Fe-Ni alloy sheet and method for producing same

Abstract

The present invention relates to an Fe-Ni alloy sheet and a method for manufacturing the same. The alloy sheet comprises, in mass%, 0.001 to 0.05% of C, 0.05 to 0.50% of Si, 0.25 to 1.00% of Mn, 0.001 to 0.030% of P, 0.0001 to 0.0050% of S, 35.0 to 44.0% of Ni, 0.01 to 0.50% of Cr, 0.005 to 0.10% of Mo, 0.01 to 2.00% of Cu, 0.0001 to 0.10% of Al, 0.050% or less of Ti, 0.01 to 2.00% of Co, 0.01 to 0.50% of W, 0.001 to 0.05% of N, 0.0001 to 0.05% of Sn, 0.050% or less of Mg, 0.0001 to 0.05% of Zr, 0.0020% or less of Ca, and 0.0002 to 0.01% of O, with the remainder being Fe and unavoidable impurities.

Description

Technical Field

[0001] This invention relates to Fe-Ni alloy plates and their manufacturing methods. Background Technology

[0002] Fe-Ni soft magnetic alloys are generally classified according to their Ni content, as specified in JIS C2531 and IEC standards, into permalloy C (Ni: 72~83 wt%), permalloy B (Ni: 45~50 wt%), and permalloy D (Ni: 35~40 wt%), etc. High-grade permalloy C, due to its high permeability and low holding force, is used in magnetic components such as magnetic shielding materials and magnetic sensor materials. However, because permalloy C contains a large amount of Ni and is expensive, it is being replaced by the cheaper permalloy B as a material for magnetic components. Furthermore, due to its high saturation magnetic flux density, permalloy B is also used in watch stators and magnetic lens pole pieces.

[0003] In recent years, the demand for soft magnetic materials such as automotive sensors and magnetic shielding materials has been increasing, while the price of Ni has been rising. Therefore, Permalloy B is gradually being replaced by Alloy 42 and Permalloy D, which have lower Ni content and are cheaper. However, the decrease in magnetic properties and corrosion resistance as the Ni content decreases is considered a problem, thus there is an urgent need to maintain the characteristics of Permalloy B, namely, high saturation magnetic flux density. Especially in automotive sensors and magnetic shielding materials, soft magnetic materials with an initial relative permeability of ≥3,000, a maximum relative permeability of ≥30,000, and a saturation magnetic flux density of ≥1.4 T are preferred.

[0004] As a method to improve the magnetic properties of permalloy, Patent Document 1 proposes a method to improve magnetic properties by performing homogenization heat treatment on the continuously cast billet to reduce segregation. However, Patent Document 1 does not mention the saturation magnetic flux density.

[0005] Furthermore, Patent Document 2 proposes a method to promote grain growth and improve magnetic properties by limiting the magnetic annealing temperature and time of the Fe-Ni alloy material to be rolled, as well as the amount of type A (Mn-S) inclusions in the Fe-Ni alloy. However, this method aims to improve the coercivity, initial relative permeability, and maximum relative permeability of the obtained soft magnetic component material, without investigating the saturation magnetic flux density.

[0006] (Existing technical literature) (Patent Documents) Patent Document 1: Japanese Patent Application Publication No. 2002-173745 Patent Document 2: Japanese Patent Application Publication No. 2015-196838 Summary of the Invention

[0007] The problem that the invention aims to solve In view of the above, the object of the present invention is to provide an Fe-Ni alloy and a method for manufacturing the same, which can impart excellent initial relative permeability, as well as good maximum relative permeability and saturation magnetic flux density, while controlling the yield during manufacturing.

[0008] Methods for solving problems The inventors conducted in-depth research to solve the above-mentioned problems and found that by strictly controlling the alloy composition of Fe-Ni alloys, the magnetic properties of initial relative permeability, maximum relative permeability and saturation magnetic flux density can be improved, thereby obtaining Fe-Ni alloys manufactured with controllable yield, thus realizing the present invention.

[0009] The key points of this invention are as follows.

[0010] [1] An Fe-Ni alloy plate, characterized in that it comprises Carbon (C): 0.001–0.05% by mass Silicon (Si): 0.05–0.50% by mass Manganese (Mn): 0.25–1.00% by mass Phosphorus (P): 0.001–0.030% by mass Sulfur (S): 0.0001–0.0050% by mass Nickel (Ni): 35.0–44.0% by mass Chromium (Cr): 0.01–0.50% by mass Molybdenum (Mo): 0.005–0.10% by mass Copper (Cu): 0.01–2.00% by mass Aluminum (Al): 0.0001–0.10% by mass Titanium (Ti): less than 0.050% by mass Cobalt (Co): 0.01–2.00% by mass Tungsten (W): 0.01–0.50% by mass Nitrogen (N): 0.001–0.05% by mass Tin (Sn): 0.0001~0.05% by mass Magnesium (Mg): less than 0.050% by mass Zirconium (Zr): 0.0001–0.05% by mass Calcium (Ca): less than 0.0020% by mass Oxygen (O): 0.0002–0.01% by mass The balance consists of iron (Fe) and unavoidable impurities.

[0011] [2] The Fe-Ni alloy plate described in [1] contains Cu, Co and W and satisfies the following formula (A).

[0012] 1.5≤20[Cu%]+20[Co%]+80[W%]<50.0…(A) (In formula (A), % represents mass%.) [3] The Fe-Ni alloy plate described in [1] or [2] above contains Cu, Co, W, Cr, Mo, P and S, and satisfies the following formula (B).

[0013] 10≤50([Cu%]+[Co%])+100[W%]+200[Cr%]+800[Mo%]-100[P%]-1000[S%] …(B) (In formula (B), % represents mass%.) [4] A method for manufacturing a Fe-Ni alloy plate according to any one of [1] to [3] above, characterized in that it includes the following steps: The process of oxidative refining of molten metal containing Fe-Ni alloy raw materials in any of the secondary refining containers of an AOD furnace or a VOD furnace. The process of deoxidation and desulfurization involves adding Al and / or FeSi alloy to the molten metal after oxidative refining for deoxidation and desulfurization, such that the content of Al in the molten metal is in the range of 0.0001 to 0.10% by mass, the content of Si is in the range of 0.05 to 0.50% by mass, the content of S is in the range of 0.0001 to 0.0050% by mass, and the content of O is in the range of 0.0002 to 0.01% by mass. The process of continuously casting deoxidized and desulfurized molten metal to form slabs; and The process of hot rolling the obtained slab followed by cold rolling.

