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US-12618127-B2 - Fe—Mn—Al—C lightweight steel, production method thereof, terminal, steel mechanical part, and electronic device

US12618127B2US 12618127 B2US12618127 B2US 12618127B2US-12618127-B2

Abstract

This application provides Fe—Mn—Al—C lightweight steel, including: Fe, wherein a weight percentage of the Fe is greater than or equal to 50.4 wt %; Mn, wherein a weight percentage of the Mn is 25-35 wt %; Al, wherein a weight percentage of the Al is 6-12 wt %; C, wherein a weight percentage of the C is 0.8-2.0 wt %; and O, wherein a weight percentage of the O is 0.005-0.6 wt %. This application further provides a terminal to which the Fe—Mn—Al—C lightweight steel is applied, a production method for the Fe—Mn—Al—C lightweight steel, a steel mechanical part, and an electronic device. The lightweight steel in this application has low density, high strength, and high elongation.

Inventors

  • Longyu LI
  • Ming Cai
  • Mantang Duan
  • Meiling ZHU
  • Zhongyong Deng

Assignees

  • HUAWEI TECHNOLOGIES CO., LTD.
  • SHANGHAI FUTURE HIGH-TECH CO., LTD.

Dates

Publication Date
20260505
Application Date
20230223
Priority Date
20200825

Claims (20)

