Aluminum-silicon plated hot formed part and method of making same

Abstract

The application provides an aluminum-silicon plated layer hot-formed part and a preparation method thereof, and belongs to the field of metal material preparation.The method comprises the following steps: obtaining a steel base plate with a set chemical composition; performing hot-dip plating on the steel base plate to obtain a steel base plate containing an aluminum-silicon plated layer; obtaining the particle size of the metal powder based on the parameters of a spraying device and the particle density value of the metal powder; spraying the metal powder with the particle size on at least part of the surface of the aluminum-silicon plated layer, and then performing hot stamping to obtain an aluminum-silicon plated layer hot-formed part.By adding the metal powder to the aluminum-silicon plated layer through spraying, the metal powder will react with Al, Si, Fe and other elements in the plated layer, and the metal powder can also undergo oxidation reaction, thereby improving the corrosion resistance of the hot-formed steel.The set particle size of the metal powder is obtained based on the parameters of the device and the particle density value of the metal powder, so that the size of the added element and the parameters of the device during spraying can be determined, and the reliability and uniformity of the spraying can be ensured.

Description

Technical Field

[0001] This application relates to the field of metal material preparation technology, and in particular to a thermoformed part and its preparation method. Background Technology

[0002] Hot-formed steel has been widely used to improve automotive crash performance and reduce weight. However, hot-formed steel produces oxide scale during the heating process, leading to the development of aluminum-silicon coated hot-formed steel. Aluminum-silicon coatings are primarily composed of aluminum. Currently, aluminum-silicon coated hot-formed steel is widely used in the hot stamping field.

[0003] Aluminum-silicon coated hot-formed steel with varying thicknesses can prevent the formation of iron oxide scale during heating. However, the corrosion resistance of this coating is limited, thus necessitating improvements in coating composition to enhance its corrosion resistance. Therefore, there is an urgent need to develop a method to improve the corrosion resistance of hot-formed steel. Summary of the Invention

[0004] This application provides a thermoformed part with an aluminum-silicon coating and a method for preparing the same. The method involves spraying metal powder into the aluminum-silicon coating to solve the technical problem of poor corrosion resistance of existing thermoformed parts.

[0005] In a first aspect, this application provides a method for preparing a thermoformed part with an aluminum-silicon coating, the method comprising:

[0006] A steel substrate with a specified chemical composition is obtained;

[0007] The steel substrate is hot-dip coated to obtain a steel substrate with an aluminum-silicon coating.

[0008] The particle size of the metal powder is obtained based on the parameters of the spraying equipment and the particle density value of the metal powder.

[0009] The metal powder having the stated particle size is sprayed onto at least a portion of the surface of the aluminum-silicon coating, and then hot stamped to obtain a thermoformed part with an aluminum-silicon coating.

[0010] Optionally, the particle size of the metal powder satisfies the following relationship:

[0011]

[0012] In the formula, d p The particle size ρ of the metal powder is indicated. p The values ​​represent the particle density of the metal powder, g represents the gravitational acceleration, ρ represents the air density, C represents the drag coefficient of the spraying equipment, Q represents the air volume provided by the fan of the spraying equipment, D represents the diameter of the air supply duct of the spraying equipment, and n represents the fan power related adjustment coefficient of the spraying equipment.

[0013] The air volume Q provided by the fan of the spraying equipment and the adjustment coefficient n related to the fan power of the spraying equipment satisfy the following relationship:

[0014] If Q ≥ 34, then n = 1.1;

[0015] If 34 > Q ≥ 17, then n = -(9 / 170)Q + 2.9;

[0016] If Q < 17, then n = 2.

[0017] Optionally, the metal powder can react with the alloying elements in the aluminum-silicon coating, and the metal powder includes at least one of Zn, Al, Mg, Ni, Cr, Cu, La, and Sn.

[0018] Optionally, the spraying temperature is greater than the melting point of the metal powder.

[0019] Optionally, after spraying, the metal powder coverage of the aluminum-silicon coating surface is ≥50%.

