WO2023025251A1 - 轻质钢及其制备方法、钢结构件和电子设备 - Google Patents

轻质钢及其制备方法、钢结构件和电子设备 Download PDF

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WO2023025251A1
WO2023025251A1 PCT/CN2022/114865 CN2022114865W WO2023025251A1 WO 2023025251 A1 WO2023025251 A1 WO 2023025251A1 CN 2022114865 W CN2022114865 W CN 2022114865W WO 2023025251 A1 WO2023025251 A1 WO 2023025251A1
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Prior art keywords
steel
lightweight steel
weight percentage
lightweight
steel according
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PCT/CN2022/114865
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English (en)
French (fr)
Inventor
李龙雨
蔡明�
徐小明
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华为技术有限公司
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Priority to EP22860597.8A priority Critical patent/EP4386101A1/en
Publication of WO2023025251A1 publication Critical patent/WO2023025251A1/zh
Priority to US18/587,584 priority patent/US20240200174A1/en

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    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/005—Modifying the physical properties by deformation combined with, or followed by, heat treatment of ferrous alloys
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C30/00—Alloys containing less than 50% by weight of each constituent
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/10—Sintering only
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/12—Both compacting and sintering
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/22—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces for producing castings from a slip
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/24—After-treatment of workpieces or articles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F5/00—Manufacture of workpieces or articles from metallic powder characterised by the special shape of the product
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D6/00—Heat treatment of ferrous alloys
    • C21D6/005—Heat treatment of ferrous alloys containing Mn
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C21D9/0068—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for particular articles not mentioned below
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C21D9/28—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for plain shafts
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C33/00—Making ferrous alloys
    • C22C33/02—Making ferrous alloys by powder metallurgy
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/12—Ferrous alloys, e.g. steel alloys containing tungsten, tantalum, molybdenum, vanadium, or niobium
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C11/00—Pivots; Pivotal connections
    • F16C11/04—Pivotal connections
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M1/00—Substation equipment, e.g. for use by subscribers
    • H04M1/02—Constructional features of telephone sets
    • H04M1/0202—Portable telephone sets, e.g. cordless phones, mobile phones or bar type handsets
    • H04M1/0206—Portable telephones comprising a plurality of mechanically joined movable body parts, e.g. hinged housings
    • H04M1/0208—Portable telephones comprising a plurality of mechanically joined movable body parts, e.g. hinged housings characterized by the relative motions of the body parts
    • H04M1/0214—Foldable telephones, i.e. with body parts pivoting to an open position around an axis parallel to the plane they define in closed position

Definitions

  • the application relates to a light steel and its preparation method, as well as steel structural parts and electronic equipment using the light steel.
  • the shaft mechanism of the existing folding screen mobile phone is basically composed of two materials, one is precipitation hardened steel, which has good comprehensive performance in mechanical properties, high strength, good toughness, yield strength of about 1000MPa, and The ratio is about 6%, but the density is higher, about 7.8g/cm 3 ; the other is made of aluminum alloy, which has a lower density, about 2.7g/cm 3 , but the strength is lower, which is the highest strength grade widely used in commercial use.
  • High-quality 7-series aluminum alloys, such as 7075 have a yield strength of about 500 MPa and are prone to deformation during use.
  • the first aspect of the embodiment of the present application provides a light steel, including:
  • the weight percentage is 30.01wt% ⁇ 35.01wt%
  • the weight percentage is 12.01wt% ⁇ 15.01wt%
  • the weight percentage content is 0.03wt% ⁇ 0.3wt%.
  • composition of the lightweight steel of the present application is innovatively designed with a high content of aluminum (12.01wt% to 15.01wt%) and a high content of oxygen (0.03wt% to 0.3wt%), oxygen and aluminum form alumina, In this way, the aluminum oxide strengthening phase is generated in the light steel grade, and the strength and ductility of the light steel are improved.
  • the present application makes the light steel have a relatively high Al content (12.01wt% ⁇ 15.01wt%), so that the light steel has a low density of 5.9 ⁇ 6.3g/cm 3 , which can significantly reduce the Reduce the weight of consumer electronics products with lightweight steel and enhance the user experience.
  • the lightweight steel of this application is a material with high strength, high ductility, and low density.
  • aluminum oxide particles are distributed in the light steel, and the aluminum oxide particles are basically composed of aluminum oxide particles whose length and width are both ⁇ 5 ⁇ m.
  • the particle size of the alumina phase is small, dispersed in the light steel, mainly at the phase interface, and plays a role of dispersion strengthening, thereby improving the strength of the light steel.
  • the light steel further includes V, and the weight percentage of V is ⁇ 0.6wt%.
  • V element mainly plays two roles.
  • V is a strong carbide forming element, which can improve the stability of carbon element in sintering. After carbon element forms ⁇ phase, the excess carbon cooperates with V element. On the one hand, it reduces the carbon and Oxygen cooperates to form CO 2 to escape, thereby reducing the content of oxygen in the steel material. On the other hand, the formed VC also improves the strength of the steel.
  • the weight percentage of V in the light steel is 0.2wt%-0.55wt%.
  • the weight percentage of Mn in the light steel is 30.01wt%-32.01wt%.
  • the weight percentage of Al in the light steel is 12.5wt%-13.5wt%.
  • the weight percentage of C in the light steel is 1.1wt%-1.45wt%.
  • the weight percentage of O in the light steel is 0.05wt%-0.2wt%.
  • the light steel also includes other elements, the other elements include nitrogen, copper, chromium, nickel, titanium, sulfur, phosphorus, boron, hydrogen, zirconium, silicon, tantalum, calcium, zinc and rare earth
  • the weight percentage of the other elements is ⁇ 1%.
  • the lightweight steel is formed by metal injection molding process using powder raw materials.
  • the metal injection molding process can be used to produce small, precise, and complex curved light steel parts, which can be widely used in various electronic products.
  • the density of the lightweight steel is 5.9-6.3 g/cm 3 .
  • the yield strength of the lightweight steel is 700-1200 MPa, and the elongation is 1.5%-20%.
  • the light steel has low density, high strength, and high ductility; the strength of the steel is relatively high, and the steel structural parts using this light steel do not need to increase the thickness to ensure the reliability of the steel structural parts, which is beneficial to the stability of the steel structural parts. Miniaturization, which is conducive to the miniaturization of electronic equipment.
  • the second aspect of the embodiment of the present application provides a steel structure, and the material used for the steel structure includes the lightweight steel described in the first aspect of the embodiment of the present application.
  • the third aspect of the embodiment of the present application provides a method for preparing light steel, including:
  • described powder raw material comprises:
  • the weight percent content is 30.01wt% ⁇ 36wt%
  • the weight percent content is 12.01wt% ⁇ 15.01wt%
  • the weight percentage is 0.003wt% ⁇ 0.1wt%
  • the sintered compact is heat treated.
  • the lightweight steel formed by the metal injection molding process provided by this application can effectively obtain three-dimensional complex and precise steel structural parts at one time.
  • computer numerical control machine tools form complex and precise steel structural parts without additional processing , improve the production efficiency of preparing complex and precise steel products, reduce the cost of preparing steel products, and facilitate the large-scale production of steel products.
  • mixing and molding the powder raw material and the binder into a green body includes:
  • the feed granules are molded into the green body by injection molding.
  • the green body of light steel is formed by injection molding, which not only has high forming efficiency and low cost, but also can effectively obtain a three-dimensional complex and precise green body of light steel at one time, which improves the production efficiency of preparing complex and precise light steel .
  • the powder raw material is mixed with the binder, and the powder raw material has a certain fluidity, which reduces or avoids defects such as cracks or drop corners in the green body.
