Search

CN-121992312-A - Austenitic stainless steel and preparation method and application thereof

CN121992312ACN 121992312 ACN121992312 ACN 121992312ACN-121992312-A

Abstract

The invention provides austenitic stainless steel, a preparation method and application thereof, and relates to the field of high-temperature-resistant austenitic stainless steel, wherein the austenitic stainless steel comprises the following ：C≤0.10%,N≤0.12%,Si≤2.0%,Mn：1.0~2.0%,Cr：16.0~18.0%,Ni：10.0~14.0%,Mo：2.0~3.0%,Nb：0.05~0.10%,Ti：0.05~0.10%,S≤0.02%,P：0.04~0.06%, percent by weight of Fe and unavoidable residual elements as the rest. According to the invention, by increasing the content of P in the stainless steel, the interaction of P and vacancies at high temperature can reduce the diffusion rate of solute atoms such as Cr, mo and the like, inhibit nucleation of M 23 C 6 carbide and the like at a grain boundary, remarkably reduce the precipitation quantity, and simultaneously, the P is discharged outwards in the coarsening process of M 23 C 6 carbide to form a core-shell result that the M 23 C 6 carbide is coated by the P element, so that the coarsening rate is reduced, creep voids caused by precipitation phases in the creep process are further inhibited, and the creep rupture strength is improved.

Inventors

  • CHEN SHENGHU
  • ZHANG QIJI
  • CHEN SIHAN
  • SU YUANFEI
  • JIANG HAICHANG
  • YAN DESHENG
  • RONG LIJIAN

Assignees

  • 中国科学院金属研究所

Dates

Publication Date
20260508
Application Date
20251218

Claims (10)

  1. 1. The austenitic stainless steel is characterized by comprising the following ：C≤0.10%,N≤0.12%,Si≤2.0%,Mn：1.0~2.0%,Cr：16.0~18.0%,Ni：10.0~14.0%,Mo：2.0~3.0%,Nb：0.05~0.10%,Ti：0.05~0.10%,S≤0.02%,P：0.04~0.06%, parts by weight of Fe and unavoidable residual elements.
  2. 2. The austenitic stainless steel according to claim 1, wherein the sum a of the mass percentages C, N, P in the austenitic stainless steel satisfies a≤0.15%.
  3. 3. Austenitic stainless steel according to claim 1 or 2, characterized in that the mass percentage of C in the austenitic stainless steel is not more than 0.05%.
  4. 4. The austenitic stainless steel according to claim 1, wherein the sum of the mass percentages of Nb and Ti in the austenitic stainless steel is b, the mass percentages of P are c, b and c satisfy b/c≤3.
  5. 5. The austenitic stainless steel according to claim 1, wherein the mechanical properties of the austenitic stainless steel at room temperature are yield strength Rp0.2 not less than 230MPa, tensile strength Rm not less than 540MPa, elongation A not less than 50%, impact toughness KV2 not less than 350J, and/or The mechanical properties of the austenitic stainless steel are that the yield strength Rp0.2 is more than or equal to 116MPa, the tensile strength Rm is more than or equal to 396MPa, and/or At 550 ℃ and 3000h, the creep rupture strength of the austenitic stainless steel is more than or equal to 302MPa, and/or At 550 ℃ and 10000h, the creep rupture strength of the austenitic stainless steel is more than or equal to 277MPa, and/or The size of M 23 C 6 carbide in the austenitic stainless steel is <200nm at 550 ℃ under 3000h conditions.
  6. 6. The method for preparing austenitic stainless steel according to any one of claims 1 to 5, characterized by comprising the steps of: and (3) preparing materials according to the chemical components of the austenitic stainless steel, smelting and casting the prepared raw materials to obtain a casting blank, and sequentially carrying out homogenization treatment, thermal processing treatment, solution treatment and water quenching on the casting blank to obtain the austenitic stainless steel.
  7. 7. The method for producing austenitic stainless steel according to claim 6, wherein the temperature of the solution treatment is 1100-1150 ℃, and the heat-preserving time of the solution treatment is 30-60 min.
  8. 8. The method for producing austenitic stainless steel according to claim 6, wherein the temperature of the homogenization treatment is 1230 to 1250 ℃, and the heat preservation time of the homogenization treatment is not less than 20 hours.
  9. 9. The method of producing austenitic stainless steel according to claim 6, wherein the step of heat working treatment includes a cogging forging treatment and a rolling treatment which are sequentially performed; preferably, the initial rolling temperature of the rolling treatment is 1100-1200 ℃, and the final rolling temperature is more than or equal to 900 ℃.
  10. 10. The use of an austenitic stainless steel according to any of claims 1-5, characterized in that the austenitic stainless steel is processed into a sheet, bar or forging for quaternary nuclear, thermal or petrochemical use.

