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CN-121428430-B - Ta and Cu synergistically reinforced fine-grain high-strength and high-toughness soft magnetic stainless steel, section bar containing same and preparation method of section bar

CN121428430BCN 121428430 BCN121428430 BCN 121428430BCN-121428430-B

Abstract

The invention belongs to the field of stainless steel. Specifically, the invention relates to Ta and Cu synergistically reinforced fine-grain high-strength and high-toughness soft magnetic stainless steel and a soft magnetic stainless steel section bar comprising the same. The soft magnetic stainless steel of the present invention is composed of elements Cr, cu, mo, ta, C, fe and unavoidable impurities. In the preparation process of the soft magnetic stainless steel section, smelting is carried out according to component ingredients, and the process parameters in the processes are strictly regulated and controlled through solid solution, hot rolling, cold drawing, recrystallization annealing, aging and the like, so that the soft magnetic stainless steel section which is fine and uniform in structure, jointly strengthened by micro carbide precipitation and high-density dispersion coherent nano precipitation phase and has excellent low-temperature toughness and soft magnetic performance is prepared. The Ta and Cu synergistically reinforced fine-grain high-strength and high-toughness soft magnetic stainless steel section can be effectively applied to electromagnetic valves and related products which are served in low-temperature media and require certain strength and toughness, and has good popularization prospect and application value.

Inventors

  • LI JINGYUAN
  • CAO ZHU

Assignees

  • 北京科技大学

Dates

Publication Date
20260508
Application Date
20251106

Claims (9)