  • the powder raw material is mixed with the binder, and the formed green body has a certain strength, and it can maintain its shape when it comes out of the mold cavity, reducing or avoiding the deformation of the green body, thereby improving the yield.
  • the green body before sintering the green body, it further includes: removing the binder in the green body by degreasing.
  • the binder is removed from the green body by catalytic debinding.
  • Catalytic degreasing to remove the binder is to use the characteristics of the rapid degradation of the polymer in a specific atmosphere, so that the green body is degreased in the corresponding atmosphere, and the binder is decomposed to remove the binder.
  • the binder in the green body is removed by catalytic degreasing, which not only enables fast and defect-free degreasing, but also increases the efficiency of degreasing, thereby improving the efficiency of steel production.
  • the heat treatment of the sintered compact includes: solid-solution of the sintered compact; and aging treatment of the solid-soluted sintered compact.
  • Heat treatment can further enhance the properties of the lightweight steel.
  • the powder raw material further includes V with a weight percentage ⁇ 0.6 wt%.
  • the fourth aspect of the embodiment of the present application provides a steel structure, which is manufactured by the method for preparing lightweight steel described in the third aspect of the embodiment of the present application.
  • the fifth aspect of the embodiment of the present application provides an electronic device, including the steel structure described in the second aspect or the fourth aspect of the embodiment of the present application.
  • the light steel has low density, high strength, and high ductility. It is applied to electronic equipment, reduces the risk of fracture and deformation of structural parts in electronic equipment, improves the quality of electronic equipment, and has a low density, which is beneficial to electronic equipment. Lightweight equipment.
  • the electronic device further includes a flexible display and a folding device for carrying the flexible display, the folding device is used to drive the flexible display to deform; the folding device includes the Steel structural parts.
  • the folding device includes a rotating shaft, and the rotating shaft is the steel structural member.
  • FIG. 1 is a schematic structural diagram of an electronic device according to an embodiment of the present application.
  • FIG. 2A and FIG. 2B are scanning electron micrographs of the lightweight steel of the embodiment of the present application.
  • Fig. 3 is a schematic flow chart of a method for preparing lightweight steel according to an embodiment of the present application.
  • Structural components of consumer electronics products are generally small precision parts with complex three-dimensional structures, which undertake the requirements of smooth operation and structural reliability. Therefore, the requirements for materials are multi-dimensional, except for lightweight and low-density In addition to the requirements, it includes at least strength (such as yield strength, tensile strength), plasticity (such as elongation), forming process (casting, forging, stamping, CNC, etc.), and the mutual constraints between each dimension.
  • strength such as yield strength, tensile strength
  • plasticity such as elongation
  • forming process such as insufficient strength, brittle quality and poor ductility, or insufficient ability to form complex parts, or high forming costs.
  • the electronic device of the embodiment of the present application includes lightweight steel.
  • the light steel has the advantages of low density/light weight, high strength, and can be prepared by metal injection molding (Metal injection molding, MIM) technology.
  • MIM Metal injection molding
  • the metal injection molding process is suitable for the preparation of small, precise and complex curved parts due to its molding characteristics.
  • the electronic device is a consumer electronic product, such as a mobile phone, a tablet computer, an e-reader, a notebook computer, a vehicle-mounted device, a wearable device, or a rollable and foldable electronic newspaper.
  • the electronic equipment includes structural parts, and at least one structural part is made of the light steel.
  • the electronic device 100 is a folding screen mobile phone as an example for description.
  • the folding screen mobile phone shown in Figure 1 is in a half-expanded state.
  • an electronic device 100 includes a flexible display 20 and a folding device 30 .
  • the flexible display screen 20 is used for displaying pictures.
  • the folding device 30 is used to drive the flexible display screen 20 to deform.
  • the folding device 30 is connected to the flexible display 20 for driving the flexible display 20 to fold or unfold.
  • the folding device 30 includes a rotating shaft, which can rotate under the action of a driving force to drive the flexible display screen 20 to bend or unfold.
  • the flexible display screen 20 is located on the same plane. As shown in FIG.
  • the electronic device 100 in another state, the electronic device 100 is not fully unfolded, and a part of the structure of the flexible display 20 is located on a different plane from another part of the structure of the flexible display 20 .
  • the electronic device 100 provided in the present application can be folded or unfolded correspondingly according to different usage scenarios, and the electronic device 100 presents different forms to meet different needs of users.
  • the description is made by taking the steel structural part of light steel as the rotating shaft of the electronic device 100 (foldable screen mobile phone) as an example, but it is not limited thereto.
  • the steel structure may also be other types of structural parts in the electronic device 100, such as camera decorations, gears, bracket parts that need to be bent, etc., which are not limited in this application.
  • the lightweight steel can also be applied to vehicles as vehicle-mounted structural parts.
  • the steel structural parts in the folding device are easily deformed under the condition of large force, and even have the risk of breaking.
  • the steel structure may withstand the flexible display screen, affecting the display screen of the flexible display screen, thereby affecting the quality of electronic equipment.
  • the stainless steel material used in the folding device is not strong enough and has poor toughness.
  • the steel structure in the folding device is easy to break, which affects the service life of the electronic device.
  • This application provides a lightweight steel with low density, high strength and high elongation.
  • due to its light weight it is beneficial to the light weight of electronic equipment;
  • the risk of fracture failure of structural parts; at the same time, the strength of steel structural parts is relatively high, and there is no need to increase the thickness of steel structural parts to ensure the reliability of steel structural parts, which is conducive to the miniaturization of steel structural parts, which is beneficial to electronic equipment 100 miniaturization.
  • the weight percentage is 30.01wt% ⁇ 35.01wt%
  • the weight percentage is 12.01wt% ⁇ 15.01wt%
  • the weight percentage content is 0.03wt% ⁇ 0.3wt%.
  • the lightweight steel further includes V, and the weight percentage of V is ⁇ 0.6wt%. In some embodiments, the weight percentage of V in the light steel is 0.2wt%-0.55wt%.
  • the weight percentage of Fe in the light steel is ⁇ 56.95wt%. In some embodiments, the weight percentage of Mn in the light steel is 30.01wt%-32.01wt%. In some embodiments, the weight percentage of Al in the light steel is 12.5wt%-13.5wt%. In some embodiments, the weight percentage of C in the light steel is 1.1wt%-1.45wt%. In some embodiments, the weight percentage of O in the light steel is 0.05wt%-0.2wt%.
  • the lightweight steel also includes other elements, and the other elements include one or more of nitrogen, copper, chromium, nickel, titanium, sulfur, phosphorus, boron, hydrogen, zirconium, silicon, tantalum, calcium, zinc and rare earth metals multiple, and the weight percentage of the other elements is ⁇ 1%.
  • the light steel may also contain other unavoidable impurity elements, but their content is extremely low and negligible.
  • the light steel mainly includes austenite, ferrite and ⁇ phase, these three structures are common structures in low-density steel, in which austenite is the main phase of the steel matrix, and ferrite is distributed in the austenite grain At the boundary, the ⁇ phase is a conventional strengthening phase of low-density steel, which mainly exists in the austenite crystal or at the grain boundary.
  • austenite is a lamellar microstructure of iron and steel, usually a solid solution formed by dissolving one or several other elements (such as carbon) in ⁇ -Fe, also known as Vossfield iron or ⁇ -Fe -Fe; austenite is a face-centered cubic structure, the most densely packed lattice structure, high density; austenite has good plasticity, low strength, certain toughness, and no ferromagnetism.
  • Ferrite is a solid solution in which iron or one or several other elements (such as carbon) are solid-dissolved in it, and the crystal lattice is a body-centered cubic solid solution; it has good plasticity and toughness, but low strength and hardness.