Description

Austenitic stainless steel and preparation method and application thereof Technical Field The invention belongs to the technical field of high-temperature-resistant austenitic stainless steel, and particularly relates to austenitic stainless steel with high creep rupture strength, and a preparation method and application thereof. Background Austenitic stainless steel is widely applied to key structural materials in the fields of petrochemical industry, nuclear power, aerospace and the like by virtue of good cold and hot processing performance, corrosion resistance and mechanical properties. In the long-term service process, M 23C6 carbide, sigma phase, laves and other brittle phases can be gradually separated out, so that the high-temperature stability of austenitic stainless steel is reduced, and the service life of the material is influenced if the phenomena of reduced impact toughness, reduced creep rupture strength, improved irradiation swelling rate and the like occur. With the development of technology, the design service life and service temperature of components are continuously improved, such as reactor vessel internal components of a fourth-generation nuclear power reactor, high-temperature cracking furnace tubes in petrochemical industry and the like. Therefore, there is a need to develop a novel austenitic stainless steel that is resistant to high temperatures and has a long life. How to reduce the phase precipitation tendency in the service process is the key for improving the high-temperature stability of austenitic stainless steel, and the prior art proposes that the reduction of the C content, the N alloying, the addition of Nb/Ti stabilizing elements and the like reduce the phase precipitation tendency to a certain extent and develop various grades of austenitic stainless steel. However, with the continuous improvement of the service life requirements of advanced equipment, for example, the design life of the fourth-generation sodium-cooled fast reactor is improved from 40 years to 60-100 years, and the creep rupture strength of the existing austenitic stainless steel is difficult to meet the long-term service requirements. Disclosure of Invention Accordingly, the invention provides an austenitic stainless steel, a preparation method and application thereof, and mainly aims to provide an austenitic stainless steel with high creep rupture strength. In order to solve the above problems, in one aspect, the present invention provides an austenitic stainless steel, which comprises the following ：C≤0.10%,N≤0.12%,Si≤2.0%,Mn：1.0~2.0%,Cr：16.0~18.0%,Ni：10.0~14.0%,Mo：2.0~3.0%,Nb：0.05~0.10%,Ti：0.05~0.10%,S≤0.02%,P：0.04~0.06%, parts by weight of chemical components, the balance being Fe and unavoidable residual elements. Further, the sum a of the mass percentages C, N, P in the austenitic stainless steel satisfies that a is less than or equal to 0.15 percent. Further, the mass percentage of C in the austenitic stainless steel is less than or equal to 0.05 percent. Further, the sum of the mass percentages of Nb and Ti in the austenitic stainless steel is b, the mass percentage of P is c, and b and c are satisfied that b/c is less than or equal to 3. Further, at room temperature, the mechanical properties of the austenitic stainless steel are that the yield strength Rp0.2 is more than or equal to 230MPa, the tensile strength Rm is more than or equal to 540MPa, the elongation A is more than or equal to 50%, the impact toughness KV2 is more than or equal to 350J, and/or The mechanical properties of the austenitic stainless steel are that the yield strength Rp0.2 is more than or equal to 116MPa, the tensile strength Rm is more than or equal to 396MPa, and/or At 550 ℃ and 3000h, the creep rupture strength of the austenitic stainless steel is more than or equal to 302MPa, and/or At 550 ℃ and 10000h, the creep rupture strength of the austenitic stainless steel is more than or equal to 277MPa, and/or The size of M 23C6 carbide in the austenitic stainless steel is <200nm at 550 ℃ under 3000h conditions. In another aspect, the present invention provides a method for preparing an austenitic stainless steel according to any one of the above, comprising the steps of: And (3) preparing materials according to the chemical components of the austenitic stainless steel, smelting and casting the prepared raw materials to obtain a casting blank, and sequentially carrying out homogenization treatment, thermal processing treatment and solution treatment on the casting blank to obtain the austenitic stainless steel. Further, the temperature of the solution treatment is 1100-1150 ℃, and the heat preservation time of the solution treatment is 30-60 min. Further, the temperature of the homogenization treatment is 1230-1250 ℃, and the heat preservation time of the homogenization treatment is more than or equal to 20 hours. Further, the step of the heat processing treatment comprises a cogging forging treatment and a rolling treatm