[0014] Invention Effects According to the present invention, an Fe-Ni alloy plate and its manufacturing method are provided, which, by strictly controlling the alloy composition of the Fe-Ni alloy, can impart excellent initial relative permeability as well as good maximum relative permeability and saturation magnetic flux density, and can be manufactured in a manner that controls the yield. Attached Figure Description

[0015] Figure 1It is a graph showing the relationship between the value of Equation (A) and the saturation magnetic flux density and the maximum relative permeability in the magnetic property test; Figure 2 It is Figure 1 A magnified image of the region where the value of Chinese expression (A) is lower. Detailed Implementation

[0016] The Fe-Ni alloy plate and its manufacturing method according to the present invention will be described below. The Fe-Ni alloy plate of the present invention comprises: carbon (C): 0.001–0.05 wt%, silicon (Si): 0.05–0.50 wt%, manganese (Mn): 0.25–1.00 wt%, phosphorus (P): 0.001–0.030 wt%, sulfur (S): 0.0001–0.0050 wt%, nickel (Ni): 35.0–44.0 wt%, chromium (Cr): 0.01–0.50 wt%, molybdenum (Mo): 0.005–0.10 wt%, copper (Cu): 0.01–2.00 wt%, and aluminum (Al): 0.0 wt%. The composition of Fe-Ni alloys is as follows: 0.001–0.10% by mass, titanium (Ti): less than 0.050% by mass, cobalt (Co): 0.01–2.00% by mass, tungsten (W): 0.01–0.50% by mass, nitrogen (N): 0.001–0.05% by mass, tin (Sn): 0.0001–0.05% by mass, magnesium (Mg): less than 0.050% by mass, zirconium (Zr): 0.0001–0.05% by mass, calcium (Ca): less than 0.0020% by mass, oxygen (O): 0.0002–0.01% by mass, with the balance being iron (Fe) and unavoidable impurities. By strictly controlling the alloy composition of Fe-Ni alloys as described above, Fe-Ni alloy plates with excellent initial relative permeability, good maximum relative permeability, and saturation magnetic flux density can be provided, and these alloy plates can be manufactured in a controlled yield manner. Because the Fe-Ni alloy plate of the present invention can impart such excellent magnetic properties, it is suitable for use as a soft magnetic material in automotive sensors, magnetic shielding materials, watch stators, etc.

[0017] In addition, the Fe-Ni alloy plate of the present invention preferably contains Cu, Co and W in a manner that satisfies the above-mentioned composition, in addition to satisfying the following formula (A).

[0018] 1.5≤20[Cu%]+20[Co%]+80[W%]<50.0…(A) (In formula (A), % represents mass%.) Equation (A) above is a relational expression for Cu and Co, whose atomic radii are similar to Ni, and W, whose ionic radii are similar to Ni. It is used to express the effect of the addition amount of Cu, Co and W on the maximum relative permeability and saturation magnetic flux density of Fe-Ni alloys. Figure 1 This is a graph showing the relationship between the maximum relative permeability and saturation magnetic flux density measured by the following test method (magnetic property test) and the value of the above equation (A). Figure 2 It is a graph showing the relationship between the saturation magnetic flux density and the value of equation (A) in the region where the value of equation (A) is below 5.0. Figure 1 This indicates that when the value of equation (A) is above 50.0, the maximum relative permeability is below 30,000. Figure 2 This indicates that when the value of formula (A) is less than 1.5, the saturation magnetic flux density is less than 1.4T. Therefore, by including Cu, Co, and W in the Fe-Ni alloy plate in such a way that the value of formula (A) is greater than or equal to 1.5 and less than 50.0, it is possible to obtain an Fe-Ni alloy plate that imparts excellent maximum relative permeability and saturation magnetic flux density.

[0019] <Magnetic Properties Test> Fe-Ni alloys containing approximately 39.3% by mass Ni as the base component were melted in a 10 kg experimental high-frequency induction furnace. During the melting process, the amounts of Cu, Co, and W added to each alloy were varied, as shown in Table 1 below. The molten alloy was then cast into a mold to form ingots, which were then hot-forged into forged plates with a thickness of 10 mm. Subsequently, the surface oxide scale was removed by annealing and grinding, and the plate was cold-rolled to a thickness of 0.8 mm. The cold-rolled plate was then processed according to JIS C2531. φ A 45mm × 33mm ring-shaped test piece was tested under vacuum (≤5.0 × 10⁻⁶). -3 In a Pa atmosphere, magnetic annealing was performed at 1125°C for 2.5 hours under homogenous heating conditions. Subsequently, 50 turns of enameled copper wire as specified in JIS C3202 or JIS C3215 were wound on both the primary and secondary sides, and the maximum relative permeability was measured. μ max ) and saturation magnetic flux density (B 800 The maximum relative permeability was measured under a reverse magnetic field of 16 A / m, and the saturation magnetic flux density was measured under a magnetic field of 1600 A / m. The results are shown in Table 2. It should be noted that the values ​​of each component in Table 1 represent "mass %".

[0020] Table 1 Table 2 As described above, Cu, Co, and W are important elements for obtaining excellent saturation magnetic flux density. By setting the value of Equation (A), which relates the amounts of Cu, Co, and W added, to 1.5 or more, a saturation magnetic flux density of 1.4 T or more can be obtained. On the other hand, when the value of Equation (A) is 50.0 or more, the maximum relative permeability is lower than 30,000. Therefore, the value of Equation (A) is preferably in the range of 1.5 or more and less than 50.0, more preferably in the range of 1.5 or more and less than 40.0, and even more preferably in the range of 1.5 or more and less than 25.0.

[0021] In addition, the Fe-Ni alloy plate of the present invention, in addition to satisfying the above-mentioned composition, preferably contains Cu, Co, W, Cr, Mo, P and S, and satisfies the formula (B) shown below.

