Iron-based alloy foil and method for manufacturing the same, and component using the same

Abstract

The objective of this invention is to minimize the causes of etching defects or pinholes in ultrathin ferroalloy foils with a thickness of 10–30 μm, which are suitable for high-precision metal masks for electronic components. To solve the above-mentioned technical problems, an iron alloy foil is manufactured as follows: comprising C: 0.150% or less, Si: 2.00% or less, Mn: 10.00% or less, Ni: 2.00 to 50.00%, Cr: 19.00% or less, N: 0.20% or less, Al: 0.030% or less, Co: 5.00% or less, Mg: 0.0005% or less, Ca: 0.0005% or less, Ti: 0.01% or less, P: 0.035% or less, S: 0.0300% or less, with the remainder consisting of Fe and impurities; relative to the total mass of inclusions with a particle size of 2.00 μm or more, Al2O3: 30% or less by mass, MgO: 15% or less by mass; among the inclusions with a particle size of 2.00 μm or more, the proportion of inclusions with a particle size of 5.00 μm or less is 80.00% or more.

Description

Technical Field

[0001] This invention relates to ferrous alloy foils and methods for manufacturing the same, as well as components using the ferrous alloy foils. For example, it can be applied to components for electronic devices such as metal masks and hard disk drive mounts, or to components used in the manufacture of electronic devices. Background Technology

[0002] With the miniaturization and high-density installation of electronic devices, there is a demand for simplification or weight reduction of the various electronic components that make up the electronic devices.

[0003] In most cases, the simplification of electronic components necessitates higher precision. For example, photolithography is a widely used technique in the high-precision processing of electronic components. Examples of applications of photolithography in achieving higher precision in electronic components include the high pixel density of OLEDs (Organic Light Emitting Diodes) and the miniaturization of suspensions used in hard disk drives (HDDs), achieved through the miniaturization of mask apertures based on metal masks. The metal masks used in these processes are manufactured by etching a dissolved metal plate after forming a pattern on its surface using photolithography.

[0004] The mask apertures of the metal mask need to correspond 1:1 to the RGB of the manufactured OLED pixels. Therefore, the spacing between the mask apertures must be at least the same as the pixel density of the OLED, and the aperture diameter of the mask apertures must be correspondingly smaller.

[0005] Typically, the mask aperture of a metal mask is conical trapezoidal (with a conical cross-section). To achieve this, the metal plate serving as the mask is masked with a dry film, with one surface side having a small aperture and the other surface side having a large aperture, and is manufactured by etching from each surface to half the thickness of the plate.

[0006] In metal plates used for manufacturing metal masks, the presence of inclusions that are difficult to dissolve in the etching solution can sometimes lead to poor etching. For example, if an inclusion with a size greater than half the thickness of the metal plate is present in the area where the mask holes are formed, the metal portion surrounding the inclusion will dissolve during half-etching from one side.

[0007] Furthermore, the portion of the dry film on the opposite surface will also dissolve, and the dry film on the opposite side will peel off. Moreover, during the semi-etching of the metal plate from the opposite side, the portion of the metal plate where the dry film has peeled off is also etched, thus forming a state with irregular holes centered on the inclusions.

[0008] Although this is just one example, the etching defects caused by inclusions become more pronounced as the pixel density of the manufactured OLED increases. This is because, as mentioned earlier, the metal mask is formed by etching a metal plate with a thickness corresponding to the pixel density of the manufactured OLED. Therefore, in the case of OLEDs with a pixel density of 800–1000 PPI, it is necessary to reduce the thickness of the metal mask from the current 20.00–30.00 μm to 12.00–15.00 μm. Consequently, the size of the inclusions needs to be limited to less than 10.00 μm.

[0009] Inclusions are primarily hard inclusions such as alumina (Al₂O₃) or magnesium-aluminum spinel (MgO·Al₂O₃), or soft inclusions such as silicon dioxide (SiO₂) and CaO. Hard inclusions tend to agglomerate at high interfacial energies, and their size tends to increase after agglomeration. Furthermore, hard inclusions are difficult to refine during hot or cold rolling, resulting in the presence of large inclusion particles. Therefore, to improve etching defects associated with high-precision machining, it is important to reduce both the size and number of inclusions in the metal sheet.

[0010] To manufacture such a metal mask, patent documents 1 and 2 propose a scheme using Invar alloy.

[0011] Patent document 1 discloses a method for manufacturing a metal mask for OLEDs with a thickness of approximately 100.00 μm, which is made by sequentially vacuum melting, forging, hot rolling, cold rolling, and intermediate annealing of Fe-Ni alloy.

[0012] Patent document 2 discloses the following: In order to reduce the oxygen concentration of molten metal, steel ingots are cast after the cleanliness of the molten metal is improved by vacuum induction melting or the like, thereby preventing poor etching of the metal mask material.

[0013] However, continuous casting and vacuum melting involve the process of pouring molten alloy (hereinafter referred to as "molten metal") from a tundish or furnace into a container of a certain shape, and then cooling the container to produce steel sheets. Steel sheets produced by continuous casting and vacuum melting take time to reach complete solidification. Therefore, steel sheets produced by continuous casting and vacuum melting solidify from the outside while still molten at the center, making it easy for inclusions to segregate and solidify inside the steel sheet.

[0014] Furthermore, during continuous casting, even if the molten slag in the tundish is removed, the alumina and spinel remaining in the molten metal, due to their high interfacial energy, tend to cluster during the cooling of the molten metal, easily becoming large inclusions.

[0015] Patent documents 3 and 4 disclose methods for manufacturing Fe-Ni alloy plates for etching processes. These methods estimate the size of the largest non-metallic inclusions in the Fe-Ni alloy slab, thus determining the final quality of the rolled sheets, coils, etc. However, in patent documents 3 and 4, the Fe-Ni alloy ingots are manufactured using ordinary ingot casting or continuous casting. Therefore, the steel sheets manufactured using the methods disclosed in patent documents 3 and 4 take a long time to fully solidify, making it easy for inclusions to segregate and solidify within the steel sheet.

[0016] Patent document 5 discloses the production of Fe-31%Ni-5%Co super Invar alloy steel ingots using a vacuum induction melting furnace, followed by heating to 1100°C for solution treatment, forging and hot rolling to produce plates, and then subjecting the plates to niobium nitride precipitation treatment at 800-900°C, followed by repeated cold rolling and annealing to produce cold-rolled parts with a thickness of 0.1 mm. However, in the process of producing steel ingots using a vacuum induction melting furnace and the subsequent solution treatment, as mentioned above, time is spent until solidification, thus inclusions tend to segregate and solidify within the steel sheet.

