perforation properties, essentially consists of the following: There is. Nickel: 30 to 45 wt.
%, manganese: 0.1 to 1.0
wt. %, the remainder, iron and unavoidable impurities, provided that the unavoidable impurities such as silicon, chromium, titanium,
The respective contents of carbon, nitrogen, sulfur, phosphorus, oxygen, aluminum and non-metallic inclusions are: 0.4 wt. for silicon; % or less, for chromium, 0.1 wt. % or less, for titanium,
0.6 wt. % or less, for carbon, 0.005
wt. % or less, for nitrogen, 0.005 wt. %
Hereinafter, regarding sulfur, 0.005 wt. % or less, for phosphorus, 0.010 wt. % or less, for oxygen, 0.002 wt. % or less, for aluminum, 0.030 wt. % or less and non-metallic inclusions are converted to oxygen and are 0.002
wt. % or less, and the nonmetallic inclusions mainly consist of titanium oxide.

[0012] The method of manufacturing a cold-rolled Fe--Ni alloy sheet having excellent cleanliness and etching perforation properties according to the present invention comprises the following steps. 30 to 45wt. Dephosphorized and decarburized Fe containing an amount of nickel in the range of %
- Prepare a Ni-based molten alloy, and prepare a 20 to 40 wt. The thus prepared Fe
-Adding aluminum and titanium to Ni-based molten alloy, and adding aluminum and titanium to the Fe-N
The i-based molten alloy is placed in the ladle into a CaO- Al2O3-Ti02-MgO-based slag consisting of:
CaO and Al2O3: 57 wt. % or more, T
i02: 30 wt. % or less, provided that CaO / (CaO + Al2O3 + Ti0
2) The ratio is 0.7 or more, MgO
: 25 wt. % or less, SiO2
: 15 wt. % or less, and metal oxides with a weaker oxygen affinity than silicon.
: 3 wt. % or less, the Fe-Ni
The deoxidized Fe-Ni based molten alloy is deoxidized, the deoxidized Fe-Ni based molten alloy is cast into an ingot, and the ingot is bloomed, hot rolled, and cold rolled to determine its grain size. is 6 μm or less, and 0.00 in terms of oxygen
2 wt. % or less of non-metallic inclusions.
A Ni-based alloy cold-rolled sheet is manufactured.

The chemical composition of the cold-rolled Fe-Ni alloy sheet of the present invention, which has excellent cleanliness and etching perforation properties, is as follows:
The reason for limiting the range 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. The nickel content is 30 to 45 wt. %, the coefficient of thermal expansion of the alloy plate is small. However, the nickel content
30wt. %, the coefficient of thermal expansion of the alloy plate becomes high. On the other hand, the nickel content is 45wt. %, the coefficient of thermal expansion of the alloy increases. Fe- with high coefficient of thermal expansion
When a Ni-based alloy cold-rolled plate is used as a shadow mask material, it causes color shift. Therefore, the nickel content is between 30 and 45 wt. It should be limited within the range of %. As raw materials for nickel, Inconickel (trade name of nickel manufactured by International Co., Ltd.) and electrolytic nickel are usually used. In order to reduce costs, cobalt-containing Tonimet (trade name of nickel manufactured by Tokyo Nickel Co., Ltd.) may be used. At this time, 1 wt
．． % or less, but there is no problem as long as the nickel content is within the above-mentioned range.

(2) Manganese: Manganese is Fe-Ni
It has the effect of improving the hot workability of alloy sheets. However, the manganese content is 0.1wt. If the amount is less than %, the desired effects described above cannot be obtained. on the other hand,
Manganese content is 1.0 wt. %, the hardness of the alloy plate becomes excessively high, making it unsuitable as a shadow mask material. Therefore, the manganese content is between 0.1 and 1.0
wt. It should be limited within the range of %.

(3) Silicon: Silicon is Fe-Ni
It is one of the impurities that inevitably mix into the alloy. The lower the silicon content is, the more preferable it is, but it is difficult from an economic standpoint to significantly reduce the silicon content on an industrial scale. However, the silicon content is 0.4 wt. %, the etching solution becomes dirty during etching holes in the Fe-Ni alloy plate, reducing productivity. Therefore, the silicon content is 0.4
wt. % or less.

(4) Chromium: Chromium is one of the impurities that inevitably mixes into Fe-Ni alloys. The lower the chromium content, the better.
It is difficult to significantly reduce it on an industrial scale from an economic standpoint. However, the content of chromium is 0.1
wt. %, the etching rate of the Fe--Ni alloy plate becomes slow, reducing productivity, and the coefficient of thermal expansion of the alloy plate increases, resulting in color shift. Therefore, the chromium content is 0.1 wt. % or less.