[0022] 10≤50([Cu%]+[Co%])+100[W%]+200[Cr%]+800[Mo%]-100[P%]-1000[S%] …(B) (In formula (B), % represents mass%.) Fe-Ni soft magnetic materials sometimes rust during manufacturing due to changes in temperature and humidity, posing a risk of deterioration in magnetic properties. Cu, Co, W, Cr, Mo, P, and S are elements that affect rust resistance. This invention, by incorporating Cu, Co, W, Cr, Mo, P, and S into the Fe-Ni alloy sheet in a manner satisfying formula (B), achieves Fe-Ni alloy sheets that possess both excellent magnetic properties and rust resistance. As described above, since the Fe-Ni alloy sheet exhibits rust resistance, additional processes such as rust removal and rust prevention treatment can be eliminated. Consequently, reduced workability and decreased production efficiency due to increased process steps can be prevented. The value of formula (B) is preferably 10 or more, more preferably 15 or more, and even more preferably 20 or more.

[0023] C: 0.001~0.05% by mass Carbon (C) in Fe-Ni alloy plates is an essential element for maintaining alloy strength. When the C content is less than 0.001% by mass, this effect cannot be fully achieved. On the other hand, if the C content exceeds 0.05% by mass, it reacts with Cr and Ti in the alloy to form carbides, hindering grain growth and domain wall movement, thereby deteriorating magnetic properties. Therefore, the C content is 0.001 to 0.05% by mass, preferably 0.001 to 0.01% by mass, and more preferably 0.001 to 0.008% by mass.

[0024] Si: 0.05–0.50% by mass The Si contained in Fe-Ni alloy sheets is an effective element for the deoxidation treatment performed during the manufacture of Fe-Ni alloy sheets. When the Si content is less than 0.05% by mass, this effect cannot be fully achieved. On the other hand, if the Si content exceeds 0.50% by mass, the regular lattice of the Fe-Ni alloy is no longer in its optimal state, leading to a deterioration in magnetic properties. Therefore, the Si content is 0.05 to 0.50% by mass, with a preferred lower limit of 0.10% by mass and a preferred upper limit of 0.25% by mass. That is, the Si content is preferably 0.05 to 0.25% by mass, and more preferably 0.10 to 0.25% by mass.

[0025] Mn: 0.25~1.00% by mass Mn, contained in Fe-Ni alloy sheets, is an effective element. It combines with sulfur (S) to form MnS, which reduces hot workability, thus suppressing the reduction in hot workability caused by S. Furthermore, the formation of MnS improves stampability. This effect cannot be fully obtained when the Mn content is less than 0.25% by mass. On the other hand, if the Mn content exceeds 1.00% by mass, excessive MnS is formed, hindering grain growth and domain wall movement, thereby deteriorating magnetic properties. Therefore, the Mn content is 0.25 to 1.00% by mass, preferably 0.25 to 0.60% by mass, and more preferably 0.25 to 0.57% by mass.

[0026] P: 0.001~0.030% by mass Phosphorus (P) in Fe-Ni alloy plates is an effective element that suppresses sulfur (S) segregation to grain boundaries by segregating to them, promotes the dispersion and precipitation of MnS, and improves stamping properties. This effect is not fully achieved when the P content is less than 0.001% by mass. On the other hand, if the content exceeds 0.030% by mass, excessive P segregation at grain boundaries not only worsens hot workability but also reduces rust resistance. Therefore, the P content is 0.001–0.030% by mass, preferably 0.001–0.020% by mass, and more preferably 0.001–0.019% by mass.

[0027] S: 0.0001~0.0050% by mass Sulfur (S) in Fe-Ni alloy plates is an effective element for improving stamping properties by combining with Mn and Mg to form MnS and MgS. This effect is not fully achieved when the S content is less than 0.0001% by mass. On the other hand, if the S content exceeds 0.0050% by mass, S segregates at grain boundaries, forming low-melting-point compounds, which significantly reduces both hot workability and rust resistance. Therefore, the S content is preferably 0.0001 to 0.0050% by mass, with a preferred lower limit of 0.0003% by mass, more preferably 0.0005% by mass, and a preferred upper limit of 0.0040% by mass, more preferably 0.0030% by mass. That is, the S content is preferably 0.0003 to 0.0040% by mass, more preferably 0.0005 to 0.0030% by mass.

[0028] Ni: 35.0–44.0% by mass Ni, contained in Fe-Ni alloy sheets, is a crucial element for ensuring magnetic properties. When the Ni content is less than 35.0% by mass, this effect cannot be fully achieved. On the other hand, if the Ni content exceeds 44.0% by mass, scratches or cracks will appear on the surface of the rolled sheet during hot rolling, thus reducing the yield. Therefore, the Ni content is 35.0 to 44.0% by mass, with a preferred lower limit of 35.7% by mass, more preferably 40.5% by mass, and a preferred upper limit of 42.6% by mass, more preferably 41.5% by mass. That is, the Ni content is preferably 35.7% to 42.6% by mass, more preferably 40.5% to 41.5% by mass.

[0029] Cr: 0.01–0.50% by mass Cr, contained in Fe-Ni alloy plates, is an effective element for ensuring rust resistance. This effect cannot be fully achieved when the Cr content is less than 0.01% by mass. On the other hand, if the Cr content exceeds 0.50% by mass, it combines with C present in the Fe-Ni alloy to form Cr-based carbides, hindering the movement of magnetic domain walls and thus deteriorating magnetic properties. Therefore, the Cr content is preferably 0.01 to 0.50% by mass, with a lower limit of 0.02% by mass, more preferably 0.03% by mass, and a higher limit of 0.10% by mass, more preferably 0.08% by mass. That is, the Cr content is preferably 0.02 to 0.10% by mass, more preferably 0.03 to 0.08% by mass.

[0030] Mo: 0.005–0.10% by mass Mo, contained in Fe-Ni alloy plates, is an effective element for ensuring rust resistance and is also an important element for controlling the ordered lattice formation conditions that affect the magnetic anisotropy and magnetostriction of the crystal. When the Mo content is less than 0.005% by mass, this effect cannot be fully obtained. On the other hand, if the Mo content exceeds 0.10% by mass, the saturation magnetic flux density decreases. Therefore, the Mo content is preferably 0.005 to 0.10% by mass, with a preferred lower limit of 0.01% by mass and a preferred upper limit of 0.05% by mass. That is, the preferred Mo content is 0.01 to 0.05% by mass.