[0020] Optionally, the hot-dip galvanizing temperature is 650℃~680℃, and the hot-dip galvanizing solution composition includes Al and Si, with the mass fraction of Si element being 6%~16%.

[0021] Optionally, the heating temperature of the hot stamping is 860℃~960℃, and the holding time of the hot stamping is 3min~20min.

[0022] Optionally, the specified chemical composition includes: C, Si, Mn, Cr, Al, B, S, P, Ti, Nb, Ni, Cu, Mo, V, and Fe; by mass fraction,

[0023] The content of C is 0.05%–0.50%, the content of Si is 0.08%–1.2%, the content of Mn is 0.8%–8.0%, the content of Cr is ≤1.5%, the content of Al is ≤0.10%, the content of B is ≤0.01%, the content of S is ≤0.01%, the content of P is ≤0.01%, the content of Ti is ≤0.4%, the content of Nb is ≤0.1%, the content of Ni is ≤1%, the content of Cu is ≤0.5%, the content of Mo is ≤1%, and the content of V is ≤0.25%.

[0024] Secondly, this application provides an aluminum-silicon coated thermoformed part, the part being prepared by the method described in any one embodiment of the first aspect, wherein the overall coating of the part contains Al, Si, Fe and alloy phases and oxides of the metal powder, the mass fraction of Si element in the overall coating is ≤12%, the thickness of the overall coating is 7um to 60um, and the standard deviation / average thickness of the overall coating is ≤0.3.

[0025] Optionally, the tensile strength of the part is 500MPa to 2000MPa.

[0026] The technical solutions provided in this application have the following advantages compared with the prior art:

[0027] This application involves adding metal powder to an aluminum-silicon coating via spraying. The metal powder reacts with elements such as Al, Si, and Fe in the coating and undergoes oxidation to generate alloy phases and oxides, thereby improving the corrosion resistance of the hot-formed steel and creating a hot-formed steel product with a novel coating. Furthermore, this application determines the particle size of the metal powder based on equipment parameters and the particle density value, allowing for the selection of appropriate particle sizes for the added metal powder and the control of the spraying equipment parameters. This ensures the reliability and uniformity of the spraying process, further enhancing the corrosion resistance of the hot-formed steel. Attached Figure Description

[0028] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0029] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 A schematic flowchart illustrating a method for preparing an aluminum-silicon coated thermoformed part according to an embodiment of this application;

[0031] Figure 2 This is a surface morphology diagram of the aluminum-silicon coated thermoformed part provided in Embodiment 1 of this application;

[0032] Figure 3 This is a microscopic morphology image of the surface of the aluminum-silicon coated steel sheet (before heat treatment for hot forming) provided in Embodiment 1 of this application;

[0033] Figure 4 This is a microscopic morphology image of the surface of the aluminum-silicon coated thermoformed part (after heat treatment after thermoforming) provided in Embodiment 1 of this application.

[0034] Figure 5 A comparison diagram of Zn content before and after heat treatment for thermoforming provided in Embodiment 1 of this application;

[0035] Figure 6 A comparison chart of the O element content before and after heat treatment for thermoforming provided in Embodiment 1 of this application; Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0037] Various embodiments of this application may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a hard limitation on the scope of this application; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Furthermore, whenever a numerical range is referred to herein, it means including any referenced number (fraction or integer) within the referred range.

[0038] Furthermore, in the description of this application, the terms "comprising," "including," etc., mean "including but not limited to." In this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. In this document, "and / or" describes the relationship between related objects, indicating that three relationships can exist; for example, A and / or B can represent: A alone, A and B simultaneously, or B alone. A and B can be singular or plural. In this document, "at least one" means one or more, and "more than" means two or more. "At least one," "at least one of the following," or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, "at least one of a, b, or c" or "at least one of a, b, and c" can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be a single or multiple.

[0039] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

[0040] Firstly, this application provides a method for preparing a thermoformed part with an aluminum-silicon coated layer; please refer to [link to relevant documentation]. Figure 1 The method includes:

[0041] S1. Obtain a steel substrate with a set chemical composition;

[0042] In some embodiments, prior to step S1, the process includes hot metal pretreatment, converter smelting, refining, continuous casting, and rolling to obtain a steel substrate.

