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EP-4495282-B1 - NI-CR ALLOY MEMBER COMPRISING ADDITIVELY MANUFACTURED ARTICLE, METHOD FOR MANUFACTURING NI-CR ALLOY MEMBER, AND PRODUCT USING NI-CR ALLOY MEMBER

EP4495282B1EP 4495282 B1EP4495282 B1EP 4495282B1EP-4495282-B1

Inventors

  • KUWABARA KOUSUKE
  • DAIGO YUZO

Dates

Publication Date
20260506
Application Date
20230308

Claims (9)

  1. A Ni-Cr alloy member comprising, by a mass ratio, 25% or more and 49% or less of Cr, 0.5% or more and 5.0% or less of Mo, 2.5% or less of Ta, 5% or less of W, 7.00% or less of Fe, 2.50% or less of Co, 0.04% or less of N, 0.50% or less of Mn, 0.01% or less of Mg, 0.20% or less of Si, 0.50% or less of A1, 0.50% or less of Ti, 0.25% or less of Cu, 0.30% or less of V, 0.05% or less of B, 0.20% or less of Zr, 0.10% or less of O, and a balance of Ni and unavoidable impurities, wherein the Ni-Cr alloy member comprises an additively manufactured article (A) obtained by additive manufactured using a laser beam or an electron beam which primarily has a face-centered cubic structure and in which a phase fraction of a phase having a body-centered cubic structure is less than 2.5% determined by a phase map according to electron back-scattered diffraction measurement, wherein the additively manufactured article (A) is composed of a crystal grain (2) having a plurality of columnar cell structures (3), and an accumulation part of dislocations is present between the plurality of columnar cell structures (3) adjacent to each other.
  2. The Ni-Cr alloy member according to claim 1, wherein a size of the phase having a body-centered cubic structure included in the additively manufactured article (A) is less than 10 µm determined by scanning electron microscopy.
  3. The Ni-Cr alloy member according to claim 1, wherein a matrix phase composed of the crystal grain (2) is composed of a Ni-based phase, and segregation of Cr is not included in the matrix phase.
  4. The Ni-Cr alloy member according to claim 1, wherein a Vickers hardness is 240 HV or more measured in accordance with JIS Z 2244 at a load of 0.5 kgf and a holding duration of 10 s.
  5. The Ni-Cr alloy member according to claim 1, wherein a yield strength is 400 MPa or more measured at room temperature in accordance with ASTM E8.
  6. A component obtained by using the Ni-Cr alloy member according to claim 1 and contained in a burner, a combustor, an incinerator, a jet engine, a rocket engine, a semiconductor fabrication apparatus or a chemical plant.
  7. A method for manufacturing a Ni-Cr alloy member comprising an additively manufactured article (A), the method comprising: an additive manufacturing process of obtaining an additively manufactured article (A) composed of a Ni-Cr alloy that comprises, by a mass ratio, 25% or more and 49% or less of Cr, 0.5% or more and 5.0% or less of Mo, 2.5% or less of Ta, 5% or less of W, 7.00% or less of Fe, 2.50% or less of Co, 0.04% or less of N, 0.50% or less of Mn, 0.01% or less of Mg, 0.20% or less of Si, 0.50% or less of Al, 0.50% or less of Ti, 0.25% or less of Cu, 0.30% or less of V, 0.05% or less of B, 0.20% or less of Zr, 0.10% or less of O, and a balance of Ni and unavoidable impurities, by additive manufacturing using a laser beam or an electron beam, wherein during melting and solidification accompanying the additive manufacturing, by performing rapid cooling in a temperature range above 300°C and below a solidification point, a precipitation amount of a phase having a body-centered cubic structure with respect to a phase having a face-centered cubic structure is configured to be less than 2.5% in phase fraction determined by a phase map according to electron back-scattered diffraction measurement, wherein the additively manufactured article (A) is composed of a crystal grain (2) having a plurality of columnar cell structures (3), and an accumulation part of dislocations is present between the plurality of columnar cell structures (3) adjacent to each other.
  8. The method for manufacturing a Ni-Cr alloy member according to claim 7, wherein a heat treatment is performed on the additively manufactured article (A) at a temperature of 1000°C or higher and 1350°C or lower.
  9. The method for manufacturing a Ni-Cr alloy member according to claim 8, wherein the heat treatment is performed for 0.5 hours or more and 3 hours or less.