[0031] Cu: 0.01–2.00% by mass Cu, a crucial element in Fe-Ni alloy plates, ensures both saturation magnetic flux density and rust resistance. When the Cu content is below 0.01% by mass, sufficient rust resistance cannot be achieved. Conversely, if the Cu content exceeds 2.00% by mass, burrs or edge collapse occur during grooving or stamping processes, leading to deterioration of the product shape. Therefore, the Cu content is 0.01–2.00% by mass, preferably 0.01–0.50% by mass, and more preferably 0.01–0.40% by mass.

[0032] Al: 0.0001~0.10% by mass Al, contained in Fe-Ni alloy sheets, is an effective element for deoxidation treatment during the manufacturing process. When the Al content is below 0.0001% by mass, this effect is not fully achieved, and the O concentration in the Fe-Ni alloy increases, leading to an increase in oxide inclusions and a decrease in magnetic properties. On the other hand, if the Al content exceeds 0.10% by mass, its ability to reduce MgO in the slag is too strong, increasing the Mg concentration in the Fe-Ni alloy and generating the low-melting-point intermetallic compound Ni₂Mg, which reduces hot workability. Furthermore, its ability to reduce CaO in the slag is also excessively enhanced, increasing the Ca concentration in the steel and decreasing magnetic properties. Therefore, the Al content is 0.0001–0.10% by mass, preferably 0.0001–0.050% by mass, and more preferably 0.0001–0.045% by mass.

[0033] Ti: less than 0.050% by mass The Ti contained in the Fe-Ni alloy plate combines with the C and N present in the Fe-Ni alloy to form Ti-based carbides and nitrides. If the Ti content is too high, it hinders grain growth and the movement of magnetic domain walls, thus deteriorating the magnetic properties. On the other hand, Ti, by forming nitrides, becomes an effective nucleus for MnS, improving its stampability and promoting its precipitation. Therefore, considering the balance between magnetic properties and stampability, the Ti content is preferably 0.050% by mass or less, with a preferred lower limit of 0.001% by mass and a preferred upper limit of 0.020% by mass. That is, the Ti content is preferably 0.001 to 0.020% by mass.

[0034] Co: 0.01~2.00% by mass Co, a crucial element in Fe-Ni alloy plates, ensures both saturation magnetic flux density and rust resistance. When the Co content is less than 0.01% by mass, sufficient rust resistance cannot be achieved. Conversely, if the Co content exceeds 2.00% by mass, burrs or edge collapse occur during grooving or stamping processes, leading to deterioration of the product shape. Therefore, the Co content is 0.01–2.00% by mass, preferably 0.01–1.00% by mass, and more preferably 0.01–0.50% by mass.

[0035] W: 0.01~0.50% by mass W, contained in Fe-Ni alloy sheets, is an important element for ensuring both saturation magnetic flux density and rust resistance. When the W content is below 0.01% by mass, sufficient rust resistance cannot be achieved. On the other hand, if the W content exceeds 0.50% by mass, warping occurs during grooving or stamping, leading to deterioration of the product shape. Therefore, the W content is 0.01 to 0.50% by mass, preferably 0.01 to 0.10% by mass, and more preferably 0.01 to 0.05% by mass.

[0036] N: 0.001~0.05% by mass Ni (N) is an essential element for ensuring the strength of Fe-Ni alloys. When the N content is below 0.001% by mass, this effect cannot be adequately achieved. On the other hand, if the N content exceeds 0.05% by mass, it combines with Ti in the presence of the Fe-Ni alloy to form nitrides, hindering grain growth and domain wall movement, thus deteriorating magnetic properties. Therefore, the N content is preferably 0.001 to 0.05% by mass, and the upper limit of the Ni content is preferably 0.01% by mass, more preferably 0.006% by mass. That is, the Ni content is preferably 0.001 to 0.01% by mass, more preferably 0.001 to 0.006% by mass.

[0037] Sn: 0.0001~0.05% by mass Sn, an element essential for ensuring plating properties in Fe-Ni alloy plates, is crucial. When the Sn content is below 0.0001% by mass, this effect cannot be adequately achieved. Conversely, if the Sn content exceeds 0.05% by mass, hot workability decreases. Therefore, the Sn content is preferably 0.0001 to 0.05% by mass, with an upper limit of 0.01% by mass, and more preferably 0.005% by mass. In other words, the Sn content is preferably 0.0001 to 0.01% by mass, and more preferably 0.0001 to 0.005% by mass.

[0038] Mg: less than 0.05% by mass In Fe-Ni alloy plates, Mg combines with S present in the Fe-Ni alloy to form MgS. If the Mg content is too high, excessive MgS is formed, hindering grain growth and domain wall movement, thus deteriorating magnetic properties. However, due to the manufacturing process, Mg is inevitably mixed in. Therefore, from the perspective of magnetic properties, the Mg content is 0.05% by mass or less, preferably 0.01% by mass or less, and more preferably 0.005% by mass or less.

[0039] Zr: 0.0001~0.05% by mass Zr, contained in Fe-Ni alloy plates, is an essential element for ensuring the strength of Fe-Ni alloys. When the Zr content is below 0.0001% by mass, this effect cannot be sufficiently obtained. On the other hand, if the Zr content exceeds 0.05% by mass, the magnetic properties decrease. Therefore, the Zr content is 0.0001 to 0.05% by mass, preferably 0.0001 to 0.01% by mass, and more preferably 0.0001 to 0.008% by mass.

[0040] Ca: less than 0.0020% by mass In Fe-Ni alloy plates, Ca combines with Al present in the Fe-Ni alloy to form Ca-Al oxide inclusions. If the Ca content is excessive, excessive formation of Ca-Al oxide inclusions hinders grain growth and domain wall movement, deteriorating magnetic properties. On the other hand, Ca is an important element for suppressing SiO2 activity and controlling O content to reduce inclusion content. Therefore, from a magnetic property perspective, the Ca content is preferably 0.0020% by mass or less, with a preferred lower limit of 0.0001% by mass and a preferred upper limit of 0.0010% by mass. That is, the Ca content is preferably 0.0001 to 0.0010% by mass.

[0041] O: 0.0002~0.01% by mass When the oxygen content in the Fe-Ni alloy plate (in the molten metal) is less than 0.0002% by mass, the CaO in the slag is reduced, increasing the Ca concentration in the molten metal and forming excessive Ca-Al oxide inclusions. This hinders grain growth and domain wall movement, deteriorating magnetic properties. Conversely, if the oxygen content exceeds 0.01% by mass, it forms oxide inclusions with other elements, further hindering domain wall movement and deteriorating magnetic properties. Therefore, the oxygen content is preferably 0.0002–0.01% by mass, with a lower limit of 0.0005% by mass and an upper limit of 0.008% by mass. That is, the oxygen content is preferably 0.0005–0.008% by mass.

