Fe-ni-cr alloy material and fe-ni-cr alloy member

Abstract

An Fe-Ni-Cr alloy material according to the present disclosure contains, by mass, C: 0.001-0.050%, Si: 0.05-1.00%, Mn: 0.05-2.00%, P: 0.035% or less, S: 0.0015% or less, Cr: 18.0-25.0%, Ni: 18.0-50.0%, Al: 0.05-1.00%, Ti: 0.05-1.00%, N: 0.020% or less, and V: 0.05-0.25%, the balance being Fe and impurities, and the amount of solid solution V being 0.05% or more by mass.

Description

Fe-Ni-Cr alloy material and Fe-Ni-Cr alloy component 【0001】 This disclosure relates to Fe-Ni-Cr alloy materials and Fe-Ni-Cr alloy components. 【0002】 A sheathed heater comprises an alloy material, such as an alloy tube, and a heating element inserted inside the alloy tube. The heating element is, for example, a nichrome wire. A sheathed heater generates heat through the resistance heating of the heating element. Therefore, the alloy material used in a sheathed heater must have corrosion resistance. Fe-Ni-Cr alloy material has corrosion resistance. For this reason, Fe-Ni-Cr alloy material is used as the alloy material for sheathed heaters. 【0003】 Techniques for improving the corrosion resistance of Fe-Ni-Cr alloy materials are disclosed in Japanese Patent Publication No. 06-033264 (Patent Document 1) and Japanese Patent Publication No. 06-033216 (Patent Document 2). 【0004】 The Fe-Ni-Cr alloy material disclosed in Patent Document 1 contains one or two types of Ti: 0.02 to 1.0% and Al: 0.02 to 1.0%, and an oxide film mainly composed of Ti and / or Al is formed on its surface, which has been smoothed in advance to have a maximum roughness of 1 μm or less. 【0005】 In the Fe-Ni-Cr alloy material disclosed in Patent Document 2, the total content of Ti and Al is less than 0.02 mass%, and an oxide film with a thickness of 100 to 1000 Å is formed on the surface, which has been smoothed in advance so that the maximum roughness is 1 μm or less, with a Cr content of 60 atomic percent or more in the outermost layer. 【0006】 In the Fe-Ni-Cr alloy materials disclosed in Patent Documents 1 and 2, corrosion resistance is enhanced by the formation of an oxide film. 【0007】 JP-A No. 06-033264 JP-A No. 06-033216 【0008】When Fe-Ni-Cr alloy materials are used in sheath heater applications, they are subjected to thermal cycling loads where temperature fluctuations between high temperatures of approximately 600-800°C and room temperature are repeated. In such thermal cycling loads, oxide scale forms on the surface of the Fe-Ni-Cr alloy material at high temperatures. However, due to temperature fluctuations in thermal cycling loads, some of the oxide scale formed on the surface may peel off. In this case, the corrosion resistance of the alloy material decreases in the areas where the oxide scale has peeled off. Therefore, excellent corrosion resistance is required for Fe-Ni-Cr alloy materials even in the thermal cycling loads described above. 【0009】 The purpose of this disclosure is to provide Fe-Ni-Cr alloy materials and Fe-Ni-Cr alloy components that exhibit excellent corrosion resistance even in thermal cycling environments. 【0010】 The Fe-Ni-Cr alloy material disclosed herein has the following composition in mass%, C: 0.001-0.050%, Si: 0.05-1.00%, Mn: 0.05-2.00%, P: 0.035% or less, S: 0.0015% or less, Cr: 18.0-25.0%, Ni: 18.0-50.0%, Al: 0.05-1.00%, Ti: 0.05-1.00%, N: 0.020% or less, V: 0.05-0.25%, C It contains o: 0-1.00%, B: 0-0.0030%, Ca: 0-0.0070%, Mg: 0-0.0060%, Mo: 0-5.0%, W: 0-2.00%, Cu: 0-3.00%, Nb: 0-1.00%, Ta: 0-1.00%, Sn: 0-0.10%, and rare earth elements: 0-0.10%, with the remainder being Fe and impurities, and the solid solution V amount is 0.05% or more by mass%. 【0011】The Fe-Ni-Cr alloy member of this disclosure comprises an Fe-Ni-Cr alloy material and an oxide scale formed on the Fe-Ni-Cr alloy material. The Fe-Ni-Cr alloy material has the following composition in mass%, C: 0.001 to 0.050%, Si: 0.05 to 1.00%, Mn: 0.05 to 2.00%, P: 0.035% or less, S: 0.0015% or less, Cr: 18.0 to 25.0%, Ni: 18.0 to 50.0%, Al: 0.05 to 1.00%, Ti: 0.05 to 1.00%, N: 0.020% or less, V: 0.05 to 0.25%, Co: It contains 0-1.00% of the following elements: B: 0-0.0030%, Ca: 0-0.0070%, Mg: 0-0.0060%, Mo: 0-5.0%, W: 0-2.00%, Cu: 0-3.00%, Nb: 0-1.00%, Ta: 0-1.00%, Sn: 0-0.10%, and rare earth elements: 0-0.10%, with the remainder being Fe and impurities, and the solid solution V content is 0.05% or more by mass%. In the elemental concentration profile showing the relationship between sputtering depth and elemental concentration by mass%, obtained by glow discharge emission spectroscopy in the depth direction from the surface of the oxide scale, the maximum value of the V concentration in the oxide scale is 0.12% or more by mass%. 【0012】 The Fe-Ni-Cr alloy material and Fe-Ni-Cr alloy component of this disclosure exhibit excellent corrosion resistance even in thermal cycling environments. 【0013】 Figure 1 shows an example of an elemental concentration profile obtained by glow discharge emission spectroscopy analysis performed on the surface of the oxide scale of an Fe-Ni-Cr alloy member in the thickness direction of the oxide scale. Figure 2 is an enlarged view of region 100 in Figure 1. 【0014】The inventors first investigated Fe-Ni-Cr alloy materials that can obtain sufficient corrosion resistance from the viewpoint of chemical composition. As a result, in mass%, C: 0.001-0.050%, Si: 0.05-1.00%, Mn: 0.05-2.00%, P: 0.035% or less, S: 0.0015% or less, Cr: 18.0-25.0%, Ni: 18.0-50.0%, Al: 0.05-1.00%, Ti: 0.05-1.00%, N: 0.020% or less, V: 0.05-0.25%, Co: 0-1.00%, B: 0-0.00% We considered that an Fe-Ni-Cr alloy material having a chemical composition of 30% Ca: 0-0.0070%, Mg: 0-0.0060%, Mo: 0-5.0%, W: 0-2.00%, Cu: 0-3.00%, Nb: 0-1.00%, Ta: 0-1.00%, Sn: 0-0.10%, and rare earth elements: 0-0.10%, with the remainder being Fe and impurities, could potentially provide sufficient corrosion resistance. 【0015】 Therefore, the inventors further investigated means to improve the corrosion resistance of the Fe-Ni-Cr alloy material having the above-mentioned chemical composition even when used in a thermal cycle load environment in which temperature fluctuations between high temperatures of about 600 to 800°C and room temperature are repeated. 【0016】 Here, the inventors focused on the oxide scale formed on the surface of Fe-Ni-Cr alloy material. For example, in applications such as sheath heaters, as mentioned above, the material is used in a thermal cycling load environment. Therefore, at high temperatures in the thermal cycling load environment, oxide scale is formed on the surface of the Fe-Ni-Cr alloy material. In addition, in some cases, heat treatment is performed on the Fe-Ni-Cr alloy material before use in a thermal cycling load environment to form oxide scale in advance. 【0017】 Excellent corrosion resistance can be obtained if an oxide scale is formed on the surface of an alloy material. However, in a thermal cycling environment, thermal stress due to temperature fluctuations is applied to the oxide scale. Therefore, some of the oxide scale may peel off during use in a thermal cycling environment. In areas of the alloy material surface where the oxide scale has peeled off, the corrosion resistance will decrease. 【0018】Based on the above findings, the inventors hypothesized that corrosion resistance could be improved by increasing the adhesion of oxide scale to the alloy material. Improved adhesion of oxide scale would reduce the peeling of oxide scale during use under thermal cycling loads. As a result, corrosion resistance is expected to be enhanced. 【0019】 Therefore, the inventors investigated means to improve the adhesion of oxide scale. As a result, the inventors obtained the following findings: When oxide scale is formed, the solid solution V in the alloy diffuses from the surface of the alloy to the oxide scale, and becomes concentrated in the region near the interface with the alloy surface. This densifies the oxide scale region near the interface. As a result, the adhesion of the oxide scale to the alloy surface is improved. Consequently, when used in a thermal cycling environment, partial peeling of the oxide scale is suppressed, and corrosion resistance is improved. 【0020】 Based on the above findings, the inventors further investigated the amount of solid-solution V in the alloy material. As a result, it was found that if the amount of solid-solution V in the Fe-Ni-Cr alloy material having the above chemical composition is 0.05% by mass or more, partial peeling of oxide scale is suppressed and corrosion resistance is improved when used in a thermal cycling environment. 【0021】 The Fe-Ni-Cr alloy material and Fe-Ni-Cr alloy member of this embodiment were completed based on the above findings and have the following configuration. 【0022】The first form of Fe-Ni-Cr alloy material has the following composition in mass%, C: 0.001-0.050%, Si: 0.05-1.00%, Mn: 0.05-2.00%, P: 0.035% or less, S: 0.0015% or less, Cr: 18.0-25.0%, Ni: 18.0-50.0%, Al: 0.05-1.00%, Ti: 0.05-1.00%, N: 0.020% or less, V: 0.05-0.25%. It contains Co: 0-1.00%, B: 0-0.0030%, Ca: 0-0.0070%, Mg: 0-0.0060%, Mo: 0-5.0%, W: 0-2.00%, Cu: 0-3.00%, Nb: 0-1.00%, Ta: 0-1.00%, Sn: 0-0.10%, and rare earth elements: 0-0.10%, with the remainder being Fe and impurities, and the solid solution V content is 0.05% or more by mass. 