  1. 1 . An Fe—Mn—Al—C steel, comprising: Fe, wherein a weight percentage of the Fe is greater than or equal to 50.4 wt %; Mn, wherein a weight percentage of the Mn is 25-35 wt %; Al, wherein a weight percentage of the Al is 6-12 wt %; C, wherein a weight percentage of the C is 0.8-2.0 wt %; and O, wherein a weight percentage of the O is 0.11-0.6 wt %.
  2. 2 . The Fe—Mn—Al—C steel according to claim 1 , wherein the Fe—Mn—Al—C steel further comprises Si, Ni, and Cr, a weight percentage of the Si is ≤0.2 wt %, a weight percentage of the Ni is ≤0.6 wt %, and a weight percentage of the Cr is ≤0.4 wt %.
  3. 3 . The Fe—Mn—Al—C steel according to claim 1 , wherein the Fe—Mn—Al—C steel further comprises at least one of Cu, V, Ti, Nb, W, Zr, Mo, and Re, and a total weight percentage of Cu, V, Ti, Nb, W, Zr, Mo, and Re is ≤1 wt %.
  4. 4 . The Fe—Mn—Al—C steel according to claim 1 , wherein the Fe—Mn—Al—C steel is formed by using a powder raw material and a metal injection molding process.
  5. 5 . The Fe—Mn—Al—C steel according to claim 4 , wherein the powder raw material comprises the following chemical components: 28 wt %≤Mn≤35 wt %, 6 wt %≤Al≤12 wt %, 0.7 wt %≤C≤1.8 wt %, 0.003 wt %≤0≤0.4 wt %, 0≤Si≤0.2 wt %, 0≤Ni≤0.6 wt %, 0≤Cr≤0.4 wt %, and 0≤Cu+V+Ti+Nb+W+Zr+Mo+Re≤1 wt %, and the rest is Fe, wherein Cu+V+Ti+Nb+W+Zr+Mo+Re means that at least one of Cu, V, Ti, Nb, W, Zr, Mo, and Re is comprised and indicates a total weight percentage of Cu, V, Ti, Nb, W, Zr, Mo, and Re.
  6. 6 . The Fe—Mn—Al—C steel according to claim 1 , wherein density of the Fe—Mn—Al—C steel is 5.9-7.0 g/cm 3 , yield strength of the Fe—Mn—Al—C steel is 800-1200 MPa, and elongation of the Fe—Mn—Al—C steel is 2% to 20%.
  7. 7 . The Fe—Mn—Al—C steel according to claim 1 , wherein a functional coating is formed on a surface of the Fe—Mn—Al—C steel.
  8. 8 . A terminal, comprising an Fe—Mn—Al—C steel comprising: Fe, wherein a weight percentage of the Fe is greater than or equal to 50.4 wt %; Mn, wherein a weight percentage of the Mn is 25-35 wt %; Al, wherein a weight percentage of the Al is 6-12 wt %; C, wherein a weight percentage of the C is 0.8-2.0 wt %; and O, wherein a weight percentage of the O is 0.11-0.6 wt %.
  9. 9 . The terminal according to claim 8 , wherein the Fe—Mn—Al—C steel further comprises Si, Ni, and Cr, a weight percentage of the Si is ≤0.2 wt %, a weight percentage of the Ni is ≤0.6 wt %, and a weight percentage of the Cr is ≤0.4 wt %.
  10. 10 . The terminal according to claim 8 , wherein the Fe—Mn—Al—C steel further comprises at least one of Cu, V, Ti, Nb, W, Zr, Mo, and Re, and a total weight percentage of Cu, V, Ti, Nb, W, Zr, Mo, and Re is ≤1 wt %.
  11. 11 . The terminal according to claim 8 , wherein the Fe—Mn—Al—C steel is formed by using a powder raw material and a metal injection molding process.
  12. 12 . The terminal according to claim 11 , wherein the powder raw material comprises the following chemical components: 28 wt %≤Mn≤35 wt %, 6 wt %≤Al≤12 wt %, 0.7 wt %≤C≤1.8 wt %, 0.003 wt %≤0≤0.4 wt %, 0≤Si≤0.2 wt %, 0≤Ni≤0.6 wt %, 0≤Cr≤0.4 wt %, and 0≤Cu+V+Ti+Nb+W+Zr+Mo+Re≤1 wt %, and the rest is Fe, wherein Cu+V+Ti+Nb+W+Zr+Mo+Re means that at least one of Cu, V, Ti, Nb, W, Zr, Mo, and Re is comprised and indicates a total weight percentage of Cu, V, Ti, Nb, W, Zr, Mo, and Re.
  13. 13 . The terminal according to claim 8 , wherein density of the Fe—Mn—Al—C steel is 5.9-7.0 g/cm 3 , yield strength of the Fe—Mn—Al—C steel is 800-1200 MPa, and elongation of the Fe—Mn—Al—C steel is 2% to 20%.
  14. 14 . The terminal according to claim 8 , wherein the terminal is a consumer electronics product, and comprises structural parts, and at least one of the structural parts comprises the Fe—Mn—Al—C steel.
  15. 15 . The terminal according to claim 8 , wherein the terminal is a foldable mobile phone comprising a rotating shaft, and the rotating shaft comprises the Fe—Mn—Al—C steel.
  16. 16 . A production method for the Fe—Mn—Al—C steel of claim 1 , comprising: producing a powder raw material, wherein the powder raw material comprises the following chemical components: 28 wt %≤Mn≤35 wt %, 6 wt %≤Al≤12 wt %, 0.7 wt %≤C≤1.8 wt %, 0.003 wt %≤0≤0.4 wt %, 0≤Si≤0.2 wt %, 0≤Ni≤0.6 wt %, 0≤Cr≤0.4 wt %, and 0≤Cu+V+Ti+Nb+W+Zr+Mo+Re≤1 wt %, and the rest is Fe, wherein Cu+V+Ti+Nb+W+Zr+Mo+Re means that at least one of Cu, V, Ti, Nb, W, Zr, Mo, and Re is comprised and indicates a total weight percentage of Cu, V, Ti, Nb, W, Zr, Mo, and Re; and producing the Fe—Mn—Al—C steel by using the powder raw material and a metal injection molding process.
  17. 17 . The production method according to claim 16 , wherein the metal injection molding process comprises: forming a green body based on the powder raw material; sintering the green body to form a sintered body; and performing heat treatment on the sintered body.
  18. 18 . The production method according to claim 17 , wherein the forming the green body based on the powder raw material comprises: mixing the powder raw material with a binder; and molding a mixture of the powder raw material and the binder into the green body through injection molding.
  19. 19 . The production method according to claim 18 , wherein before the sintering the green body, the production method further comprises: degreasing the green body to remove a part of binder in the green body.