[0042] In the Fe-Ni alloy plate of the present invention, the balance other than the above-mentioned components is Fe and unavoidable impurities, and Fe is contained as the main component.

[0043] The thickness of the Fe-Ni alloy plate is not particularly limited, but it is preferably 0.05 mm or more and 6.00 mm or less, and more preferably 0.08 mm or more and 4.00 mm or less.

[0044] Next, the manufacturing method of the Fe-Ni alloy plate according to the present invention will be described. The manufacturing method of the Fe-Ni alloy plate of the present invention includes the following steps: (a) (a) A process of oxidative refining of molten metal containing Fe-Ni alloy raw materials in either of the secondary refining vessels of an AOD furnace or a VOD furnace (hereinafter also referred to as "process (a)"); (b) A process of adding Al and / or FeSi alloy to the oxidized and refined molten metal for deoxidation and desulfurization treatment (hereinafter also referred to as "process (b)"), wherein the content of Al in the molten metal is 0.0001 to 0.10% by mass, the content of Si is 0.05 to 0.50% by mass, the content of S is 0.0001 to 0.0050% by mass, and the content of O is in the range of 0.0002 to 0.01% by mass; (c) A process of continuously casting the deoxidized and desulfurized molten metal to form a slab (hereinafter also referred to as "process (c)"); and (d) A process of hot rolling the obtained slab and then cold rolling (hereinafter also referred to as "process (d)").

[0045] Process (a) In step (a), molten metal containing Fe-Ni alloy raw materials is oxidatively refined using either an AOD (Argon Oxygen Decarburization) furnace or a VOD (Vacuum Oxygen Decarburization) furnace as a secondary refining vessel. Molten metal is obtained by melting the Fe-Ni alloy raw materials in an electric furnace. Raw materials can include, for example, iron filings, nickel, ferronickel, Fe-Ni alloy slabs, or Fe-Ni alloy scraps. The obtained molten metal is decarburized using either an AOD furnace or a VOD furnace, thereby discharging the decarburized oxidizing slag, i.e., FeO-CaO-SiO2 slag containing FeO. This slag also contains chromium oxides, tungsten oxides, titanium oxides, and phosphorus oxides, which are also discharged outside the system. Therefore, in the obtained Fe-Ni alloy plate, the Cr content can be controlled within the aforementioned range, and consequently, the W and Ti contents are also easily controlled within the aforementioned range. Furthermore, the P content, as a harmful impurity element, can be reduced to below 0.030% by mass. As described above, by using either an AOD furnace or a VOD furnace as a secondary refining vessel for oxidative refining, the aforementioned oxidizing slag can be discharged outside the system. It should be noted that because the VOD furnace first moves the ladle to the slag removal area and then uses a slag remover for slag removal, the molten metal temperature tends to drop; therefore, using an AOD furnace is more effective.

[0046] Furthermore, through process (a), the contents of Cu, Co, and W can be appropriately controlled so that the obtained Fe-Ni alloy plate satisfies the above formula (A). That is, the value of the above formula (A) can be easily controlled within the range of 1.5 or more and less than 50.0, preferably within the range of 1.5 or more and less than 40.0, and more preferably within the range of 1.5 or more and less than 25.0.

[0047] Process (b) In step (b), Al and / or FeSi alloys are added to the molten metal after oxidative refining to perform deoxidation and desulfurization treatment. Even after the oxidative slag is discharged through oxidative refining, approximately 1 ton of oxidative slag remains in the molten metal. Therefore, considering the FeO concentration in the remaining oxidative slag and the oxygen concentration in the molten metal, an appropriate amount of Al and / or FeSi alloy is added to the molten metal to deoxidize and desulfurize it. In particular, by adding Al and FeSi alloys, the Al content in the molten metal is adjusted to the range of 0.0001 to 0.1% by mass, and the Si content is adjusted to the range of 0.05 to 0.5% by mass, thereby deoxidation and desulfurization are carried out in the most optimal manner. In the resulting Fe-Ni alloy plate, the O content can be controlled to the range of 0.0002 to 0.01% by mass, and the S content can be controlled to the range of 0.0001 to 0.0050% by mass, respectively. In addition, other thermodynamically unstable elements can also be controlled within the above ranges. The theory behind this will be explained below.

[0048] In the refining process including steps (a) and (b) above, the resulting slag plays a very important role. There are no particular limitations on the type of slag formed, but a CaO-SiO2-Al2O3-MgO-F series slag is preferred. The CaO in such slag can be formed by adding quicklime (obtained by decomposing limestone to remove CO2) to the molten metal, and the SiO2 can be formed by oxidation after adding FeSi alloy. CaO plays a particularly important role in the slag, and the CaO concentration in the slag is preferably controlled at 40–70% by mass. MgO can be formed by using dolomite-based bricks, magnesia bricks, MgO-C-based bricks, or other magnesia-containing bricks in the refractory material of any secondary refining vessel in either the AOD or VOD furnace, causing MgO to melt into the slag. Furthermore, since such bricks are expensive, it is preferable to extend the brick's lifespan as much as possible to control costs; waste bricks containing MgO can also be used. F can be controlled by adding fluorite to the molten metal. F is an important component, ensuring the fluidity of the slag and promoting the following reactions between the slag and molten metal, thereby controlling the O content within the range of 0.0002–0.01% by mass, the S content within the range of 0.0001–0.0050% by mass, and the Ca content below 0.0020% by mass. Therefore, the F concentration in the slag is preferably controlled between 1 and 10% by mass. It should be noted that in the following reactions, the underlined components are those contained in the molten metal, and the components in parentheses are those contained in the slag.

