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CN-121674778-B - High-strength corrosion-resistant niobium-free zirconium alloy and manufacturing method thereof

CN121674778BCN 121674778 BCN121674778 BCN 121674778BCN-121674778-B

Abstract

A high-strength corrosion-resistant niobium-free zirconium alloy and a manufacturing method thereof belong to the field of nuclear engineering materials. The high-strength corrosion-resistant niobium-free zirconium alloy comprises, by weight, 0.7% -1.5% of Sn,0.1% -0.4% of Fe,0.15% -0.35% of Cr,0.02% -0.08% of Ni,0.1% -0.18% of O, 0.001% -0.1% of Ge and 0.001% -0.15% of Cu, and the balance of Zr and unavoidable impurities, wherein the atomic number ratio of Fe/Cr is more than or equal to 1 and less than or equal to 1.8,0.13 and the atomic number ratio of Ni/Fe is less than or equal to 0.3. The alloy has good corrosion resistance, can prevent furuncle-like corrosion, and has good tolerance to uniform corrosion in high-temperature water environment.

Inventors

  • ZENG QIFENG
  • ZHANG LEFU
  • CHEN FULIANG
  • LU JUNQIANG
  • DING JIE
  • LI CONG
  • YAO MEIYI
  • XU SHITONG
  • LIU QINGDONG
  • ZHOU YUNQING

Assignees

  • 上海核工程研究设计院股份有限公司

Dates

Publication Date
20260508
Application Date
20260204

Claims (9)

  1. 1. The manufacturing method of the high-strength corrosion-resistant niobium-free zirconium alloy is characterized by comprising the following steps of: Smelting to obtain an alloy ingot, wherein the alloy ingot comprises 0.7-1.5% of Sn, 0.1-0.4% of Fe, 0.15-0.35% of Cr, 0.02-0.08% of Ni, 0.1-0.18% of O, 0.001-0.1% of Ge and 0.001-0.15% of Cu, the balance of Zr and unavoidable impurities, and the alloy ingot is subjected to beta-phase zone homogenization heat treatment, hot rolling and cold rolling in sequence according to the atomic number ratio, wherein the Fe/Cr is more than or equal to 1 and less than or equal to 1.8,0.13 and the Ni/Fe is more than or equal to 0.3, so as to obtain an alloy blank; Step b), carrying out vacuum heating treatment on the alloy blank for 5-15 h at 450-500 ℃ to obtain an aging blank with a dispersed precipitated phase in a tissue; And C), performing heat treatment on the aging blank for 2-6 hours at the temperature of 530-590 ℃ to obtain a high-strength corrosion-resistant niobium-free zirconium alloy finished product.
  2. 2. The method for producing a high-strength corrosion-resistant niobium-free zirconium alloy according to claim 1, wherein in the step c), the composition of the alloy is, by weight, When the Sn content in the high-strength corrosion-resistant niobium-free zirconium alloy is not more than 1.2%, the heat treatment temperature is 530-550 ℃, and the heat preservation time is 2-4 hours; when Sn in the high-strength corrosion-resistant niobium-free zirconium alloy is more than 1.2%, the heat treatment temperature is 570-590 ℃, and the heat preservation time is 3-6 h.
  3. 3. The method for producing a high-strength corrosion-resistant niobium-free zirconium alloy according to claim 1 or 2, wherein in the step a), the alloy ingot is produced by a vacuum consumable arc melting process.
  4. 4. The method for manufacturing the high-strength corrosion-resistant niobium-free zirconium alloy according to claim 1 or 2, wherein in the step a), the homogenizing heat treatment of the beta phase region is carried out by heating the alloy cast ingot to 1000-1050 ℃ and preserving heat for 30-60 min, and then carrying out water cooling quenching.
  5. 5. The method for producing a high-strength corrosion-resistant niobium-free zirconium alloy according to claim 1 or 2, wherein the hot rolling treatment is carried out at a working temperature of 650 ℃ to 750 ℃.
  6. 6. The method for producing a high-strength corrosion-resistant niobium-free zirconium alloy according to claim 1 or 2, wherein the total deformation amount of the cold rolling process in the step a) is 70 to 90%.
  7. 7. A high strength corrosion resistant niobium-free zirconium alloy, characterized in that it is manufactured by the manufacturing method of any one of claims 1 to 6.
  8. 8. The high-strength corrosion-resistant niobium-free zirconium alloy according to claim 7, wherein the base body of the high-strength corrosion-resistant niobium-free zirconium alloy is alpha-Zr, wherein dispersed Zr 2 (Fe,Ni)、Zr(Fe,Cr) 2 and Cu and Ge particles are distributed, and the total amount of solid solution elements in the alpha-Zr is more than or equal to 0.27% and less than or equal to 0.45% in weight ratio.
  9. 9. The high-strength corrosion-resistant niobium-free zirconium alloy according to claim 7 or 8, wherein the atomic ratio of Fe/Cr is 1.2 or less and 1.5 or less.