  • the ⁇ phase is a precipitated phase formed by covalent bonds of at least three elements of Fe, Al and C, and may optionally contain Mn.
  • the Al element is one of the core elements of light steel.
  • the Al element content ranges from 12.01wt% to 15.01wt%, especially in the range of 12.5wt% to 13.5wt%, in addition to the aforementioned lower density can be obtained
  • higher strength and/or higher elongation can be obtained through appropriate processing technology, as shown in Table 1 below, in the case of consistent content of other elements, the performance rules obtained through a large number of experiments are explored: this application Through higher aluminum content, the performance upper limit of yield strength is improved, while the elongation is basically consistent, and it is found that the combination of aluminum element content (12.5wt% ⁇ 13.5wt%) and oxygen content (0.05 ⁇ 0.2wt%) has the best performance. Excellent overall performance.
  • the light steel has a relatively high Al content (12.01wt% ⁇ 15.01wt%), so that the light steel has a low density, the density is 5.9 ⁇ 6.3g/ cm3 ; compared with the density of conventional steel 7.98g /cm 3 , reducing weight by 21% to 26%, thereby significantly reducing the weight of consumer electronic products using the lightweight steel and improving user experience.
  • the O element in conventional smelted steel is usually controlled as an impurity element.
  • the lower the oxygen content the higher the steel quality grade. It is treated as P and S to be controlled.
  • the oxygen content in steel is generally required to be ⁇ 0.005 wt%, if the oxygen element content exceeds this requirement and is too high, it will become inferior steel and cannot be formed or used.
  • composition of the lightweight steel in the embodiment of the present application is innovatively designed with a high content of aluminum (12.01wt% to 15.01wt%) and a high content of oxygen (0.03wt% to 0.3wt%), oxygen and aluminum Alumina is formed, thereby introducing an alumina strengthening phase in the lightweight steel grade.
  • the oxygen element in this application exists uniformly in light steel.
  • the method for measuring the O content of the light steel in the present application sample any sampling position of the light steel sample, including grinding the surface to remove the oxide layer to obtain a fresh and clean surface, and obtain the oxygen content.
  • the method of introducing oxygen and aluminum elements to form alumina not only improves the strength of the material, but also improves the plasticity of the material.
  • Table 2 under the premise of other characteristics being the same, the steel with high oxygen content has higher strength and elongation. As shown in Table 2, when other conditions remain unchanged, steels with oxygen content in the oxygen content range (0.03wt%-0.3wt%) in this application have significantly higher strength and plasticity.
  • Oxygen mainly plays two roles. On the one hand, oxygen and aluminum form an alumina phase, which is small in size and dispersedly distributed in the lightweight steel of the composition described in this application, mainly at the phase interface, which plays a role of dispersion strengthening, thereby improving the strength of the lightweight steel .
  • the particles marked by the arrows are the alumina strengthening phases generated in situ (not directly adding alumina, but formed by chemical reaction), and the alumina strengthening phase is granular and Diffuse distribution (uniform distribution) in the lightweight steel matrix, the shape can be equiaxed, ellipsoid or long strip.
  • the length and width of granular alumina are both ⁇ 5 ⁇ m, for example, between 500nm and 5 ⁇ m, but it does not rule out that a small amount of alumina particles grow abnormally, and the size is larger than 5 ⁇ m, but the proportion of large-sized alumina particles is generally Not more than 20%.
  • the combination of oxygen and aluminum eliminates the brittleness caused by excessive aluminum that cannot form the ⁇ phase, thereby improving the plasticity of the material.
  • Aluminum element is a ferrite-forming element. Excessive aluminum element will promote the ferrite phase. Once the ferrite content is too high, it will significantly reduce the strength and plasticity of the material after forming a network.
  • the light steel has high strength, with a yield strength of 800-1200 MPa; high plasticity and toughness, with an elongation of 2%-20%.
  • the light steel is prepared by the MIM forming process, which can realize high-precision and low-cost forming of small precision parts with complex three-dimensional shapes.
  • V element mainly plays two roles.
  • V is a strong carbide forming element, which can improve the stability of carbon element in sintering. After the carbon element forms ⁇ phase, the excess carbon cooperates with V element.
  • the combination of carbon and oxygen elements is reduced, and CO 2 escapes to reduce the content of oxygen elements in the steel material.
  • the formed VC also improves the strength of the steel.
  • the surface of the light steel can be formed with a functional coating as required, and the coating can be formed by processes such as passivation, electroplating, spraying, and physical vapor deposition (PVD).
  • PVD physical vapor deposition
  • the lightweight steel can be formed by metal injection molding process using powder raw material. As shown in Fig. 3, the preparation method of the lightweight steel specifically includes the following steps.
  • the weight percent content is 30.01wt% ⁇ 36wt%
  • the weight percent content is 12.01wt% ⁇ 15.01wt%
  • the weight percentage content is 0.003wt% ⁇ 0.1wt%.
  • atomization method, reduction method, mechanical grinding method, etc. may be used to prepare the powder raw material.
  • the particle size D50 of the powder raw material is 5-15 ⁇ m (the particle size of 90% of the particles is ⁇ 45 ⁇ m), and can be adjusted accordingly as required.
  • the powder raw material may also include V with a weight percent content ⁇ 0.6wt%.
  • Powder raw materials can generally be divided into two methods: one is pre-alloyed and made into powder, and each element exists in the form of an alloy; the other is a variety of elemental elements or a variety of compounds, which are mixed in adjusted proportions. It is still manifested as multiple simple substances or multiple compounds.
  • Oxygen (O) in the embodiment of the present application may exist in the form of iron oxide or the like, or microscopically, oxygen atoms exist in the gaps of metal atoms (such as Fe).
  • step S2 Preparing feed granules: mixing the powder raw material in step S1 with a binder and then granulating to form feed granules.
  • the powder raw material and binder in step S1 are mixed according to a certain volume ratio (56:44), and then mixed uniformly to form a paste feed; the paste feed is granulated to form feed granules.
  • a granulator can be used for granulation.
  • the binder is a special binder for alloy powder, usually an organic binder, which is used to bond the powder raw materials together to facilitate subsequent injection molding.
  • step S3 Injection molding the feed granules in step S2 into a green body.
  • step S2 Add the feed granules in step S2 into the injection molding machine, inject them into the mold cavity, and perform injection molding to obtain a green body.
  • the green body of light steel is formed by injection molding, which not only has high forming efficiency and low cost, but also can effectively obtain a three-dimensional complex and precise green body of light steel at one time, which improves the production efficiency of preparing complex and precise light steel .
  • the powder raw material is mixed with the binder, and the powder raw material has a certain fluidity, which reduces or avoids defects such as cracks or drop corners in the green body.
  • the powder raw material is mixed with the binder, and the formed green body has a certain strength, and it can maintain its shape when it comes out of the mold cavity, reducing or avoiding the deformation of the green body, thereby improving the yield.
  • the green body is subjected to catalytic degreasing (the temperature is set at 110° C. to 160° C., and fuming nitric acid is used as a catalyst) to remove part of the binder in the green body.
  • catalytic degreasing the temperature is set at 110° C. to 160° C., and fuming nitric acid is used as a catalyst
  • Catalytic degreasing to remove the binder is to use the characteristics of the rapid degradation of the polymer in a specific atmosphere, so that the green body is degreased in the corresponding atmosphere, and the binder is decomposed to remove the binder.
  • the binder in the green body is removed by catalytic degreasing, which not only enables fast and defect-free degreasing, but also increases the efficiency of degreasing, thereby improving the efficiency of steel production.
  • the catalytically degreased green body into a sintering furnace, and sinter it at a certain temperature (such as 1150°C to 1300°C) and atmospheric conditions (such as Ar, H2 or in vacuum).