(5) Titanium Titanium is one of the impurities inevitably mixed into Fe-Ni alloys. The lower the titanium content, the more preferable it is, but it is difficult to significantly reduce the titanium content on an industrial scale from an economic standpoint. However, the titanium content is 0.6 wt. %, the blackening processability of the alloy plate is reduced and a titanium oxide film is formed, resulting in a reduction in etching performance. Therefore, the titanium content is 0.6 wt. % or less, more preferably 0
．． 1 wt. % or less.

(6) Carbon: Carbon is one of the impurities that inevitably mixes into Fe-Ni alloys. The lower the carbon content is, the more preferable it is, but it is difficult from an economic standpoint to significantly 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 alloy plate, impeding the etching perforation of the alloy plate and causing perforation defects. Furthermore, the carbon content is 0.005
wt. %, the press formability of the alloy plate decreases. Therefore, the carbon content is 0.005wt. % or less.

(7) Nitrogen: Nitrogen is one of the impurities that inevitably mixes into Fe-Ni alloys. The lower the nitrogen content is, the more preferable it is, but it is difficult from an economic standpoint to significantly 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 impedes the etching perforation of the alloy plate and causes perforation defects. Therefore, the nitrogen content is 0.005 wt. %
It should be limited to:

(8) Sulfur: Sulfur is one of the impurities that inevitably mixes into Fe-Ni alloys. The lower the sulfur content is, the more preferable it is, but it is difficult from an economic standpoint to significantly 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 will be generated in the Fe--Ni alloy plate, impeding the etching perforation of the alloy plate and causing perforation defects. Therefore, the sulfur content is 0.005 wt. % or less.

(9) Phosphorus: Phosphorus is one of the impurities that inevitably mixes into Fe-Ni alloys. The phosphorus content is
The smaller the amount, the better, but it is difficult to significantly reduce the phosphorus content on an industrial scale from an economic standpoint. However, the phosphorus content is 0.010wt. %, the hot workability of the Fe-Ni alloy plate will be significantly degraded. Therefore, the phosphorus content is 0.010 wt. % or less.

(10) Oxygen: Oxygen is one of the impurities that inevitably mixes into Fe-Ni alloys. The lower the oxygen content, the better, but it is difficult to significantly reduce the oxygen content on an industrial scale from an economic standpoint. However, if the oxygen content is 0.002 wt. %, a large amount of oxide-based nonmetallic inclusions are generated in the alloy, which impedes the etching perforation of the alloy plate and causes perforation defects. Therefore, the oxygen content is 0.002
wt. % or less.

(11) Aluminum: Aluminum is
Impurities inevitably mixed into Fe-Ni alloys
It is one. The lower the aluminum content, the more preferable it is, but it is difficult from an economic standpoint to significantly reduce the aluminum content on an industrial scale. However, aluminum is 0.030wt. If it exceeds %,
The blackening treatment properties of the alloy plate deteriorate. Therefore, the aluminum content is 0.030wt. % or less.

(12) Nonmetallic inclusions: Nonmetallic inclusions are one of the impurities that inevitably mix into the Fe-Ni alloy plate. The nonmetallic inclusions are mainly composed of titanium oxide, and are a component that greatly affects the etching perforation of the Fe-Ni alloy plate. The content of nonmetallic inclusions in the alloy plate is 0.002 w in terms of oxygen
t. If it exceeds %, the etching perforation properties of the alloy plate will be inhibited, causing perforation defects. Therefore, the content of nonmetallic inclusions is 0.002 wt. in terms of oxygen. % or less.

Next, according to the present invention, 20 to 40 wt. Mg containing an amount of CaO within %
The reason for using a ladle made of O-CaO refractory will be described below. (1) The content of CaO in the refractory is 20 wt.
%, the penetration depth of slag into the refractory (pene
tration depth) increases, causing deterioration of the refractory. On the other hand, the CaO content was 40wt.
%, the melting point of the refractory becomes low and the degree of erosion (
slag refining of the molten alloy at high temperatures for long periods of time becomes impossible. Therefore, the content of CaO in the refractory is between 20 and 40 wt. It should be limited within the range of %.