[0043] In some embodiments, the specified chemical composition includes: C, Si, Mn, Cr, Al, B, S, P, Ti, Nb, Ni, Cu, Mo, V, and Fe; by mass fraction,

[0044] The content of C is 0.05%–0.50%, the content of Si is 0.08%–1.2%, the content of Mn is 0.8%–8.0%, the content of Cr is ≤1.5%, the content of Al is ≤0.10%, the content of B is ≤0.01%, the content of S is ≤0.01%, the content of P is ≤0.01%, the content of Ti is ≤0.4%, the content of Nb is ≤0.1%, the content of Ni is ≤1%, the content of Cu is ≤0.5%, the content of Mo is ≤1%, and the content of V is ≤0.25%.

[0045] The C content can be 0.05%, 0.10%, 0.20%, 0.30%, 0.40%, 0.50%, etc.; the Si content can be 0.08%, 0.20%, 0.40%, 0.80%, 1.0%, 1.1%, 1.2%, etc.; the Mn content can be 0.8%, 1.0%, 3.0%, 4.0%, 6.0%, 7.0%, 8.0%. The content of Cr can be 0%, 0.2%, 0.6%, 1.0%, 1.2%, 1.5%, etc.; the content of Al can be 0%, 0.02%, 0.06%, 0.08%, 0.10%, etc.; the content of B can be 0%, 0.002%, 0.006%, 0.008%, 0.01%, etc.; the content of S can be 0%, 0.002%, 0.0%, etc. The content of P can be 0%, 0.002%, 0.006%, 0.008%, 0.01%, etc.; the content of Ti can be 0%, 0.05%, 0.1%, 0.2%, 0.3%, 0.4%, etc.; the content of Nb can be 0%, 0.002%, 0.006%, 0.008%, 0.01%, etc. The Ni content can be 0%, 0.1%, 0.5%, 0.7%, 1%, etc.; the Cu content can be 0%, 0.1%, 0.3%, 0.4%, 0.5%, etc.; the Mo content can be 0%, 0.1%, 0.3%, 0.6%, 0.8%, 1.0%, etc.; and the V content can be 0%, 0.05%, 0.10%, 0.20%, 0.25%, etc.

[0046] S2. The steel substrate is hot-dip coated to obtain a steel substrate with an aluminum-silicon coating.

[0047] In some embodiments, the hot-dip plating temperature is 650°C to 680°C, and the plating solution composition includes Al and Si, wherein the mass fraction of Si is 6% to 16%.

[0048] The hot-dip galvanizing temperature can be 650℃, 660℃, 670℃, 680℃, etc., and the mass fraction of Si element can be 6%, 8%, 10%, 12%, 14%, 16%, etc.

[0049] S3. Based on the parameters of the spraying equipment and the particle density value of the metal powder, the particle size of the metal powder is obtained.

[0050] In some embodiments, the metal powder can react with the alloying elements in the aluminum-silicon coating, and the metal powder includes at least one of Zn, Al, Mg, Ni, Cr, Cu, La, and Sn.

[0051] In some embodiments, the spraying temperature is greater than the melting point of the metal powder.

[0052] When adding elements, the temperature of the steel substrate needs to be higher than the melting temperature of the added metal powder to ensure that the added metal powder can be incorporated into the coating on the surface of the steel substrate. The added elements will react with elements such as Al, Si, and Fe in the coating, as well as undergo oxidation reactions with the sprayed elements, to generate alloy phases and oxides, thereby improving the corrosion resistance of the hot-formed steel.

[0053] In some embodiments, when the metal powder is zinc, the surface temperature of the steel substrate is ≥420°C.

[0054] This is because zinc powder has a melting point of 419.53℃, ensuring that the zinc powder can melt after being added to the coating surface of the steel substrate. The temperature of the aluminum-silicon plating bath is 650℃~680℃. After the aluminum-silicon coating is prepared on the hot-formed steel surface, the temperature is usually higher than 420℃. Therefore, zinc powder spraying at this temperature ensures that the zinc powder completely melts and integrates into the coating, and further reacts with other elements in the coating. This ensures that a certain amount of zinc is present in the coating.