[0049] Si +2 O → (SiO2) (1) 2(CaO)+ Si → (SiO2)+2 Ca (2) Ca + S → (CaS) (3) In order for the reaction represented by the above equation (1) to proceed effectively to the right and to control the O content within the range of 0.0002 to 0.01% by mass, the SiO2 activity in the slag needs to be controlled at 10. -2 ~10 -3 The low level. For this reason, as mentioned above, CaO is effective in controlling the SiO2 activity by adding quicklime to the molten metal. Furthermore, if the reaction represented by the above formula (2) proceeds to the right, the generated Ca reacts with S in the molten metal to undergo the desulfurization reaction represented by the above formula (3), and the S content can be controlled in the range of 0.0001 to 0.0050% by mass. Moreover, once the Ca transferred to the molten metal reacts with S, Ca is consumed, thereby controlling the Ca content to below 0.0020% by mass.

[0050] Additionally, Al can also be used for deoxidation, as indicated by equation (4) below. Industrial FeSi alloys typically contain approximately 1% by mass of Al as an impurity. Therefore, by adding FeSi alloy to the molten metal, the Al content can be controlled within the range of 0.0001 to 0.10% by mass. Furthermore, Al₂O₃ in the slag can also react with Si in the molten metal, so caution is necessary. That is, if the reaction indicated by equation (5) below is active, the Al content will exceed 0.10% by mass. To control the reaction indicated by equation (5) below, if the activity of Al₂O₃ in the slag is controlled to 10... -2 ~10 -3 If the concentration of Al is low, it is easy to control the Al content within the range of 0.0001 to 0.10% by mass. Therefore, it is preferable to operate as described above to control the CaO concentration in the slag so that the reaction represented by the above formula (2) proceeds to the right and the reaction represented by the following formula (5) reaches an equilibrium state, thereby stabilizing the reaction.

[0051] 2 Al +3 O → (Al2O3) (4) 2(Al2O3)+3 Si → 3(SiO2)+4 Al (5) To control the Mg content below 0.050% by mass, it is necessary to suppress the reaction represented by the following formula (6). In this case, although it is effective to reduce the MgO in the slag as much as possible, considering the need to melt bricks and add waste bricks, it is preferable to control the MgO concentration in the slag within the range of 5 to 20% by mass. In addition, to suppress the Mg concentration, it is preferable to control the Si concentration in the molten metal within the above range, and the CaO concentration in the slag within the above range. Thus, the Mg content can be controlled below 0.050% by mass.

[0052] 2(MgO)+ Si → (SiO2)+2 Mg (6) W forms WO3 oxide during decarburization, some of which volatilizes, while some is transferred to the slag as shown in equation (7) below. By adjusting the amount of W added during ladle refining, the W content can be controlled within the range of 0.01 to 0.50% by mass. However, it is preferable to control the CaO, MgO, and F concentrations in the slag within the above ranges, so that the reaction represented by equation (7) below reaches equilibrium and the reaction is stable.

[0053] W +3 O → (WO3) (7) In order to control the Zr content within the range of 0.0001 to 0.05% by mass, the amount of Zr added can be adjusted in the ladle refining process in the same way as W. However, as shown in equation (8) below, Zr is an easily oxidized element. Therefore, it is preferable to maintain the equilibrium relationship of the reaction represented by equation (7) below by controlling the concentrations of CaO, MgO, and F in the slag within the above ranges, and controlling the O content within the range of 0.0002 to 0.01% by mass, so as to stabilize the reaction.

[0054] Zr +2 O → (ZrO2) (8) To control the Ti content below 0.050% by mass, the reaction represented by equation (9) is effectively promoted to the right. Similarly, by controlling the CaO, MgO, and F concentrations in the slag within the above ranges, the TiO2 activity in the slag is reduced, and the O content is controlled within the range of 0.0002 to 0.01% by mass, the reaction represented by equation (9) is effectively promoted to the right, and the Ti content can ultimately be controlled below 0.050% by mass.

[0055] Ti +2 O → (TiO2) (9) To control the N content within the range of 0.001 to 0.05% by mass, the reaction represented by the following formula (10) is effectively promoted to the right. When melting raw materials in an electric furnace, nitrogen is easily introduced from the atmosphere. However, by using an AOD furnace or a VOD furnace, the reaction of the following formula (10) can be promoted to the right during decarburization, thereby controlling the N content within the aforementioned range. Specifically, during oxygen refining, CO gas is generated through the reactions represented by the following formulas (11) and (12). The CO gas bubbles generated in this way can absorb dissolved nitrogen in the molten metal and transfer it to the CO gas as nitrogen gas, ultimately being discharged outside the furnace through CO bubbles, thus removing nitrogen gas. Even after removing CO gas from the system, the thermodynamic equilibrium value of nitrogen will not be lower than 0.001% by mass, therefore the N content can be controlled within the range of 0.001 to 0.05% by mass.

[0056] 2 N → N2 [gas] (10) O2 [gas] + 2 Fe → 2FeO [Oxygen bubble surface] (11) FeO [Oxygen bubble surface] + C →CO [gas] + Fe [liquid] (12) Process (c) In step (c), the deoxidized and desulfurized molten metal is continuously cast to form a slab. There are no particular limitations on the conditions for continuous casting, and continuous casting can be carried out using a vertical continuous casting machine.

[0057] Process (d) In step (d), the obtained slab is hot-rolled, followed by cold rolling. The hot rolling process produces a hot-rolled strip, which is then cold-rolled to produce a cold-rolled sheet. The conditions for hot rolling and cold rolling are not particularly limited; hot rolling can be performed using a Steckel-mill, and cold rolling can be performed using a Sendzimir-type cold rolling mill. Furthermore, before the cold rolling process, annealing and pickling can be performed as needed to remove surface oxide scale. This allows the manufacture of the Fe-Ni alloy sheet of the present invention.

[0058] Magnetic properties of Fe-Ni alloys are imparted by magnetic annealing of cold-rolled sheets. The conditions for magnetic annealing are not particularly limited and can be suitably performed using existing known methods. Through this process, Fe-Ni alloy sheets exhibiting the following magnetic properties can be obtained: preferably, an initial relative permeability (μ... i The value is 3,000 or more, more preferably 3,500 or more, and the maximum relative permeability is preferred. μ maxThe saturation magnetic flux density (B) is 30,000 or more, more preferably 35,000 or more, and preferably 30,000 or more. 800 The engine power is 1.4T or higher, and more preferably 1.45T or higher.

[0059] Example The following describes embodiments of the present invention, but the present invention is not limited to these embodiments as long as it does not depart from its spirit.