  1. 1. A method for preparing Ta and Cu synergistically reinforced fine-grain high-strength and high-toughness soft magnetic stainless steel section, Wherein the soft magnetic stainless steel profile has any one or more of the following properties: The yield strength R e of the soft magnetic stainless steel section is more than or equal to 650 MPa; the tensile strength R m of the soft magnetic stainless steel section is more than or equal to 750 MPa; the elongation e of the soft magnetic stainless steel section is more than or equal to 25%; the impact energy KV 2 of the soft magnetic stainless steel section bar at the temperature of minus 40 ℃ is more than or equal to 30J; the saturation magnetic induction intensity B s of the soft magnetic stainless steel section is more than or equal to 1.50T; the coercive force H c of the soft magnetic stainless steel section is less than or equal to 300A/m; The microstructure of the soft magnetic stainless steel section comprises more than 99.99% of ferrite, and The effective grain size of the microstructure of the soft magnetic stainless steel section bar is less than or equal to 15 mu m, The method is characterized in that it comprises the following steps: Step 1, providing molten steel, and casting and forming the molten steel into a casting blank, wherein the molten steel consists of elements Cr, cu, mo, ta, C, fe and unavoidable impurities, and the content of the elements is as follows: based on the total weight of the molten steel, The elemental Cr content by weight [ Cr ] is 14.0 to 18.0 wt%; the elemental Cu content [ Cu ] is 1.5 to 3.0 wt%; the weight percentage content [ Mo ] of the element Mo is 1.0 to 2.0 weight percent; the content of element Ta [ Ta ] is 0.2 to 0.5 wt%; The content of element C in weight percentage [ C ] is 0.01 to 0.03 weight percent; And the balance of Fe and unavoidable impurities; Step 2, carrying out solution heat treatment on the casting blank obtained in the step 1; step 3, rolling the casting blank subjected to solution heat treatment obtained in the step 2 into a blank, and cooling; Step 4, performing multiple cold drawing on the rolled and cooled blank obtained in the step 3 to obtain a section, wherein the total elongation coefficient mu caused by the cold drawing is in the range of 1.4 to 1.7, the elongation coefficient caused by single cold drawing is not more than 1.2, and heat treatment is not performed in the cold drawing process; step 5, subjecting the cold drawn profile obtained in step 4 to recrystallization annealing treatment, and then cooling to a temperature below 40 ℃ at a cooling rate of not less than 30 ℃ per second; step 6, aging the recrystallized annealed profile obtained from step 5 at a temperature of 600 ℃ to 700 ℃ and then cooling the recrystallized annealed profile to a temperature below 40 ℃ at a cooling rate of not less than 30 ℃ per second, thereby forming the soft magnetic stainless steel profile, wherein the aging is performed for a heat preservation time of: (1) When the sectional area S of the section bar is less than or equal to 100 mm 2 , the heat preservation time of the aging treatment is Wherein The value of t 2 in minutes is rounded up, wherein t 2 = 75-T/10, Wherein T is the holding temperature of the aging treatment in units of DEG C, and (2) When the sectional area S of the section bar is more than 100 mm 2 , the heat preservation time of the aging treatment is Wherein The value of t 3 in minutes is rounded up, wherein t 3 = 70-T/10+S/20, Wherein T is the holding temperature of the ageing treatment in degrees Celsius and S is the cross-sectional area of the profile in mm 2 .
  2. 2. The method for producing a Ta, cu co-strengthened fine-grain high strength and toughness soft magnetic stainless steel section according to claim 1, characterized in that the solution heat treatment time in said step 2 is 6 to 10 hours, and the temperature of said solution heat treatment is , wherein, The value representing T 1 in degrees Celsius is rounded up, wherein T 1 = 1100 + 2500 × [C] + 312.5 × [Ta]; Wherein, the Ta is the weight percentage content of element Ta in weight percent in the molten steel, and [C] the content of the element C in the molten steel is expressed as weight percent.
  3. 3. The method for producing a Ta, cu co-strengthened fine-grain high-strength and high-toughness soft magnetic stainless steel profile according to claim 1, characterized in that in the step 3, the total deformation rate caused by the rolling is in the range of 98% to 99.5%, the initial rolling temperature is in the range of 1150 ℃ to 1250 ℃, the furnace return treatment is not performed during the rolling, and the final rolling temperature is not lower than 850 ℃, then the billet is air-cooled to 780 ℃ to 820 ℃, and finally cooled to a temperature below 40 ℃ at a cooling rate of not lower than 30 ℃ per s.
  4. 4. A method of producing a Ta, cu co-strengthened fine-grain high-strength soft magnetic stainless steel profile according to any one of claims 1 to 3, wherein the recrystallization annealing treatment in step 5 comprises holding at a temperature of 930 ℃ to 970 ℃ and then cooling to a temperature below 40 ℃ at a cooling rate of not less than 30 ℃ per s, wherein the holding time of the recrystallization annealing is: (1) When the sectional area S of the profile is less than or equal to 100 mm 2 , the holding time of the recrystallization annealing is 5 minutes, and (2) When the sectional area S of the section is more than 100 mm 2 , the heat preservation time of the recrystallization annealing is , wherein, The value of t 1 in minutes is rounded up, wherein t 1 = 5+[0.085×(S-100)]/μ, Where S is the cross-sectional area of the profile in mm 2 and μ is the total elongation due to the cold drawing.
  5. 5. Ta, cu co-reinforced fine grain high strength and toughness soft magnetic stainless steel profile prepared by the method for preparing Ta, cu co-reinforced fine grain high strength and toughness soft magnetic stainless steel profile according to any one of claims 1 to 4, characterized in that the soft magnetic stainless steel profile consists of elements Cr, cu, mo, ta, C, fe and unavoidable impurities, the contents of the elements are: Based on the total weight of the soft magnetic stainless steel profile: the elemental Cr content by weight [ Cr ] is 14.0 to 18.0 wt%; the elemental Cu content [ Cu ] is 1.5 to 3.0 wt%; the weight percentage content [ Mo ] of the element Mo is 1.0 to 2.0 weight percent; the content of element Ta [ Ta ] is 0.2 to 0.5 wt%; The content of element C in weight percentage [ C ] is 0.01 to 0.03 weight percent; and the balance of Fe and unavoidable impurities.
  6. 6. The soft magnetic stainless steel profile according to claim 5, characterized in that the elements to be the unavoidable impurities are based on the total weight of the soft magnetic stainless steel profile: N is controlled to be less than 0.005 wt%, and/or The weight percentage of O [ O ] is controlled below 0.005 wt%, and/or S is controlled to be less than 0.005 wt%, and/or The weight percentage content [ P ] of P is controlled below 0.005 wt%.
  7. 7. Soft magnetic stainless steel profile according to claim 5 or 6, characterized in that the weight percentage content [ Ta ] of element Ta and the weight percentage content [ C ] of element C in the soft magnetic stainless steel profile fulfil the following requirements: [ Ta ] + [ C ] =0.2-0.5 wt%, and/or [Ta] : [C] = (16-30):1。
  8. 8. An article prepared from the soft magnetic stainless steel profile of any one of claims 5 to 7.
  9. 9. An article prepared from the soft magnetic stainless steel profile prepared by the method of preparing a Ta, cu synergistically enhanced fine grain high strength and toughness soft magnetic stainless steel profile according to any one of claims 1 to 4.