【0023】 The second form of the Fe-Ni-Cr alloy material is the first form of the Fe-Ni-Cr alloy material, and contains, by mass%, one or more elements selected from the group consisting of Co: 0.01 to 1.00%, B: 0.0001 to 0.0030%, Ca: 0.0001 to 0.0070%, Mg: 0.0001 to 0.0060%, Mo: 0.1 to 5.0%, W: 0.01 to 2.00%, Cu: 0.01 to 3.00%, Nb: 0.01 to 1.00%, Ta: 0.01 to 1.00%, Sn: 0.01 to 0.10%, and rare earth elements: 0.01 to 0.10%. 【0024】 The third form of the Fe-Ni-Cr alloy material is the Fe-Ni-Cr alloy material of the first or second form, containing Co: 0.10 to 1.00% by mass. 【0025】The first embodiment of the Fe-Ni-Cr alloy member comprises an Fe-Ni-Cr alloy material and an oxide scale formed on the Fe-Ni-Cr alloy material. The Fe-Ni-Cr alloy material has the following composition in mass%, C: 0.001-0.050%, Si: 0.05-1.00%, Mn: 0.05-2.00%, P: 0.035% or less, S: 0.0015% or less, Cr: 18.0-25.0%, Ni: 18.0-50.0%, Al: 0.05-1.00%, Ti: 0.05-1.00%, N: 0.020% or less, V: 0.05-0.25%, Co: It contains 0-1.00% of the following elements: B: 0-0.0030%, Ca: 0-0.0070%, Mg: 0-0.0060%, Mo: 0-5.0%, W: 0-2.00%, Cu: 0-3.00%, Nb: 0-1.00%, Ta: 0-1.00%, Sn: 0-0.10%, and rare earth elements: 0-0.10%, with the remainder being Fe and impurities, and the solid solution V content is 0.05% or more by mass%. In the elemental concentration profile showing the relationship between sputtering depth and elemental concentration by mass%, obtained by glow discharge emission spectroscopy in the depth direction from the surface of the oxide scale, the maximum value of the V concentration in the oxide scale is 0.12% or more by mass%. 【0026】 The second embodiment of the Fe-Ni-Cr alloy member is the Fe-Ni-Cr alloy member of the first embodiment, wherein the chemical composition of the Fe-Ni-Cr alloy material contains one or more elements selected from the group consisting of, by mass%, Co: 0.01 to 1.00%, B: 0.0001 to 0.0030%, Ca: 0.0001 to 0.0070%, Mg: 0.0001 to 0.0060%, Mo: 0.1 to 5.0%, W: 0.01 to 2.00%, Cu: 0.01 to 3.00%, Nb: 0.01 to 1.00%, Ta: 0.01 to 1.00%, Sn: 0.01 to 0.10%, and rare earth elements: 0.01 to 0.10%. 【0027】The third embodiment of the Fe-Ni-Cr alloy member is the Fe-Ni-Cr alloy member of the first or second embodiment, wherein the Fe-Ni-Cr alloy material contains 0.10 to 1.00% Co by mass. In the elemental concentration profile showing the relationship between sputtering depth and elemental concentration by mass%, obtained by performing glow discharge emission spectroscopy in the depth direction from the surface of the oxide scale, the maximum value of Co concentration at the surface of the Fe-Ni-Cr alloy material is 0.20% or more by mass. 【0028】 The Fe-Ni-Cr alloy material and Fe-Ni-Cr alloy member of this embodiment will be described in detail below. In the following description, unless otherwise specified, "%" in relation to elements refers to mass percent. 【0029】 [Characteristics of the Fe-Ni-Cr alloy material of this embodiment] The Fe-Ni-Cr alloy material of this embodiment satisfies the following characteristics: (Characteristic 1) The chemical composition, in mass%, is: C: 0.001 to 0.050%, Si: 0.05 to 1.00%, Mn: 0.05 to 2.00%, P: 0.035% or less, S: 0.0015% or less, Cr: 18.0 to 25.0%, Ni: 18.0 to 50.0%, Al: 0.05 to 1.00%, Ti: 0.05 to 1.00%, N: 0.020% or less, V: 0.05 to 0. It contains 25% of the following: Co: 0-1.00%, B: 0-0.0030%, Ca: 0-0.0070%, Mg: 0-0.0060%, Mo: 0-5.0%, W: 0-2.00%, Cu: 0-3.00%, Nb: 0-1.00%, Ta: 0-1.00%, Sn: 0-0.10%, and rare earth elements: 0-0.10%, with the remainder being Fe and impurities. (Feature 2) The amount of solid solution V obtained by the extraction residue method is 0.05% or more by mass. The following describes each feature. 【0030】 [(Feature 1) Chemical Composition] The Fe-Ni-Cr alloy material of this embodiment has the following chemical composition, containing the elements listed below. In the following description, "Fe-Ni-Cr alloy material" will also be simply referred to as "alloy material". 【0031】C: 0.001 to 0.050% Carbon (C) forms carbides in high-temperature environments. Carbides increase the high-temperature strength of the alloy material through precipitation strengthening. If the C content is less than 0.001%, the above effect cannot be effectively obtained, even if the content of other elements is within the range of this embodiment. On the other hand, if the C content exceeds 0.050%, excessive carbides are formed, and the amount of solid-solution Ti and solid-solution Cr in the alloy material is excessively reduced. In this case, even if the content of other elements is within the range of this embodiment, oxide scale formation becomes difficult, and corrosion resistance decreases in high-temperature environments. Therefore, the C content is 0.001 to 0.050%. The preferred lower limit of the C content is 0.002%, more preferably 0.003%, and even more preferably 0.005%. The preferred upper limit for the C content is 0.045%, more preferably 0.040%, more preferably 0.035%, more preferably 0.030%, more preferably 0.025%, and more preferably 0.020%. 【0032】 Si: 0.05 to 1.00% Silicon (Si) solid-dissolves into the oxide scale formed on the surface of the alloy material, making the oxide scale denser. This suppresses the peeling of the oxide scale from the alloy material. Si further deoxidizes the alloy during the refining process. If the Si content is less than 0.05%, the above effects cannot be fully obtained, even if the content of other elements is within the range of this embodiment. On the other hand, if the Si content exceeds 1.00%, the hot workability of the alloy material decreases, even if the content of other elements is within the range of this embodiment. Furthermore, the susceptibility of solidification cracking and liquefaction cracking during welding of the alloy material increases. Therefore, the Si content is 0.05 to 1.00%. The preferred lower limit of the Si content is 0.08%, more preferably 0.10%, more preferably 0.15%, more preferably 0.20%, more preferably 0.25%, and more preferably 0.30%. The preferred upper limit for the Si content is 0.90%, more preferably 0.80%, more preferably 0.70%, and still more preferably 0.60%. 【0033】Mn: 0.05-2.00% Manganese (Mn) stabilizes austenite. Mn further dissolves in the oxide scale formed on the alloy material, making the oxide scale denser. This suppresses the peeling of the oxide scale from the alloy material. If the Mn content is less than 0.05%, the above effect cannot be fully obtained, even if the content of other elements is within the range of this embodiment. On the other hand, if the Mn content exceeds 2.00%, intermetallic compounds are more likely to form. In this case, even if the content of other elements is within the range of this embodiment, the heat resistance (oxidation resistance) of the alloy material decreases. Furthermore, the susceptibility of the alloy material to solidification cracking decreases. Therefore, the Mn content is 0.05-2.00%. The preferred lower limit of the Mn content is 0.10%, more preferably 0.20%, more preferably 0.30%, more preferably 0.40%, and still more preferably 0.50%. The preferred upper limit for the Mn content is 1.90%, more preferably 1.80%, more preferably 1.70%, more preferably 1.60%, more preferably 1.50%, more preferably 1.30%, and more preferably 1.00%. 【0034】 P: 0.035% or less. Phosphorus (P) is inevitably present. In other words, the P content is greater than 0%. If the P content exceeds 0.035%, even if the content of other elements is within the range of this embodiment, the solidification cracking susceptibility of the alloy material will be excessively increased. Therefore, the P content is 0.035% or less. It is preferable that the P content be as low as possible. However, excessive reduction of the P content increases manufacturing costs. Therefore, in industrial production, the preferred lower limit of the P content is 0.001%, more preferably 0.003%, and even more preferably 0.005%. The preferred upper limit of the P content is 0.030%, more preferably 0.025%, and even more preferably 0.020%. 【0035】S: 0.0015% or less. Sulfur (S) is inevitably present. In other words, the S content is greater than 0%. If the S content exceeds 0.0015%, even if the content of other elements is within the range of this embodiment, the hot workability of the alloy material will decrease and the oxidation resistance of the alloy material will decrease. Therefore, the S content is 0.0015% or less. It is preferable that the S content be as low as possible. However, excessive reduction of the S content increases manufacturing costs. Therefore, in industrial production, the preferred lower limit of the S content is 0.0001%, more preferably 0.0003%, and even more preferably 0.0005%. The preferred upper limit of the S content is 0.0012%, more preferably 0.0010%, and even more preferably 0.0008%. 【0036】 Cr: 18.0-25.0% Chromium (Cr) promotes the formation of oxide scale on the surface of the alloy material, thereby improving the corrosion resistance of the alloy material. If the Cr content is less than 18.0%, the above effect cannot be fully obtained, even if the content of other elements is within the range of this embodiment. On the other hand, if the Cr content exceeds 25.0%, the microstructure stability of the alloy material in high-temperature environments decreases, and intermetallic compounds may be formed. In this case, even if the content of other elements is within the range of this embodiment, the corrosion resistance and heat resistance properties of the alloy material will decrease. Therefore, the Cr content is 18.0-25.0%. The preferred lower limit of the Cr content is 18.5%, more preferably 19.0%, still more preferably 19.5%, and still more preferably 20.0%. The preferred upper limit of the Cr content is 24.5%, more preferably 24.0%, still more preferably 23.5%, and still more preferably 23.0%. 