Low-cost anti-oxidation hot forming steel as well as preparation method and application thereof

Abstract

The invention discloses low-cost antioxidant hot forming steel as well as a preparation method and application thereof. The invention relates to low-cost antioxidant hot forming steel, which comprises the following components in percentage by mass: 0.2-0.3% of C; 1.0 to 2.5 percent of Mn; 1.0 to 2.0 percent of Si; and the balance of Fe. The tensile strength of the low-cost anti-oxidation hot forming steel is 1400-1800 MPa, and the ductility of the low-cost anti-oxidation hot forming steel is 6-9%. According to the low-cost anti-oxidation hot-forming steel disclosed by the embodiment of the invention, the Cr content is lower than that of traditional hot-forming steel, the oxidation resistance of the low-cost anti-oxidation hot-forming steel is improved by increasing the Si content, the oxidation resistance of the low-cost anti-oxidation hot-forming steel is obviously superior to that of hot-forming steel without Si or with a small amount of Si, and the low-cost anti-oxidation hot-forming steel has the oxidation resistance equivalent to or even better than that of high-Cr hot-forming steel. The low-cost oxidation-resistant hot forming steel disclosed by the embodiment of the invention is excellent in oxidation resistance and mechanical property, simple in preparation process and low in production cost.

Description

Technical Field

[0001] The present invention belongs to the technical field of steel preparation, and in particular relates to low-cost anti-oxidation hot-formed steel and a preparation method and application thereof. Background Art

[0002] Due to its ultra-high strength, good hot stamping forming performance, weldability and paintability, the application scope and proportion of hot-formed steel in the field of automotive safety structural parts are constantly increasing. It is often used in body structural parts such as automobile A / B / C pillars and automobile chassis, as well as safety parts such as front and rear bumpers, door anti-collision beams, etc.

[0003] At present, commonly used hot-formed steel plates are divided into bare plates and coated steel plates, among which coated steel plates are mainly Al-Si coated hot-formed steel. Compared with bare plates, coated steel plates form a dense Al-Si covering layer on the outer layer and an Al-Fe-Si transition layer between the substrate and the covering layer, which plays a good protective role. Therefore, the coated hot-formed steel does not need to be shot peened and oiled after hot stamping. It has better corrosion resistance and part dimensional stability, so it has been widely used in the automotive industry. However, Al-Si coated hot-formed steel with good oxidation resistance also has some problems. Its production process is more complicated and the cost is higher. In addition, due to the presence of the coating, hydrogen diffusion will be hindered, causing hydrogen embrittlement. Therefore, it is urgent to develop hot-formed steel that is free of Al-Si coating, resistant to oxidation and low in cost by designing the alloy composition of hot-formed steel.

[0004] At present, adding a high content of Cr to the traditional 22MnB5 alloy composition is a typical representative of anti-oxidation hot-forming steel without Al-Si coating. Since the affinity of element Cr to O is higher than that of Fe, Cr preferentially combines with O to form a Cr2O3 protective film during the hot forming process, which effectively hinders the further oxidation of Fe.

[0005] Chinese patent CN114990434B proposes that increasing the Cr content to 3.0% can improve the oxidation resistance of hot-formed steel. After hot stamping at 930°C for 3.5 minutes in an inert atmosphere, the oxide layer is thinner and the protective layer or shot blasting process can be omitted.

[0006] Chinese patent CN114045440B proposes a high-strength and high-plasticity hot-formed steel with oxidation resistance for automobiles and a hot-forming process. The traditional production process is used to add 1.5% to 3.2% Cr and 0.1% to 0.3% Mo to the Mn-B component system to achieve an antioxidant effect. After hot forming, subsequent production processes can be carried out directly without shot peening.

[0007] Chinese patent CN117551852A proposes that the oxidation resistance of an alloy with a Cr content of 1.5% to 3.0% can be improved by pre-oxidizing it at a temperature of 700 to 820°C and then hot stamping it.

[0008] In summary, although the oxidation resistance of steel during hot stamping can be improved by alloy composition design or pretreatment before hot stamping, the addition of a large amount of precious element Cr, or even more precious element Mo, will increase the production cost of hot-formed steel. Moreover, a high content of Cr will significantly increase the carbon equivalent of steel, reduce the stability of retained austenite, promote the precipitation of carbides, and thus increase brittleness. Summary of the invention

[0009] In view of this, some embodiments disclose low-cost oxidation-resistant hot-formed steel. The components of the low-cost oxidation-resistant hot-formed steel include, by mass percentage:

[0010] C: 0.2-0.3%;

[0011] Mn: 1.0-2.5%;

[0012] Si: 1.0-2.0%;

[0013] The balance is Fe;

[0014] The low-cost oxidation-resistant hot-formed steel has a tensile strength of 1400-1800 MPa and an elongation of 6-9%.