Description

High-strength corrosion-resistant niobium-free zirconium alloy and manufacturing method thereof Technical Field The invention belongs to the field of nuclear engineering materials, and particularly relates to a high-strength corrosion-resistant niobium-free zirconium alloy and a manufacturing method thereof. Background The zirconium alloy has good high-temperature mechanical property, good corrosion resistance in water environment and low thermal neutron absorption section, so that the zirconium alloy is widely applied to manufacturing of reactor fuel assembly structural members of pressurized water reactor nuclear power plants. The mechanical properties can be effectively improved by adding Nb into the zirconium alloy, but the corrosion resistance of the zirconium alloy in a high-dissolved-oxygen environment can be obviously reduced by adding Nb, such as ZIRLO alloy, M5 alloy and the like, and the oxidation resistance of the zirconium alloy in a water environment can not meet the design requirements of a new generation of miniaturized reactor. Zr-Sn alloys such as Zr-4 and the like are not added with Nb element, but the mechanical property and the corrosion resistance are difficult to be compatible, and the uniform corrosion acceleration of the zirconium alloy can be caused by the high Sn content. Patent CN111254315A discloses a corrosion-resistant zirconium alloy, which improves the furuncle-like corrosion resistance of the zirconium alloy by adding elements such as Si, ni, V and the like into the zirconium alloy, but the solution still cannot solve the problem of uniform corrosion resistance attenuation under high Sn content, and the protective performance of the provided zirconium alloy oxide film still can be obviously reduced after being in a steam corrosion environment for a long time. Patent CN111394617a adds a trace amount of Nb to improve the performance of the zirconium alloy, resulting in the risk of insufficient corrosion resistance of the zirconium alloy in a high dissolved oxygen environment, and at the same time, the zirconium alloy provided by the scheme has a phenomenon of reduced α - β transformation temperature, which increases the complexity of the heat treatment process of the zirconium alloy. Therefore, the niobium-free zirconium alloy with good comprehensive performance is provided, and has high practical value. Disclosure of Invention The invention aims to provide a high-strength corrosion-resistant niobium-free zirconium alloy, which improves the mechanical property and corrosion resistance of the zirconium alloy. The invention also provides a manufacturing method of the high-strength corrosion-resistant niobium-free zirconium alloy. According to an embodiment of one aspect of the invention, a high-strength corrosion-resistant niobium-free zirconium alloy is provided, which comprises 0.7-1.5% of Sn, 0.1-0.4% of Fe, 0.15-0.35% of Cr, 0.02-0.08% of Ni, 0.1-0.18% of O and at least one of the following elements of 0.001-0.1% of Ge and 0.001-0.15% of Cu, wherein 0.27-0.45% of Fe+Cr+Ni is less than or equal to, the balance of Zr and unavoidable impurities, and 1-1.8,0.13% of Fe/Cr-less than or equal to Ni/Fe-less than or equal to 0.3 in terms of atomic number ratio. In the zirconium alloy, t-ZrO 2 is a key phase of a protective zirconium alloy oxide film, and the addition of Ge element can delay the phase transition process of t-ZrO 2 and improve the protectiveness of the zirconium alloy oxide film. The Ge 4+ ion radius (53 pm) is smaller than the Zr 4+ ion radius (72 pm), and the solid solution in ZrO 2 can delay the phase transition of t-ZrO 2, thereby inhibiting the accumulation of phase transition stress and delaying the corrosion transition period, and further counteracting the negative influence of high tin content on the corrosion of the zirconium alloy. By introducing Cu element, the nano Cu second phase exists in the zirconium alloy, a hydrogen trap effect is generated, diffused hydrogen is captured, the risk of hydrogen induced cracking in the service process of the fuel rod cladding is reduced, meanwhile, cu particles can inhibit the growth of recrystallized grains of a zirconium alloy matrix, and the adhesion of an oxide film on the surface of the zirconium alloy is improved. By controlling the atomic number ratio of Fe/Cr (hereinafter referred to as Fe/Cr ratio), a Zr (Fe, cr) 2 Laves phase with stable components and moderate volume expansion after oxidation can be formed in the alloy matrix, and the alloy component with the Fe/Cr ratio Zr (Fe, cr) 2 has better corrosion resistance compared with the Zr-4 alloy with higher Fe/Cr ratio (about 2:1). NiO has a high solid solubility (about 5 mol%) in ZrO 2 matrix, significantly higher than Fe 2O3 or Cr 2O3 (about 2 mol%), thus improving the compatibility of alloy matrix with oxide film. Furthermore, the ratio of NiO, ranging-Bedworth (p.b.), was 1.65, much lower than Fe 2O3 (2.09) and Cr 2O3 (2.00), and closer to the p.b. ratio o