The above will be explained in detail with reference to FIG. In Figure 2, "●" indicates the infiltration depth of 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. Show a curve. In FIG. 2, the vertical axis indicates the infiltration depth and the degree of erosion. The horizontal axis indicates the content of MgO and CaO. That is, the upper scale of the horizontal axis ranges from 0 to 10.
0 wt. % MgO content, and the lower scale is from 100 to 0 wt. % of CaO
Indicates the content. Therefore, the horizontal axis represents MgO and Ca
The total amount of O is always 100 wt. %. For example, if the content of MgO is 100 wt
．． %, the CaO content is 0 wt. %
and the MgO content is 20 wt. %
When , the CaO content is 80 wt. %. As is clear from Figure 2, the content of CaO is 20
From 40wt. %, both the depth of slag infiltration and the degree of erosion of the refractory are small.

(2) A ladle made of MgO-CaO-based refractories has a low content of oxides such as Fe2O3, SiO2, and Cr2O3, which are sources of alloy oxides, so the oxygen concentration in the molten alloy can be maintained low. to prevent silicon and chromium pickup. Therefore,
A ladle made of MgO-CaO type refractory should be used.

Next, according to the present invention, when refining Fe-Ni based molten alloy in a ladle, CaO-Al2O3-Ti02-MgO based slag consisting of:
CaO and Al2O3: 57 wt. % or more, T
i02: 30 wt. % or less, provided that CaO / (CaO + Al2O3 + Ti0
2) The ratio is 0.7 or more, MgO
: 25 wt. % or less, SiO2
: 15 wt. % or less, and metal oxides with a weaker oxygen affinity than silicon:
The reason for using 3 wt or less will be described below.

(1) CaO/(CaO+Al2O3
+Ti02) is less than 0.7, the activity of Al2O3 and Ti02 in the slag exceeds 0.5. When the activity of Al2O3 and Ti02 in the slag exceeds 0.5, the deoxidizing power of Al and Ti decreases when the amounts of Al and Ti are kept constant. Therefore, CaO/(Ca
The ratio of O+Al2O3 +Ti02) should be limited to 0.7 or more.

The above will be explained in detail with reference to FIG. Figure 3 shows the respective activities of Al2O3, Ti02 and CaO in CaO-Al2O3-Ti02-MgO slag and CaO/(CaO+Al2O3 +Ti0).
2) is a graph showing the relationship between the ratio of The vertical axis is
Each activity of Al2O3, Ti02 and CaO
(aAl2O3, aTio2 and aCaO)
and the horizontal axis is CaO / (CaO+
The ratio of Al2O3+Ti02) is shown. Furthermore, FIG.
Three types of generally known isoactivity curves for Al2O3, Ti02 and CaO2 are shown. As is clear from Fig. 3, CaO/(CaO+Al2O3+Ti02)
When the ratio of Al2O3, Ti is 0.7 or more,
Also in the isoactivity line of 02, Al2O3 and Ti0
The activity of 2 is suppressed to 0.5 or less. As a result, Ca
The ratio of O / (CaO + Al2O3 + Ti02) is
When it is 0.7 or more, a slag with a strong ability to deoxidize aluminum and titanium can be obtained.

(2) If 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 molten alloy decreases. Therefore, the content of MgO is 25 wt. % or less.

(3) When the content of SiO2 in the slag is 15 wt. %, the activity of SiO2 in the slag (aSiO2) increases, and the amount of oxygen in the Fe-Ni molten alloy increases due to SiO2. As a result, the oxygen content present in the Fe-Ni alloy cold-rolled sheet was 0.0020wt. Exceeds %. Therefore, Si
The content of O2 is 15 wt. % or less.

(4) The total amount of metal oxides having a weaker oxygen affinity than Si in the slag is 3 wt.
．． %, the oxygen content present in the Fe-Ni alloy cold-rolled sheet will be 0.0020 wt. Exceeds %. Therefore, the total amount of metal oxides that have a weaker oxygen affinity than silicon is 3 wt. % or less, and more preferably 1.5 wt. % or less.

Furthermore, using the above-mentioned slag, Fe-N
The reason why a Fe--Ni alloy cold-rolled sheet with excellent cleanliness can be obtained by deoxidizing the i-based molten alloy will be explained in detail with reference to FIG. 4. Figure 4 shows that 36 wt. Fe-Ni containing % nickel
In the system molten alloy, when deoxidation reaches an equilibrium state with aluminum, silicon or titanium, the dissolved amount of aluminum, silicon or titanium used for deoxidation in the molten alloy, and the amount of oxygen in the molten alloy It is a graph showing the relationship between dissolved amount.