  • a certain temperature such as 1150°C to 1300°C
  • atmospheric conditions such as Ar, H2 or in vacuum
  • the sintering refers to the process of transforming the powdery material (the powder raw material described in this application) into a dense body. By heating, the molecules or atoms in the solid state obtain enough energy to migrate, so that the powder body produces particle bonding. , a process that develops strength and leads to densification and recrystallization.
  • the sintering in the embodiment of the present application may be heating to 1150° C. to 1300° C. for 2 to 3 hours. During sintering, the binder will be removed.
  • step S5 The sintered compact obtained in step S5 is subjected to solid solution (for example, the temperature is set at 1000°C to 1180°C for 1 hour) and aging treatment (for example, the temperature is raised to 350°C to 550°C and kept for 2 hours) in a heat treatment furnace, and finally A steel with good comprehensive mechanical properties is obtained.
  • solid solution for example, the temperature is set at 1000°C to 1180°C for 1 hour
  • aging treatment for example, the temperature is raised to 350°C to 550°C and kept for 2 hours
  • the solid solution refers to heating the alloy (the product after sintering of the present application) to a high-temperature single-phase zone to keep it at a constant temperature, so that the excess phase is fully dissolved in the solid solution and then rapidly cooled to obtain a supersaturated solid solution; solid solution treatment
  • the purpose is to dissolve the second phase in the matrix and ⁇ ' are equal to obtain a uniform supersaturated solid solution, which is convenient for re-precipitation of fine particles and uniformly distributed precipitated phases and strengthening phases such as ⁇ ' during aging, and at the same time eliminates due to hot and cold processing. Stress causes the alloy to recrystallize.
  • the aging refers to the heat treatment process in which the product after solid solution of the present application is placed at a higher temperature or at room temperature to maintain its shape and size, and its performance changes with time.
  • the embodiment of the present application also provides a steel structure (not shown in the figure), which is formed by the above-mentioned preparation method.
  • the steel structure is manufactured by the above method, so that the steel structure has low density, high strength, and high ductility; the steel structure is not easy to break and deform, and has a long service life.
  • the embodiment of the present application also provides a steel structure (not shown in the figure), and the material used for the steel structure includes the above-mentioned lightweight steel.
  • the material used in the steel structure includes the above-mentioned lightweight steel, so that the strength of the steel structure is increased, and the steel structure does not need to increase the thickness of the steel structure to further ensure the reliability of the steel structure, which is beneficial to the steel structure. Miniaturization of structural parts.
  • the preparation method of the lightweight steel of Example 1 is specifically as follows.
  • the powder and the binder are fully mixed at 180°C to prepare feed materials.
  • the binder components used are polyoxymethylene (POM): ethylene-vinyl acetate copolymer (EVA): The weight ratio of polyethylene (PE): microcrystalline wax (CW): stearic acid (SA) is 85:1:5.5:2:1;
  • Example 1 32.2 12.31 1.192 0.1609 0.29 margin
  • Example 2 33.4 12.53 1.2049 0.2339 0.4 margin
  • Example 3 32.05 13.01 1.1784 0.1877 0.21 margin
  • Example 4 33.8 13.43 1.1491 0.1554 0.22 margin