[0055] In some embodiments, the particle size of the metal powder satisfies the following relationship:

[0056]

[0057] The meaning, value, and unit of each parameter in the relation are shown in Table 1.

[0058] Table 1. Meaning, values, and units of each parameter in the relational expression.

[0059] name symbol numerical values unit Particle size (diameter) of metal powder <![CDATA[d p ]]> To be sought m Particle density value of metal powder <![CDATA[ρ p ]]> Particle density value <![CDATA[g / cm 3 ]]> gravitational acceleration g 9.8 <![CDATA[Kg / N,m / s 2 ]]> air density ρ 1.29 <![CDATA[Kg / m 3 ]]> Traction coefficient C 0.44 - The fan provides air volume Q Reference field equipment <![CDATA[m 3 / min]]> Air supply duct diameter D Reference field equipment mm Wind turbine power related adjustment coefficient n Fan power related -

[0060] To achieve successful spraying, the particle size of the metal powder and the compatibility with the equipment must be considered. The equipment parameters primarily consider the fan power and duct size, as these determine the air velocity within the duct, ensuring the metal powder is lifted and delivered to the strip surface. To guarantee that the metal powder can be lifted by the powder feeding mechanism and delivered to the strip surface, a critical particle size calculation model based on the equipment parameters is proposed. This powder feeding mechanism mainly consists of a fan and ducts. The fan provides power, supplying air into the ducts, where the metal powder is added and blown onto the strip surface by the airflow.

[0061] The air volume Q provided by the fan of the spraying equipment and the adjustment coefficient n related to the fan power of the spraying equipment satisfy the following relationship:

[0062] If Q ≥ 34, then n = 1.1;

[0063] If 34 > Q ≥ 17, then n = -(9 / 170)Q + 2.9;

[0064] If Q < 17, then n = 2.

[0065] Because the uniformity of metal powder cannot be guaranteed during manufacturing, the presence of some powder particles with sizes exceeding the theoretical value must be considered. Therefore, the n-value needs to be greater than 1. When the fan power is low, it is more likely that large-sized metal powder particles will not be blown away; therefore, as the fan power decreases, the n-value increases. The finer the sprayed metal powder is relative to the theoretical critical value, the better the uniformity of the spraying can be guaranteed, which is the significance of the n-value.

[0066] In some embodiments, after the spraying, the coverage of the metal powder on the aluminum-silicon coating is ≥50%.

[0067] The coverage of the coating surface after spraying can be 50%, 60%, 70%, 80%, 90%, etc.

[0068] In some embodiments, after the spraying, the coverage of the metal powder on the aluminum-silicon coating is ≥80%.

[0069] To further improve the corrosion resistance of hot-formed steel, the coverage of the coating surface after spraying can be 80%, 85%, 90%, 95%, 98%, etc.

[0070] S4. Spray the metal powder having the specified metal powder size onto at least a portion of the surface of the aluminum-silicon coating, and then perform hot stamping to obtain a thermoformed part with an aluminum-silicon coating.

[0071] In some embodiments, the heating temperature of the hot stamping is 860°C to 960°C, and the holding time of the hot stamping is 3 min to 20 min.

[0072] During hot stamping, the sheet metal is first heated to 860℃~960℃ and held at that temperature for 3min~20min. Then, it is transferred to a hot stamping die for forming. After forming, it undergoes pressure quenching to complete the martensitic transformation of the substrate. The hot-stamped parts are then subjected to performance testing to ensure they meet requirements. The heating temperature for hot stamping can be 860℃, 870℃, 900℃, 930℃, 950℃, 960℃, etc., and the holding time can be 3min, 5min, 8min, 12min, 16min, 18min, 20min, etc.

[0073] Secondly, this application provides an aluminum-silicon coated thermoformed part, the part being prepared by the method described in any one of claims 1-8, wherein the overall coating of the part contains Al, Si, Fe and alloy phases and oxides of the metal powder, the mass fraction of Si element in the overall coating is ≤12%, the thickness of the overall coating is 7um to 60um, and the standard deviation / average thickness of the overall coating is ≤0.3.