[0015] Some embodiments disclose low-cost anti-oxidation hot-formed steels, which further include Cr. In terms of mass percentage, the content of Cr is not greater than 0.2%.

[0016] Some embodiments disclose low-cost oxidation-resistant hot-forming steels, wherein surface oxides of the low-cost oxidation-resistant hot-forming steels include Fe2SiO4, Fe2O3, and Fe3O4.

[0017] Some embodiments disclose a low-cost oxidation-resistant hot-formed steel, wherein the oxidation weight gain of the low-cost oxidation-resistant hot-formed steel after being kept at 950° C. for 5 minutes is less than 0.6 mg / cm 2 .

[0018] Some embodiments disclose low-cost oxidation-resistant hot-formed steel, wherein the oxide layer thickness of the low-cost oxidation-resistant hot-formed steel is less than 2 μm.

[0019] Some embodiments disclose a method for preparing low-cost oxidation-resistant hot-formed steel, comprising:

[0020] The low-cost oxidation-resistant hot-formed steel is batched according to the mass percentage of each component to obtain a mixed material;

[0021] The mixture is placed in a water-cooled copper crucible in a vacuum arc melting furnace;

[0022] The melting is carried out by non-consumable arc melting method in an inert protective atmosphere, and electromagnetic stirring is applied;

[0023] Repeated smelting several times to obtain an alloy ingot with uniform composition;

[0024] The alloy ingot is melted and formed into an antioxidant hot-formed steel precursor by a copper mold suction casting process. The antioxidant hot-formed steel precursor is hot-rolled at a starting temperature of 1100-1200°C and a reduction of more than 80%. Subsequently, a simulated coiling process is performed at a temperature of 650-680°C. Finally, a simulated hot stamping process is performed to obtain a low-cost antioxidant hot-formed steel.

[0025] Some embodiments disclose a method for preparing low-cost oxidation-resistant hot-formed steel, wherein the simulated hot stamping forming comprises: heating and cooling the steel after the simulated coiling treatment, wherein the heating treatment temperature is 900-950°C, argon gas is used as the protective atmosphere, the insulation time is 3-5 minutes, and the cooling treatment method is oil quenching.

[0026] Some embodiments disclose applications of low-cost oxidation-resistant hot-formed steel, which is used to produce automotive parts.

[0027] The low-cost anti-oxidation hot-forming steel disclosed in the embodiment of the present invention has a Cr content lower than that of the existing high-Cr anti-oxidation hot-forming steel. The oxidation resistance of the low-cost anti-oxidation hot-forming steel is improved by increasing the Si content. Its oxidation resistance is significantly better than that of hot-forming steel without Si or with a small amount of Si added, and has oxidation resistance equivalent to or even better than that of high-Cr hot-forming steel. The low-cost anti-oxidation hot-forming steel disclosed in the embodiment of the present invention has excellent oxidation resistance and mechanical properties, a simple preparation process, and low production cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Continuous oxidation weight gain curves of the oxidation resistant hot-formed steels in Examples 1 to 4, Comparative Examples 3 to 4, and the experimental steels in Comparative Examples 1 to 2 during the 20 min heat preservation at 950°C;

[0029] Figure 2 Bar chart of oxidation weight gain values ​​of the oxidation resistant hot-formed steels in Examples 1 to 4, Comparative Examples 3 to 4, and the experimental steels in Comparative Examples 1 to 2 when kept at 950° C. for 5 min and 10 min;

[0030] Figure 3 Example 4: Cross-sectional view of surface oxidation of low-cost anti-oxidation hot-formed steel after simulated hot stamping;

[0031] Figure 4Comparative Example 1: Cross-sectional view of the surface oxidation of the experimental steel after simulated hot stamping;

[0032] Figure 5 Comparative Example 3: Cross-sectional view of the surface oxidation of the anti-oxidation hot-formed steel after simulated hot stamping;

[0033] Figure 6 Example 4 Schematic diagram of the phase composition of the surface oxide layer of low-cost anti-oxidation hot-formed steel after simulated hot stamping;

[0034] Figure 7 Comparative Example 1 Schematic diagram of the phase composition of the surface oxide layer of the experimental steel after simulated hot stamping;