【0037】Ni: 18.0-50.0% Nickel (Ni) stabilizes austenite. If the Ni content is less than 18.0%, the above effect cannot be fully obtained, even if the content of other elements is within the range of this embodiment. On the other hand, if the Ni content exceeds 50.0%, the manufacturing cost becomes excessively high. Therefore, the Ni content is 18.0-50.0%. The preferred lower limit of the Ni content is 18.5%, more preferably 19.0%, still more preferably 19.5%, and still more preferably 20.0%. The preferred upper limit of the Ni content is 49.0%, more preferably 48.0%, still more preferably 45.0%, still more preferably 40.0%, and still more preferably 35.0%. 【0038】 Al: 0.05-1.00% Aluminum (Al) solid-solves in the oxide scale formed on the surface of the alloy material, making the oxide scale denser. This suppresses the peeling of the oxide scale from the alloy material. If the Al content is less than 0.05%, the above effect cannot be fully obtained, even if the content of other elements is within the range of this embodiment. On the other hand, if the Al content exceeds 1.00%, cracks may occur during the casting process in the manufacturing process of the alloy material, even if the content of other elements is within the range of this embodiment. Therefore, the Al content is 0.05-1.00%. The preferred lower limit of the Al content is 0.08%, more preferably 0.10%, more preferably 0.15%, more preferably 0.20%, and more preferably 0.25%. The preferred upper limit of the Al content is 0.90%, more preferably 0.80%, more preferably 0.70%, and more preferably 0.60%. 【0039】Ti: 0.05 - 1.00% Titanium (Ti) dissolves in the oxide scale formed on the surface of the alloy material, making the oxide scale dense. This suppresses the peeling of the oxide scale from the alloy material. If the Ti content is less than 0.05%, even if the contents of other elements are within the range of this embodiment, the above effects cannot be sufficiently obtained. On the other hand, if the Ti content exceeds 1.00%, even if the contents of other elements are within the range of this embodiment, cracks may occur in the casting process during the manufacturing process of the alloy material. Therefore, the Ti content is 0.05 - 1.00%. The preferred lower limit of the Ti content is 0.08%, more preferably 0.10%, even more preferably 0.15%, even more preferably 0.20%, and even more preferably 0.25%. The preferred upper limit of the Ti content is 0.90%, more preferably 0.80%, even more preferably 0.70%, and even more preferably 0.60%. 【0040】 N: 0.020% or less Nitrogen (N) is inevitably contained. That is, the N content is more than 0%. N combines with Ti and Cr to form nitrides such as Ti nitride and Cr nitride. The formation of nitrides reduces the above-described effects of Ti and Cr. If the N content exceeds 0.020%, even if the contents of other elements are within the range of this embodiment, excessive nitrides are generated, and the effects of containing Ti and Cr cannot be sufficiently obtained. Therefore, the N content is 0.020% or less. It is preferable that the N content is as low as possible. However, an excessive reduction in the N content increases the manufacturing cost. Therefore, in industrial production, the preferred lower limit of the N content is 0.001%, more preferably 0.003%, and even more preferably 0.005%. The preferred upper limit of the N content is 0.018%, more preferably 0.015%, even more preferably 0.012%, and even more preferably 0.010%. 【0041】V: 0.05 to 0.25% Vanadium (V) dissolves in the oxide scale formed on the surface of the alloy material, making the oxide scale dense. This suppresses the peeling of the oxide scale from the alloy material. As a result, the corrosion resistance of the alloy material is enhanced. If the V content is less than 0.05%, even if the contents of other elements are within the range of this embodiment, the above effects cannot be fully obtained. On the other hand, if the V content exceeds 0.25%, excessive V precipitates are generated. Also, even if the contents of other elements are within the range of this embodiment, the solidification cracking susceptibility of the alloy material increases excessively. Therefore, the V content is 0.05 to 0.25%. The preferable lower limit of the V content is 0.07%, more preferably 0.10%, and even more preferably 0.12%. The preferable upper limit of the V content is 0.22%, more preferably 0.20%, and even more preferably 0.18%. 【0042】 The remainder of the chemical composition of the Fe—Ni—Cr alloy material of this embodiment consists of Fe and impurities. Here, the impurities are those mixed in from ores, scraps, or the manufacturing environment as raw materials when the Fe—Ni—Cr alloy material is industrially manufactured, and are meant to be those allowed within a range that does not adversely affect the Fe—Ni—Cr alloy material of this embodiment. 【0043】 [Optional Elements] The chemical composition of the Fe—Ni—Cr alloy material of this embodiment may further contain one or more selected from the group consisting of, in mass %, Co: 0 to 1.00%, B: 0 to 0.0030%, Ca: 0 to 0.0070%, Mg: 0 to 0.0060%, Mo: 0 to 5.0%, W: 0 to 2.00%, Cu: 0 to 3.00%, Nb: 0 to 1.00%, Ta: 0 to 1.00%, Sn: 0 to 0.10%, and rare earth elements: 0 to 0.10%, in place of a part of Fe. These elements are all optional elements, and even if these optional elements are contained, the effects of the Fe—Ni—Cr alloy material of this embodiment can be fully obtained. Hereinafter, each optional element will be described. 【0044】Co: 0-1.00% Cobalt (Co) is an optional element and may not be included. In other words, the Co content may be 0%. If it is included, that is, if the Co content is greater than 0%, Co does not readily dissolve in the oxide scale formed on the surface of the alloy material. Therefore, Co becomes concentrated in the surface layer of the alloy material near the oxide scale. The concentration of Co in the surface region increases the corrosion resistance of the alloy material. Even if only a small amount of Co is included, the above effect can be obtained to some extent. However, if the Co content exceeds 1.00%, the effect saturates, and the manufacturing cost also increases. Therefore, the Co content is 0-1.00%. The preferred lower limit for the Co content is 0.01%, more preferably 0.05%, and even more preferably 0.08%. As described later, in order to further improve corrosion resistance in a thermal cycle load environment, the even more preferred lower limit is 0.10%, more preferably 0.15%, and even more preferably 0.20%. The preferred upper limit for the Co content is 0.95%, more preferably 0.90%, more preferably 0.80%, more preferably 0.70%, and still more preferably 0.60%. 【0045】 B: 0 to 0.0030% Boron (B) is an optional element and may not be present. In other words, the B content may be 0%. If it is present, that is, if the B content is greater than 0%, B increases the high-temperature strength (high-temperature creep strength) of the alloy material. Even if only a small amount of B is present, the above effect can be obtained to some extent. However, if the B content exceeds 0.0030%, the melting point of the alloy material decreases. In this case, even if the content of other elements is within the range of this embodiment, the susceptibility of the alloy material to solidification cracking and liquefaction cracking will be excessively increased. Therefore, the B content is 0 to 0.0030%. The preferred lower limit of the B content is 0.0001%, more preferably 0.0003%, and still more preferably 0.0005%. The preferred upper limit of the B content is 0.0028%, more preferably 0.0025%, more preferably 0.0023%, more preferably 0.0020%, and still more preferably 0.0010%. 【0046】Ca: 0 to 0.0070% Calcium (Ca) is an optional element and may not be present. In other words, the Ca content may be 0%. If it is present, that is, if the Ca content is greater than 0%, Ca combines with S to form CaS, reducing the amount of dissolved S. This improves the hot workability of the alloy material. Even if only a small amount of Ca is present, the above effect can be obtained to some extent. However, if the Ca content exceeds 0.0070%, the hot workability of the alloy material will decrease, even if the content of other elements is within the range of this embodiment. Therefore, the Ca content is 0 to 0.0070%. The preferred lower limit of the Ca content is 0.0001%, more preferably 0.0003%, and still more preferably 0.0005%. The preferred upper limit of the Ca content is 0.0068%, more preferably 0.0065%, more preferably 0.0060%, and still more preferably 0.0055%. 