  • Example 5 30.1 12.02 1.3319 0.0956 0.42 margin
  • Example 6 31.6 12.11 1.4493 0.1617 0.51 margin
  • this application can adopt the heat treatment method of powder sintering and subsequent solid solution and aging to obtain light weight with a density of 5.9-6.3g/cm 3 , a yield strength of 700-1200MPa, and an elongation of 1.5%-15%.
  • Quality steel, the microstructure of the steel products obtained in each embodiment has the above-mentioned fine and dispersed alumina particle phase.
  • the acquisition of the current density and mechanical properties is attributed to the material composition, the in-situ alumina strengthening phase generated by the reaction in the tissue matrix of the sintering treatment and other processes of the present application. It can be understood that the performance of the product depends on the composition of the product, as well as on the preparation process.
  • the particle size distribution range of powder raw materials, binder system and ratio, and binder removal methods can be adjusted according to the equipment environment.
  • the composition and properties disclosed in this application can be obtained through adjustment and appropriate processing technology, and the appropriate processing technology of this application has the possibility to further reduce the density and improve the strength and toughness.

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Abstract

本申请提供一种轻质钢，包括：Fe，重量百分含量≥48.18wt％；Mn，重量百分含量为30.01wt％～35.01wt％；Al，重量百分含量为12.01wt％～15.01wt％；C，重量百分含量为1.0wt％～1.5wt％；O，重量百分含量为0.03wt％～0.3wt％。本申请还提供应用该种轻质钢的钢结构件和电子设备、该轻质钢的制备方法。本申请的轻质钢具有低密度、高强度和高延展性。

Description

轻质钢及其制备方法、钢结构件和电子设备
相关申请的交叉引用
本申请要求在2021年8月27日提交中国专利局、申请号为202110994339.8、申请名称为“轻质钢及其制备方法、钢结构件和电子设备”的中国专利的优先权，其全部内容通过引用结合在本申请中。
技术领域
本申请涉及一种轻质钢及其制备方法，以及应用该轻质钢的钢结构件和电子设备。
背景技术
现有的折叠屏手机的转轴机构，基本由两种材质组成，一种是为沉淀硬化型钢材，该种材质力学性能上具备良好的综合性能，强度高，韧性良好，屈服强度约1000MPa，延伸率约6％，但密度较高，约7.8g/cm 3；另一种为铝合金材质，具有较低的密度，约2.7g/cm 3，但强度较低，对于目前广泛商用最高强度等级的7系铝合金，如7075，屈服强度约500MPa，使用过程中易于发生变形。
发明内容
本申请实施例第一方面提供了一种轻质钢，包括：
Fe，重量百分含量≥48.18wt％；
Mn，重量百分含量为30.01wt％～35.01wt％；
Al，重量百分含量为12.01wt％～15.01wt％；
C，重量百分含量为1.0wt％～1.5wt％；
O，重量百分含量为0.03wt％～0.3wt％。
本申请的轻质钢的成分创新性地通过设计高含量的铝元素(12.01wt％～15.01wt％)与高含量的氧元素(0.03wt％～0.3wt％)，氧与铝形成氧化铝，从而在所述轻质钢种生成氧化铝强化相，提升轻质钢的强度和延展性。
钢中添加Al元素可改善钢的密度，使钢具有达到轻质的效果。本申请通过使所述轻质钢中具有较高的Al含量(12.01wt％～15.01wt％)，使得所述轻质钢具有低密度达到5.9～6.3g/cm 3，从而可明显降低应用所述轻质钢的消费电子产品的重量，提升用户体验。本申请的轻质钢为具有高强度、高延展性、低密度的材料。
本申请实施方式中，所述轻质钢中分布有氧化铝颗粒，所述氧化铝颗粒基本上由长度和宽度尺寸均≤5μm的氧化铝颗粒组成。
氧化铝相颗粒尺寸较小，弥散分布于所述轻质钢中，主要在相界面处，起到弥散强化的作用，从而提升所述轻质钢的强度。
本申请实施方式中，所述轻质钢还包括V，V的重量百分含量≤0.6wt％。
V元素，主要起两方面的作用，V为强碳化物形成元素，可以提升烧结中碳元素的稳定性，碳元素形成κ相后，多余的碳与V元素进行配合，一方面减少了碳与氧元素配合，形成CO 2逸出从而减少了钢材料中氧元素的含量，另一方面形成的VC也提升了钢的强度。
本申请实施方式中，所述轻质钢中V的重量百分含量为0.2wt％～0.55wt％。
本申请实施方式中，所述轻质钢中Mn的重量百分含量为30.01wt％～32.01wt％。
本申请实施方式中，所述轻质钢中Al的重量百分含量为12.5wt％～13.5wt％。
本申请实施方式中，所述轻质钢中C的重量百分含量为1.1wt％～1.45wt％。
本申请实施方式中，所述轻质钢中O的重量百分含量为0.05wt％～0.2wt％。
本申请实施方式中，所述轻质钢还包括其他元素，所述其他元素包括氮、铜、铬、镍、钛、硫、磷、硼、氢、锆、硅、钽、钙、锌以及稀土金属中的一种或多种，所述其他元素的重量百分比≤1％。
本申请实施方式中，所述轻质钢使用粉末原料经金属注射成型工艺形成。
采用金属注射成型工艺可制得小型、精密、复杂曲面的轻质钢零件，从而可广泛应用到各类电子产品中。
本申请实施方式中，所述轻质钢的密度为5.9～6.3g/cm 3。
本申请实施方式中，所述轻质钢的屈服强度为700～1200MPa，延伸率为1.5％～20％。
所述轻质钢具有低密度、高强度、高延展性；钢的强度较大，采用此轻质钢的钢结构件无需通过增加厚度来保证钢结构件的可靠性，有利于钢结构件的小型化，从而有利于电子设备的小型化。
本申请实施例第二方面提供了一种钢结构件，所述钢结构件采用的材料包括本申请实施例第一方面所述的轻质钢。
本申请实施例第三方面提供了一种轻质钢的制备方法，包括：
提供粉末原料，所述粉末原料包括：
Fe，重量百分含量≥47.39wt％，
Mn，重量百分含量为30.01wt％～36wt％，
Al，重量百分含量为12.01wt％～15.01wt％，
C，重量百分含量为0.8wt％～1.5wt％，
O，重量百分含量为0.003wt％～0.1wt％；
将所述粉末原料和粘结剂混合成型为生坯；
烧结所述生坯，以形成烧结坯；以及
热处理所述烧结坯。
采用本申请提供的金属注射成型工艺成形的轻质钢，能够一次有效地获得三维复杂精密的钢结构件，相比于传统机械加工，例如计算机数字控制机床成形复杂精密的钢结构件无需额外加工，提高了制备复杂精密的钢材的生产效率，降低了制备钢材的成本，有利于钢材的大规模生产。
本申请实施方式中，将所述粉末原料和所述粘结剂混合成型为生坯包括：
混合所述粉末原料与粘结剂，以形成膏状喂料；
将所述膏状喂料进行造粒，以形成喂料颗粒；以及
将所述喂料颗粒通过注塑方式成型为所述生坯。