[0074] By adding elements to the aluminum-silicon coating, these added elements react with elements such as Al, Si, and Fe in the coating, and undergo oxidation reactions to generate alloy phases and oxides, thereby improving the corrosion resistance of hot-formed steel and forming hot-formed steel products with novel coatings. The mass fraction of Si in this overall coating can be 2%, 4%, 6%, 10%, 12%, etc., and the thickness of the overall coating can be 7µm, 10µm, 15µm, 30µm, 40µm, 50µm, 60µm, etc., with the standard deviation / average thickness of the overall coating being 0.1, 0.2, 0.3, etc.

[0075] In some embodiments, when the added element is Zn, the area of ​​the overall coating is 1m². 2 The Zn element coating mass is ≤16g.

[0076] When the added element is Zn, the total area of ​​the coating is 1m². 2 The Zn element can be sprayed in quantities of 2g, 5g, 8g, 12g, 16g, etc.

[0077] In some embodiments, the tensile strength of the part is 500 MPa to 2000 MPa.

[0078] The tensile strength of this part can be 500MPa, 800MPa, 1000MPa, 1500MPa, 2000MPa, etc.

[0079] The present application is further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the application. Experimental methods in the following embodiments that do not specify specific conditions are generally determined according to national standards. If there is no corresponding national standard, then general international standards, conventional conditions, or conditions recommended by the manufacturer are followed.

[0080] Example 1

[0081] The preparation of the thermoformed part in this embodiment includes the following steps:

[0082] S11. Preparation of the steel substrate. The chemical composition and mass content of the steel substrate are as follows: C: 0.23%; Si: 0.26%; Mn: 1.26%; Cr: 0.18%; Al: 0.06%; B: 0.0029%; S: 0.001%; ​​P: 0.006%; Ti: 0.03%; Nb: 0.05%; Ni: 0.03%; Cu: 0.005%; Mo: 0.006%; V: 0.003%.

[0083] S21. A steel substrate is hot-dip coated to obtain a steel substrate with an aluminum-silicon coating. The hot-dip coating temperature is 665℃. The main component of the hot-dip coating solution is Al, and the mass fraction of Si is 10%.

[0084] S31. Based on the formula of the critical size calculation model for sprayed metal powder using equipment parameters, the particle size of the metal powder is calculated. The values ​​of each parameter in the formula during zinc powder spraying are shown in Table 2.

[0085] Table 2 shows the values ​​of each parameter in the relationship formula under zinc powder spraying conditions.

[0086]

[0087]

[0088] The critical metal powder size of Zn powder was calculated to be 17.98 μm, while the zinc powder size for this air supply equipment was 16 μm.

[0089] S41. Zn element powder is added to the aluminum-silicon coating by spraying, with a coverage rate of 80%. Then, hot stamping is performed to obtain the aluminum-silicon coated thermoformed part. The heating temperature for hot stamping is 910℃, and the holding time is 5 minutes.

[0090] The performance of the thermoformed part prepared in this embodiment was tested. The mass fraction of Si in the overall coating was 10%, the thickness of the overall coating was 36 μm, and the standard deviation / average thickness of the overall coating was 0.2. The tensile strength of the part was 1468 MPa.

[0091] This embodiment improves the corrosion resistance of hot-formed steel by adding Zn to the aluminum-silicon coating. Zn reacts with elements such as Al, Si, and Fe in the coating and undergoes oxidation to generate alloy phases and oxides.

[0092] Appendix Figure 2-6 Detailed explanation:

[0093] like Figure 2 As shown, the surface morphology of aluminum-silicon coated thermoformed parts is different from that of traditional aluminum-silicon coated steel sheets with aluminum flower patterns.

[0094] like Figure 3 As shown, the microstructure of the aluminum-silicon coated steel sheet (before heat treatment for hot forming) exhibits a discontinuous planar morphology, mainly due to the chemical reaction between the zinc powder and the original aluminum and silicon elements after melting.

