CN-121976114-A - Method for inhibiting Cr-rich carbide in FeCrAl as-cast alloy by synergistic purification of Zr-Ce double microalloy

Abstract

The invention belongs to the technical field of microstructure control of metal materials, and provides a method for cooperatively purifying and inhibiting Cr-rich carbide in FeCrAl as-cast alloy by using Zr-Ce double microalloy. According to the invention, the FeCrAl alloy is prepared by adopting a thermodynamic simulation calculation-vacuum melting method, and the Cr-rich precipitated phase content and segregation distribution thereof in the as-cast FeCrAl alloy can be obviously reduced by adopting a competitive growth mechanism of combining the Zr-Ce double microalloy with the Cr-rich precipitated phase and the C element, so that the mechanical strength and corrosion resistance of the FeCrAl alloy material are improved, the scientific research and industrial requirements on the aspects of reducing the precipitation uniform distribution of the Cr-rich precipitated phase, improving the corrosion resistance and the mechanical properties of the alloy are met, and the application requirements on the improvement of the high-temperature strength of the as-cast structure of the nuclear reaction cladding material FeCrAl alloy are met.

Inventors

• LIU YUXIN
• WANG FEI
• CAI XINMIAO
• YANG JIE
• Min Hengfa
• ZHU YONGYAN

Assignees

• 江苏大学

Dates

Publication Date

20260505

Application Date

20260210

Claims (9)

1. 1. A method for inhibiting Cr-rich carbide in FeCrAl as-cast alloy by synergistic purification of Zr-Ce double microalloy is characterized by comprising the following steps: (1) Adding two microalloy elements of Zr and Ce into the FeCrAl alloy to obtain preset FeCrAl alloy components; (2) In the range of the preset FeCrAl alloy components in the step (1), utilizing an iron-based database TCFE14 in Thermo-Calc simulation software to carry out combination collocation on the alloy components of the preset FeCrAl alloy and carrying out thermodynamic simulation calculation, and analyzing the phase change process of the alloy and the precipitation prediction behavior of Cr-rich carbide to obtain the FeCrAl alloy components meeting the specific service temperature requirement and mechanical performance index; (3) According to the FeCrAl alloy component obtained in the step (2), mixing pure Fe, fe-Si, fe-Mn, fe-Cr alloy and Al according to a proportion, alloying, adjusting a smelting process until the alloy component removes Zr and Ce elements to reach the FeCrAl alloy component in the step (2), adding pure Zr powder firstly, after the alloy component is stable, adding pure Ce powder finally, pouring an alloy billet after the alloy component is detected to be qualified, and air-cooling until the alloy is formed, thus obtaining the Zr-Ce double micro alloy element added FeCrAl alloy.
2. 2. The method of claim 1, wherein in step (1), the predetermined FeCrAl alloy composition comprises ,C 0.01~0.05%,Si 0.1~0.12%,Mn 0.1~0.5%,P 0.002~0.008%,S 0.002~0.006%,Cr 13~23%,Al 4~8%,N 0.01~0.06%,Zr 0.1~1%,Ce 0.1~1%, mass percent Fe as the balance.
3. 3. The method of claim 1, wherein in the step (2), in the thermodynamic simulation calculation, the set temperature interval is 200 ℃ to 1400 ℃ and the calculation step length is 10 ℃, the precipitation temperature, the precipitation quantity and the distribution characteristics of Cr-rich carbide CrC, cr 23 C 6 ,Cr 6 C and the precipitation temperature, the precipitation quantity and the distribution characteristics of the FCC micro-alloyed precipitation phase of the ZrC are calculated and analyzed with emphasis, and the FeCrAl alloy composition combination with the minimum precipitation quantity of the Cr-rich carbide is selected according to the service temperature and the mechanical performance requirements.
4. 4. The method according to claim 1, wherein in the step (3), the alloy smelting components are made uniform by means of electromagnetic stirring during the alloying.
5. 5. The method according to claim 1, wherein in the step (3), vacuum electromagnetic stirring is required when pure Zr powder is added to the alloy, and vacuum electromagnetic stirring is required when pure Ce powder is added to the alloy after the components of Zr in the alloy are uniformly stabilized.
6. 6. The method of claim 1, wherein in step (3), the diameter of the cast alloy ingot is 200 to 500mm.
7. 7. The method of claim 1, wherein in step (3), the alloy composition is detected using a spectrometer until an optimized FeCrAl alloy composition is achieved.
8. 8. A Zr-Ce double microalloy element containing additive FeCrAl alloy, characterized in that it is produced by the method of any one of claims 1 to 7.
9. 9. The use of the Zr-Ce double microalloy element containing additive FeCrAl alloy of claim 8 in nuclear fuel cladding materials.