[0017] Patent Document 6 discloses a stainless steel sheet suitable for components in HDDs (Hard Disk Drives) or precision instrument components such as thin-film silicon solar cell substrates. The presence of tiny pits distributed on the surface of the stainless steel sheet significantly affects its cleanliness. It also discloses that these tiny pits are caused by inclusions or carbide particles leaving marks during the rolling process. Furthermore, Patent Document 6 describes that MgO-Al2O3 inclusions have low deformation energy during cold rolling, thus easily creating vacancies or voids at the metal / inclusion interface, which can easily become the starting point for tiny pits or fractures. To address this, it discloses the generation of non-metallic inclusions with Mn(O,S)-SiO2 as the main component, while adjusting the concentrations of MgO and Al2O3 to below a specified level, thereby rendering the non-metallic inclusions harmless.

[0018] Patent document 7 discloses a method for using Fe-Ni alloy plates for vapor deposition masks, such that every 1 mm 3 The metal plate has 3000 or fewer particles larger than 1 μm, 50 or fewer particles larger than 3 μm, and a ratio of 1-3 μm particles to the total number of particles larger than 1 μm of 70% or more. However, the metal plate manufacturing method disclosed in Patent Document 7 is based on the premise that inclusions float during the solidification of steel ingots. Since it does not take into account segregation that occurs during normal solidification (especially segregation towards the center of the steel ingot), it is not applicable to actual metal plate manufacturing. Therefore, Patent Document 7 essentially only discloses a selection criterion that is obvious to those skilled in the art: "selecting a metal plate with fewer coarse inclusions for use as a metal plate for vapor deposition masks."

[0019] Existing technical documents

[0020] Patent documents

[0021] Patent Document 1: Japanese Patent Application Publication No. 2004-183023

[0022] Patent Document 2: Japanese Patent Application Publication No. 2017-88915

[0023] Patent Document 3: Japanese Patent Application Publication No. 2005-256049

[0024] Patent Document 4: Japanese Patent Application Publication No. 2005-274401

[0025] Patent Document 5: Japanese Patent Application Publication No. 2001-262278

[0026] Patent Document 6: Japanese Patent Application Publication No. 2011-202253

[0027] Patent Document 7: Japanese Patent No. 6788852 Summary of the Invention

[0028] The technical problem that the invention aims to solve

[0029] As mentioned earlier, etching defects caused by inclusions become more pronounced as electronic components become more precise or streamlined. For example, the higher the pixel density of an OLED, the more significant the need for miniaturization of the suspension used in HDDs.

[0030] The inventors of this invention conducted an in-depth study on the relationship between the size of inclusions and etching defects in metal mask materials. The results showed that when the thickness of the metal mask material is ultra-thin at approximately 10.00 μm, reducing inclusions larger than 5.00 μm reduces etching defects in the metal mask material.

[0031] Furthermore, it was found that reducing the number of inclusions larger than 5.00 μm in the metal mask material also reduced pinholes.

[0032] Therefore, the present invention addresses the problem of reducing the number of coarse inclusions with a particle size greater than 5.00 μm in ultrathin ferroalloy foils with a thickness of 10.00 μm or more, and aims to provide a ferroalloy foil with reduced coarse inclusions, a method for manufacturing the same, and components using the same. Hereinafter, unless otherwise specified, inclusions with a particle size greater than 5.00 μm will be referred to as coarse inclusions.

[0033] Methods for solving technical problems

[0034] The inventors of this invention focused on the basic components of inclusions: Al2O3, MgO, SiO2, CaO, Mn(O, S), and CrS. They discovered that inclusions composed of at least one of SiO2, CaO, Mn(O, S), and CrS are difficult to cluster, and are also low-melting-point and soft. Therefore, by stretching or breaking them during hot or cold rolling processes, large inclusions can be reduced. (Sometimes SiO2, CaO, Mn(O, S), and CrS are referred to as soft inclusions.)

[0035] On the other hand, inclusions such as alumina (Al₂O₃) or magnesium-aluminum spinel (MgO·Al₂O₃, sometimes referred to as spinel below) have high interfacial energy and tend to segregate and aggregate during solidification, resulting in larger aggregate sizes. Furthermore, because alumina or spinel inclusions are hard, they are not easily broken up during hot or cold rolling, resulting in larger inclusion particles remaining as inclusions. (Sometimes alumina or magnesium-aluminum spinel are referred to as hard inclusions.)

[0036] Therefore, the following findings have been made: by reducing the ratio of alumina or spinel contained in inclusions, reconsidering the manufacturing conditions of ferroalloy foil, especially the rolling conditions, reducing the number of coarse alumina or spinel inclusions, and by finely dispersing soft inclusions, it is possible to obtain ferroalloy foil with reduced coarse inclusions.

[0037] This invention is based on the above insights, and its purpose is as follows. (1)

[0039] A ferrous alloy foil, characterized by having the following composition:

[0040] In terms of mass%, it contains

[0041] C: Below 0.150%

[0042] Si: below 2.00%

[0043] Mn: below 10.00%

[0044] Ni: 2.00~50.00%

[0045] Cr: less than 19.00%

[0046] N: below 0.20%

[0047] Al: below 0.030%

[0048] Co: less than 5.00%

[0049] Mg: less than 0.0005%

[0050] Ca: less than 0.0005%

[0051] Ti: less than 0.01%

[0052] P: below 0.035%

[0053] S: below 0.0300%,

[0054] The remaining portion consists of Fe and impurities;

[0055] The total mass relative to inclusions with a particle size of 2.00 μm or larger is less than 30% by mass for Al2O3 and less than 15% by mass for MgO.

[0056] Of the inclusions with a particle size of 2.00 μm or larger, the proportion of inclusions with a particle size of 5.00 μm or smaller is 80.00% or more.