[0095] like Figure 4 As shown, the surface of the aluminum-silicon coated thermoformed parts (after heat treatment) exhibits a granular appearance, mainly due to the chemical reactions, including oxidation reactions, of the zinc, iron, aluminum, and silicon elements on the surface during the heat treatment process of thermoforming.

[0096] like Figure 5 , Figure 6 As shown, the zinc and oxygen content on the coating surface was analyzed using GDS. After the heat treatment of hot forming, the Zn thickness increased, mainly due to the formation of oxide particles. Furthermore, the oxygen content was measured, and it was found that the oxygen content on the coating surface increased significantly after heat treatment, resulting in a significant increase in coating thickness.

[0097] As can be seen from the above embodiments, the element addition method described in this application can successfully spray metal powder onto the coating surface. After heat treatment, the sprayed elements remain in the original coating, improving the corrosion resistance of the hot-formed steel.

[0098] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for preparing a thermoformed part with an aluminum-silicon coating, characterized in that, The method includes: A steel substrate with a specified chemical composition is obtained; The steel substrate is hot-dip coated to obtain a steel substrate with an aluminum-silicon coating. The particle size of the metal powder is obtained based on the parameters of the spraying equipment and the particle density value of the metal powder. The metal powder having the specified particle size is sprayed onto at least a portion of the surface of the aluminum-silicon coating, and then hot stamped to obtain a thermoformed part with an aluminum-silicon coating. The particle size of the metal powder satisfies the following relationship: In the formula, d p This indicates the particle size of the metal powder. ρ p This represents the particle density value of the metal powder. g Represents gravitational acceleration. ρ Indicates air density, C This indicates the drag coefficient of the spraying equipment. Q This indicates the air volume provided by the fan in the spraying equipment. D This indicates the diameter of the air supply duct of the spraying equipment. n This indicates the adjustment coefficient related to the fan power of the spraying equipment; The fan of the spraying equipment provides the air volume. Q Adjustment coefficient related to the fan power of the spraying equipment n The following relationship must be satisfied: If Q ≥34, then n =1.1; If 34> Q ≥17, then n = -(9 / 170) Q +2.9; If Q <17, then n =2; The metal powder can react with the alloying elements in the aluminum-silicon coating, and the metal powder includes at least one of Zn, Al, Mg, Ni, Cr, Cu, La, and Sn.

2. The method according to claim 1, characterized in that, The spraying temperature is greater than the melting point of the metal powder.

3. The method according to claim 1, characterized in that, After spraying, the metal powder coverage of the aluminum-silicon coating surface is ≥50%.

4. The method according to claim 1, characterized in that, The hot-dip galvanizing temperature is 650℃~680℃, and the hot-dip galvanizing solution composition includes Al and Si, with the mass fraction of Si element being 6%~16%.

5. The method according to claim 1, characterized in that, The heating temperature for hot stamping is 860℃~960℃, and the holding time for hot stamping is 3min~20min.

6. The method according to claim 1, characterized in that, The specified chemical composition includes: C, Si, Mn, Cr, Al, B, S, P, Ti, Nb, Ni, Cu, Mo, V, and Fe; wherein, by mass fraction, The content of C is 0.05%~0.50%, the content of Si is 0.08%~1.2%, the content of Mn is 0.8%~8.0%, the content of Cr is ≤1.5%, the content of Al is ≤0.10%, the content of B is ≤0.01%, the content of S is ≤0.01%, the content of P is ≤0.01%, the content of Ti is ≤0.4%, the content of Nb is ≤0.1%, the content of Ni is ≤1%, the content of Cu is ≤0.5%, the content of Mo is ≤1%, and the content of V is ≤0.25%.

7. A thermoformed part with an aluminum-silicon coating, characterized in that, The part is prepared by the method according to any one of claims 1-6, the overall coating of the part contains Al, Si, Fe and the alloy phase and oxide of the metal powder, the mass fraction of Si element in the overall coating is ≤12%, the thickness of the overall coating is 7um~60um, and the standard deviation / average thickness of the overall coating is ≤0.

3.

8. The part according to claim 7, characterized in that, The tensile strength of the part is 500MPa~2000MPa.

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