【0047】 Mg: 0 to 0.0060% Magnesium (Mg) is an optional element and may not be present. In other words, the Mg content may be 0%. If Mg is present, that is, if the Mg content is greater than 0%, Mg improves the hot workability of the alloy material. Even if only a small amount of Mg is present, the above effect can be obtained to some extent. However, if the Mg content exceeds 0.0060%, the hot workability of the alloy material will decrease, even if the content of other elements is within the range of this embodiment. Therefore, the Mg content is 0 to 0.0060%. The preferred lower limit of the Mg content is 0.0001%, more preferably 0.0003%, more preferably 0.0005%, and still more preferably 0.0010%. The preferred upper limit for the Mg content is 0.0055%, more preferably 0.0050%, more preferably 0.0045%, more preferably 0.0040%, more preferably 0.0030%, and more preferably 0.0020%. 【0048】Mo: 0-5.0% Molybdenum (Mo) is an optional element and may not be present. In other words, the Mo content may be 0%. If present, that is, if the Mo content is greater than 0%, Mo enhances the corrosion resistance of the alloy material. Even if only a small amount of Mo is present, the above effect can be obtained to some extent. However, if the Mo content exceeds 5.0%, the effect saturates, and furthermore, the manufacturing cost increases. Therefore, the Mo content is 0-5.0%. The preferred lower limit of the Mo content is 0.1%, more preferably 0.2%, more preferably 0.3%, more preferably 0.4%, and more preferably 0.5%. The preferred upper limit of the Mo content is 4.9%, more preferably 4.8%, more preferably 4.5%, more preferably 4.3%, more preferably 4.0%, more preferably 3.8%, more preferably 3.5%, and more preferably 3.0%. 【0049】 W: 0-2.00% Tungsten (W) is an optional element and may not be present. In other words, the W content may be 0%. If it is present, that is, if the W content is greater than 0%, W enhances the strength and corrosion resistance in high-temperature environments. Even if only a small amount of W is present, the above effects can be obtained to some extent. However, if the W content exceeds 2.00%, the hot workability of the alloy material will decrease, even if the content of other elements is within the range of this embodiment. Therefore, the W content is 0-2.00%. The preferred lower limit of the W content is 0.01%, more preferably 0.05%, more preferably 0.10%, more preferably 0.20%, and still more preferably 0.30%. The preferred upper limit for the W content is 1.90%, more preferably 1.80%, more preferably 1.70%, more preferably 1.60%, more preferably 1.50%, more preferably 1.00%, more preferably 0.80%, more preferably 0.70%, and more preferably 0.60%. 【0050】Cu: 0-3.00% Copper (Cu) is an optional element and may not be included. In other words, the Cu content may be 0%. If Cu is included, that is, if the Cu content is greater than 0%, Cu increases the high-temperature strength of the alloy material. Cu also increases the corrosion resistance of the alloy material. Even if only a small amount of Cu is included, the above effects can be obtained to some extent. However, if the Cu content exceeds 3.00%, the alloy material becomes brittle, even if the content of other elements is within the range of this embodiment. Therefore, the Cu content is 0-3.00%. The preferred lower limit of the Cu content is 0.01%, more preferably 0.05%, and even more preferably 0.10%. The preferred upper limit for the Cu content is 2.90%, more preferably 2.80%, more preferably 2.50%, more preferably 2.00%, more preferably 1.50%, more preferably 1.00%, more preferably 0.80%, more preferably 0.70%, and more preferably 0.60%. 【0051】 Nb: 0-1.00% Niobium (Nb) is an optional element and may not be present. In other words, the Nb content may be 0%. If Nb is present, that is, if the Nb content is greater than 0%, Nb enhances the high-temperature strength and creep strength of the alloy material through solid solution strengthening and precipitation strengthening. Even if only a small amount of Nb is present, the above effects can be obtained to some extent. However, if the Nb content exceeds 1.00%, the hot workability of the alloy material will decrease, even if the content of other elements is within the range of this embodiment. Therefore, the Nb content is 0-1.00%. The preferred lower limit of the Nb content is 0.01%, more preferably 0.03%, and even more preferably 0.05%. The preferred upper limit for the Nb content is 0.95%, more preferably 0.90%, more preferably 0.85%, more preferably 0.80%, more preferably 0.70%, more preferably 0.50%, more preferably 0.30%, and more preferably 0.20%. 【0052】Ta: 0-1.00% Tantalum (Ta) is an optional element and may not be present. In other words, the Ta content may be 0%. If it is present, that is, if the Ta content is greater than 0%, Ta increases the high-temperature strength and creep strength of the alloy material through precipitation strengthening. Even if only a small amount of Ta is present, the above effect can be obtained to some extent. However, if the Ta content exceeds 1.00%, the hot workability of the alloy material will decrease, even if the content of other elements is within the range of this embodiment. Therefore, the Ta content is 0-1.00%. The preferred lower limit of the Ta content is 0.01%, and more preferably 0.05%. The preferred upper limit of the Ta content is 0.95%, more preferably 0.90%, more preferably 0.85%, more preferably 0.80%, more preferably 0.75%, more preferably 0.50%, more preferably 0.30%, and more preferably 0.20%. 【0053】 Sn: 0-0.10% Tin (Sn) is an optional element and may not be present. In other words, the Sn content may be 0%. If Sn is present, that is, if the Sn content is greater than 0%, Sn enhances the corrosion resistance of the alloy material. Even if only a small amount of Sn is present, the above effect can be obtained to some extent. However, if the Sn content exceeds 0.10%, the hot workability of the alloy material will decrease, even if the content of other elements is within the range of this embodiment. Therefore, the Sn content is 0-0.10%. The preferred lower limit of the Sn content is 0.01%, and more preferably 0.02%. The preferred upper limit of the Sn content is 0.09%, more preferably 0.08%, more preferably 0.07%, and still more preferably 0.06%. 【0054】Rare Earth Elements: 0-0.10% Rare earth elements (REM) are optional and do not need to be included. In other words, the REM content may be 0%. If REM is included, that is, if the REM content is greater than 0%, the REM dissolves into the oxide scale formed on the surface of the alloy material, making the oxide scale denser. This suppresses the peeling of the oxide scale from the alloy material. As a result, the corrosion resistance of the alloy material is increased. Even if only a small amount of REM is included, the above effect can be obtained to some extent. However, if the REM content exceeds 0.10%, coarse oxides or coarse nitrides are generated, which can clog nozzles or increase surface defects in cast slabs during the refining and casting processes. Therefore, the REM content is 0-0.10%. The preferred lower limit of the REM content is 0.01%, more preferably 0.02%, and even more preferably 0.03%. The preferred upper limit for the REM content is 0.09%, more preferably 0.08%, more preferably 0.07%, and still more preferably 0.06%. 【0055】 In this specification, REM means one or more elements selected from the group consisting of scandium (Sc), atomic number 21; yttrium (Y), atomic number 39; and lanthanides, lanthanum (La), atomic number 57 to lutetium (Lu), atomic number 71. In this specification, REM content means the total content of these elements. 【0056】 [(Feature 2) Amount of solid solution V] In the Fe-Ni-Cr alloy material of this embodiment, the amount of solid solution V is 0.05% or more by mass. 【0057】 In high-temperature environments with an oxidizing atmosphere, oxide scale forms on the surface of alloy materials. The formation of oxide scale on the alloy surface increases the corrosion resistance of the alloy. However, for example, when an alloy is used in a thermal cycling environment where temperature fluctuations between high and room temperature are repeated, some of the oxide scale formed on the surface may peel off. In areas where the oxide scale has peeled off the alloy surface, the corrosion resistance decreases. 【0058】During the formation of oxide scale, the solid solution V in the alloy diffuses from the surface of the alloy into the oxide scale, becoming concentrated in the region near the interface with the alloy surface. This densifies the oxide scale region near the interface, thereby increasing the adhesion of the oxide scale to the alloy surface. As a result, partial peeling of the oxide scale is suppressed when used in a thermal cycling environment. Consequently, the corrosion resistance of the alloy in a thermal cycling environment is improved. 【0059】 If the amount of dissolved V in the alloy material is 0.05% or more by mass, a sufficient amount of dissolved V will diffuse into the oxide scale. Therefore, excellent corrosion resistance can be obtained in thermal cycling environments. 【0060】 The preferred lower limit for the amount of dissolved V is 0.06% by mass, more preferably 0.07%, more preferably 0.08%, more preferably 0.09%, and more preferably 0.10%. The upper limit for the amount of dissolved V is not particularly limited. The upper limit for the amount of dissolved V in the alloy material is, for example, the upper limit of the V content in the chemical composition of the alloy material. The preferred upper limit for the amount of dissolved V is 0.25%, more preferably 0.20%, and more preferably 0.15%. If the amount of dissolved V is 0.25% or less, the susceptibility of the alloy material to solidification cracking can be significantly reduced. 