[0035] Figure 8 Comparative Example 3 Schematic diagram of the phase composition of the surface oxide layer of the oxidation-resistant hot-formed steel after simulated hot stamping;

[0036] Fig. 9 Example 4: Tensile curve of low-cost oxidation-resistant hot-formed steel. DETAILED DESCRIPTION

[0037] The word "embodiment" used here as an "exemplary" does not necessarily mean that any embodiment described is superior to or better than other embodiments. Unless otherwise specified, the performance index tests in the embodiments of this application are performed using conventional test methods in the art. It should be understood that the terms described in this application are only used to describe specific implementation methods and are not used to limit the content disclosed in this application.

[0038] Unless otherwise specified, the technical and scientific terms used in this document have the same meanings as commonly understood by ordinary technicians in the technical field to which this application belongs; other experimental methods and technical means not specifically specified in this application refer to experimental methods and technical means commonly used by ordinary technicians in this field.

[0039] The terms "substantially" and "approximately" used herein are used to describe small fluctuations. For example, they can refer to less than or equal to ±5%, such as less than or equal to ±2%, such as less than or equal to ±1%, such as less than or equal to ±0.5%, such as less than or equal to ±0.2%, such as less than or equal to ±0.1%, such as less than or equal to ±0.05%. The numerical data represented or presented in the range format herein are used only for convenience and brevity, and should therefore be flexibly interpreted as including not only the values ​​clearly listed as the limits of the range, but also all independent values ​​or sub-ranges contained in the range. For example, the numerical range of "1-5%" should be interpreted as including not only the clearly listed values ​​of 1% to 5%, but also the independent values ​​and sub-ranges within the range shown. Therefore, independent values ​​such as 2%, 3.5% and 4% and sub-ranges such as 1%-3%, 2%-4% and 3%-5% are included in this numerical range. This principle also applies to the range of only one numerical value. In addition, such an interpretation applies regardless of the width of the range or the characteristics described.

[0040] In this document, including in the claims, transitional words such as "comprises," "includes," "with," "having," "containing," "involving," "accommodating," etc. are understood to be open-ended, i.e., meaning "including but not limited to." Only the transitional words "consisting of" and "composed of" are closed transitional words.

[0041] In order to better illustrate the content of the present application, numerous specific details are provided in the specific examples below. It should be understood by those skilled in the art that the present application can also be implemented without certain specific details. In the embodiments, some methods, means, instruments, equipment, etc. well known to those skilled in the art are not described in detail in order to highlight the main purpose of the present application.

[0042] Under the premise of no conflict, the technical features disclosed in the embodiments of the present application can be arbitrarily combined, and the obtained technical solutions belong to the contents disclosed in the embodiments of the present application. It should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like mentioned in the present application indicate the orientation or position relationship based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the technical features and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention, unless it conflicts with the context. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance, unless it conflicts with the context.

[0043] In some embodiments, the composition of the low-cost oxidation resistant hot-formed steel includes, by mass percentage:

[0044] C: 0.2-0.3%;

[0045] Mn: 1.0-2.5%;

[0046] Si: 1.0-2.0%;

[0047] The balance is Fe;

[0048] The low-cost oxidation-resistant hot-formed steel has a tensile strength of 1400-1800 MPa and an elongation of 6-9%.

[0049] In some embodiments, the low-cost anti-oxidation hot-forming steel further includes Cr, and the content of Cr is not more than 0.2% by mass. The Cr content in the existing high-Cr anti-oxidation hot-forming steel is higher than 2% to improve the oxidation resistance of the hot-forming steel, while the low-cost anti-oxidation hot-forming steel disclosed in the embodiment of the present invention does not need to add a large amount of Cr to improve the oxidation resistance, and the Cr content is controlled below 0.2%; at the same time, the Si content is increased to improve the oxidation resistance of the low-cost anti-oxidation hot-forming steel. By reducing the Cr content and increasing the Si content to 1.0-2.0%, the oxidation resistance of the obtained low-cost anti-oxidation hot-forming steel reaches or even exceeds the existing high-Cr anti-oxidation hot-forming steel.

[0050] Some embodiments disclose low-cost anti-oxidation hot-formed steels, wherein the surface oxides of the low-cost anti-oxidation hot-formed steels include Fe2SiO4, Fe2O3, and Fe3O4, wherein the content of Fe2SiO4 is relatively high, and the contents of Fe2O3 and Fe3O4 are relatively low.