[0057] The plate thickness is 10.00–30.00 μm. (2)

[0059] The ferrous alloy foil as described in (1) is characterized in that,

[0060] In the ferrous alloy foil, by mass%,

[0061] Ni: 30.00~50.00%. (3)

[0063] The ferrous alloy foil as described in (1) or (2) is characterized in that,

[0064] In the ferrous alloy foil, at least one of the following is satisfied, by mass percentage:

[0065] C: Below 0.050%

[0066] Ca: less than 0.0005%

[0067] Mn: below 0.30%

[0068] Si: below 0.30%

[0069] Mg: less than 0.0005%

[0070] Al: below 0.030%. (4)

[0072] The ferrous alloy foil as described in any one of (1) to (3) is characterized in that,

[0073] The number of inclusions with a particle size greater than 5.00 μm was 15 per cm. 2 the following. (5)

[0075] The ferrous alloy foil as described in any one of (1) to (4) is characterized in that,

[0076] The surface of the ferrous alloy foil has a pinhole density of 5 pins with a diameter of 20 μm or more per 1000 μm. 2 the following. (6)

[0078] The ferrous alloy foil described in (1) has the following characteristics:

[0079] The ferrous alloy foil, by mass%, contains

[0080] C: Below 0.150%

[0081] Si: 0.1–2.00%

[0082] Mn: 0.10~1.20%

[0083] S: less than 0.007%

[0084] Ni: 2.00~15.00%

[0085] Cr: 15.00~19.00%

[0086] N: below 0.20%

[0087] Al: below 0.010%;

[0088] The remaining portion is austenitic stainless steel composed of Fe and impurities, with a pinhole density of 5 pins / 1000m in diameter or larger on the surface. 2 Below that, the yield strength of 0.2% is above 700MPa. (7)

[0090] The ferrous alloy foil as described in (6) is characterized in that,

[0091] The inclusions larger than 2.00 μm in the surface are 1 to 100 ppm in terms of area ratio. (8)

[0093] A type of metal mask material,

[0094] It is composed of iron alloy foil as described in any one of (1) to (7). (9)

[0096] A metal mask,

[0097] It is composed of iron alloy foil as described in any one of (1) to (7). (10)

[0099] A component,

[0100] Iron alloy foil having any one of (1) to (7). (11)

[0102] A hard drive suspension,

[0103] It is composed of iron alloy foil as described in any one of (1) to (7). (12)

[0105] A sealing component for electronic devices,

[0106] The component described in (10) is used. (13)

[0108] A method for manufacturing an iron alloy foil, characterized in that,

[0109] Includes: a process of hot rolling steel sheets composed of any one of the components (1) to (3) and (6), and

[0110] The hot-rolled plate is subjected to a cold rolling process that includes finishing rolling;

[0111] The rolling ratio in the cold rolling process is above 99.0%, and the rolling ratio of each rolling pass (hereinafter sometimes simply referred to as pass) in the finishing rolling process is 1 to 18%.

[0112] Invention Effects

[0113] According to the present invention, a ferroalloy foil that reduces large inclusions and is less prone to defects during rolling and etching processes can be provided. Furthermore, when applied to metal masks or hard disk mounts, etching defects are significantly reduced, enabling high-precision machining with high yield. Moreover, this high-precision machining allows for the acquisition of further streamlined electronic components. Attached Figure Description

[0114] Figure 1 This is an example used to verify the appropriateness of the evaluation area of ​​inclusions on the surface of an alloy foil, and is a graph showing the imbalance between the measured area and the number density of inclusions relative to it. Detailed Implementation

[0115] The ferrous alloy foil of the present invention will now be described in detail. Unless otherwise specified, "%" in relation to composition indicates the percentage by mass in the steel. Where no lower limit is specified, it may also include cases where it is not present (0%).

[0116] [steel component]

[0117] The ferrous alloy foil of the present invention has the following composition: by mass%, C: 0.150% or less, Si: 2.00% or less, Mn: 10.00% or less, Ni: 2.00 to 50.00%, Cr: 19.00% or less, N: 0.20% or less, Al: 0.030% or less, Co: 5.00% or less, Mg: 0.0005% or less, Ca: 0.0005% or less, Ti: 0.01% or less, P: 0.035% or less, S: 0.0300% or less, with the remainder being Fe and impurities.

[0118] Ni (Ni) improves corrosion resistance and processability, and is a key element used to adjust the coefficient of thermal expansion of alloys. From the viewpoint of improving corrosion resistance, a Ni content of 2.00% or more is acceptable. Preferably, a Ni content of 5.00%, 10.00%, 15.00%, 20.00%, or 25.00% or more is acceptable. Furthermore, from the viewpoint of suppressing thermal expansion, a Ni content of 30.00%, 31.00%, 32.00%, 34.00%, or 35.00% or more is preferred.

[0119] However, Ni is a high-valence element, and if its content is too high, bainite structure is easily formed in the steel after hot rolling or hot forging. Therefore, the Ni content is preferably set to below 50.00%, 45.00%, 40.00%, 38.00%, or 37.00%.

[0120] Cr is an essential alloying component for improving corrosion resistance. However, excessive Cr content hardens the steel and reduces its machinability; therefore, a Cr content of 19.00% or less is preferable. The lower limit for Cr content is not particularly limited and can be 0%. On the other hand, the effect of adding Cr is significant when the Cr content is 15.00% or more; therefore, a content of 15.00% or more is preferred.

[0121] Co is a component whose thermal expansion coefficient of the alloy decreases by one level when its content is increased, in relation to Ni content. Co can be absent, but if present, it should be set at 0.01%, 0.02%, or 0.05% or more. On the other hand, since Co is a very expensive element, the upper limit for Co content should be set at 5.00%, preferably below 4.00% or 3.00%.

[0122] Carbon (C) may be absent, but it can be included to increase the strength of metal foils such as metal mask materials. If C is included, it should be 0.001% or more, 0.003% or more, 0.005% or more, 0.010% or more, or 0.020% or more. However, if C is present in excess, the coefficient of thermal expansion increases, and the amount of Cr-based inclusions (Cr carbides) precipitated at the grain boundaries increases, which can cause pinholes. Therefore, the C content should be 0.150% or less, preferably 0.100% or less, or 0.050% or less.

[0123] Ca dissolves in sulfides, causing them to disperse finely and forming spherical shapes. It is also possible to omit Ca, but if present, the Ca content should be 0.0001% or more, or 0.0002% or more. On the other hand, if a large amount of Ca is present, the Ca not dissolved in the sulfides will form coarse oxides, potentially leading to poor etching. Therefore, the Ca content should be 0.0005% or less, preferably 0.0004% or less.

[0124] Mn is actively used as a deoxidizer, replacing Mg and Al, to prevent spinel formation. However, if the Mn content is too high, it will segregate to the grain boundaries, promoting grain boundary destruction and reducing resistance to hydrogen embrittlement. Therefore, the Mn content should be set below 10.00%, preferably below 5.00%, 2.00%, 1.50%, 1.20%, 1.00%, 0.80%, 0.60%, 0.50%, 0.40%, or 0.30%.

[0125] It is also possible to omit Mn. However, if the Mn content is too low, it is difficult to adjust the inclusions to a Mn(O,S)-SiO2 system composition. Therefore, the Mn content is preferably set to 0.01% or more, 0.03% or more, 0.05% or more, or 0.10% or more.