Description

Method for inhibiting Cr-rich carbide in FeCrAl as-cast alloy by synergistic purification of Zr-Ce double microalloy Technical Field The invention belongs to the technical field of microstructure control of metal materials, and particularly relates to a method for inhibiting Cr-rich carbide in FeCrAl as-cast alloy by synergistic purification of Zr-Ce double microalloy. Background The FeCrAl alloy is an iron-based heat-resistant alloy, and has excellent high-temperature oxidation resistance and corrosion resistance by virtue of an Al 2O3 film and a Cr 2O3 film formed on the surface of the iron-based heat-resistant alloy, so that the iron-based heat-resistant alloy is widely applied to the high-temperature fields such as automobile exhaust pipes, metal electric heating materials, nuclear fuel cladding materials and the like. Especially, as the development requirements of nuclear power safety technology become more and more strict, the nuclear fuel cladding material needs to further bear the high temperature, high pressure and hydrogen corrosion resistance, thereby improving the nuclear power safety production. The FeCrAl alloy matrix structure mainly comprises single ferrite and a small amount of precipitated phases, wherein the single ferrite comprises micro-alloying precipitated phases and Cr-rich precipitated phases. The Cr-rich precipitated phase in the FeCrAl alloy has the characteristic of hardness and brittleness, is generally enriched at the grain boundary of alloy grains, can cause a microcrack source to be generated in the deformation process of the grain boundary to reduce the mechanical property of the FeCrAl alloy, and can cause a large amount of Cr elements to exist in a matrix in the form of second phase particles due to the precipitation of the Cr-rich precipitated phase, particularly the enrichment and segregation of the Cr 23C6 precipitated phase in the grain boundary to reduce the formation of Cr 2O3 oxide film to cause the poor Cr on the alloy surface and seriously damage the corrosion resistance of the FeCrAl alloy. Therefore, the offset precipitation of the Cr-rich precipitated phase at the FeCrAl alloy grain boundary is reduced, the strength of the FeCrAl alloy material can be improved, the corrosion resistance of an oxide film of the FeCrAl alloy material can be enhanced, and the FeCrAl alloy can be used as an important competitiveness of a nuclear fuel cladding material. At present, the measure of reducing the Cr-rich precipitated phase of the FeCrAl alloy mainly adopts low-carbon smelting, and the formation of the Cr-rich precipitated phase is reduced in a mode of reducing the content of C. However, the method can not completely eliminate the problem of segregation of the Cr-rich precipitated phase while increasing the cost of manufacturing the FeCrAl alloy by low-carbon smelting, and can not reduce the strengthening effect of the microalloyed precipitated phase by reducing the content of C in the alloy because the element C is an important component element of the microalloyed carbide precipitated phase. Therefore, there is an urgent need for a novel FeCrAl alloy that can obtain good hydrogen corrosion resistance and good mechanical properties while purifying the Cr-rich precipitated phase. Disclosure of Invention The invention aims to provide a method for inhibiting Cr-rich carbide in FeCrAl as-cast alloy by synergistic purification of Zr-Ce double microalloy, which can obviously reduce the content of Cr-rich precipitated phase and improve the mechanical strength and corrosion resistance of the FeCrAl alloy material. In order to achieve the above object, the present invention provides the following technical solutions: The invention provides a method for cooperatively purifying and inhibiting Cr-enriched carbide in FeCrAl as-cast alloy by using Zr-Ce double microalloy, which comprises the following steps: (1) Adding two microalloy elements of Zr and Ce into the FeCrAl alloy to obtain preset FeCrAl alloy components; (2) In the range of the preset FeCrAl alloy components in the step (1), utilizing an iron-based database TCFE14 in Thermo-Calc simulation software to carry out combination collocation on the alloy components of the preset FeCrAl alloy and carrying out thermodynamic simulation calculation, and analyzing the phase change process of the alloy and the precipitation prediction behavior of Cr-rich carbide to obtain the FeCrAl alloy components meeting the specific service temperature requirement and mechanical performance index; (3) According to the FeCrAl alloy component obtained in the step (2), mixing pure Fe, fe-Si, fe-Mn, fe-Cr alloy and Al according to a proportion, alloying, adjusting a smelting process until the alloy component removes Zr and Ce elements to reach the FeCrAl alloy component in the step (2), adding pure Zr powder firstly, after the alloy component is stable, adding pure Ce powder finally, after the alloy component is detected to be qualified, casting an a