In FIG. 4, the vertical axis represents the amount of oxygen dissolved in the molten alloy, and the horizontal axis represents the amount of aluminum, silicon, or titanium dissolved in the molten alloy. Furthermore, in FIG. 4, the diagonal solid line indicates Al2O3
The diagonal dashed line shows the isoactivity line of SiO2. Furthermore, 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, which is obtained by deoxidizing the molten alloy using the above-mentioned slag of the present invention, Then, “A(A
No. 1, A2)" and "B" are methods outside the scope of the present invention (hereinafter referred to as "comparative deoxidation method") that do not use the slag of the present invention. The amount of dissolved silicon, aluminum, or titanium and the amount of dissolved oxygen in the molten alloy deoxidized according to 1 or 2 are shown.

As is clear from FIG. 4, the amount of dissolved oxygen in the molten alloy of the present invention is small. That is, by strongly stirring the molten alloy in the presence of sufficient amounts of aluminum, titanium, and the above-mentioned slag, the respective activities aAl2O3, aTio2, and aSiO2 in the equilibrium state are lowered, and the activities in the equilibrium state are reduced. Oxygen concentration becomes lower and more stable. In this way, nonmetallic inclusions consisting of oxides in the molten alloy are adsorbed to the slag and removed. As a result, the molten alloy can be cleaned and trace amounts of non-metallic inclusions with extremely fine particle sizes can be distributed in the molten alloy.

[0037] In the blooming of Fe--Ni alloy ingots, it is desirable that the rolling ratio be 70% or more and that the rolling temperature be within the range of 1,150 to 1,250°C. The reason is as follows. (1) When the rolling ratio is 70% or more, the structure of the alloy and non-metallic inclusions in the alloy during blooming are crushed to make the particle size of the non-metallic inclusions in the cold-rolled sheet extremely fine. effective. Therefore, the rolling rate should be limited to 70% or more. (2) When the rolling temperature is less than 1,150°C, blooming is difficult; on the other hand, when the rolling temperature is 1,250°C
When it exceeds , the deformation resistance of the matrix metal decreases, making it difficult to crush nonmetallic inclusions. Therefore,
The rolling temperature should be limited to within the range of 1,150 to 1,250°C.

[0038]

[Example] Next, the Fe-Ni alloy cold-rolled sheet with excellent cleanliness and etching perforation property of the present invention and its manufacturing method will be compared with comparative examples outside the scope of the present invention. This will be explained in more detail. Using the raw materials shown in Table 1, a cold-rolled Fe--Ni alloy sheet was prepared through the following manufacturing process.

[0039]

[Table 1]

1. Refining using a converter2. Refining Dephosphorization Refining Nickel Melting Using VAD (Vacuum-Electric Arc-Degassing Abbreviation) equipment including:3. Refining, acid feeding, decarburization, vacuum decarburization, slag deoxidation using VOD (vacuum-oxygen-abbreviation of decarburization) equipment4. Ingot formation5. Blossom rolling6. Hot rolling7. cold rolling

FIG. 1 shows the refining process using the above-mentioned VAD and VOD equipment. That is, dephosphorized hot metal is refined in a 250t top-blown converter equipped with a bottom plug for blowing in stirring gas to obtain undeoxidized molten steel,
This was then transferred into a 250t ladle. Next, of the 250 tons of molten steel thus obtained, 20 tons were
50 tons were placed in the ladle from 0 tons. The composition of the molten steel was as follows.

[0042]

[0043] The above-mentioned 20t of molten steel was converted into 57.2wt
．． % MgO, 38.4 wt. % CaO,
1.6 wt. % SiO2 and 0.2 wt. A separate 20 ton ladle made of magnesia-dolomite bricks with % Al2O3 was poured with a rotary nozzle. The ladle was then placed in a VAD (vacuum-electric arc-degassing) facility, where the molten steel was dephosphorized. In this way, by using undeoxidized molten steel, absorption of nitrogen into the molten steel was prevented. Then,
After removing the slag, pure nickel ingots and nickel alloy ingots were heated in the ladle under reduced pressure to a temperature of 1,600°C or higher using a three-phase electrode heating device under the following conditions. and dissolved it.

[0044] Degree of vacuum: 200
~600 Torr, bottom-blown argon gas flow rate: 0
．． 5 to 1.5 Nl/min. t, Slag agent input time: VAD Immediately before the start of smelting, Slag agent composition: Burnt lime 15 Kg/T
, Fluorite 4 Kg/T.