[0126] Here, Mn(O, S) refers to MnO monomers, MnS monomers, and inclusions composed of MnO and MnS, indicating that the ratio of O to S is not fixed, and that inclusions are composed of oxides and sulfides.

[0127] Si is actively used as a deoxidizer, replacing Mg and Al, to avoid spinel formation. However, Si increases the coefficient of thermal expansion of the alloy. Metal mask materials, allowing organic EL light-emitting materials emitted from the vapor deposition source to pass through mask holes, are sometimes used at temperatures around 200°C. Furthermore, the deoxidized MnO-SiO2 is a glassy, ​​soft inclusion that extends and splits during hot rolling, becoming finer. Therefore, it exhibits high resistance to hydrogen embrittlement. On the other hand, if the Si content exceeds 2.00%, the strength becomes excessively high, resulting in hardening. In cold rolling, many rolling passes are required to achieve the specified thickness when manufacturing thin sheets, significantly reducing productivity. Therefore, a Si content of 2.00% or less, preferably 1.00% or less, 0.50% or less, or 0.30% or less, is preferable.

[0128] It can also be without Si. However, if the content is too low, deoxidation will be insufficient, the concentration of Cr2O3 in the inclusions will increase, and inclusions that can easily cause processing fractures will be generated. Therefore, the Si content is preferably set to 0.01% or more, 0.03% or more, 0.05% or more, or 0.10% or more.

[0129] Mg is used for deoxidation of steel. However, if the Mg content exceeds 0.0005%, coarse inclusions may form. Furthermore, to avoid the formation of spinel, a lower Mg content is preferred, and therefore it may be omitted. Therefore, the Mg content is preferably 0.0005% or less, and more preferably 0.0003%, 0.0002%, or 0.0001% or less.

[0130] Al is also used in the deoxidation of steel. However, if the Al content is higher than 0.030%, coarse inclusions may be formed. Furthermore, to avoid the formation of spinel, the lower the Al content, the better. Therefore, the Al content is set to 0.030% or less, preferably 0.020%, 0.010%, or 0.005% or less.

[0131] P and S are elements that combine with alloying elements such as Mn in ferrous alloys to form inclusions. Therefore, their content is preferably low, and they can also be absent. Thus, the P content is set to 0.035% or less, preferably 0.010%, 0.007%, or 0.005% or less, and the S content is set to 0.0300% or less, preferably 0.0100%, 0.0070%, or 0.0050% or less.

[0132] Ti increases the coefficient of thermal expansion of the alloy, so a lower value is preferred. Therefore, although it is possible to omit Ti, its content should be set to less than 0.01%.

[0133] Like carbon, nitrogen (N) is a solid solution strengthening element. While a high N content increases the yield strength by 0.2%, it also hardens the steel and significantly deteriorates its manufacturability. Therefore, although it is possible to omit N, the upper limit for N content should be set at 0.20%, preferably below 0.10%.

[0134] The remaining portion of the steel composition is Fe and unavoidable impurities. Here, "unavoidable impurities" refers to components that are mixed in during the manufacturing process of steel, represented by raw materials such as ores or waste, for various reasons. It refers to substances that are permissible within the scope of not adversely affecting the present invention.

[0135] [Miscellaneous materials]

[0136] Inclusions should be as few as possible, ideally completely absent. However, they can be introduced during manufacturing or generated from the steel composition, making complete elimination difficult. As mentioned earlier, when used as materials for metal masks, inclusions approximately half the thickness of the sheet are detrimental to etching and can cause poor results. Furthermore, it is known that large inclusions on the surface can detach during rolling, easily causing pinholes or surface pits. Therefore, in the case of large inclusions, such as ultrathin alloy foils with a sheet thickness of 10 μm, it is crucial to minimize inclusions with a circular equivalent particle size of 5 μm or larger.

[0137] The inventors of this invention focused on the following basic components of inclusions: Al2O3, MgO, SiO2, CaO, Mn(O, S), and CrS. It is known that soft inclusions such as SiO2, CaO, Mn(O, S), and CrS are difficult to cluster, have low melting points, and are soft; therefore, they can be stretched or broken during rolling to suppress coarsening. On the other hand, hard inclusions such as alumina or magnesium-aluminum spinel have high interfacial energy and are prone to segregation and aggregation during solidification, thus resulting in larger aggregate sizes. Furthermore, it is known that alumina or spinel inclusions are hard and therefore difficult to stretch or break during rolling, resulting in large-sized inclusion particles remaining.

[0138] Based on these insights, it is important to suppress the formation of soft inclusions, and subsequently to refine the formed soft inclusions by adjusting rolling conditions (e.g., rolling ratio). On the other hand, hard inclusions are difficult to refine based on rolling, so it is also important not to form or allow hard inclusions to be incorporated, or even if they are formed or incorporated, to prevent their aggregation (coarsening).

[0139] First, since it is necessary to ensure the mechanical strength of the alloy foil without generating inclusions in either the soft or hard systems, the steel composition mentioned above can be used.

[0140] To avoid the introduction of inclusions, it is important to improve the process. For example, improving the refractory used in molten metal processing can be achieved by using refractory materials with less Al or Mg.

[0141] Furthermore, the agglomeration of inclusions, such as segregation during the solidification of molten metal, is one of the causes. Avoiding segregation during solidification is not easy; therefore, methods such as stirring the molten metal in a manner that minimizes agglomeration should be considered. Moreover, steel ingots can be manufactured using processes that do not employ molten metal solidification, such as HIP (hot isostatic pressing). The manufacturing process will be explained later.

[0142] For measurement purposes, the inclusions contained in the ferrous alloy foil of one embodiment of the present invention are those with a particle size (equivalent circle diameter) of 2.00 μm or larger (hereinafter, unless otherwise specified, they are sometimes simply referred to as "inclusions"). Coarse inclusions with a particle size larger than 5.00 μm are detrimental and should be minimized as much as possible. On the other hand, while it is preferable to reduce inclusions with a particle size of 2.00 to 5.00 μm, they are not directly detrimental.

[0143] As one aspect of the present invention, the ratio of the number of inclusions with a particle size of 2.00 to 5.00 μm to the total number of inclusions with a particle size of 2.00 μm or larger is 80.00% or more. Preferably, it is set to 85.00% or more, 90.00% or more, 95.00% or more, 97.00% or more, 98.00% or more, 99.00% or more, or 100%.

[0144] Furthermore, hard inclusions such as alumina or spinel tend to be large particles, so their size should be minimized. Therefore, relative to the total mass of inclusions with a particle size of 2.00 μm or larger, Al2O3 should be set to 30% by mass or less, and MgO should be set to 15% by mass or less. These hard inclusions are preferably minimal, so the Al2O3 ratio is preferably 25% or less, 20% or less, 15% or less, 10% or less, 5% or less, 3% or less, or 1% or less. Similarly, the MgO ratio is preferably 10% or less, 8% or less, 6% or less, 5% or less, 4% or less, 3% or less, 2% or less, or 1% or less.

