Aluminum-plated steel plate as well as preparation method and application thereof

Abstract

The invention relates to an aluminized steel plate and a preparation method and application thereof, and belongs to the technical field of aluminized steel plates. The steel plate comprises a base plate, an aluminum-containing coating and a zinc-containing layer, the aluminum-containing coating is attached to the base plate, the zinc-containing layer is attached to the side, away from the base plate, of the aluminum-containing coating, and the zinc-containing layer comprises a zinc-containing alloy layer and / or a zinc-containing oxide layer; the zinc-containing layer formed by the zinc-containing alloy layer and / or the zinc-containing oxide layer is arranged on the aluminum-containing plating layer, so that the friction coefficient can be reduced in the hot stamping process, and the problem that galling or die damage is easily caused in the hot stamping forming process of an aluminum-plated steel plate at present can be solved; meanwhile, the phosphating performance can be improved, so that the subsequent electrophoresis corrosion resistance and adhesion performance are facilitated, and the adhesion of a paint surface is facilitated.

Description

Technical Field

[0001] The present application relates to the technical field of aluminum-coated steel plates, and in particular to an aluminum-coated steel plate and a preparation method and application thereof. Background Art

[0002] At present, high-strength and ultra-high-strength steel plates are of great significance to the lightweighting of automobile bodies. However, with the continuous increase in the strength required for automobile body steel, the plasticity of the body steel has dropped significantly, and the forming performance has also been greatly reduced. In particular, cracking and springback are prone to occur during the steel forming process, which seriously affects the shape and dimensional accuracy of cold stamping components.

[0003] Hot stamping technology uses the characteristics of steel plates that their plasticity increases and their forming resistance decreases at high temperatures. After the steel plate blank with low initial strength is heated at high temperature, it is quickly stamped and formed in a mold with a cooling system and quenched to obtain ultra-high strength hot stamping components. This can effectively solve the problems of steel plates being prone to cracking and severe rebound during cold forming. Hot stamping is used to form ultra-high strength components, and the steel plate needs to be heated in the atmosphere or in a protective gas.

[0004] In the related art, aluminum alloy coated steel is a steel material coated with an aluminum alloy coating on a substrate. The aluminum alloy coating has excellent corrosion resistance. Since aluminum has a high melting point, it can cause rapid mutual diffusion between the aluminum alloy coating and the substrate at high temperatures, thereby forming high-melting-point intermetallic compounds Fe-Al phase and Fe-Al-Si phase. Therefore, it can well solve the problem of a large amount of surface oxide scale generated during the heating process of uncoated hot stamping components, thereby extending the service life of the mold and improving production efficiency. However, the high-hardness Fe-Al phase and Fe-Al-Si phase are prone to cause a certain degree of roughening or damage to the mold. In addition, the surface of the aluminum alloy-coated material cannot be normally phosphated after hot forming, and the adhesion of the paint film after electrophoresis is completely guaranteed by the high roughness of the coating. There is a risk that the aluminum alloy coating will not have sufficient paint film adhesion to meet the use requirements. Summary of the invention

[0005] The present application provides an aluminum-plated steel plate and a preparation method and application thereof, so as to improve the problem that the aluminum-plated steel plate is prone to roughening or damage to the mold during hot stamping, and at the same time improve the problem of low paint adhesion.

[0006] In a first aspect, the present application provides an aluminum-plated steel plate, which comprises a substrate, an aluminum-containing coating and a zinc-containing layer, wherein the aluminum-containing coating is attached to the substrate, the zinc-containing layer is attached to a side of the aluminum-containing coating away from the substrate, and the zinc-containing layer comprises a zinc-containing alloy layer and / or a zinc-containing oxide layer.

[0007] As an optional implementation, a diffusion bonding layer exists between the zinc-containing layer and the aluminum-containing coating layer.

[0008] As an optional embodiment, the area coverage of the zinc content of the zinc-containing layer on one side of the steel plate that is greater than 0.5% by mass is ≥ 80%; and / or

[0009] The depth of the zinc-containing layer ranges from 0.4 μm to 29 μm; and / or

[0010] The zinc content of the zinc-containing layer is 0.1 g / m 2 ~8g / m 2 .

[0011] As an optional embodiment, the aluminum-containing coating comprises an alloy coating containing an Al-Fe-Si system; and / or

[0012] The aluminum-containing coating comprises a plurality of alloy phases and intermetallic compound phases; and / or

[0013] The thickness of the aluminum-containing coating is 4 μm to 50 μm; and / or

[0014] The single-sided loading of the aluminum-containing coating is 10 g / m 2 ~100g / m 2 ; and / or

[0015] The chemical composition of the aluminum-containing coating includes, by mass percentage, Si: 7% to 12%, Fe: 1% to 3%, and the remainder is Al and other inevitable impurities.

[0016] As an optional embodiment, the chemical composition of the substrate includes, by mass percentage: C: 0.05% to 0.4%, Si: 0.05% to 0.3%, Mn: 0.8% to 2%, P≤0.03%, S≤0.01%, Al≤0.5%, N: ≤0.01%, B: 0.0005% to 0.005%, Cr: 0.10% to 0.5%, Ni: 0.001% to 0.5%, Mo: 0.001% to 0.5%, and one or more of Ti0.01% to 0.10%, Nb 0.01% to 0.10% and V 0.02% to 0.15%, and the rest is Fe and unavoidable impurities; and / or

[0017] The chemical composition of the substrate, in terms of mass percentage, satisfies the following relationship: 1.5%≤(Cr+Mn+Ni+Mo)≤2.5% and 0.5×Mn+Cr+0.5×Ni>0.7%; 0.03%≤(Ti+Nb+V)≤0.30%.