After melting the nickel, the thus obtained molten Fe-Ni alloy in the ladle, now increased to about 30 tons, is heated to 1,700° C. or more, more preferably 1,700° C. or higher, under the following conditions. , heated to a temperature of 750°C or higher. Vacuum degree: 2
00 to 400 Torr, flow rate of bottom-blown argon gas: 0.5 to 1.5 Nl/min. t. Adding slag agent: None.

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

By the above-mentioned heating after melting the nickel,
No further heating was required after completion of refining using VOD (vacuum-oxygen-decarburization) equipment. Then, the ladle was heated to VO
It was transferred to equipment D, where the Fe-Ni based molten alloy was decarburized. Decarburization of the molten alloy consisted of decarburization performed while blowing oxygen with a top blowing lance (hereinafter referred to as ``oxygen decarburization using a top blowing lance''), and vacuum decarburization under reduced pressure.

[0048] First, decarburization by oxygen supply using a top 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 Nm3/min. t, oxygen supply amount
: 2 to 5 Nm3/t, distance between lance and molten alloy surface: 700 to 900 mm, slag agent added
:none.

[0049] In this way, oxygen-enriched Fe-N
By promoting the carbon-oxygen reaction while stirring the i-based molten alloy with bottom-blown argon gas,
Its carbon content is 0.005wt. The molten alloy was decarburized under reduced pressure until it was reduced to less than %. In addition, at the final stage of the oxygen decarburization using the above-mentioned top blowing lance, the ladle was transferred to the VOD equipment again, and nickel was added to the molten alloy to finely adjust the nickel component in the molten alloy. The temperature of the molten alloy was adjusted to approximately 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,
The test 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. Adding slag agent
: None, temperature of molten alloy at the start of vacuum decarburization: 1,745
℃ As a result, its carbon content was 0.0009wt.
It was possible to decarburize the Fe-Ni based molten alloy until it decreased to less than %.

[0052] Next, in the VOD equipment,
A deoxidizing agent and a slag agent such as a titanium alloy or aluminum are added to the Fe-Ni molten alloy, and while the molten alloy is strongly stirred with bottom-blown argon gas, the molten alloy and slag are mixed under the following conditions. The molten alloy was deoxidized by the reaction between
).

Vacuum degree: 1 Torr or less, bottom-blown argon flow rate: 0.5 to 2.5 Nl/
min. t, Injection of slag agent and deoxidizing agent (2 times) First injection Composition of slag agent: Burnt lime: 30 Kg/t, Fluorite: 5 Kg/t, Composition of deoxidizing agent: Aluminum: 10 Kg/t, ferrosilicon: 2 Kg/t, ferrotitanium:
8 Kg/t, time of addition: Immediately before the start of deoxidation refining, composition of the second input additive: fine adjustment agent for molten alloy components, time of addition
: Mid-stage of deoxidation refining.

Before deoxidizing the molten alloy with slag,
Titanium, silicon and S in Fe-Ni based molten alloy
ol. The content of Al was as follows.

[0055] The above-mentioned CaO- reacted with the molten alloy
The Al2O3-Ti02-MgO-based slag consisted of the following. (a) Component composition (b) CaO / (CaO+Al2O3 +Ti0
2) Ratio of: 0.58 (c) Total content of oxides of metals with weaker oxygen affinity than Si (i.e., T.
Fe+MnO+Cr2O3): 0.9 wt. %

00
56] The results of the above-mentioned deoxidation refining in the VOD facility of Fe-Ni molten alloy were as follows. Si content in molten alloy: 0
．． 1 to 0.3 wt. %, estimated value of SiO2 activity (aSiO2): 0.
001 ~ 0.005, content of Ti in molten alloy
:0.1 ~0.6wt
．． %, estimated value of TiO2 activity (a TiO2): 1
0-2 to 10-8, estimated concentration of equilibrium oxygen
:1 to 2 ppm, and T. Actual content of oxygen: 7-14 p
p.m.

Furthermore, the above-mentioned deoxidation of the molten alloy by the reaction between the Fe-Ni molten alloy and the slag was carried out under a high degree of vacuum while stirring the molten alloy strongly. It was possible to prevent nitrification from entering. In addition,
The above-described deoxidation of the Fe-Ni based molten alloy by slag was carried out without applying arc heating to prevent carbon pickup.

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

Next, after the processing in the VAD equipment and VOD equipment is completed, Fe-Ni is made by bottom pouring ingots using a wide-top 7t or 5t mold under the following conditions.
The molten alloy was cast into an ingot. (1) Temperature of injection stream: 1,490 to 1,525°C
, (2) Casting speed: 150 ~ 190m
m/min, (3) Seal condition: A cover is placed between the ladle nozzle and the injection tube, and argon gas is injected at 130 m/min.
It was supplied at a ratio of Nm3/Hr.