[0145] The size of the inclusions was determined as follows. Inclusions on the surface of the metal foil were observed using a scanning electron microscope (SEM). For example, a JSM-IT500HR manufactured by NEC Corporation can be used as the SEM. An example of the SEM setup is shown.

[0146] • Detector: BED-C reflective electron detector

[0147] • Observation magnification: 80x

[0148] Accelerating voltage: 20.0kV

[0149] • Working distance (WD): 10.0mm

[0150] • Irradiation current: 80%

[0151] Furthermore, inclusions are detected in images obtained via SEM using automated inclusion analysis software, and compositional analysis of the inclusions is performed in an energy-dispersive X-ray spectrometer (hereinafter, the EDS apparatus). For example, the particle analysis mode of Aztec, manufactured by Oxford Corporation, can be used for the automated inclusion analysis software. For example, the ULTIMMAX65, manufactured by Oxford Corporation, can be used for the EDS apparatus.

[0152] In the inclusion identification process based on automatic inclusion analysis software, SEM images used in the software are first acquired. Next, in the SEM images, inclusions are identified as inclusions if their equivalent circle diameter (equivalent area equivalent circle diameter) is 2.00 μm or larger, and if they are detected by EDS with one or more of the elements Al, Mg, Si, Ca, Mn, and S. Images from the EDS analysis are combined using software and output as a single image. At this time, the equivalent circle diameter and elemental composition of the inclusions identified by the automatic inclusion analysis software are also obtained. This inclusion identification sequence is repeated until a predetermined area is reached. For example, the measured area of ​​the image is 10 cm². 2 One field of view, as the unit of measurement, was used to perform 10 field-of-view measurements, totaling 100cm. 2 The evaluation area can be used as the evaluation area. In addition, the diameter of a circle with the same area as the measured inclusion is taken as the diameter of the equivalent circle (equivalent circle diameter) and set as the "particle size".

[0153] The composition of inclusions, for each inclusion identified by the automatic inclusion analysis software, is calculated as follows: First, the mass percentage of elements Al, Mg, Si, Ca, Mn, Cr, and S obtained through EDS analysis is divided by their respective atomic weights to obtain the apparent amount of substance of each element. Next, for the above seven elements, the basic composition of the inclusions is defined as oxides or sulfides. In the inclusions, Al, Mg, Si, and Ca mainly exist as oxides.

[0154] Mn and Cr mainly exist as sulfides, and Mn sometimes exists as the oxide MnO. In addition to the aforementioned sulfide MnS, S sometimes exists as the chromium sulfide CrS. When the apparent amount of S is greater than the apparent amount of Mn, there is an amount of MnS equal to the apparent amount of Mn. In this case, there is an amount of CrS equal to the apparent amount of S minus the apparent amount of Mn. When the apparent amount of S is less than the apparent amount of Mn, there is an amount of MnS equal to the apparent amount of S. In this case, there is an amount of MnO equal to the apparent amount of Mn minus the apparent amount of S. When the apparent amounts of Mn and S are completely equal, there is an amount of MnS equal to the amounts of both Mn and S.

[0155] Since they are in the state of oxides or sulfides, which are the basic components of inclusions, the amount of element O (oxygen) or S corresponding to the apparent amount of each element is assigned according to the stoichiometric ratios of Al:O=2:3, Mg:O=1:1, Si:O=1:2, Ca:O=1:1, Mn:O=1:1, Mn:S=1:1, and S:Cr=1:1. This is then multiplied by their respective molecular weights to derive the oxide equivalent mass. By dividing each of the obtained oxide equivalent masses by the sum of the seven oxide equivalent masses, the oxide equivalent mass percentages of Al2O3, MgO, SiO2, CaO, MnO, MnS, and CrS (hereinafter sometimes referred to as "oxides") are obtained. The inclusion area obtained from the automatic inclusion analysis software is then accumulated using the seven oxide equivalent mass percentages to obtain the inclusion area (μm) of Al2O3, MgO, SiO2, CaO, MnO, MnS, and CrS. 2 .

[0156] Next, the area of ​​each inclusion identified by the automatic inclusion analysis software was calculated. The areas of each of the seven oxides or sulfides were summed to obtain the total areas of Al₂O₃, MgO, SiO₂, CaO, MnO, MnS, and CrS. This sum of seven areas was taken as the total area of ​​all inclusions. The sum of the areas of each oxide, etc., was then divided by the total area of ​​all inclusions to calculate the component ratio (mass %) of the inclusions.

[0157] [Regarding area ratio]

[0158] The area ratio of inclusions is calculated by dividing the sum of the areas of each oxide, etc., or the sum of the areas of all inclusions by the evaluation area, and is taken as the area ratio of each oxide, etc., or the area ratio of all inclusions.

[0159] [Regarding the evaluation area]

[0160] Furthermore, considering the uneven presence of inclusions in the metal foil, the presence of inclusions may vary depending on the location observed via SEM. Therefore, the appropriateness of the evaluation area is verified using the following method. First, a 200cm² area is examined. 2 SEM measurements were performed, and inclusions were identified using automated inclusion analysis software. The measured area was divided into 200 equal grids. Each grid cell was a square with 1 cm sides and an area of ​​1 cm². 2 Next, to increase the statistical sample size, k cells were randomly selected from the 200 cells, leading to the assumption that the measurement was 1 cm. 2 ×k items = kcm 2 The number density of all inclusions at that time was measured, and this was repeated 1000 times to obtain 1000 samples with a measured area of ​​kcm². 2 The number density at that time. Here, the number density of all inclusions is determined by measuring the area in kcm². 2 The number of all observed inclusions was derived by dividing the measured area, with k being 1, 2, 4, 5, 8, 10, 20, 25, 40, 50, 100, and 200. Next, using... Figure 1 The average (solid line) indicates k = 200cm 2 The number density of all inclusions in the sample is used as the maximum and minimum values ​​of the 1000 number densities obtained. Figure 1 The error bars are shown. According to Figure 1 This verifies that if the evaluation area is 100cm² 2 The area is limited to an average of ±10%. Based on this result, a preferred evaluation area of ​​100 cm² is considered. 2 The evaluation area is set at 100cm². 2 .