[0051] In some embodiments, the oxidation weight gain of low-cost oxidation-resistant hot-formed steel after 950°C holding for 5 minutes is less than 0.6 mg / cm 2 After 10 minutes of heat preservation at 950℃, the oxidation weight gain is less than 1.2mg / cm 2 , which is equivalent to high Cr steel with a Cr content of 2.0 to 3.0%.

[0052] In some embodiments, the oxide layer thickness of the low-cost oxidation-resistant hot-formed steel is less than 2 μm. After the low-cost oxidation-resistant hot-formed steel is placed in an argon environment and kept at 950° C. for 5 minutes, it is transferred to air and cooled to room temperature. The oxide layer thickness is less than 2 μm, which is equivalent to high Cr steel with a Cr content of 2.0-3.0%.

[0053] In some embodiments, a method for preparing low-cost oxidation-resistant hot-formed steel comprises:

[0054] The low-cost oxidation-resistant hot-formed steel is batched according to the mass percentage of each component to obtain a mixed material;

[0055] The mixture is placed in a water-cooled copper crucible in a vacuum arc melting furnace;

[0056] The melting is carried out by non-consumable arc melting method in an inert protective atmosphere, and electromagnetic stirring is applied;

[0057] Repeat the smelting several times, generally at least 4 times, to obtain an alloy ingot with uniform composition;

[0058] The alloy ingot is melted and formed into an antioxidant hot-formed steel precursor by a copper mold suction casting process. The antioxidant hot-formed steel precursor is hot-rolled at a starting temperature of 1100-1200°C and a reduction of more than 80%. Subsequently, a simulated coiling process is performed at a temperature of 650-680°C. Finally, a simulated hot stamping process is performed to obtain a low-cost antioxidant hot-formed steel.

[0059] In some embodiments, the simulated hot stamping forming includes: heating and cooling the steel after the simulated coiling treatment, wherein the heating treatment temperature is 900-950°C, argon is used as the protective atmosphere, the insulation time is 3-5 minutes, and the cooling treatment method is oil quenching.

[0060] In some embodiments, low-cost oxidation-resistant hot-formed steel is used to produce automotive parts, such as body structural parts, automotive anti-collision safety parts, etc.

[0061] The technical details are further illustrated below in conjunction with embodiments.

[0062] Example 1

[0063] Example 1 discloses a method for preparing low-cost oxidation-resistant hot-formed steel, comprising:

[0064] Prepare 140g of mixed material; wherein C is 0.22wt%, Si is 1.00wt%, Mn is 1.20wt%, and the balance is Fe;

[0065] The mixture is placed in a water-cooled copper crucible in a vacuum arc melting furnace;

[0066] The melting is carried out by non-consumable arc melting method under argon gas, and electromagnetic stirring is applied;

[0067] Repeat the smelting for at least 4 times to obtain an alloy ingot with uniform composition;

[0068] The alloy ingot is melted, and the melt is sucked into a rectangular copper mold cavity by a copper mold suction casting process to shape the alloy ingot melt to obtain an oxidation-resistant hot-formed steel precursor with a cross-section of 15×15 mm and a length of 90 mm;

[0069] The antioxidant hot-formed steel precursor was hot rolled with a starting rolling temperature of 1200°C, a reduction of more than 80%, and a final thickness of 2 mm. It was then subjected to simulated coiling at 680°C and finally to simulated hot stamping. The heating temperature of the simulated hot stamping was 950°C, argon was used as the protective atmosphere, the holding time was 5 minutes, and the cooling treatment method was oil quenching to obtain low-cost antioxidant hot-formed steel.

[0070] Example 2

[0071] Example 2 discloses a method for preparing low-cost oxidation-resistant hot-formed steel, referring to Example 1;

[0072] Among them, in the mixture of Example 2, C is 0.22wt%, Si is 1.50wt%, Mn is 1.20wt%, and the balance is Fe.

[0073] Example 3

[0074] Example 3 discloses a method for preparing low-cost oxidation-resistant hot-formed steel, referring to Example 1;

[0075] Among them, in the mixture of Example 3, C is 0.22wt%, Si is 2.00wt%, Mn is 1.20wt%, and the balance is Fe.

[0076] Example 4

[0077] Example 4 discloses a method for preparing low-cost oxidation-resistant hot-formed steel, referring to Example 1;

[0078] Among them, in the mixture of Example 4, C is 0.22wt%, Si is 1.29wt%, Mn is 1.20wt%, Cr is 0.03wt%, and the balance is Fe.