通过注塑成型的方式形成轻质钢的生坯，不仅成形效率高、成本低，而且能够一次有效地获得三维复杂精密的轻质钢的生坯，提高了制备复杂精密的轻质钢的生产效率。粉末原料与粘结剂混合，粉末原料具有一定的流动性，减小了或避免了生坯出现裂纹或掉角等缺陷。 与此同时，粉末原料与粘结剂混合，成形后的生坯具有一定的强度，自模腔中脱出能够维持形状，减小了或避免了生坯的形变，从而提高了成品率。
本申请实施方式中，在烧结所述生坯之前还包括：脱脂去除所述生坯中的粘结剂。
在一些实施例中，通过催化脱脂的方式去除生坯中的粘结剂。催化脱脂去除粘结剂是利用聚合物在特定气氛下可以发生快速降解的特性，使生坯在相应的气氛中发生脱脂，分解粘结剂以去除粘结剂。在本申请实施例中，通过催化脱脂的方式去除生坯中的粘结剂，不仅能够快速无缺陷的脱脂，而且能够增加脱脂的效率，从而提高制备钢材的效率。
本申请实施方式中，热处理所述烧结坯包括：固溶所述烧结坯；以及时效处理固溶后的所述烧结坯。
热处理可进一步强化所述轻质钢的性能。
本申请实施方式中，所述粉末原料还包括重量百分含量≤0.6wt％的V。
本申请实施例第四方面提供了一种钢结构件，采用本申请实施例第三方面所述的轻质钢的制备方法制得。
本申请实施例第五方面提供了一种电子设备，包括本申请实施例第二方面或第四方面所述的钢结构件。
所述轻质钢具有低密度、高强度、高延展性，应用于电子设备，降低了电子设备中的结构类零部件发生断裂、变形的风险，提升电子设备的质量，且密度低，利于电子设备的轻型化。
本申请实施方式中，所述电子设备还包括柔性显示屏及用于承载所述柔性显示屏的折叠装置，所述折叠装置用于带动所述柔性显示屏发生形变；所述折叠装置包括所述钢结构件。
本申请实施方式中，所述折叠装置包括转轴，所述转轴为所述钢结构件。
附图说明
图1是本申请实施例的电子设备的结构示意图。
图2A和图2B为本申请实施例的轻质钢的扫描电镜图。
图3是本申请实施例的轻质钢的制备方法的流程示意图。
主要元件符号说明
电子设备 100
柔性显示屏 20
折叠装置 30
具体实施方式
下面结合本申请实施例中的附图对本申请实施例进行描述。本申请所涉及的参数范围如无特别说明均包括端点值。
消费性电子产品的结构类零部件，一般均为小型精密零件、具备复杂三维结构，承担机构运转顺畅性与结构可靠性的要求，因而对材料的要求是多维度的，除了轻质低密度的要求外，至少包含强度(如屈服强度、抗拉强度)、塑韧性(如延伸率)、成型工艺(铸造、锻压、冲压、CNC等)，各维度之间相互制约，对于轻质钢材，无论是当前的金属基复合材料、加 工硬化的冷轧板材、溶炼铸材，均存在或者强度不足、或者质脆而塑韧性差，或者成型复杂零件能力不足，或者成型成本高等问题。
本申请实施例的电子设备，其包括轻质钢。所述轻质钢具有低密度/轻质、高强度、可采用金属注射成型(Metal injection molding，MIM)工艺制备的优点。金属注射成型工艺因其成型特性适合于小型、精密、复杂曲面零件的制备。所述电子设备为消费电子产品，例如手机、平板电脑、电子阅读器、笔记本电脑、车载设备、可穿戴设备或可卷曲折叠的电子报纸等设备。所述电子设备包括结构类零部件，至少一结构类零部件为所述轻质钢构成。
参阅图1，以电子设备100是折叠屏手机为例进行描述。图1所示的折叠屏手机为半展开的状态。如图1所示，电子设备100包括柔性显示屏20及折叠装置30。柔性显示屏20用于显示画面。折叠装置30用于带动柔性显示屏20发生形变。示例性的，折叠装置30连接柔性显示屏20，用于带动柔性显示屏20折叠或展开。折叠装置30包括转轴，转轴在驱动力的作用下能够转动，以带动柔性显示屏20弯折或展开。当电子设备100处于展开状态时，柔性显示屏20位于同一平面。如图1所示，另一种状态下，电子设备100处于未完全展开的状态，此时柔性显示屏20的一部分结构与柔性显示屏20的另一部分结构位于不同的平面。本申请提供的电子设备100能够根据不同的使用场景对应折叠或展开，电子设备100呈现不同的形态，以满足用户不同的需求。
本申请实施例中，以所述轻质钢的钢结构件为电子设备100(折叠屏手机)的转轴为例来进行描写，但不以此为限。在其他实施例中，钢结构件也可以为电子设备100中其他类型的结构类零部件，例如摄像头装饰件、齿轮、需要弯折的支架零件等等，本申请并不限定。可以理解的，所述轻质钢还可应用于车辆上，作为车载结构件。
传统技术中，折叠装置中的钢结构件在受力较大的情况下容易变形，甚至有断裂的风险，不仅会造成折叠装置卡死，使电子设备无法实现折叠与展开的切换，而且断裂的钢结构件可能顶住柔性显示屏，影响柔性显示屏显示画面，从而影响电子设备的质量。例如，传统技术中，折叠装置中所用的不锈钢材料强度不足，且韧性差，电子设备在高处跌落时，折叠装置中的钢结构件容易断裂，影响了电子设备的使用寿命。
本申请提供一种密度小、强度较大且延伸率较高的轻质钢，一方面由于质轻，有利于电子设备的轻型化，另一方面，可有效降低电子设备100在跌落过程中钢结构件断裂失效的风险；与此同时，钢结构件的强度较大，钢结构件无需通过增加厚度来保证钢结构件的可靠性，有利于钢结构件的小型化，从而有利于电子设备100的小型化。
本申请实施例的所述轻质钢，包括如下化学成分：
Fe，重量百分含量≥48.18wt％；
Mn，重量百分含量为30.01wt％～35.01wt％；
Al，重量百分含量为12.01wt％～15.01wt％；
C，重量百分含量为1.0wt％～1.5wt％；
O，重量百分含量为0.03wt％～0.3wt％。
一些实施例中，所述轻质钢还包括V，V的重量百分含量≤0.6wt％。一些实施例中，所述轻质钢中V的重量百分含量为0.2wt％～0.55wt％。
一些实施例中，所述轻质钢中Fe的重量百分含量≤56.95wt％。一些实施例中，所述轻质钢中Mn的重量百分含量为30.01wt％～32.01wt％。一些实施例中，所述轻质钢中Al的重量百 分含量为12.5wt％～13.5wt％。一些实施例中，所述轻质钢中C的重量百分含量为1.1wt％～1.45wt％。一些实施例中，所述轻质钢中O的重量百分含量为0.05wt％～0.2wt％。
所述轻质钢还包括其他元素，所述其他元素包括氮、铜、铬、镍、钛、硫、磷、硼、氢、锆、硅、钽、钙、锌以及稀土金属中的一种或多种，所述其他元素的重量百分比≤1％。
可以理解的，所述轻质钢中可能还含有其他不可避免杂质元素，但其含量极低，可忽略不计。
所述轻质钢主要包括奥氏体、铁素体和κ相，此三种组织是低密度钢中的常见组织，其中奥氏体作为钢基体主相，铁素体分布于奥氏体晶界处，κ相为低密度钢常规强化相，主要存在于奥氏体晶体内或者晶界处。其中，奥氏体是钢铁的一种层片状的显微组织，通常是γ-Fe中固溶一种或数种其他元素(例如碳)形成的固溶体，也称为沃斯田铁或γ-Fe；奥氏体是面心立方结构，最密排的点阵结构，致密度高；奥氏体塑性很好，强度较低，具有一定韧性，不具有铁磁性。铁素体为铁或其内固溶有一种或数种其他元素(例如碳)所形成的晶体点阵为体心立方的固溶体；具有良好的塑性和韧性，而强度与硬度较低。κ相为Fe、Al和C至少三种元素以共价键形成的析出相，还可选择性含有Mn。
本申请中，Al元素是轻质钢的核心元素之一，更高的铝元素含量，可以得到更低的密度，若不考虑点阵畸变，仅以简单的混合法则进行估算，铝元素含量超过10wt％后，每增加1wt％的铝元素，密度降低约0.1g/cm 3。在保证钢材料性能的前提下(如本申请所描述的屈服强度与延伸率的性能)，如何将铝元素含量上限拓宽，一直是重大难题，本申请将铝元素含量拓展至12.01wt％～15.01wt％，仍具备良好的强度与延展性。
在其他元素含量区间满足本申请要求的情况下，Al元素含量范围为12.01wt％～15.01wt％，尤其在12.5wt％-13.5wt％的范围区间内时，除前述可以获得更低的密度之外，通过合适的处理工艺还可以获得更高的强度和/或更高的延伸率，如下表一所示，在其他元素含量一致的情况下，通过大量实验摸索所获得的性能规律：本申请通过更高的铝含量，提升了屈服强度的性能上限，同时延伸率基本保持一致，并发现铝元素含量(12.5wt％～13.5wt％)与氧含量(0.05～0.2wt％)配合下具备最优的综合性能。
表一
Figure PCTCN2022114865-appb-000001
所述轻质钢中具有较高的Al含量(12.01wt％～15.01wt％)，使得所述轻质钢具有低密度，密度为5.9～6.3g/cm 3；相较常规钢材的密度7.98g/cm 3，减重21％～26％；从而可明显降低应用该轻质钢的消费电子产品的重量，提升用户体验。
常规熔炼钢材中(包括低密度钢材)O元素通常作为杂质元素加以管控，氧含量越低钢材质量等级越高，将其视同P、S加以控制，钢材中的氧元素含量一般均要求＜0.005wt％，若氧元素含量超出该要求过高将成为劣质钢材而不可成型或者不可使用。