[0161] The iron alloy foil of this invention significantly reduces the proportion of spinel-based inclusions, thus making it difficult for large inclusions to exist. When Mn and Si are mainly used as deoxidizers, the proportion of MnO-SiO2-based inclusions increases. This is because MnO-SiO2-based inclusions are difficult to cluster, and are also low-melting-point and soft, making them prone to stretching or breaking during hot or cold rolling processes, thus making it difficult for them to exist as large inclusions.

[0162] Furthermore, the number density of inclusions with a particle size greater than 5.00 μm can be set to 15 inclusions / cm³. 2 Therefore, the number of inclusions that result in poor etching is reduced. The fewer coarse inclusions with a particle size greater than 5.00 μm, the better; preferably, 12 inclusions / cm². 2 Below, 10 per cm 2Below, 8 per cm 2 Below, 6 per cm 2 Below, 5 per cm 2 the following.

[0163] [Plate thickness]

[0164] As mentioned earlier, soft inclusions are stretched, broken, and refined during rolling, reducing coarse particles larger than 5.00 μm. Therefore, increasing the rolling rate during the rolling process of ferrous alloy foil is sufficient. Thus, the thickness of the ferrous alloy foil is not particularly limited, but in typical manufacturing processes, the size of the steel ingot (cast ingot) needs to be within a certain range; therefore, a thickness of 30.00 μm or less is preferred. Preferably, it is 27.50 μm or less, 25.00 μm or less, or 22.50 μm or less. On the other hand, when the thickness is less than 10.00 μm, the difficulty of processing during etching or rolling increases, potentially leading to defects such as wrinkles; therefore, a thickness of 10.00 μm or more is preferable.

[0165] [Pinhole]

[0166] If large inclusions are present on the surface of the alloy foil, they will detach during rolling, forming a recess. In this state, the recess will expand during rolling, becoming an equivalent circle with a diameter of 20 μm. Pinholes on the left and right sides or above. The ferrous alloy foil of this invention reduces large inclusions, and the pinholes caused by the shedding of these large inclusions are also reduced, thus... The above pinholes are set at 5 per 1000m 2 the following.

[0167] [Yield Strength]

[0168] If the composition is as specified above, the 0.2% yield strength can be set to 700 MPa or higher. If the 0.2% yield strength is 700 MPa or higher, it can be used for metal masks, etc., without curling under normal operating conditions.

[0169] [Manufacturing method of ferrous alloy foil]

[0170] The ferrous alloy foil of the present invention can be manufactured, for example, as follows. The method shown below is illustrative and is not intended to be limiting.

[0171] For example, in 10 －1 In a vacuum atmosphere below (Torr), the raw material, adjusted to a specified composition, is vacuum melted to obtain molten metal of the target alloy composition. At this time, in order to deoxidize the molten metal, Mn and Si are added in such a way that the Mn and Si contents of the molten metal after slag removal are respectively specified.

[0172] Next, an inert gas such as Ar or N2 is used to atomize (powder) the metal through gas spraying. To reduce viscosity, the molten metal temperature during gas spraying is preferably set to the range of melting point +50°C to 200°C. Furthermore, the gas flow rate (m³ / s) during gas spraying... 3 The ratio of ( / min) / molten metal flow rate (kg / min) is set to 0.3 (m 3 / kg or above is acceptable. Gas flow rate (m³ / kg) 3 The ratio of ( / min) to molten metal flow rate (kg / min) is less than 0.3 (m 3 When the liquidus rate is reduced to 6 kg / kg, the liquidus rate of the droplets when they collide with the surface of the ingot is too high, resulting in coarser inclusions.

[0173] Therefore, the ratio of gas flow rate to molten metal flow rate is 0.3 (m³ / s). 3 / kg or higher, preferably set at 0.5 or higher, 0.7 or higher, 0.9 or higher, 1.0 or higher, 1.5 or higher, or 2.0 or higher. Gas flow rate (m³ / kg) 3 The upper limit of the ratio of ( / min) / molten metal flow rate (kg / min) is not particularly limited, but it is within 5.0 (m 3 Cooling capacity saturates when the volume exceeds 5.0 (m³ / kg), therefore the upper limit is set at 5.0 (m³ / kg). 3 ( / kg) is sufficient.

[0174] The alloy powder obtained through the atomization process is sintered by hot pressing or HIP (High-Intensity Interval Pressing) to produce steel ingots. The sintering method is not particularly limited; it can be set appropriately according to common methods such as hot pressing.

[0175] Smaller alloy powder particles are easier to sinter, but this reduces productivity compared to larger particle sizes. On the other hand, larger particle sizes make it easier for impurities from the furnace material to be incorporated. Therefore, the alloy powder has a particle size of 300 μm or less, preferably 250 μm or less, 200 μm or less, 150 μm or less, or 100 μm or less.

[0176] The atomization (powdering) method described above can suppress the content of Al or Mg. Furthermore, since the sintering method is performed in the solid phase, unlike the solidification method (casting), there is no incorporation of Al or Mg from the refractory, thus suppressing the formation of coarse inclusions (e.g., 5 μm or larger). Therefore, the formation of Al₂O₃ or spinel-based inclusions is ultimately reduced, especially the formation of coarse inclusions larger than 5 μm can be significantly suppressed.

[0177] Next, the manufactured alloy steel ingot is processed into steel sheets through hot forging, cutting, or grinding. These steel sheets are then rolled to a thickness of 3.0 mm to 200 mm. This rolling process can be either hot rolling or cold rolling. The rolled sheet, with a thickness of 3.0 mm to 200 mm, is then subjected to further repeated rolling processes to form an ferrous alloy foil.

[0178] The steel ingot can also be annealed before or after hot rolling, hot forging, or cold rolling. Furthermore, to prevent the agglomeration of inclusions, the temperatures in the annealing, hot forging, and hot rolling processes are lower than the melting point of the ferrous alloy, preferably above -500°C, and more preferably below -200°C.

[0179] Cold rolling can be performed after hot rolling or hot forging. Intermediate annealing can also be carried out during cold rolling. Rolling stretches and breaks up inclusions, especially soft inclusions, thus refining them. Cold rolling is more effective than hot rolling at refining inclusions, and it is more efficient at thinner plates. Therefore, based on the plate thickness after hot rolling (the plate thickness before cold rolling), the total rolling ratio of cold rolling should be set to 97.0% or higher. Preferably, it should be set to 98.0%, 99.0%, or 99.5% or higher. Furthermore, a higher rolling ratio in each rolling pass is more effective at refining inclusions; therefore, for example, excluding the final rolling or shape-correcting rolling to achieve the target plate thickness, the rolling ratio in each rolling pass should be set to 20% or higher. By performing cold rolling at such a rolling ratio, soft inclusions can be refined and dispersed through stretching and breaking.