Since the injection stream was completely sealed from the atmosphere with argon gas, the oxygen concentration within the envelope was 0.1% or less after 2 minutes from the start of casting. As a result, it was possible to prevent the reoxidation of the molten alloy or the absorption of nitrogen into the molten alloy due to the entrainment of air.

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

[0062] As a result of SEM (scanning electron microscopy) analysis of the nonmetallic inclusions in the solidified mass of the runner part of the bottom poured ingot prepared in this way, it was found that the nonmetallic inclusions were composed of titanium oxide. . And So in the coagulated mass in the runner
l. The contents of Al, nitrogen and oxygen were as follows.

[0063] Then, the ingot thus prepared was subjected to a rolling reduction of 70% or more and a rolling reduction of 1,150 to 1
, 250° C., followed by a series of steps consisting of slab surface treatment, hot rolling, descaling, cold rolling, annealing, cold rolling and strain relief heat treatment. As shown in Table 3, specimen No. 1 of the Fe-Ni alloy cold-rolled sheet of the present invention (hereinafter referred to as "the specimen of the present invention") having a thickness of 0.15 mm is shown in Table 3. 1-3
was prepared.

[0064]

[Table 3]

[0065] Specimen No. of the present invention. The component composition of 1 is
It was as follows:

Furthermore, specimen No. of the present invention. manganese, silicon, sulfur at the top and bottom ends of 1;
The results of investigating the distribution of nitrogen and oxygen were as follows. From the above, it can be seen that the present invention specimen No. Manganese in 1,
At a practical level, silicon, sulfur, nitrogen and oxygen are
It can be seen that the distribution is extremely uniform.

Next, for comparison, deoxidation refining was carried out under reduced pressure using silicon and manganese without using slag (hereinafter referred to as "comparative deoxidation method").
No. 0.15 m as shown in Table 3 by the same process as in the present invention described above except for
A specimen of a cold-rolled Fe-Ni alloy sheet outside the scope of the present invention having a thickness of m (hereinafter referred to as "comparative specimen")
No. 1 and 2 were prepared.

Comparative deoxidation method No. 1, the non-metallic inclusions made of oxides in deoxidizing refining mainly consist of Al2O3, MnO and SiO2, and their composition is within the region of spessartite, as shown in Figure 1. And its melting point is low, and
It had high extensibility during hot rolling.

Comparative deoxidation method No. 1 described above. The results of deoxidation refining in No. 1 were as follows. Si content in molten alloy: 0
．． 1 to 0.3 wt. %, activity of SiO2 (aSiO
Estimated value of 2): 0.1 to 0.3, Sol. Al content: 0.0004
~0.0020 wt. %, estimated value of activity of Al2O3 (a Al2O3): 0
．． 10-0.20, estimated concentration of equilibrium oxygen
:10-15 ppm, and T. Actual oxygen content: 25-35
ppm.

Furthermore, for comparison, deoxidation refining was carried out under reduced pressure using aluminum without using slag (hereinafter referred to as "comparative deoxidation method No. 2").
A Fe-Ni alloy cold-rolled sheet specimen outside the scope of the present invention (hereinafter referred to as , referred to as "comparative specimen") No. 3 and 4 were prepared. Comparative deoxidation method No. According to No. 2, nonmetallic inclusions made of oxides in deoxidizing refining were mainly made of Al2O3, had a high melting point, and had low malleability in hot rolling.

[0071] The above-mentioned comparative deoxidation method No. The results of deoxidizing refining in No. 2 were as follows. Si content in molten alloy: 0
．． 1 to 0.3 wt. %, activity of SiO2 (aSiO
Estimated value of 2): 0.1 to 0.2, Sol. Al content: 0.005
~0.030 wt. %, estimated value of Al2O3 activity (a Al2O3 ): 1
, estimated concentration of equilibrium oxygen:
3 ppm, and T. 3 ppm in the molten alloy. Actual content of oxygen: 15-20 ppm.

As is clear from Table 3, T. The O content is the same as that of the present invention specimen No. It was the least in No. 1 to No. 3, followed by Comparative Specimen No. 3 and 4 followed, and comparative specimen no. In 1 and 2, there were many. That is, as is clear from FIG. 4, in the deoxidizing method of the present invention, comparative deoxidizing method No.
Compared to 1 and 2, the equilibrium oxygen concentration is lower, and due to the effect of adsorption and removal of suspended inclusions by the slag, T. Oxygen content is decreasing.