【0061】 [Method for measuring the amount of solid-solution V] The amount of solid-solution V in Fe-Ni-Cr alloy material is measured by the following method. A test piece is taken from the alloy material. 【0062】 All surfaces of the test specimen are wet-polished with #600 emery paper. The polished test specimen is then immersed in a methanol aqueous solution containing 10% by mass of maleic anhydride and 2% by mass of tetramethylammonium chloride (hereinafter referred to as the test solution). After immersion, constant potential electrolysis is performed at a constant potential of -100 mV to dissolve an amount equivalent to 1 g of the test specimen (alloy material). 【0063】After constant potential electrolysis, the test specimen is immersed in an alcohol solution. Then, ultrasonic cleaning is performed to remove any deposits from the surface of the test specimen. The mass of the test specimen after the deposits have been removed, i.e., the mass of the test specimen after constant potential electrolysis, MM1 (g), is measured. Based on the mass of the test specimen before constant potential electrolysis, MM0 (g), and the mass of the test specimen after constant potential electrolysis, MM1 (g), the mass of the test specimen dissolved by constant potential electrolysis, M2 (= MM0 - MM1) (g), is determined. 【0064】 Furthermore, the test solution and the alcohol solution used for ultrasonic cleaning are filtered by suction using a 0.2 μm mesh filter to extract the residue. The extracted residue is washed with pure water and dried. The residue is dissolved in acid to obtain a solution. Chemical elemental analysis is performed on the solution using ICP-AES to determine the mass of V (g) in the residue. Based on the mass of the dissolved test piece MM2 (g) and the mass of V (g) in the residue, the mass % of V in the residue (hereinafter referred to as the amount of precipitated V) is determined, with the mass of the alloy material set to 100%. The amount of solid-solution V (mass %) in the alloy material is determined by subtracting the amount of precipitated V (%) from the V content (%) in the chemical composition of the alloy material. 【0065】 [Effects of the Fe-Ni-Cr alloy material of this embodiment] In the Fe-Ni-Cr alloy material of this embodiment, the adhesion of oxide scale is enhanced in a thermal cycling load environment. As a result, excellent corrosion resistance is obtained in a thermal cycling load environment. 【0066】 [Shape of Fe-Ni-Cr alloy material in this embodiment] The shape of the Fe-Ni-Cr alloy material in this embodiment is not particularly limited. The Fe-Ni-Cr alloy material in this embodiment may be an alloy plate, an alloy tube, or an alloy rod or alloy wire having a longitudinal direction. When the Fe-Ni-Cr alloy material in this embodiment is an alloy tube, it is preferably a welded alloy tube. 【0067】 [Microstructure of the Fe-Ni-Cr alloy material of this embodiment] The microstructure of the Fe-Ni-Cr alloy material of this embodiment consists of austenite. In other words, the Fe-Ni-Cr alloy material of this embodiment has a single-phase austenite structure. 【0068】[Preferred form of Fe-Ni-Cr alloy material of this embodiment] Preferably, the Fe-Ni-Cr alloy material of this embodiment further contains, in mass%, Co: 0.10 to 1.00% in its chemical composition. 【0069】 As described above, when alloy materials are used in a thermal cycling environment, an oxide scale forms on the surface of the alloy material. When an oxide scale forms, alloying elements present on the surface of the alloy material generally tend to diffuse into the oxide scale. However, Co has a low affinity for oxide scale. Therefore, even when an oxide scale forms, the diffusion of Co into the oxide scale is suppressed. As a result, Co remains on the surface of the alloy material and becomes concentrated in that surface region. 【0070】 As mentioned above, in a thermal cycling environment, some of the formed oxide scale may peel off. Co enhances corrosion resistance. Therefore, if Co is concentrated in the surface region of the alloy material, even if some of the oxide scale peels off, the concentrated Co can maintain the corrosion resistance of the alloy material. As a result, the corrosion resistance of Fe-Ni-Cr alloy material in a thermal cycling environment is further enhanced. 【0071】 From the viewpoint of achieving the above effects even more effectively, a more preferable lower limit for the Co content is 0.15%, more preferably 0.20%, and even more preferably 0.25%. 【0072】 [Manufacturing Method] An example of a manufacturing method for the Fe-Ni-Cr alloy material of this embodiment will be described below. Note that the manufacturing method for the Fe-Ni-Cr alloy material of this embodiment is not limited to the method described below, as long as an Fe-Ni-Cr alloy material satisfying features 1 and 2 can be manufactured. An example of a manufacturing method for the Fe-Ni-Cr alloy material of this embodiment includes the following steps. Note that the cold working step is an optional step and may not be performed. (Step 1) Material preparation step (Step 2) Hot working step (Step 3) Cold working step (Step 4) Heat treatment step Each manufacturing step will be described in detail below. 【0073】[Material Preparation Process] In the material preparation process, molten metal (molten alloy) is produced by a well-known method. The method of producing the molten metal is not particularly limited. For example, the molten metal may undergo a well-known primary refining process, followed by a well-known secondary refining process. During refining, alloying elements for component adjustment are added to produce molten metal (molten alloy) that satisfies the chemical composition of Feature 1. 【0074】 The material is manufactured using the molten metal (molten alloy) produced. Specifically, cast slabs, blooms, or billets are produced using the molten metal by continuous casting. Alternatively, ingots are produced using the molten metal by the ingot-making method. 【0075】 [Hot Working Process] In the hot working process, the material (cast slab or ingot) manufactured in the material preparation process is hot-worked to produce an intermediate alloy material. In this specification, an intermediate alloy material is a plate-shaped alloy material when the final product is an alloy plate, and a rod-shaped alloy material extending in the axial direction when the final product is an alloy rod or alloy wire. If the final product is an alloy tube, the alloy plate is welded to form the alloy tube. The hot working may be hot forging, hot extrusion, or hot rolling. The method of hot working is not particularly limited and any well-known method may be used. 【0076】 If the intermediate alloy material is in the form of a plate, first, a slab or ingot is heated in a heating furnace. The heating temperature is, for example, 1100 to 1300°C. Hot rolling is performed on the slab or ingot extracted from the heating furnace to produce a plate-shaped intermediate alloy material. The produced plate-shaped alloy material is cooled. The cooling method is not particularly limited. For example, the cooling method is air cooling. 【0077】If the intermediate alloy material is a rod-shaped alloy material, a billet is produced by bloc rolling of the bloom or ingot. The heating temperature for bloc rolling is, for example, 1100 to 1300°C. The billet produced by bloc rolling may be further hot-rolled in a continuous rolling mill to produce smaller billets. The produced billet is cooled to room temperature. The cooling method is not particularly limited. For example, it may be air-cooled. The billet is reheated. The heating temperature is, for example, 1100 to 1300°C. The heated billet is hot-rolled using a continuous rolling mill in which multiple rolling stands are arranged in a row to produce a rod-shaped alloy material. The produced rod-shaped alloy material is cooled. The cooling method is not particularly limited. For example, it may be air-cooled. 【0078】 [Cold Working Process] The cold working process is optional and does not have to be performed. If performed, the cold working process is carried out on the intermediate alloy material after the hot working process. If the intermediate alloy material is a rod-shaped alloy material, the cold working process is, for example, cold drawing. 【0079】 When the intermediate alloy material is in the form of a plate, the cold working is, for example, cold rolling. Cold rolling is carried out using, for example, a reverse rolling mill (e.g., a Zenzimir mill). An intermediate heat treatment for the purpose of softening may be performed on the intermediate alloy material after the hot working process but before the cold rolling process. When performing intermediate heat treatment, the material is held at a temperature of 1000 to 1150°C for 1 to 2 minutes, and then allowed to cool. In addition, cold rolling may be performed multiple times using a reverse rolling mill. In this case, after cold rolling, intermediate heat treatment may be performed, and then cold rolling may be performed again. The cumulative reduction ratio in cold rolling is not particularly limited, but for example, it is 70 to 90%. 