Description

Ta and Cu synergistically reinforced fine-grain high-strength and high-toughness soft magnetic stainless steel, section bar containing same and preparation method of section bar Technical Field The invention relates to the technical field of stainless steel. In particular, the invention relates to a soft magnetic stainless steel and a soft magnetic stainless steel section bar comprising the same, a preparation method of the soft magnetic stainless steel section bar and an article prepared from the soft magnetic stainless steel section bar. Background With the development of miniaturization, high frequency and high power of high-end electromagnetic actuating elements, the core soft magnetic component also faces to higher and higher performance requirements. Electromagnetic devices represented by fuel oil precision injection valves and miniature servo motors require that ferrite soft magnetic stainless steel cores have higher mechanical strength and toughness reserves to bear long-term high-frequency complex stress impact while maintaining high saturation magnetic induction strength and low magnetic loss. Currently, conventional ferritic soft magnetic stainless steel increases strength mainly by solid solution strengthening or introducing a large number of dislocations. However, such methods have inherent limitations in that excessive and complex solid solution atoms and severe plastic deformation can effectively increase strength, but strongly pin domain walls, resulting in a sharp increase in coercivity, and sacrificing the toughness of the material. While fine-grain strengthening and nano precipitation strengthening are necessary technical paths for breaking the performance dilemma However, the prior art still faces challenges in the synergistic modulation of multi-scale microstructures. How to stably prepare fine and uniform grain structure in soft magnetic stainless steel, and synchronously introduce dispersed nano precipitated phases with controllable size distribution is a complex system engineering involving the whole flow of alloy design, thermal processing and thermal treatment. At present, a systematic overall fine-grain strengthening and nano precipitation strengthening are needed in the technical field of soft magnetic stainless steel, so that an industrial technical scheme for realizing the cooperative breakthrough of multiple performance indexes of strength, low-temperature toughness and soft magnetic performance is realized. Disclosure of Invention Object of the Invention In view of the problems in the prior art described in the background section above, an object of the present invention is to provide a Ta, cu synergistically strengthened fine-grain high strength and toughness soft magnetic stainless steel and a soft magnetic stainless steel profile comprising the same. The invention also aims to provide a method for preparing the soft magnetic stainless steel section bar and an article prepared from the soft magnetic stainless steel section bar. Technical proposal In order to achieve the purpose of the invention as described above, the invention provides the following technical scheme: Scheme 1 is a Ta, cu synergistically reinforced fine-grain high-strength and high-toughness soft magnetic stainless steel, wherein the soft magnetic stainless steel consists of elements Cr (chromium), cu (copper), mo (molybdenum), ta (tantalum), C (carbon), fe (iron) and unavoidable impurities, and the contents of the elements are as follows: based on the total weight of the soft magnetic stainless steel: the elemental Cr content by weight [ Cr ] is from about 14.0 to about 18.0 wt.%; The elemental Cu content [ Cu ] is from about 1.5 to about 3.0 wt.%; the elemental Mo is present in an amount of about 1.0 to about 2.0 wt.%; the elemental Ta weight percent content [ Ta ] is from about 0.2 to about 0.5 weight percent; the weight percentage content of element C [ C ] is from about 0.01 to about 0.03 weight percent; and the balance of Fe and unavoidable impurities. Scheme 2. The soft magnetic stainless steel according to the above scheme 1, wherein the element to be the unavoidable impurities is based on the total weight of the soft magnetic stainless steel: N (nitrogen) is controlled to less than about 0.005 wt%, and/or The weight percentage of O (oxygen) [ O ] is controlled below about 0.005 weight percent, and/or S (sulfur) is controlled to less than about 0.005 wt%, and/or The weight percentage content [ P ] of P (phosphorus) is controlled below about 0.005 wt%. Scheme 3. The soft magnetic stainless steel according to the above scheme 1 or2, wherein the weight percentage content [ Ta ] of the element Ta and the weight percentage content [ C ] of the element C in the soft magnetic stainless steel satisfy the following requirements: [ Ta ] + [ C ] = about 0.2-0.5 wt%, and/or [ Ta ]: [ C ] = about (16-30): 1. Scheme 4 Ta, cu co-reinforced fine grain high strength and toughness soft magnetic stainless steel profil