[0073] Next, the specimen No. 1 of the present invention prepared in this manner. 1 to 3, and comparative specimen No. 1-4
60 mm2 in the longitudinal plate thickness section in each of
The area was observed under a microscope at 800x magnification to measure the width and length of non-metallic inclusions present within the area. At that time, the nonmetallic inclusions were classified as follows according to shape and size, and the number of nonmetallic inclusions present per 1 mm2 was measured. (a) Nonmetallic inclusions with a length/width ratio of 3 or less (hereinafter referred to as
(referred to as "spherical nonmetallic inclusions"), and (b) nonmetallic inclusions with a length/width ratio exceeding 3 (hereinafter referred to as "linear nonmetallic inclusions"). The results are shown in Table 4.

[0074]

[Table 4]

As shown in Table 4, the present invention specimen No.
The number of nonmetallic inclusions in Samples 1 to 3 was as follows. That is, the present invention specimen No. In 1, the width is 3 μm
There were only 6 spherical nonmetallic inclusions less than 6, and the number of spherical nonmetallic inclusions was less than 6. In specimen No. 2, there were eight spherical nonmetallic inclusions with a width of less than 8 μm and only one spherical nonmetallic inclusion with a width of 3 μm to less than 6 μm. In No. 3, there were only seven spherical nonmetallic inclusions with a width of less than 3 μm. Thus, in the specimen of the present invention, only a small amount of spherical nonmetallic inclusions with extremely small particle sizes were present.

On the other hand, comparative specimen No. The number of nonmetallic inclusions in 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
3μm or more: 8 pieces. As mentioned above, comparative specimen No. In No. 1, a large number of linear nonmetallic inclusions were present, and therefore, it was found that the particle size of the nonmetallic inclusions was large. What was mentioned above is
Comparison specimen No. The same was true for 2.

Furthermore, comparative specimen No. The number of nonmetallic inclusions in No. 3 was as follows. Number of spherical nonmetallic inclusions: Width less than 3 μm: 10 pieces, width
3μm to less than 6μm: 4 pieces, width 6μm
~ Less than 14 μm: 1 piece, Number of linear nonmetallic inclusions: Width less than 3 μm: 1 piece,
Width 3μm or more None.

That is, comparative specimen No. In 5, the present invention specimen No. Compared to samples 1 to 3, the number of spherical nonmetallic inclusions was large. The above is based on the comparative specimen.
No. The same was true for 6.

As mentioned above, comparative specimen No. 1
In all of samples 4 to 4, the number of nonmetallic inclusions was large and/or the particle size of the nonmetallic inclusions was large. As a result, Fe
-Etching perforation of the Ni-based alloy cold-rolled sheet was inhibited. In contrast, the present invention specimen No. In samples 1 to 3, the number of nonmetallic inclusions was small and the particle size thereof was small. As a result, the cold-rolled Fe-Ni alloy sheet had excellent etching perforation properties.

Next, the above-mentioned present invention specimen No. 1~
3, and comparative specimen No. Pitch etching holes with a diameter of 135 to 280 μm were actually performed for Nos. 1 to 4, and the results were investigated. When each specimen subjected to etching perforation was observed under a microscope, the etching perforation defects were shown in Fig. 5 (A).
, (B), (C) and (D). The results are also shown in Table 4.

Invention specimen No. In No. 1 and No. 3, the incidence of etching perforation defects was zero. As mentioned above, due to the small number of nonmetallic inclusions and the small particle size, specimen No. It was clear that Samples Nos. 1 and 3 had excellent etching perforation properties. Invention specimen No. In 2, type (C) and type (D) defects also occurred, but
The occurrence rate was extremely low, and it was clear that the etching perforation properties were excellent.

On the other hand, comparative specimen No. In No. 1, the occurrence of etching and perforation defects 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, comparative specimen No. In No. 1, the incidence of etching perforation defects was high. That is, as mentioned above, due to the large number of linear nonmetallic inclusions, comparative specimen No. It was clear that No. 1 had poor etching perforation properties. The above is true for comparative specimen No. The same was true for 2.

Furthermore, comparative specimen No. In No. 3, the occurrence of etching and perforation defects was as follows. (A) Type failure rate: 0.75%, (B) Type failure rate: 0.04%, (C) Type failure rate: 0.50%, and (D) Type failure rate. rate:
0.01%.