[0180] On the other hand, it is known that in finishing rolling (fine rolling) where the plate thickness is thinned to a certain extent and inclusions are refined to a certain degree, the shedding of inclusions can sometimes lead to surface depressions and pinholes penetrating the alloy foil. Therefore, in finishing rolling (multi-stage cold rolling) at 2 to 3 times the final plate thickness or about 40 μm to the final plate thickness (e.g., 10 μm or 20 μm), a gentle rolling process with a reduced rolling rate is appropriate. For example, the rolling rate in each pass of finishing rolling can be set to 1 to 18%, and the cumulative rolling rate can be set to 50% or more. When the cumulative rolling rate of finishing rolling is less than 50%, the strength of the alloy foil may not be fully demonstrated. The upper limit of the cumulative rolling rate of finishing rolling is not particularly limited, but it can be set to 98% or less based on the capacity of a typical foil rolling mill.

[0181] That is, the total rolling rate is set to 97.0% or higher in cold rolling and 20% or higher in cold rolling before finishing rolling to refine the soft inclusions. Then, gentle rolling is carried out in finishing rolling to suppress the shedding of inclusions.

[0182] Generally, the pressing (cold rolling) from a thickness approximately 10 times the final sheet thickness to the final sheet thickness is sometimes referred to as foil rolling, distinguishing it from cold rolling after hot rolling. In this case, it is more preferable to reduce the rolling rate by following the sequence of cold rolling after hot rolling, followed by foil rolling before finishing rolling, and then final finishing rolling. For example, the rolling rate for each pass can be set as follows: cold rolling after hot rolling is 40% or more, foil rolling before finishing rolling is 20% or more, and finishing rolling during foil rolling is less than 20%.

[0183] Here, the so-called rolling rate, when the plate thickness before rolling is set as t1 and the plate thickness after rolling is set as t2, is expressed by the following formula.

[0184] Rolling rate = (t1 - t2) / t1

[0185] For example, when finishing rolling is a multi-stage rolling process, the cumulative rolling rate can be calculated by setting the plate thickness before finishing rolling as t1 and the plate thickness after finishing rolling as t2. The rolling rate for each pass can be calculated by setting the plate thickness before each rolling pass as t1 and the plate thickness after each rolling pass as t2.

[0186] Furthermore, the unit rolling rate (kN / mm) of each pass in the finishing rolling process should be controlled within an appropriate range. The unit rolling rate is calculated by dividing the load applied to the workpiece by the width of the workpiece. A preferred unit rolling rate is 0.4–1.3 kN / mm. When the unit rolling rate is less than 0.4 kN / mm, the heat generated during rolling is less, reducing the flexibility of the alloy foil, leading to cracks at the interface between inclusions and the foil, and increased inclusion shedding. Conversely, when the unit rolling rate exceeds 1.3 kN / mm, the heat generated during rolling increases, increasing the plastic deformation of the alloy foil itself, resulting in cracks at the interface with inclusions and increased inclusion shedding. Therefore, the unit rolling rate can be controlled instead of the aforementioned rolling rate. Of course, the rolling rate and unit rolling rate can also be controlled in combination.

[0187] Furthermore, annealing can also be performed after finishing rolling (final rolling) to relieve stress.

[0188] Next, in the case of components used in hard drive mounts, electronic device sealing parts, etc., in order to achieve non-magnetic properties, austenitic stainless steel with the following composition content can be set.

[0189] That is, by mass percent, it is an austenitic stainless steel containing C: less than 0.150%, Si: 0.1 to 2.00%, Mn: 0.10 to 1.20%, S: less than 0.007%, Ni: 2.00 to 15.00%, Cr: 15.00 to 19.00%, N: less than 0.20%, Al: less than 0.010%, with the remainder consisting of Fe and impurities.

[0190] In this case, similar to the above description, it is possible to reduce inclusions in alumina or spinel systems, and to obtain alloy foils with excellent etchability and high-precision machinability.

[0191] Example

[0192] The following are examples, but the present invention is not limited to the solutions shown in these examples.

[0193] [Example 1]

[0194] For samples 1, 2, and 4, molten metals of iron-based alloys with compositions adjusted to those shown in Table 1 were prepared using a vacuum induction melting furnace and then pulverized by N2-based gas spraying. To reduce the viscosity of the molten metal, the temperature of the molten metal during gas spraying was set to the range of liquidus temperature +50°C to +200°C. Furthermore, the gas flow rate (m³ / s) during gas spraying was... 3 The ratio of ( / min) / molten metal flow rate (kg / min) is adjusted to 1.0~3.0 (m 3 / kg).

[0195] Next, the obtained alloy powder was sealed in a metal container, and steel ingots for samples 1, 2, and 4 were manufactured using a known HIP process.

[0196] Sample 3 was also prepared as molten metal with the iron-based alloy composition shown in Table 1, adjusted by vacuum induction melting furnace. However, the molten metal was then transferred to a mold and solidified therein to produce steel ingots. During this process, the refractory used in the tundish or on the inner wall of the mold containing the molten metal was the same as that used in normal operations.

[0197] The obtained steel ingots are hot-forged to produce steel sheets with a cross-section of 80mm × 80mm. These sheets are then hot-rolled to a thickness of 3.0mm, followed by cold rolling to obtain a steel plate with a thickness of 0.30mm. The resulting steel plate is then subjected to foil rolling (which is cold rolling, but is called foil rolling to distinguish it from cold rolling after hot rolling) to produce an alloy foil (steel foil) with a thickness of 20μm. At this point, the final rolling or shape-correcting rolling to achieve the target plate thickness is omitted. The rolling rate for each pass in the cold rolling is set to 40–50%, and the rolling rate for each pass in the foil rolling process with a plate thickness of approximately 40–50μm is set to 20–50%, subsequently set to 1–18% until the plate thickness reaches 20μm. Furthermore, annealing is performed appropriately to remove stress caused by the cold rolling process, which includes foil rolling.

[0198] [Table 1]

[0199]

[0200] Inclusions on the surface of the metal foil were observed using a SEM (JSM-IT500HR manufactured by Nippon Electronics Corporation) on the surfaces of samples 1 to 4. The SEM settings were as follows.

[0201] • Detector: BED-C reflective electron detector

[0202] • Observation magnification: 80x

[0203] Accelerating voltage: 20.0kV

[0204] • Working distance (WD): 10.0mm

[0205] • Irradiation current: 80%

[0206] In addition, the images obtained by SEM were used to detect inclusions using automatic inclusion analysis software (Aztec particle analysis mode manufactured by Oxford Corporation), and the composition analysis of the inclusions was performed using an EDS device (ULTIMMAX65 manufactured by Oxford Corporation).