【0080】[Heat Treatment Process] In the heat treatment process, heat treatment is performed on the intermediate alloy material after hot working or cold working. The heat treatment is performed so that the amount of solid solution V in the manufactured Fe-Ni-Cr alloy material satisfies characteristic 2. Specifically, the heat treatment process satisfies the following requirements: (Condition 1) Hold at a heat treatment temperature of 1300°C or higher for 1 to 5 seconds. (Condition 2) After the holding time at the above heat treatment temperature has elapsed, cool at a cooling rate of 10.0°C / second or higher. 【0081】 If the heat treatment temperature is 1300°C or higher and the holding time is less than 1 second, V precipitates such as V carbides, V nitrides, and V carbonitrides formed in the intermediate alloy material will not dissolve sufficiently. As a result, the amount of V in the solid solution of the manufactured Fe-Ni-Cr alloy material will be low. On the other hand, if the holding time exceeds 5 seconds, Cr will be excessively concentrated in the oxide scale. In this case, excessive Cr-deficient regions may be formed on the surface of the alloy material, which may reduce corrosion resistance. 【0082】 If the cooling rate is less than 10.0°C / second, excess V precipitates will be generated during cooling. In this case, the amount of dissolved V in the manufactured Fe-Ni-Cr alloy material may be low. Therefore, the cooling rate should be 10.0°C / second or higher. The cooling rate is determined by the following method: Measure the surface temperature TA of the intermediate alloy material immediately after extraction from the heat treatment furnace. Furthermore, determine the time t required for the surface temperature of the intermediate alloy material to reach 500°C. Based on the surface temperature TA and time t, determine the cooling rate. 【0083】 After heat treatment, the intermediate alloy material is subjected to a well-known pickling process to remove the oxide scale generated by the heat treatment (descaling). Through these steps, the Fe-Ni-Cr alloy material is manufactured. 【0084】 Furthermore, if the Fe-Ni-Cr alloy material is a welded alloy pipe, the following steps are performed: The heat-treated steel plate is cut (slit) along the rolling direction (longitudinal direction). The slit steel plate is rolled into an open pipe shape, and TIG welding is performed along the longitudinal direction of the open pipe. Through these steps, the Fe-Ni-Cr alloy material, which is a welded alloy pipe, is manufactured. 【0085】[Fe-Ni-Cr Alloy Member] The Fe-Ni-Cr alloy member of this embodiment is manufactured using the Fe-Ni-Cr alloy material of this embodiment described above as the raw material. The Fe-Ni-Cr alloy member of this embodiment comprises the Fe-Ni-Cr alloy material of this embodiment described above and an oxide scale formed on the surface of the Fe-Ni-Cr alloy material. 【0086】 The oxide scale is formed on the surface of the Fe-Ni-Cr alloy material by the manufacturing method described later. The oxide scale is an oxide layer. The oxide scale mainly contains Cr, Fe, Si, and V. When the total concentration of the elements other than O, obtained by glow discharge emission spectroscopy analysis described later, is taken as 100%, the oxide scale contains 20-95% Cr, 0-40% Fe, 0-10% Si, and 0.02-0.30% V by mass%. 【0087】 Furthermore, when glow discharge emission spectroscopy was performed in the depth direction from the surface of the oxide scale to obtain an elemental concentration profile showing the relationship between sputtering depth in μm units and elemental concentration in mass%, the maximum value of V concentration in the oxide scale in the elemental concentration profile was 0.12% or more in mass%. 【0088】 If the maximum concentration of V in the oxide scale is 0.12% or more by mass, the oxide scale contains a sufficient amount of V. In this case, as described above, the oxide scale becomes denser, and its adhesion to the surface of the Fe-Ni-Cr alloy material increases. As a result, the Fe-Ni-Cr alloy member of this embodiment exhibits excellent corrosion resistance in a thermal cycling environment. 【0089】 The preferred lower limit for the maximum V concentration in the oxide scale is 0.13%, more preferably 0.14%, and even more preferably 0.15%. The upper limit for the maximum V concentration is not particularly limited. For example, the upper limit for the maximum V concentration is 1.00%. 【0090】[Method for measuring the maximum V concentration in oxide scale] The V concentration in oxide scale is determined by the following method. A test piece containing oxide scale and Fe-Ni-Cr alloy material is taken from an Fe-Ni-Cr alloy member. The size of the test piece is not particularly limited as long as glow discharge emission spectroscopy (GDS) can be performed. An arbitrary point on the surface of the oxide scale of the test piece is designated as the measurement point. Glow discharge emission spectroscopy is performed from the measurement point in the thickness direction of the oxide scale using a Marcus-type high-frequency glow discharge emission surface analyzer to measure the elemental concentration profiles of at least Fe, Cr, Ni, O, V, and Co. The diameter of the measurement area is set to 5 mm, the measurement time to 200 seconds, and the measurement interval to 0.1 seconds. For example, the Marcus-type high-frequency glow discharge emission surface analyzer is the GD-Profiler2 manufactured by Horiba, Ltd. 【0091】 Figure 1 shows an example of an elemental concentration profile obtained by glow discharge emission spectroscopy analysis performed on the surface of the oxide scale of an Fe-Ni-Cr alloy member in the thickness direction of the oxide scale. Figure 2 is an enlarged view of region 100 in Figure 1. Referring to Figures 1 and 2, in the elemental concentration profile, the sputtering time (seconds) is converted to sputtering depth (μm) based on the previously determined sputtering rate (μm / second). In the elemental concentration profile, the position where the sputtering depth is 0 μm corresponds to the surface position of the oxide scale. Hereinafter, the position where the sputtering depth is 0 μm will also be called the surface position D0. 【0092】 Furthermore, each elemental profile is smoothed out by applying a moving average process to the original data, using a total of five points including the two points before and after the original data, thereby reducing short-period fluctuations in the elemental profile. 【0093】In the elemental concentration profile at the measurement point, the oxygen concentration Ox is determined at a depth of 0.2 μm from the surface position D0 in the thickness direction of the oxide scale. From the depth position D0 in the thickness direction of the oxide scale, the depth position D1 where the oxygen concentration is 1 / 10 of the oxygen concentration Ox, i.e., oxygen concentration O10, is determined. Depth position D1 is defined as the interface position D1 between the oxide scale and the Fe-Ni-Cr alloy material at the measurement point. The region from surface position D0 to interface position D1 is defined as the oxide scale region, and the region from interface position D1 in the depth direction is defined as the Fe-Ni-Cr alloy material region. 【0094】 In the region of the oxide scale (the region from surface position D0 to interface position D1), determine the maximum value of V concentration, Vmax (%). 【0095】 In the Fe-Ni-Cr alloy member of this embodiment, the obtained maximum value Vmax is 0.12% or more. Therefore, the Fe-Ni-Cr alloy member of this embodiment exhibits excellent corrosion resistance in a thermal cycling environment. 【0096】 [Method for measuring Cr, Fe, Si, and V concentrations in oxide scale] The Cr, Fe, Si, and V concentrations in oxide scale can be determined by the following method. An elemental concentration profile is determined based on the method described in [Method for measuring the maximum value of V concentration in oxide scale] above. The interface position D1 is determined based on the obtained elemental concentration profile. The arithmetic mean of the Cr concentration profile in the oxide scale from surface position D0 to interface position D1 (Cr concentration every 0.1 seconds of sputtering time) is taken as the Cr concentration (mass%) of the oxide scale. The concentration (mass%) of each element contained in the chemical composition of the Fe-Ni-Cr alloy material and the O concentration (mass%) are determined by the same method as for the Cr concentration. 【0097】 The concentrations of Cr, Fe, Si, and V are determined when the total mass percentage of elements other than O is set to 100%. The obtained concentrations are defined as the Cr concentration (mass%), Fe concentration (mass%), Si concentration (mass%), and V concentration (mass%) in the oxide scale. 【0098】[Preferred form of Fe-Ni-Cr alloy member of this embodiment] Preferably, the Fe-Ni-Cr alloy member of this embodiment further contains 0.10 to 1.00% by mass of Co in the chemical composition of the Fe-Ni-Cr alloy material. Furthermore, when glow discharge emission spectroscopy is performed in the depth direction from the surface of the oxide scale to obtain an elemental concentration profile showing the relationship between the sputtering depth in μm units and the elemental concentration in mass%, the maximum value of the Co concentration at the surface of the Fe-Ni-Cr alloy material in the elemental concentration profile is 0.20% or more by mass. 