[0060] <Examples 1-40, Comparative Examples 1-10> Sixty tons of raw materials, including iron filings, nickel, and ferronickel, are melted in an electric furnace. Subsequently, oxidative refining is carried out in an AOD (Alternating Oxidation) furnace or VOD (Vacuum-Oxide) furnace to perform decarburization, dechromization, and dephosphorization treatments. Here, the refractory material for the secondary refining vessel of the AOD or VOD furnace is lined with dolomite bricks, magnesia-chrome bricks, magnesia bricks, and MgO-C series bricks each time the material is charged, depending on the operational cycle. Next, the resulting oxidizing slag, i.e., FeO-CaO-SiO2 series slag containing FeO, is discharged. This slag also contains Cr oxides, W oxides, Ti oxides, and phosphorus oxides, and is discharged outside the system as much as possible. Subsequently, the content of Al, Si, S, and O in the resulting molten metal is adjusted using Al and / or FeSi alloys, while simultaneously deoxidizing and desulfurizing the molten metal. At this point, a CaO-SiO2-Al2O3-MgO-F series slag is obtained. That is, quicklime is added to the molten metal to form CaO, and then SiO2 is formed through oxidation after the addition of FeSi alloy. The MgO source uses waste bricks containing MgO, which also serves to prevent brick melting loss. The F source is prepared by adding fluorite to the molten metal, ensuring the fluidity of the slag. Subsequently, molten steel is poured into a ladle, and the temperature is adjusted during the ladle refining process. Simultaneously, to adjust the alloy composition to the chemical composition shown in Tables 3 and 4 below, various components are added after precise calculations. It should be noted that the slag composition in Table 5 represents the slag composition at the end of AOD or VOD refining.

[0061] [Table 3] [Table 4] Table 5 Next, the deoxidized and desulfurized molten metal is continuously cast into slabs, which are then hot-rolled and annealed / pickled. Subsequently, they are cold-rolled to produce Fe-Ni alloy plates with a thickness of 0.8 mm.

[0062] <Magnetic properties> The obtained Fe-Ni alloy plate was processed into a ring-shaped test piece with a diameter of φ45mm × 33mm according to JIS C2531, and tested under vacuum (5.0 × 10⁻⁶ mm). -3 In an atmosphere below Pa, after magnetic annealing at 1125°C for 2.5 hours, enameled copper wire as specified in JIS C3202 or JIS C3215 is wound 50 turns on both the primary and secondary sides, and the initial relative permeability is measured. μ i ), maximum relative permeability ( μ max ) and saturation magnetic flux density (B 800 The initial relative permeability and maximum relative permeability were measured under a reverse magnetic field of 16 A / m, with an initial relative permeability of 0.8 A / m. The saturation magnetic flux density was measured under a magnetic field of 1600 A / m. Based on the measurement results, a comprehensive evaluation of the magnetic properties was performed. If all three criteria for initial relative permeability, maximum relative permeability, and saturation magnetic flux density shown below were met, the magnetic properties were rated as excellent (○). If only two of the criteria for initial relative permeability, maximum relative permeability, and saturation magnetic flux density were met, the magnetic properties were rated as good (△). If only one criterion was met or none were met, the magnetic properties were rated as poor (×). The results are shown in Table 6.

[0063] • Initial relative permeability: 3,000 or higher • Maximum relative permeability: 30,000 or higher • Saturation magnetic flux density: 1.4 (T) or higher Rust resistance To evaluate rust resistance, the cold-rolled sheet obtained above was cut into 40×50mm test pieces, and its surface was wet-polished with 400-grit water-resistant sandpaper to conduct a rapid rust test. The rapid rust test was conducted at 70℃ and 100% relative humidity. The test pieces were kept horizontally in a 1000ml beaker containing 200ml of distilled water for 72 hours, avoiding contact with water. Subsequently, according to JIS G0595 standard, the degree of rust was evaluated using rating numbers (RN) in three levels. The results are shown in Table 6.

[0064] • 0: RN is greater than 2.5 • △: RN is 2.0 or higher and 2.5 or lower • ×: RN is less than 2.0 <Overall Evaluation> As a comprehensive evaluation of the above experiments, the following four levels were used for evaluation. The results are shown in Table 6.

[0065] •◎: Both magnetic properties and rust resistance are rated "○". • 〇: The magnetic properties are rated as "〇" and the rust resistance is rated as "△". •△: The magnetic property is rated as "△", or the magnetic property is rated as "〇" and the rust resistance is rated as "×". • ×: The magnetic properties are rated as “×”, or the product yield is low. Table 6 As shown in Tables 3 to 6, in Examples 1 to 30, which used Fe-Ni alloy plates that met the chemical composition range specified in this invention, both the magnetic properties and rust resistance were rated as "○", and the overall rating was also "◎".

[0066] In Examples 31-34, although the obtained Fe-Ni alloy plates met the range of chemical composition specified in this invention and the evaluation of magnetic properties was "○", the evaluation of rust resistance was "△", resulting in an overall evaluation of "○".

[0067] In Example 35, although the obtained Fe-Ni alloy plate met the range of chemical composition specified in this invention, the value of formula (A) was 50.4, and the maximum relative permeability was less than 30,000, so the evaluation of magnetic properties was "△". On the other hand, since the evaluation of rust resistance was "0", the overall evaluation was "△".

[0068] In Example 36, although the obtained Fe-Ni alloy plate meets the range of chemical composition specified in this invention, the value of formula (A) is 1.4, and the saturation magnetic flux density is less than 1.4T, so the evaluation of magnetic properties is "△". On the other hand, since the evaluation of rust resistance is "0", the overall evaluation is "△".

[0069] In Example 37, although the obtained Fe-Ni alloy plate met the range of chemical composition specified in this invention, the value of formula (A) was 1.3, and the saturation magnetic flux density was less than 1.4T, so the evaluation of magnetic properties was "△". On the other hand, since the evaluation of rust resistance was "0", the overall evaluation was "△".

[0070] In Example 38, although the obtained Fe-Ni alloy plate met the range of chemical composition specified in this invention, the value of formula (A) was 50.1, and the maximum relative permeability was less than 30,000, so the evaluation of magnetic properties was "△". On the other hand, since the evaluation of rust resistance was "0", the overall evaluation was "△".

[0071] In Example 39, although the obtained Fe-Ni alloy plate meets the range of chemical composition specified in this invention, the value of formula (B) is 9 and RN is less than 2.0, so the evaluation of rust resistance is "×". On the other hand, since the evaluation of magnetic properties is "○", the overall evaluation is "△".