本申请实施例的所述轻质钢的成分创新性地通过设计高含量的铝元素(12.01wt％～15.01wt％)与高含量的氧元素(0.03wt％～0.3wt％)，氧与铝形成氧化铝，从而在所述轻质钢种引入了氧化铝强化相。
本申请的氧元素均匀存在于轻质钢中。本申请的所述轻质钢的O的含量测定方法：对该轻质钢样品的任一采样位置，包括表面打磨去除氧化层得到新鲜干净的表面后进行取样，所得到的氧含量。
本申请通过引入氧元素与铝元素形成氧化铝的方式，提升材料强度的同时，也提升了材料的塑性。如表二所示，其他特征相同的前提下，高的氧元素含量的钢具备更高的强度与延伸率。依据表二所示，其他条件不变的情况下，处于本申请中的氧含量范围区间(0.03wt％～0.3wt％)的氧含量的钢具备明显高于低氧元素含量的钢的强度与塑性。
表二
Figure PCTCN2022114865-appb-000002
氧元素主要起两方面的作用。一方面，氧与铝形成氧化铝相，尺寸较小，弥散地分布于本申请所述成分的轻质钢中，主要在相界面处，起到弥散强化的作用，从而提升轻质钢的强度。如图2A所示的轻质钢的扫描电镜图中，箭头标示的颗粒为原位生成(不是直接加氧化铝，而是化学反应生成)的氧化铝强化相，氧化铝强化相为颗粒状且弥散分布(均匀分布)于轻质钢基体内，形状可为等轴、椭球或者长条形。基本上，颗粒状的氧化铝的长度和宽度均≤5μm，例如在500nm～5μm之间，但不排除少量氧化铝颗粒异常长大，尺寸大于5μm，但大尺寸氧化铝颗粒所占数量比例一般不超过20％。
另一方面，通过氧元素与铝元素的结合，消除了无法形成κ相的过量铝元素带来的脆性，从而提升了材料的塑性。铝元素为铁素体形成元素，过量的铝元素会促进铁素体相，一旦铁素体含量过高，连成网状后，将显著降低材料的强度与塑韧性。
对图2B所示轻质钢的扫描电镜图中选取两个位置进行能谱(EDS)分析，其中谱图1位置为氧化铝的位置，谱图2是没有氧化铝的位置，对选取的两个位置进行材料微区元素种类与含量的分析。
表三
项目 C/wt％ O/wt％ Al/wt％ Mn/wt％ Fe/wt％
谱图1 0.17 21.68 22.5 21.26 34.39
谱图2 0.19 0 11.97 33.13 54.71
从表三可知：谱图2的位置未检测到O元素，而谱图1的位置检测到O元素和Al元素，且根据O元素和Al元素的质量百分含量可换算得到Al原子和O原子二者的比例接近于2：3，这验证了谱图1处氧化铝的存在。
此外，所述轻质钢的强度高，屈服强度达到800～1200MPa；塑韧性高，延伸率达到2％～20％。所述轻质钢采用MIM成型工艺制备，可实现复杂三维形状的小型精密零件高精度、低成本成型。
本申请中，加入V元素，主要起两方面的作用，V为强碳化物形成元素，可以提升烧结中碳元素的稳定性，碳元素形成κ相后，多余的碳与V元素进行配合，一方面减少了碳与氧元素配合，形成CO 2逸出从而减少了钢材料中氧元素的含量，另一方面形成的VC也提升了钢的强度。
如下表四所示，加入V后钢材样品的力学性能(抗拉强度、屈服强度、延伸率等)有明显的提升。
表四
Figure PCTCN2022114865-appb-000003
本申请的轻质钢中的几个元素，除Fe、Mn、Al、C元素外，Al与O，C与O，C与V均存在直接或间接的相互作用关系。
所述轻质钢的表面可根据需要形成有功能涂层，所述涂层可采用钝化、电镀、喷涂、物理气相沉积(PVD)等工艺形成。
所述轻质钢可使用粉末原料经金属注射成型工艺形成。如图3所示，所述轻质钢的制备方法具体包括如下步骤。
S1：制备粉末原料，所述粉末原料包括如下化学成分：
Fe，重量百分含量≥47.39wt％，
Mn，重量百分含量为30.01wt％～36wt％，
Al，重量百分含量为12.01wt％～15.01wt％，
C，重量百分含量为0.8wt％～1.5wt％，
O，重量百分含量为0.003wt％～0.1wt％。
本申请实施例，制备所述粉末原料可采用雾化法、还原法、机械研磨法等。所述粉末原料的粒径D50为5～15μm(90％的颗粒的粒径≤45um)，且可以根据需要进行相应调整。所述粉末原料还可包括重量百分含量≤0.6wt％的V。
粉末原料一般可以分为两种制法：一种是预先合金化后制成粉末，各元素均以合金的方式存在，另一种是多种单质元素或多种化合物，调整比例混合而成，仍体现为多单质或多化合物。本申请实施例中氧(O)的存在形式可以为氧化铁等，或者微观上氧原子存在于金属原子(如Fe)的间隙之中。
S2：制备喂料颗粒：将步骤S1的粉末原料与粘结剂混合后进行造粒形成喂料颗粒。
步骤S1的粉末原料与粘结剂按一定的体积比(56：44)进行混合，然后混合均匀形成膏状喂料；将膏状喂料进行造粒形成喂料颗粒。造粒可采用造粒机。所述粘结剂采用合金粉末专用的粘结剂，通常为有机粘结剂，用以将粉末原料粘结为一体，便于后续注射成型。
S3：将步骤S2的喂料颗粒注塑成型为生坯。
将步骤S2的喂料颗粒加入注射成型机中，注射到模具型腔内，注塑成型，获得生坯。
通过注塑成型的方式形成轻质钢的生坯，不仅成形效率高、成本低，而且能够一次有效地获得三维复杂精密的轻质钢的生坯，提高了制备复杂精密的轻质钢的生产效率。粉末原料与粘结剂混合，粉末原料具有一定的流动性，减小了或避免了生坯出现裂纹或掉角等缺陷。与此同时，粉末原料与粘结剂混合，成形后的生坯具有一定的强度，自模腔中脱出能够维持形状，减小了或避免了生坯的形变，从而提高了成品率。
S4：对所述生坯进行脱脂。
在一些实施例中，对所述生坯进行催化脱脂(温度设置为110℃～160℃，催化剂采用发 烟硝酸)以除去所述生坯中的部分粘结剂。
催化脱脂去除粘结剂是利用聚合物在特定气氛下可以发生快速降解的特性，使生坯在相应的气氛中发生脱脂，分解粘结剂以去除粘结剂。在本申请实施例中，通过催化脱脂的方式去除生坯中的粘结剂，不仅能够快速无缺陷的脱脂，而且能够增加脱脂的效率，从而提高制备钢材的效率。
S5：烧结所述生坯以形成烧结坯。
将催化脱脂好的生坯放入烧结炉中，于一定温度(例如1150℃～1300℃)及气氛条件(例如Ar、H 2或真空中)下烧结。
所述烧结，是指把粉状物料(本申请所述的粉末原料)转变为致密体的工艺过程，通过加热使固态中的分子或原子获得足够的能量进行迁移，使粉末体产生颗粒粘结，产生强度并导致致密化和再结晶的过程。例如，本申请实施例烧结可为加热至1150℃～1300℃保温2～3h。烧结过程中，粘结剂将被去除。
S6：热处理所述烧结坯。
将步骤S5所获得的烧结坯，于热处理炉中进行固溶(例如温度设定为1000℃～1180℃，时间1h))和时效处理(例如升温至350℃～550℃，保温2h)，最终获得综合力学性能良好的钢。
所述固溶，是指将合金(本申请烧结后的产品)加热到高温单相区恒温保持，使过剩相充分溶解到固溶体中后快速冷却，以得到过饱和固溶体的热处理工；固溶处理的目的是为了溶解基体内第二相、γ’相等以得到均匀的过饱和固溶体，便于时效时重新析出颗粒细小、分布均匀的析出相和γ’等强化相，同时消除由于冷热加工产生的应力，使合金发生再结晶。
所述时效，指本申请固溶后的产品，在较高的温度或室温放置保持其形状、尺寸，性能随时间而变化的热处理工艺。
本申请实施例还提供一种钢结构件(图未示)，其采用上述的制备方法成形。所述钢结构件采用上述的方法制得，使得钢结构件具有低密度、高强度、和高延展性；所述钢结构件不易发生断裂和变形，使用寿命长。
本申请实施例还提供一种钢结构件(图未示)，所述钢结构件采用的材料包括上述的轻质钢。所述钢结构件采用的材料包括上述的轻质钢，使得钢结构件的强度加大，此钢结构件无需通过增加钢结构件的厚度来进一步地保证钢结构件的可靠性，有利于钢结构件的小型化。
下面通过具体实施例对本申请实施例进行进一步的说明。
实施例1～6
实施例1的轻质钢的制备方法具体如下。
(1)雾化法制备合金粉末，粉末粒径D50＝5～15um，D90≤45um；
(2)粉末与粘接剂按照56/44的体积比，在180℃下充分混合制备成喂料，使用的粘结剂成分为聚甲醛(POM)：乙烯-醋酸乙烯共聚物(EVA)：聚乙烯(PE)：微晶蜡(CW)：硬脂酸(SA)的重量比为85:1:5.5:2:1；
(3)将喂料置于注射成型机中，注射到模具型腔内，塑形出成型坯材；并对塑型而成的坯材采用催化脱脂工艺，温度为130℃，催化剂采用发烟硝酸，去除其中部分粘接剂；
(4)加热至1200℃±5℃，保温2～3h烧结成形；
(5)1100±5℃温度下固溶1h；
(6)500±5℃温度下时效2h。
其他实施例2～6工艺参数与相应的测试结果如表六所示，除此之外的其它参数及步骤同实施例1。实施例1～6共制得6种钢产品，具体的成分见表五所示。表五列出Fe的重量百分含量为余量，代表1减去其他所列元素的重量百分含量，即为Fe的重量百分含量。