[0079] Comparative Example 1

[0080] Comparative Example 1 discloses a method for preparing an experimental steel, referring to Example 1;

[0081] Among them, in the mixed material of comparative example 1, C is 0.22wt%, Si is 0.15wt%, Mn is 1.20wt%, and the balance is Fe.

[0082] Comparative Example 2

[0083] Comparative Example 2 discloses a method for preparing an experimental steel, referring to Example 1;

[0084] Among them, in the mixed material of Comparative Example 2, C is 0.22wt%, Si is 0.50wt%, Mn is 1.20wt%, and the balance is Fe.

[0085] Comparative Example 3

[0086] Comparative Example 3 discloses a method for preparing oxidation-resistant hot-formed steel, referring to Example 1;

[0087] Among them, in the mixture of comparative example 3, C is 0.22wt%, Si is 1.20wt%, Mn is 1.20wt%, Cr is 2.00wt%, and the balance is Fe.

[0088] Comparative Example 4

[0089] Comparative Example 4 discloses a method for preparing oxidation-resistant hot-formed steel, referring to Example 1;

[0090] Among them, in the mixture of comparative example 4, C is 0.22wt%, Si is 0.40wt%, Mn is 1.20wt%, Cr is 2.90wt%, and the balance is Fe.

[0091] In summary, the low-cost oxidation-resistant hot-formed steels prepared in Examples 1 to 4, the experimental steels prepared in Comparative Examples 1 to 2, and the oxidation-resistant hot-formed steels prepared in Comparative Examples 3 to 4 were subjected to oxidation weight gain tests and surface oxidation simulations after hot stamping;

[0092] Among them, the processing method of oxidation weight gain test is as follows:

[0093] Take from the steel after simulated coiling The disc was used as the test sample, and the two circular surfaces were polished with 600#, 1000#, and 2000# SiC sandpaper in turn, and then cleaned with alcohol ultrasonically; the instrument used for oxidation weight gain was a differential scanning calorimeter (DSC), the instrument heating rate was 20℃ / min, argon gas was used for protection during the heating process, and when the temperature reached 950℃, the argon gas was removed and air was passed, and a continuous oxidation curve within 20 minutes was drawn.

[0094] Among them, the treatment of steel before simulating hot stamping oxidation is as follows:

[0095] Take a square sample with a size of 10×10×1mm from the steel after simulated coiling;

[0096] Use 240#, 600#, 1000#, and 2000# SiC sandpaper to grind one 10×10mm surface and four 1×10mm sections of the sample to remove machining marks;

[0097] The surface of the polished sample is mechanically polished to finally reach a mirror surface;

[0098] The mechanically polished samples were placed in an alcohol solution, cleaned by ultrasound for 5 minutes, and then blown dry;

[0099] The treated samples were placed in an argon environment and kept at 950 °C for 5 min, then transferred to air and cooled to room temperature.

[0100] The results of the oxidation weight gain test and the simulated hot stamping oxidation surface test of the oxidation-resistant hot-formed steel prepared in Examples 1 to 4, the experimental steel prepared in Comparative Examples 1 to 2, and the oxidation-resistant hot-formed steel prepared in Comparative Examples 3 to 4 are as follows: Figures 1 to 8 As shown;

[0101] Among them, Figure 1 and Figure 2 It can be seen that compared with comparative examples 1 to 2, more Si elements are added in examples 1 to 4. As the Si content gradually increases, the oxidation weight gain of the low-cost anti-oxidation hot-formed steel gradually decreases, and the oxidation resistance is improved. The oxidation weight gain of the low-cost anti-oxidation hot-formed steel prepared in example 3 at 950°C for 5 minutes is 0.51 mg / cm 2 The oxidation performance is comparable to that of Comparative Examples 3 to 4, and the oxidation weight gain after 10 min of heating at 950°C is 0.8 mg / cm 2 Compared with comparative examples 3 to 4, the anti-oxidation performance is better; and, compared with comparative examples 3 to 4, no Cr element is added in Example 3, so that the alloy cost of Example 3 is significantly lower than that of comparative examples 3 to 4;

[0102] Depend on Figures 3 to 5 It can be seen that the oxide layer thickness of the low-cost oxidation-resistant hot-formed steel prepared in Example 4 after simulated hot stamping oxidation is about 2 μm, which is equivalent to the oxide layer thickness of the high-Cr oxidation-resistant hot-formed steel prepared in Comparative Example 3, and is lower than the oxide layer thickness of the steel prepared in Comparative Example 1, indicating that Si can improve the oxidation resistance of hot-formed steel;

[0103] Depend on Figures 6 to 8 It can be seen that compared with Comparative Example 1, Example 4 and Comparative Example 3 both have stronger bcc matrix (110) diffraction peak intensity, weaker Fe2O3 and Fe3O4 diffraction peak intensity, and no Mn3O4 diffraction peak, indicating that the high-temperature oxidation of hot-formed steel can be alleviated by adding a certain amount of Si.