[0072] In Example 40, although the obtained Fe-Ni alloy plate met the chemical composition range specified in this invention, the value of formula (A) was 1.4, and the saturation magnetic flux density was less than 1.4T. Furthermore, the value of formula (B) was 0, and RN was less than 2.0. Therefore, since the evaluation of magnetic properties was "△" and the evaluation of rust resistance was "×", the overall evaluation was "△".

[0073] In Comparative Examples 1-3, the obtained Fe-Ni alloy plates did not meet the chemical composition range specified in this invention, and their initial relative permeability was less than 3,000, and their maximum relative permeability was less than 30,000. Therefore, their magnetic properties were evaluated as "×". Furthermore, the yield of the product was also poor; during this charge, one roll of material was scrapped due to severe cracking. Therefore, the overall evaluation was "×".

[0074] In Comparative Examples 4 and 5, the obtained Fe-Ni alloy plates did not meet the range of chemical composition specified in this invention, and their initial relative permeability was less than 3,000 and saturation magnetic flux density was less than 1.4T, therefore their magnetic properties were evaluated as "×". Furthermore, since the value of formula (B) was also low, especially in Comparative Example 5 where RN was less than 2.0, their rust resistance was also evaluated as "×". Therefore, the overall evaluation was "×".

[0075] In Comparative Example 6, the obtained Fe-Ni alloy plate did not meet the chemical composition range specified in this invention, and its saturation magnetic flux density was less than 1.4T, therefore its magnetic properties were evaluated as "△". Furthermore, since the value of formula (B) was 7 and RN was less than 2.0, its rust resistance was evaluated as "×". On the other hand, the yield rate of the product was poor; in this loading process, one coil was scrapped due to severe edge cracks. Therefore, the overall evaluation was "×".

[0076] In Comparative Examples 7-9, the obtained Fe-Ni alloy plates did not meet the range of chemical composition specified in this invention, and their initial relative permeability was less than 3,000 and saturation magnetic flux density was less than 1.4T, so their magnetic properties were evaluated as "×". Furthermore, since the value of formula (B) was also low, RN was less than 2.0, their rust resistance was also evaluated as "×", and the overall evaluation was "×".

[0077] In Comparative Example 10, the obtained Fe-Ni alloy plate did not meet the chemical composition range specified in this invention, and its initial relative permeability was less than 3,000, and its maximum relative permeability was less than 30,000. Therefore, its magnetic properties were evaluated as "×". Furthermore, the yield of the product was also poor; in this loading process, two rolls were scrapped due to severe edge cracks. Therefore, the overall evaluation was "×".

[0078] Industrial availability The Fe-Ni alloy plate of this invention can be used as a soft magnetic material, such as automotive sensors or magnetic shielding materials, watch stators, etc., because it can impart excellent initial relative permeability as well as good maximum relative permeability and saturation magnetic flux density, and the yield can be controlled during manufacturing.

Claims

1. A Fe-Ni alloy plate, characterized in that, It contains Carbon (C): 0.001–0.05% by mass Silicon (Si): 0.05–0.50% by mass Manganese (Mn): 0.25–1.00% by mass Phosphorus (P): 0.001–0.030% by mass Sulfur (S): 0.0001–0.0050% by mass Nickel (Ni): 35.0–44.0% by mass Chromium (Cr): 0.01–0.50% by mass Molybdenum (Mo): 0.005–0.10% by mass Copper (Cu): 0.01–2.00% by mass Aluminum (Al): 0.0001–0.10% by mass Titanium (Ti): less than 0.050% by mass Cobalt (Co): 0.01–2.00% by mass Tungsten (W): 0.01–0.50% by mass Nitrogen (N): 0.001–0.05% by mass Tin (Sn): 0.0001~0.05% by mass Magnesium (Mg): less than 0.050% by mass Zirconium (Zr): 0.0001–0.05% by mass Calcium (Ca): less than 0.0020% by mass Oxygen (O): 0.0002–0.01% by mass The balance consists of iron (Fe) and unavoidable impurities.

2. The Fe-Ni alloy plate according to claim 1, comprising Cu, Co, and W, and satisfying the following relationship (A), 1.5≤20[Cu%]+20[Co%]+80[W%]<50.0 … (A) In formula (A), % represents mass%.

3. The Fe-Ni alloy plate according to claim 1 or 2, comprising Cu, Co, W, Cr, Mo, P, and S, and satisfying the following formula (B), 10≤50([Cu%]+[Co%])+100[W%]+200[Cr%]+800[Mo%]-100[P%]-1000[S%] … (B) In formula (B), % represents mass%.

4. A method for manufacturing the Fe-Ni alloy plate according to claim 1 or 2, characterized in that, Includes the following processes: The process of oxidative refining molten metal containing Fe-Ni alloy raw materials in any of the secondary refining containers of an AOD furnace or a VOD furnace. The process of deoxidation and desulfurization involves adding Al and / or FeSi alloy to the molten metal after oxidative refining for deoxidation and desulfurization, such that the content of Al in the molten metal is in the range of 0.0001 to 0.10% by mass, the content of Si is in the range of 0.05 to 0.50% by mass, the content of S is in the range of 0.0001 to 0.0050% by mass, and the content of O is in the range of 0.0002 to 0.01% by mass. The process of continuously casting deoxidized and desulfurized molten metal to form slabs; and The process of hot rolling the obtained slab followed by cold rolling.

5. A method for manufacturing the Fe-Ni alloy plate according to claim 3, characterized in that, Includes the following processes: The process of oxidative refining molten metal containing Fe-Ni alloy raw materials in any of the secondary refining containers of an AOD furnace or a VOD furnace. The process of deoxidation and desulfurization involves adding Al and / or FeSi alloy to the molten metal after oxidative refining for deoxidation and desulfurization, such that the content of Al in the molten metal is in the range of 0.0001 to 0.10% by mass, the content of Si is in the range of 0.05 to 0.50% by mass, the content of S is in the range of 0.0001 to 0.0050% by mass, and the content of O is in the range of 0.0002 to 0.01% by mass. The process of continuously casting deoxidized and desulfurized molten metal to form slabs; and The process of hot rolling the obtained slab followed by cold rolling.

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