As is clear from the above, comparative specimen No. In 3, the present invention specimen No.
Compared to samples 1 to 3, the incidence of etching perforation defects was higher. That is, as mentioned above, due to the large number of spherical nonmetallic inclusions, comparative specimen No. It was clear that No. 3 had poor etching perforation properties. The above is true for comparative specimen No. The same was true for 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, has no defects during etching and perforation, has a low coefficient of thermal expansion, and has excellent cleanliness. Fe with excellent etching perforation properties
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 explanation of the drawing]

FIG. 1 is a process flow diagram showing one example of a process for refining a Fe-Ni based molten alloy according to the present invention.

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

[Figure 3] A in CaO-Al2O3-MgO system slag
Activities of each of l2O3 and CaO, and CaO/
It is a graph showing the relationship between the ratio of (CaO+Al2O3).

FIG. 4: 36 wt. % of nickel in a Fe-Ni based molten alloy containing
i-Dissolved silicon level in the state of “deoxidation equilibrium”, “Al
2 is a graph illustrating the relationship between dissolved aluminum levels in the "-deoxidation equilibrium" state or dissolved titanium levels in the "Ti-deoxidation equilibrium" state and the equilibrium dissolved oxygen level.

5A to 5D are schematic explanatory diagrams showing the state of defects that occur during etching holes in a Fe-Ni alloy plate.

[Fig. 6] Al2O3-MnO showing the composition range of nonmetallic inclusions present in a conventional Fe-Ni alloy cold-rolled sheet.
-SiO2 ternary system phase diagram.

Claims (5)

[Claims] [Claim 1] Nickel: 30 to 4
5wt. %, manganese: 0.1 ~
1.0 wt. %, and the remainder, iron and unavoidable impurities, provided that the respective contents of silicon, chromium, titanium, carbon, nitrogen, sulfur, phosphorus, oxygen, aluminum and non-metallic inclusions as the unavoidable impurities are as follows: is 0.4 wt. % or less, for chromium, 0.1 wt. % or less, for titanium, 0.6
wt. % or less, for carbon, 0.005 wt.
% or less, for nitrogen, 0.005 wt. %below,
For sulfur, 0.005 wt. % or less, for phosphorus, 0.010 wt. % or less, for oxygen, 0.002 wt. % or less, for aluminum, 0.030 wt. % or less, and for non-metallic inclusions, 0.002 wt.% in terms of oxygen. % or less, and the nonmetallic inclusions are mainly composed of titanium oxide. [Claim 2] 30 to 45 wt. Dephosphorized and decarburized Fe-Ni containing an amount of nickel in the range of %
A system molten alloy is prepared, and 20 to 40 wt. In a ladle made of MgO-CaO type refractory containing an amount of CaO in the range of %, the Fe-Ni
Aluminum and titanium are added to the Fe-Ni based molten alloy, and the Fe-Ni based molten alloy to which aluminum and titanium have been added is placed in the ladle, and the Fe-Ni based molten alloy consisting of the following CaO
-Al2O3-Ti02-MgO slag: CaO
and Al2O3: 57 wt. % or more, Ti0
2: 30 wt. % Below, however, CaO/(CaO+Al2O3 +Ti02)
The ratio is 0.7 or more, MgO
: 25 wt. % or less, SiO2
: 15 wt. % or less and total amount of oxides of metals with weaker oxygen affinity than silicon:
3 wt. % or less, the Fe-
The Ni-based molten alloy is deoxidized, and the deoxidized Fe-Ni
The system molten alloy is cast into an ingot, and the ingot is subjected to blooming rolling, hot rolling, and cold rolling, so that the grain size is 6 μm or less and 0.5 μm in terms of oxygen. 002 wt. Fe-Ni alloy cold-rolled sheet containing non-metallic inclusions in a total amount of % or less, which has excellent cleanliness and etching perforation properties
A method for producing a Ni-based alloy cold-rolled sheet. 3. The preparation of the Fe-Ni based molten alloy involves refining molten steel in a converter, dephosphorizing the molten steel in the ladle whose pressure is reduced to 600 torr or less, and melting the molten steel. 3. The method of claim 2, comprising adding nickel and decarburizing. 4. The method of claim 2, wherein said deoxidizing of said molten Fe--Ni alloy is carried out in said ladle at a reduced pressure of 1 Torr or less. 5. The blooming of the ingot is carried out in 7 steps.
Reduction rate of 0% or more and 1,150 to 1,250
Claims 2 to 4 are carried out at a temperature within the range of °C.
The method described in any one of the following.