[0104] Depend on Fig. 9 It can be seen that the tensile strength of the low-cost anti-oxidation hot-formed steel prepared in Example 4 can reach 1500 MPa, and the elongation is 9%, which can meet the use requirements of 1500 MPa-grade hot-formed steel.

[0105] The low-cost anti-oxidation hot-forming steel disclosed in the embodiment of the present invention has a Cr content lower than that of the existing high-Cr anti-oxidation hot-forming steel. The oxidation resistance of the low-cost anti-oxidation hot-forming steel is improved by increasing the Si content. Its oxidation resistance is significantly better than that of hot-forming steel without Si or with a small amount of Si added, and has oxidation resistance equivalent to or even better than that of high-Cr hot-forming steel. The low-cost anti-oxidation hot-forming steel disclosed in the embodiment of the present invention has excellent oxidation resistance and mechanical properties, a simple preparation process, and low production cost.

[0106] The technical solutions disclosed in the present invention and the technical details disclosed in the embodiments are merely illustrative of the inventive concept of the present invention and do not constitute a limitation on the technical solutions of the present invention. Any conventional changes, substitutions or combinations of the technical details disclosed in the embodiments of the present invention have the same inventive concept as the present invention and are within the protection scope of the claims of the present invention.

Claims

1. Low-cost oxidation-resistant hot-formed steel, characterized by: The components of the low-cost oxidation-resistant hot-formed steel include, by mass percentage: C：0.2～0.3％； Mn: 1.0-2.5%; Si: 1.0-2.0%; The balance is Fe; The low-cost anti-oxidation hot-formed steel has a tensile strength of 1400-1800 MPa and an elongation of 6-9%.

2. The low-cost oxidation-resistant hot-formed steel according to claim 1, characterized in that: The alloy also includes Cr, and the content of Cr is not more than 0.2% by mass.

3. The low-cost oxidation-resistant hot-formed steel according to claim 1, characterized in that: The surface oxides of the low-cost oxidation-resistant hot-formed steel include Fe2SiO4, Fe2O3, and Fe3O4.

4. The low-cost oxidation-resistant hot-formed steel according to claim 1, characterized in that: The oxidation weight gain of the low-cost anti-oxidation hot-formed steel after being kept at 950°C for 5 minutes is less than 0.6 mg / cm 2 .

5. The low-cost oxidation-resistant hot-formed steel according to claim 1, characterized in that: The oxide layer thickness of the low-cost oxidation-resistant hot-formed steel is less than 2 μm.

6. The method for preparing low-cost oxidation-resistant hot-formed steel according to claim 1, characterized in that: include: The low-cost oxidation-resistant hot-formed steel is batched according to the mass percentage of each component to obtain a mixed material; The mixture is placed in a water-cooled copper crucible in a vacuum arc melting furnace; The melting is carried out by non-consumable arc melting method in an inert protective atmosphere, and electromagnetic stirring is applied; Repeated smelting several times to obtain an alloy ingot with uniform composition; The alloy ingot is melted and formed into an antioxidant hot-formed steel precursor by a copper mold suction casting process. The antioxidant hot-formed steel precursor is hot-rolled at a starting temperature of 1100-1200°C and a reduction of more than 80%. Subsequently, a simulated coiling process is performed at a temperature of 650-680°C. Finally, a simulated hot stamping process is performed to obtain a low-cost antioxidant hot-formed steel.

7. The method for preparing low-cost oxidation-resistant hot-formed steel according to claim 6, characterized in that: The simulated hot stamping forming includes: heating and cooling the steel after the simulated coiling process, wherein the heating temperature is 900-950° C., argon gas is used as the protective atmosphere, the insulation time is 3-5 minutes, and the cooling process is oil quenching.

8. Application of the low-cost oxidation-resistant hot-formed steel according to claim 1, characterized in that: The low-cost oxidation-resistant hot-formed steel is used to produce automotive parts.

Images