表五
wt％ Mn Al C O V Fe
实施例1 32.2 12.31 1.192 0.1609 0.29 余量
实施例2 33.4 12.53 1.2049 0.2339 0.4 余量
实施例3 32.05 13.01 1.1784 0.1877 0.21 余量
实施例4 33.8 13.43 1.1491 0.1554 0.22 余量
实施例5 30.1 12.02 1.3319 0.0956 0.42 余量
实施例6 31.6 12.11 1.4493 0.1617 0.51 余量
表六
Figure PCTCN2022114865-appb-000004
从表六可以看出，本申请可以采用粉末烧结及后续固溶与时效的热处理方式获取密度为5.9～6.3g/cm 3，屈服强度为700～1200MPa，延伸率为1.5％～15％的轻质钢，各实施例所得钢制品的显微组织中均存在前述细小弥散分布的氧化铝颗粒相。当前密度与力学性能的获得归因于材料成分，本申请的烧结处理等工艺在组织基体中反应生成的原位氧化铝强化相。可以理解的，产品的性能取决于产品的组成成分，同时取决于制备工艺。而对于MIM成型工艺，工序多，参数变量多，如MIM成型技术中，粉末原料的粒径分布范围、粘结剂体系与配比、脱除粘结剂方式等均可依据设备环境进行相应的调整，合适的处理工艺均可以获取本申请公开的成分与性能，且本申请合适的处理工艺，存在进一步降低密度，提升强度与塑韧性的可能。
需要说明的是，以上仅为本申请的具体实施方式，但本申请的保护范围并不局限于此，任何熟悉本技术领域的技术人员在本申请揭露的技术范围内，可轻易想到变化或替换，都应涵盖在本申请的保护范围之内；在不冲突的情况下，本申请的实施方式及实施方式中的特征可以相互组合。因此，本申请的保护范围应以权利要求的保护范围为准。

Claims (22)

  1. 一种轻质钢，其特征在于，包括：
    Fe，重量百分含量≥48.18wt％；
    Mn，重量百分含量为30.01wt％～35.01wt％；
    Al，重量百分含量为12.01wt％～15.01wt％；
    C，重量百分含量为1.0wt％～1.5wt％；
    O，重量百分含量为0.03wt％～0.3wt％。
  2. 根据权利要求1所述的轻质钢，其特征在于，所述轻质钢中分布有氧化铝颗粒，所述氧化铝颗粒基本上由长度和宽度尺寸均≤5μm的氧化铝颗粒组成。
  3. 根据权利要求1或2所述的轻质钢，其特征在于，所述轻质钢还包括V，V的重量百分含量≤0.6wt％。
  4. 根据权利要求3所述的轻质钢，其特征在于，所述轻质钢中V的重量百分含量为0.2wt％～0.55wt％。
  5. 根据权利要求1至4中任一项所述的轻质钢，其特征在于，所述轻质钢中Mn的重量百分含量为30.01wt％～32.01wt％。
  6. 根据权利要求1至5中任一项所述的轻质钢，其特征在于，所述轻质钢中Al的重量百分含量为12.5wt％～13.5wt％。
  7. 根据权利要求1至6中任一项所述的轻质钢，其特征在于，所述轻质钢中C的重量百分含量为1.1wt％～1.45wt％。
  8. 根据权利要求1至7中任一项所述的轻质钢，其特征在于，所述轻质钢中O的重量百分含量为0.05wt％～0.2wt％。
  9. 根据权利要求1至8中任一项所述的轻质钢，其特征在于，所述轻质钢还包括其他元素，所述其他元素包括氮、铜、铬、镍、钛、硫、磷、硼、氢、锆、硅、钽、钙、锌以及稀土金属中的一种或多种，所述其他元素的重量百分比≤1％。
  10. 根据权利要求1至9中任一项所述的轻质钢，其特征在于，所述轻质钢使用粉末原料经金属注射成型工艺形成。
  11. 根据权利要求1至10中任一项所述的轻质钢，其特征在于，所述轻质钢的密度为5.9～6.3g/cm 3。
  12. 根据权利要求1至11中任一项所述的轻质钢，其特征在于，所述轻质钢的屈服强度为700～1200MPa，延伸率为1.5％～20％。
  13. 一种钢结构件，其特征在于，所述钢结构件采用的材料包括如权利要求1至12中任一项所述的轻质钢。
  14. 一种轻质钢的制备方法，其特征在于，包括：
    提供粉末原料，所述粉末原料包括：
    Fe，重量百分含量≥47.39wt％，
    Mn，重量百分含量为30.01wt％～36wt％，
    Al，重量百分含量为12.01wt％～15.01wt％，
    C，重量百分含量为0.8wt％～1.5wt％，
    O，重量百分含量为0.003wt％～0.1wt％；
    将所述粉末原料和粘结剂混合成型为生坯；
    烧结所述生坯，以形成烧结坯；以及
    热处理所述烧结坯。
  15. 根据权利要求14所述的轻质钢的制备方法，其特征在于，将所述粉末原料和所述粘结剂混合成型为生坯包括：
    混合所述粉末原料与粘结剂，以形成膏状喂料；
    将所述膏状喂料进行造粒，以形成喂料颗粒；以及
    将所述喂料颗粒通过注塑方式成型为所述生坯。
  16. 根据权利要求14或15所述的轻质钢的制备方法，其特征在于，在烧结所述生坯之前还包括：脱脂去除所述生坯中的粘结剂。
  17. 根据权利要求14至16任一项所述的轻质钢的制备方法，其特征在于，热处理所述烧结坯包括：固溶所述烧结坯；以及时效处理固溶后的所述烧结坯。
  18. 根据权利要求14至17任一项所述的轻质钢的制备方法，其特征在于，所述粉末原料还包括重量百分含量≤0.6wt％的V。
  19. 一种钢结构件，其特征在于，采用如权利要求14至18中任一项所述的轻质钢的制备方法制得。
  20. 一种电子设备，其特征在于，包括如权利要求13或19所述的钢结构件。
  21. 根据权利要求20所述的电子设备，其特征在于，所述电子设备还包括柔性显示屏及用于承载所述柔性显示屏的折叠装置，所述折叠装置用于带动所述柔性显示屏发生形变；所述折叠装置包括所述钢结构件。
  22. 根据权利要求21所述的电子设备，其特征在于，所述折叠装置包括转轴，所述转轴为所述钢结构件。
PCT/CN2022/114865 2021-08-27 2022-08-25 轻质钢及其制备方法、钢结构件和电子设备 WO2023025251A1 (zh)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20130048150A1 (en) * 2010-03-16 2013-02-28 Salzgitter Flachstahl Gmbh Method for producing workpieces from lightweight steel having material properties that are adjustable across the wall thickness
CN106012889A (zh) * 2016-07-18 2016-10-12 重庆市凡普特光电科技有限责任公司 路边电子信息查询装置
CN112877606A (zh) * 2021-01-12 2021-06-01 钢铁研究总院 一种超高强全奥氏体低密度钢及制备方法
CN113088823A (zh) * 2021-04-08 2021-07-09 上海富驰高科技股份有限公司 一种轻质、高强度及高耐蚀性Fe-Mn-Al-C-Cr钢及其制备方法

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20130048150A1 (en) * 2010-03-16 2013-02-28 Salzgitter Flachstahl Gmbh Method for producing workpieces from lightweight steel having material properties that are adjustable across the wall thickness
CN106012889A (zh) * 2016-07-18 2016-10-12 重庆市凡普特光电科技有限责任公司 路边电子信息查询装置
CN112877606A (zh) * 2021-01-12 2021-06-01 钢铁研究总院 一种超高强全奥氏体低密度钢及制备方法
CN113088823A (zh) * 2021-04-08 2021-07-09 上海富驰高科技股份有限公司 一种轻质、高强度及高耐蚀性Fe-Mn-Al-C-Cr钢及其制备方法

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