  20. 20 . The production method according to claim 17 , wherein the performing the heat treatment on the sintered body comprises: performing solution treatment on the sintered body; and aging the sintered body obtained after the solution treatment.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a continuation of International Application No. PCT/CN2021/090830, filed on Apr. 29, 2021, which claims priority to Chinese Patent Application No. 202010865504.5, filed on Aug. 25, 2020. The disclosures of the aforementioned applications are hereby incorporated by reference in their entireties. TECHNICAL FIELD Embodiments of this application relate to Fe—Mn—Al—C lightweight steel, a production method thereof, a terminal to which the Fe—Mn—Al—C lightweight steel is applied, a steel mechanical part, and an electronic device. BACKGROUND A rotating shaft mechanism of an existing foldable mobile phone basically includes two materials. One material is a precipitation hardened steel material. The material has good comprehensive mechanical performance, high strength, good toughness, yield strength of approximately 1000 MPa, and elongation of approximately 6%, but density is high, and is approximately 7.8 g/cm3. The other material is an aluminum alloy material with low density of approximately 2.7 g/cm3, but strength is low. For a 7000-series aluminum alloy with highest strength that is commercially available at present, for example, 7075, yield strength is approximately 500 MPa, and the aluminum alloy is prone to deformation during use. SUMMARY A first aspect of embodiments of this application provides Fe—Mn—Al—C lightweight steel, including: Fe, where a weight percentage of the Fe is greater than or equal to 50.4 wt %;Mn, where a weight percentage of the Mn is 25-35 wt %;Al, where a weight percentage of the Al is 6-12 wt %;C, where a weight percentage of the C is 0.8-2.0 wt %; andO, where a weight percentage of the O is 0.005-0.6 wt %. The Al element reduces density of the lightweight steel, so that the lightweight steel achieves a lightweight effect. The C element forms a carbide strengthening phase to improve strength of the lightweight steel. The O element forms a strengthening phase. The Fe—Mn—Al—C lightweight steel in this application is a material with high strength, high elongation, and low density. In an implementation of this application, the lightweight steel further includes Si, Ni, and Cr, a weight percentage of the Si is ≤0.2 wt %, a weight percentage of the Ni is ≤0.6 wt %, and a weight percentage of the Cr is ≤0.4 wt %. The Si is used to improve activity of the C, and promote dissolution of the C element in a precipitate during aging. The Cr improves corrosion resistance of a steel material to some extent. The Ni helps refine grains and is enriched at a second-phase interface. In an implementation of this application, the lightweight steel further includes at least one of Cu, V, Ti, Nb, W, Zr, Mo, and Re, and a total weight percentage of Cu, V, Ti, Nb, W, Zr, Mo, and Re is ≤1 wt %. The lightweight steel further includes at least one of Cu, V, Ti, Nb, W, Zr, Mo, and Re, so that performance of the lightweight steel can be further improved. For example, the Cu may be used as a dispersed phase in the lightweight steel. In an implementation of this application, the lightweight steel is formed by using a powder raw material and a metal injection molding process. The metal injection molding process may be used to produce small and complex precision curve lightweight steel parts for being widely used in various electronic products. In an implementation of this application, the powder raw material includes the following chemical components: 28 wt %≤Mn≤35 wt %, 6 wt %≤Al≤12 wt %, 0.7 wt %≤C≤1.8 wt %, 0.003 wt %≤O≤0.4 wt %, 0≤Si≤0.2 wt %, 0≤Ni≤0.6 wt %, 0≤Cr≤0.4 wt %, and 0≤Cu+V+Ti+Nb+W+Zr+Mo+Re≤1 wt %, and the rest is Fe. Cu+V+Ti+Nb+W+Zr+Mo+Re means that at least one of Cu, V, Ti, Nb, W, Zr, Mo, and Re is included and indicates a total weight percentage of Cu, V, Ti, Nb, W, Zr, Mo, and Re. The powder raw material may be used to obtain the Fe—Mn—Al—C lightweight steel with a component ratio in this application, and the Fe—Mn—Al—C lightweight steel has high strength, high elongation, and low density. In an implementation of this application, density of the lightweight steel is 5.9-7.0 g/cm3, yield strength of the lightweight steel is 800-1200 MPa, and elongation of the lightweight steel is 2% to 20%. The lightweight steel has low density, high strength, and high elongation. The strength of the steel is high. Therefore, reliability of a steel mechanical part using the lightweight steel is ensured without increasing a thickness of the steel mechanical part, to facilitate miniaturization of the steel mechanical part and miniaturization of an electronic device. In an implementation of this application, a functional coating is formed on a surface of the lightweight steel. The functional coating further beautifies the lightweight steel as a decorative layer, or further protects the lightweight steel or make the lightweight steel functional as a functional coating. A second aspect of embodiments of this application provides a terminal, including the Fe—Mn—Al—