[0207] In the inclusion identification process based on automatic inclusion analysis software, SEM images used in the software are first acquired. Next, the SEM images are identified as inclusions if the automatic inclusion analysis software detects inclusions larger than 2.00 μm in equivalent circle diameter and if EDS detects at least one of the elements Al, Mg, Si, Ca, Mn, and S. The images analyzed by EDS are then concatenated using software and output as a single image. At this point, the particle size and elemental composition of the inclusions identified by the automatic inclusion analysis software are also obtained. The evaluation area is set to 100 cm². 2 The equivalent circle diameter is set as the particle size of the inclusions.

[0208] The composition of the inclusions is determined by calculating the converted mass percentages of oxides of Al2O3, MgO, SiO2, CaO, MnO, MnS, and CrS for the inclusions identified by the automatic inclusion analysis software. This is then multiplied by the area of ​​the inclusion obtained from the software to calculate the inclusion area (μm) of each inclusion. 2 Next, the aforementioned treatment is performed on all inclusions. The total area of ​​each oxide is calculated, and the composition ratio of the inclusions is calculated by dividing the total area of ​​all inclusions by the total area of ​​all inclusions.

[0209] Regarding the various metal mask materials, Tables 2 and 3 show the percentages per 100 cm. 2 The evaluation results of the inclusions.

[0210] Samples 1-4 were cut into 100mm × 100mm pieces, and the mask hole pattern of an OLED metal mask with an assumed 1000PPI was etched (half-etched) to half the board thickness. For the half-etched samples 1-4, at a 100cm... 2 10 locations, total evaluation area 1000cm² 2 The etching defects were evaluated. Furthermore, regarding pinholes, the entire length of the metal foil (rolled steel strip) in samples 1-4 was evaluated, and measurements were taken. The above are the number of pinholes. Table 4 records the results of the etching defect evaluation and pinhole evaluation.

[0211] [Table 2]

[0212]

[0213] [Table 3]

[0214]

[0215] [Table 4]

[0216]

[0217] In sample 2, the total area fraction (ppm) of inclusions was greater than that in sample 3. However, as shown in Table 2, samples 1 and 2 had a higher proportion of inclusions with a particle size ranging from 2.00 μm to 5.00 μm, i.e., inclusions within the size range that do not adversely affect etching. On the other hand, samples 1 and 2 had a much lower number density of inclusions with a particle size greater than 5.00 μm than sample 3, which had the potential to adversely affect etching.

[0218] Furthermore, as shown in Table 3, the average composition of inclusions with a particle size greater than 2.00 μm in Sample 3 includes Al2O3: greater than 30% by mass and MgO: greater than 15% by mass, indicating the presence of numerous alumina or spinel inclusions. In contrast, the average composition of inclusions in Samples 1, 2, and 4 shows that the MgO content is relatively low, around 7.0%, and the Al2O3 content is below 20.0%, indicating that alumina or spinel is sufficiently reduced in Samples 1, 2, and 4.

[0219] As shown in Table 4, the etchability and pinhole count of samples 1, 2 and 4 were significantly improved.

[0220] Industrial availability

[0221] According to the present invention, it is possible to provide an iron alloy foil that reduces coarse inclusions and is less prone to defects during rolling and etching processes. Therefore, the iron alloy foil of the present invention is useful in simplifying or reducing the weight of electronic components and can be appropriately used in the manufacture of high-resolution OLEDs, etc.

Claims

1. A ferrous alloy foil, characterized in that, It has the following components: In terms of mass%, it includes: C: Below 0.150% Si: Below 2.00% Mn: below 10.00% Ni: 2.00~50.00% Cr: below 19.00% N: below 0.20% Al: below 0.030% Co: below 5.00% Mg: less than 0.0005% Ca: below 0.0005% Ti: below 0.01% P: below 0.035% S: Below 0.0300%, The remaining portion consists of Fe and impurities; For the total mass of inclusions with a particle size greater than 2.00 μm, Al2O3: greater than 0% and less than 30% by mass, MgO: greater than 0% and less than 15% by mass; Of the inclusions with a particle size of 2.00 μm or larger, the proportion of inclusions with a particle size of 5.00 μm or smaller is 80.00% or more; On the surface of the ferrous alloy foil, there are 15 inclusions with a particle size greater than 5.00 μm per cm. 2 the following; The surface of the ferrous alloy foil has a pinhole density of 5 pins with a diameter of 20 μm or more per 1000 μm. 2 The following; moreover, The plate thickness is 10.00–30.00 μm.

2. The ferrous alloy foil according to claim 1, characterized in that, In the ferrous alloy foil, by mass%, Ni: 30.00~50.00%.

3. The ferrous alloy foil according to claim 1 or 2, characterized in that, Of the ferrous alloy foils, at least one of the following must be satisfied, by mass percentage: C: Below 0.050% Ca: below 0.0005% Mn: below 0.30% Si: below 0.30% Mg: less than 0.0005% Al: below 0.030%.

4. The ferrous alloy foil according to claim 1, characterized in that, The ferrous alloy foil is austenitic stainless steel, containing, by mass%, C: Below 0.150% Si: 0.1–2.00% Mn: 0.10~1.20%, S: Below 0.007% Ni: 2.00~15.00% Cr：15.00～19.00%、 N: below 0.20% Al: below 0.010%, and The remaining portion consists of Fe and impurities; Specifically, on the surface, the density of pinholes with a diameter greater than 20 μm is 5 per 1000 m. 2 the following, The yield strength of 0.2% is above 700 MPa.

5. The ferrous alloy foil according to claim 4, characterized in that, The inclusions larger than 2.00 μm have an area ratio of 1 to 100 ppm on the surface.

6. A metallic mask material, It is composed of an iron alloy foil as described in any one of claims 1, 2, 4, and 5.

7. A metal mask, It is composed of an iron alloy foil as described in any one of claims 1, 2, 4, and 5.

8. A component, The ferrous alloy foil as described in any one of claims 1, 2, 4, and 5.

9. A hard disk drive suspension, It is composed of an iron alloy foil as described in any one of claims 1, 2, 4, and 5.

10. A sealing component for an electronic device, The component described in claim 8 is used.

11. A method for manufacturing an ferrous alloy foil, characterized in that, The process includes a hot rolling process of steel sheet and a cold rolling process of hot-rolled sheet including finishing rolling, wherein the steel sheet is obtained by sintering atomized powder obtained by atomizing molten metal composed of any one of the compositions described in claims 1, 2 and 4. The rolling rate in the cold rolling process is set to 99.0% or higher; The rolling rate of each pass in the finishing mill is set to 1-18%.

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