Description

Technical Field The present invention relates to a Ni-Cr alloy member including an additively manufactured article, a method for manufacturing the Ni-Cr alloy member, and a product using the Ni-Cr alloy member. Related Art Members and components used in a chemical plant, a semiconductor fabrication processes, etc. require corrosion resistance to withstand corrosive environments. Although stainless steel is generally used in such environments, Ni-based alloys are selected particularly for components exposed to severe corrosive environments. Further, as the design of the above members and components becomes increasingly complex, there is also a growing demand for complex shapes which are difficult to produce by die forging or machining. In recent years, additive manufacturing has been increasingly applied to production of members with complex shapes. As a manufacturing method for complex-shaped members used in the corrosive environments, Patent Document 1 discloses additive manufacturing (AM) for Ni-based corrosion-resistant alloys. A heat source is supplied to a raw material powder to melt and solidify (hereinafter referred to as "melting and solidification") the raw material powder, and this process is repeatedly performed to obtain an additively manufactured article in a three-dimensional shape. According to the additive manufacturing, three-dimensional products can be obtained in a net shape or a near-net shape even if the shape is complex. It has been shown that, by applying the additive manufacturing, crystal grains having multiple columnar cell structures are formed in the Ni-based alloy, and by forming segregation of Mo between the columnar cell structures, a high-strength metal additively manufactured article (hereinafter referred to as an "additively manufactured article" or simply a "manufactured article") may be obtained. As disclosed in Patent Document 2, the term "additive manufacturing" is considered an industry-standard term as defined in ASTM (American Society for Testing and Materials) F2792. In additive manufacturing, three-dimensional products may be obtained in a net shape or a near-net shape, and when applied to corrosion-resistant alloys, excellent properties in both strength and corrosion resistance can be obtained. However, in terms of high-temperature oxidation resistance in exposure to, for example, an environment of 600°C or higher, there is room for improvement in the additively manufactured article shown in Patent Document 1. Further improvements in high-temperature oxidation resistance are desired for an environment of, for example, a jet engine, a rocket engine, a burner exposed to flames in an incinerator, etc. Conventionally, in such environments, melted and forged materials composed of Ni-Cr alloys (Patent Document 3) having a large Cr amount, which forms more stable surface oxide films, are used. However, in Ni-Cr alloys with a large Cr amount, stability of a body-centered cubic (BCC) phase with respect to a face-centered cubic (FCC) phase, which is a matrix phase, also increases, and separation into two-phase structures may occur during melting. In melting materials, there is a tendency that a formed amount of the BCC phase, which is a precipitate phase, becomes large, and since a Cr concentration for forming the surface oxide film becomes non-uniform, there is a problem that corrosion resistance decreases. Related Art Documents Patent Documents Patent Document 1: International Patent Application Publication No. 2020/179766Patent Document 2: Japanese Patent Application Laid-Open No. 2016-502596Patent Document 3: Japanese Patent Application Laid-Open No. 2008-291281Non-patent document, ZHANG WEN-YA et al. "Synthetic effect of Cr and Mo elements on microstructure and properties of laser cladding NiCrxMoy alloy coatings", ACTA METALLURGICA SINICA, vol. 33, no. 10, 18 June 2020, pages 1331-1345, discloses a synthetic effect of Cr and Mo elements on microstructure and properties of laser cladding NiCrxMoy alloy coatings. Non-patent document, UETA SHIGEKI at el. "Effects of Fe, W and Mo on kinetics of discontinuous precipitation in the Ni-Cr system", MATERIALS TRANSACTIONS, vol. 53, no. 10, 5 September 2012, pages 1744-1752, discloses effects of Fe, W and Mo on kinetics of discontinuous precipitation in the Ni-Cr system. US 2022/0001449 A1 discloses a Ni-based alloy member including an additively manufactured body, a method for manufacturing a Ni-based alloy member, and a manufactured product using a Ni-based alloy member. SUMMARY OF INVENTION Problem to Be Solved by Invention In view of the above, the present invention aims to provide a Ni-Cr alloy member including an additively manufactured article, a method for manufacturing the Ni-Cr alloy member, and a product using the Ni-Cr alloy member, which exhibit improved corrosion resistance and oxidation resistance at a high temperature and are also excellent in mechanical properties. Means for Solving Problem The invention is set