【0099】 If the chemical composition of the Fe-Ni-Cr alloy material contains 0.10% or more Co, and furthermore, the maximum Co concentration on the surface of the Fe-Ni-Cr alloy material is 0.20% or more, then the surface region of the Fe-Ni-Cr alloy material is sufficiently concentrated with Co. In this case, even if some of the oxide scale of the Fe-Ni-Cr alloy member peels off in a thermal cycling environment, the concentrated Co can maintain the corrosion resistance of the Fe-Ni-Cr alloy member. As a result, the corrosion resistance of the Fe-Ni-Cr alloy member in a thermal cycling environment is further enhanced. 【0100】 The preferred lower limit for the maximum Co concentration on the surface of the Fe-Ni-Cr alloy material is 0.21%, more preferably 0.22%, more preferably 0.23%, more preferably 0.25%, and still more preferably 0.30%. The upper limit of the Co concentration is not particularly limited. For example, the upper limit of the Co concentration is 5.00%. 【0101】 [Method for measuring Co concentration on the surface of Fe-Ni-Cr alloy members] In Fe-Ni-Cr alloy members, the Co concentration on the surface of the Fe-Ni-Cr alloy material is determined by the following method. 【0102】 Based on the method described in the above-mentioned [Method for measuring V concentration in oxide scale], the elemental concentration profiles of Fe, Cr, Ni, O, V, and Co are measured. Of the elemental concentration profiles, we focus on the Co concentration profile. In the Fe-Ni-Cr alloy region, which is the region in the depth direction from the interface position D1, the maximum value of the Co concentration, Comax (%), is determined. 【0103】In the Fe-Ni-Cr alloy member of the preferred embodiment of this product, the maximum value Vmax is 0.12% or more in the oxide scale region, and furthermore, the maximum value Comax is 0.20% or more in the Fe-Ni-Cr alloy material region. Therefore, the Fe-Ni-Cr alloy member of this embodiment provides even better corrosion resistance in a thermal cycling environment. 【0104】 [Method for Manufacturing the Fe-Ni-Cr Alloy Member of This Embodiment] An example of a method for manufacturing the Fe-Ni-Cr alloy member of this embodiment will be described. Note that the method for manufacturing the Fe-Ni-Cr alloy member of this embodiment is not limited to the method described below, as long as it can produce the Fe-Ni-Cr alloy member described above. An example of a method for manufacturing the Fe-Ni-Cr alloy member of this embodiment includes the following steps: (Step 5) Alloy material preparation step (Step 6) Oxide scale formation step Each step will be described below. 【0105】 [Alloy material preparation process] In the alloy material preparation process, the Fe-Ni-Cr alloy material of the above embodiment is prepared. 【0106】 [Oxide Scale Formation Process] In the oxide scale formation process, the Fe-Ni-Cr alloy material is heat-treated in an oxidizing atmosphere to form an oxide scale. Here, the oxidizing atmosphere is not particularly limited and may be an atmospheric atmosphere. ２ Ya H ２ It may contain O, CO, etc. 【0107】 The heat treatment conditions for the oxide scale formation process are as follows: (Condition 3) The heat treatment temperature is 950 to 1050°C, and the holding time at the heat treatment temperature is 30 to 90 minutes. 【0108】If the heat treatment temperature is below 950°C or the holding time is less than 30 minutes, a sufficient amount of V will not diffuse into the oxide scale. On the other hand, if the heat treatment temperature exceeds 1050°C or the holding time exceeds 90 minutes, Cr may concentrate in the oxide scale, increasing the Cr-deficient region on the surface of the alloy material. If the heat treatment temperature is set to 950-1050°C and the holding time at that temperature is set to 30-90 minutes, the maximum value of V concentration in the oxide scale will be 0.12% or more by mass. Furthermore, if the chemical composition of the Fe-Ni-Cr alloy material contains 0.10% or more Co, the maximum value of Co concentration on the surface of the alloy material will be 0.20% or more by mass. 【0109】 The Fe-Ni-Cr alloy member of this embodiment is manufactured through the above manufacturing process. 【0110】 The effects of the Fe-Ni-Cr alloy material and Fe-Ni-Cr alloy member of this embodiment will be further explained in detail by the following examples. The conditions in the following examples are just one example of conditions adopted to confirm the feasibility and effects of the Fe-Ni-Cr alloy material and Fe-Ni-Cr alloy member of this embodiment. Therefore, the Fe-Ni-Cr alloy material and Fe-Ni-Cr alloy member of this embodiment are not limited to this one example of conditions. 【0111】 Fe-Ni-Cr alloy materials having the chemical composition shown in Table 1 were manufactured. 【0112】 【0113】 Specifically, slabs with the chemical composition of each alloy number were prepared. Hot rolling was performed on the slabs to produce intermediate alloy sheets (hot-rolled alloy sheets). The heating temperature of the slabs during hot rolling was 1100 to 1300°C. Cold rolling was performed on the intermediate alloy sheets (hot-rolled alloy sheets) to produce cold-rolled alloy sheets. Heat treatment was performed on the cold-rolled alloy sheets. The holding time (seconds) at 1300°C or higher during the heat treatment is shown in Table 2. The cooling rate after the holding time is also shown in Table 2. Through the above manufacturing process, Fe-Ni-Cr alloy material (alloy sheet) for each test number was produced. The thickness of the Fe-Ni-Cr alloy material (alloy sheet) was 0.4 mm for all test numbers. 【0114】 【0115】 [Evaluation Tests] The following evaluation tests were conducted on the Fe-Ni-Cr alloy material for each test number: (Test 1) Measurement of solid solution V content in the alloy material (Test 2) Measurement of V concentration in oxide scale after scale formation treatment (Test 3) Measurement of Co concentration on the surface of the alloy material after scale formation treatment (Test 4) Evaluation of the peeling resistance of the oxide scale (Test 5) Evaluation of corrosion resistance The following describes each test. 【0116】 [(Test 1) Measurement Test of Solid Solution V Amount in Alloy Materials] The solid solution V amount of Fe-Ni-Cr alloy materials for each test number was determined in accordance with the method described in [Method for Measuring Solid Solution V Amount] above. The size of the test specimen was 30 mm × 30 mm × plate thickness. The obtained solid solution V amount is shown in the "Solid Solution V Amount (mass%)" column in Table 2. 【0117】 [(Test 2) V concentration measurement test in oxide scale after scale formation treatment] For each test number of Fe-Ni-Cr alloy material, the oxide scale formation process was carried out under the following conditions. Specifically, the Fe-Ni-Cr alloy material was subjected to heat treatment by holding it at 1000°C for 60 minutes in an air atmosphere. Fe-Ni-Cr alloy members for each test number were manufactured by the above manufacturing process. Each test number of Fe-Ni-Cr alloy member consisted of the Fe-Ni-Cr alloy material and the oxide scale formed on the surface of the Fe-Ni-Cr alloy material. 【0118】 In accordance with the method described in [Method for Measuring V Concentration in Oxide Scale] above, the maximum value Vmax (mass%) of the V concentration in the oxide scale of the Fe-Ni-Cr alloy member for each test number was determined. The size of the test specimen was 30 mm × 30 mm × plate thickness. The obtained maximum values ​​Vmax (mass%) are shown in Table 2. 【0119】[(Test 3) Measurement Test of Co Concentration on the Surface of Alloy Material After Scale Formation Treatment] In accordance with the method described in [Method for Measuring Co Concentration on the Surface of Fe-Ni-Cr Alloy Members] above, the maximum Comax (mass%) of the Co concentration on the surface of the Fe-Ni-Cr alloy member for each test number was determined. The size of the test piece was 30 mm × 30 mm × plate thickness. The obtained maximum Comax (mass%) is shown in Table 2. 【0120】 [(Test 4) Oxide Scale Peel Resistance Evaluation Test] Test specimens measuring 30 mm x 20 mm x plate thickness were taken from the Fe-Ni-Cr alloy material of each test number. The oxide scale formation process was carried out on the test specimens under the following conditions. Specifically, a heat treatment was performed in which the test specimens were held at 1000°C for 60 minutes in an air atmosphere. Fe-Ni-Cr alloy member test specimens were prepared by the above manufacturing process. 【0121】 The following oxide scale peel resistance evaluation test was performed on Fe-Ni-Cr alloy specimens. First, the surface area (initial surface area) A0 and the mass (initial mass) M0 of the Fe-Ni-Cr alloy specimens were measured. After the measurements, the first thermal cycle load test was performed using the Fe-Ni-Cr alloy specimens. Specifically, they were placed in a heat treatment furnace maintained at a temperature of 700°C in an atmospheric environment. After 25 minutes in the furnace, the Fe-Ni-Cr alloy specimens were removed from the heat treatment furnace and allowed to cool in ambient air outside the furnace for 5 minutes. 【0122】 After the first thermal cycling load test (i.e., after cooling), the mass Mn (n=1) (unit: g) of the Fe-Ni-Cr alloy specimen was measured. The mass obtained by subtracting mass M1 from the initial mass M0 was divided by the initial surface area A0 to obtain the mass loss ΔMn (n=1) (unit: g / cm²). ２ The following equation was used to determine the mass reduction ΔMn: ΔMn = (M0 - Mn) / A0, where n is a natural number greater than or equal to 1. 【0123】 Mass reduction amount ΔMn (n=1) is 0.1 mg / cm ２If the above conditions were met, it was determined that a part of the oxide scale had peeled off, and the test was terminated. On the other hand, when ΔMn (n = 1) was less than 0.1 mg / cm ２ ２ , the (n + 1)-th, that is, the second thermal cycle load test was conducted. After the second thermal cycle load test, the mass Mn (n = 2) of the Fe-Ni-Cr alloy member test piece was measured, and similarly, the mass reduction amount ΔMn (n = 2) was obtained. If this mass reduction amount ΔMn (n = 1) was 0.1 mg / cm ２ ２ or more, it was determined that a part of the oxide scale had peeled off, and the test was terminated. On the other hand, when ΔMn (n = 1) was less than 0.1 mg / cm ２ ２ , the (n + 1)-th thermal cycle load test was conducted by the same procedure. 【0124】 By conducting the above thermal cycle load test, the number of cycles until ΔMn became 0.1 mg / cm ２ ２ or more was obtained. When ΔMn became 0.1 mg / cm ２ ２ or more at the n-th cycle, the number of peeling cycles was set to n times. The obtained number of peeling cycles is shown in Table 2. In addition, even if the thermal cycle load test was conducted 100 times and ΔMn (n = 100) was less than 0.1 mg / cm ２ ２ , it was determined that the oxide scale did not peel off (indicated as "no peeling" in the "number of peeling cycles" column in Table 3). 【0125】 [(Test 5) Corrosion resistance evaluation test] Using the Fe-Ni-Cr alloy member test pieces with test numbers where the number of peeling cycles was less than "100" in the oxide scale peeling resistance evaluation test of Test 4, a salt spray test conforming to JIS Z 2371:2015 was conducted. Note that the Fe-Ni-Cr alloy member test pieces with no peeling in the oxide scale peeling resistance evaluation test were regarded as having sufficient corrosion resistance, and the oxide scale peeling resistance evaluation test was not conducted. For the salt spray test, a salt spray tester (product name: STP-200) manufactured by Suga Test Instruments Co., Ltd. was used. Regarding the test conditions, the spray NaCl concentration was 50 ± 0.5%, and the spray amount was 1.5 mL / h / 80 cm ２The temperature was set to 35±2°C, and the pH during the test was set to 6.5-7.2. A salt spray test was conducted for 100 hours. After the salt spray test, the Fe-Ni-Cr alloy specimen was visually inspected to see if red rust had formed on the areas where the oxide scale had peeled off. If no red rust was observed, it was judged that excellent corrosion resistance had been obtained. On the other hand, if red rust was observed, it was judged that sufficient corrosion resistance had not been obtained (indicated as "B" (Bad) in the "Corrosion Resistance" column in Table 2). In addition, if the oxide scale did not peel off in Test 4, it could be considered that sufficient corrosion resistance had been obtained, so Test 5 was not performed (indicated as "-" in the "Corrosion Resistance" column in Table 2). 【0126】 [Evaluation Results] Referring to Tables 1 and 2, the Fe-Ni-Cr alloy materials of test numbers 1 to 12 satisfied characteristics 1 and 2. Therefore, when heat treatment was performed by holding at 1000°C for 60 minutes to form the Fe-Ni-Cr alloy member, the maximum value Vmax of the V concentration in the oxide scale became 0.12% or higher. As a result, the peeling of the oxide scale was sufficiently suppressed in the oxide scale peeling resistance evaluation test, and it could be considered that it had excellent corrosion resistance. Note that, when the total concentration of other elements excluding the O concentration is taken as 100%, the oxide scale of each test number contained 20-95% Cr, 0-40% Fe, 0-10% Si, and 0.02-0.30% V by mass%. 【0127】 On the other hand, in test numbers 13 to 16, the V content was too low. Therefore, when the Fe-Ni-Cr alloy members were subjected to heat treatment held at 1000°C for 60 minutes, the maximum V concentration (Vmax) in the oxide scale became less than 0.12%. As a result, in the oxide scale peeling resistance evaluation test, the oxide scale peeled off, and sufficient corrosion resistance could not be obtained in the corrosion resistance evaluation test. 【0128】In tests 17, 18, and 20, the holding time at 1300°C or higher during the heat treatment after cold working was less than 1 second. As a result, the Fe-Ni-Cr alloy material did not meet characteristic 2. Therefore, when the Fe-Ni-Cr alloy member was prepared by heat treatment at 1000°C for 60 minutes, the maximum value Vmax of the V concentration in the oxide scale was less than 0.12%. Consequently, in the oxide scale peeling resistance evaluation test, the oxide scale peeled off, and sufficient corrosion resistance could not be obtained in the corrosion resistance evaluation test. 【0129】 In test number 19, the cooling rate during the heat treatment after cold working was slow. As a result, the Fe-Ni-Cr alloy material did not meet characteristic 2. Therefore, when the Fe-Ni-Cr alloy member was subjected to heat treatment held at 1000°C for 60 minutes, the maximum value Vmax of the V concentration in the oxide scale was less than 0.12%. Consequently, in the oxide scale peel resistance evaluation test, the oxide scale peeled off, and sufficient corrosion resistance could not be obtained in the corrosion resistance evaluation test. 【0130】 The embodiments of this disclosure have been described above. However, the embodiments described above are merely examples for implementing this disclosure. Therefore, this disclosure is not limited to the embodiments described above, and the embodiments described above can be modified as appropriate without departing from the spirit of this disclosure.

Claims

1. In mass percent, C: 0.001-0.050%, Si: 0.05-1.00%, Mn: 0.05-2.00%, P: 0.035% or less, S: 0.0015% or less, Cr: 18.0-25.0%, Ni: 18.0-50.0%, Al: 0.05-1.00%, Ti: 0.05-1.00%, N: 0.020% or less, V: 0.05-0.25%, Co: 0-1.00%, B: 0-0.0030%, Ca: 0-0.0070%, Mg: 0-0.0060%, Mo: 0-5.0%, W: 0-2.00% An Fe-Ni-Cr alloy material containing Cu: 0-3.00%, Nb: 0-1.00%, Ta: 0-1.00%, Sn: 0-0.10%, and rare earth elements: 0-0.10%, with the remainder being Fe and impurities, and having a solid solution V content of 0.05% or more by mass.

2. Fe-Ni-Cr alloy material according to claim 1, comprising, by mass%, one or more elements selected from the group consisting of: Co: 0.01 to 1.00%, B: 0.0001 to 0.0030%, Ca: 0.0001 to 0.0070%, Mg: 0.0001 to 0.0060%, Mo: 0.1 to 5.0%, W: 0.01 to 2.00%, Cu: 0.01 to 3.00%, Nb: 0.01 to 1.00%, Ta: 0.01 to 1.00%, Sn: 0.01 to 0.10%, and rare earth elements: 0.01 to 0.10%.

3. An Fe-Ni-Cr alloy material according to claim 1 or claim 2, wherein the Fe-Ni-Cr alloy material contains Co: 0.10 to 1.00% by mass.

4. The Fe-Ni-Cr alloy material comprises an oxide scale formed on the Fe-Ni-Cr alloy material, wherein the Fe-Ni-Cr alloy material has a composition of mass%, C: 0.001 to 0.050%, Si: 0.05 to 1.00%, Mn: 0.05 to 2.00%, P: 0.035% or less, S: 0.0015% or less, Cr: 18.0 to 25.0%, Ni: 18.0 to 50.0%, Al: 0.05 to 1.00%, Ti: 0.05 to 1.00%, N: 0.020% or less, V: 0.05 to 0.25%, Co: 0 to 1.00%, B: 0 to 0.0030%, Ca: 0 to 0.0070%, An Fe-Ni-Cr alloy member containing Mg: 0-0.0060%, Mo: 0-5.0%, W: 0-2.00%, Cu: 0-3.00%, Nb: 0-1.00%, Ta: 0-1.00%, Sn: 0-0.10%, and rare earth elements: 0-0.10%, with the remainder being Fe and impurities, having a solid solution V content of 0.05% or more by mass%, and an elemental concentration profile showing the relationship between sputtering depth and elemental concentration by mass%, obtained by glow discharge emission spectroscopy analysis in the depth direction from the surface of the oxide scale, wherein the maximum value of V concentration in the oxide scale is 0.12% or more by mass.

5. Fe-Ni-Cr alloy member according to claim 4, wherein the Fe-Ni-Cr alloy material contains, by mass%, one or more elements selected from the group consisting of: Co: 0.01 to 1.00%, B: 0.0001 to 0.0030%, Ca: 0.0001 to 0.0070%, Mg: 0.0001 to 0.0060%, Mo: 0.1 to 5.0%, W: 0.01 to 2.00%, Cu: 0.01 to 3.00%, Nb: 0.01 to 1.00%, Ta: 0.01 to 1.00%, Sn: 0.01 to 0.10%, and rare earth elements: 0.01 to 0.10%.

6. Fe-Ni-Cr alloy member according to claim 4 or claim 5, wherein the Fe-Ni-Cr alloy material contains 0.10 to 1.00% by mass of Co, and in an elemental concentration profile showing the relationship between sputtering depth and elemental concentration by mass%, obtained by performing glow discharge emission spectroscopy analysis in the depth direction from the surface of the oxide scale, the maximum value of the Co concentration at the surface of the Fe-Ni-Cr alloy material is 0.20% or more by mass.

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