[0018] In a second aspect, the present application provides a method for preparing an aluminum-plated steel sheet, wherein the aluminum-plated steel sheet is the aluminum-plated steel sheet provided in the first aspect; the method comprises:

[0019] Rolling the steel billet to obtain a base plate;

[0020] The substrate is immersed in an aluminum-containing plating solution to perform aluminum plating to form an aluminum-containing coating, and zinc-containing particles are sprayed during the solidification process of the aluminum-containing plating solution to form a zinc-containing layer to obtain an aluminum-plated steel sheet, wherein the zinc-containing layer includes a zinc-containing alloy layer and / or a zinc-containing oxide layer.

[0021] As an optional embodiment, the zinc-containing particles include at least one of zinc powder and zinc alloy powder, and / or

[0022] The mass content of zinc in the zinc-containing particles is ≥ 50%; and / or

[0023] The zinc-containing particles have a particle size of 300 to 1200 mesh; and / or

[0024] The zinc-containing particles make the area coverage of the zinc-containing layer on one side of the substrate with a zinc content greater than 0.5% by mass greater than 80%; and / or

[0025] The number of zinc-containing particles sprayed on a single surface of the substrate satisfies 10 particles / cm 2 ~500 pieces / cm 2 ; and / or

[0026] The temperature of the aluminum-containing plating solution is 650° C. to 680° C.; and / or

[0027] During the spraying of zinc-containing particles, the temperature of the substrate is 550°C to 640°C.

[0028] In a third aspect, the present application provides a component, the material of which includes the aluminum-plated steel plate provided in the first aspect.

[0029] In a fourth aspect, the present application provides a method for preparing a component, the method comprising:

[0030] Obtaining the aluminum-plated steel plate provided by the first aspect;

[0031] heat treating the aluminum-plated steel plate;

[0032] The aluminum-plated steel sheet after heat treatment is stamped to obtain a component.

[0033] As an optional embodiment, the heat treatment includes a first heat treatment and a second heat treatment, the temperature of the first heat treatment is 650°C to 900°C, and the time of the first heat treatment is 30s to 150s; the temperature of the second heat treatment is 900°C to 960°C, and the time of the second heat treatment is 200s to 400s; and / or

[0034] The heating rate of the heat treatment does not exceed 15°C / s; and / or

[0035] The heat treatment time in the furnace is 250s to 500s; and / or

[0036] The stamping temperature is ≥ 650°C; and / or

[0037] The holding pressure of the stamping forming is ≥5MPa; and / or

[0038] The holding time of the stamping molding is ≥5s; and / or

[0039] The final temperature of the stamping process is ≤160°C.

[0040] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:

[0041] The aluminum-plated steel sheet provided in the embodiment of the present application has a zinc-containing layer consisting of a zinc-containing alloy layer and / or a zinc-containing oxide layer arranged on the aluminum-containing coating, which is beneficial to reducing the friction coefficient during the hot stamping process, thereby improving the problem that the current aluminum-plated steel sheet is prone to burring or damage to the mold during hot stamping; at the same time, it can improve the phosphating performance, which is beneficial to the subsequent electrophoretic corrosion resistance and adhesion performance, and is beneficial to the adhesion of the paint surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0043] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0044] Figure 1 A schematic diagram of a process for a method provided in an embodiment of the present application;

[0045] Figure 2 A schematic diagram of the process of spraying zinc-containing particles provided in an embodiment of the present application;

[0046] Figure 3 This is the zinc distribution diagram on the surface of the aluminum-plated steel plate before hot stamping provided in Example 1 of the present application;

[0047] Figure 4 This is the zinc distribution diagram of the part surface after hot stamping of the aluminum-plated steel plate provided in Example 1 of the present application;

[0048] Figure 5 is a SEM image of the zinc-containing layer of the aluminum-plated steel plate after hot stamping provided in Example 1 of the present application;

[0049] Figure 6 is the energy spectrum of the zinc-containing layer of the aluminum-plated steel plate after hot stamping provided in Example 1 of the present application;

[0050] Figure 7 is the GDS diagram of the aluminum-plated steel plate before and after hot stamping provided in Example 1 of the present application;

[0051] Figure 8 This is a surface morphology of the phosphate film of the aluminum-plated steel plate after heat treatment provided in Example 1 of the present application;

[0052] Fig. 9 is the energy spectrum of the phosphate film of the aluminum-plated steel plate after heat treatment provided in Example 1 of the present application;

[0053] Fig.10 This is a surface P signal diagram of an aluminum-plated steel plate after phosphating provided in Example 1 of the present application;

[0054] Fig.11 This is the surface P signal diagram of the aluminum-plated steel plate after phosphating provided in Comparative Example 1 of the present application. DETAILED DESCRIPTION

[0055] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0056] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

[0057] Aluminum alloy coated steel is a steel material with an aluminum alloy coating on a substrate. The aluminum alloy coating has excellent corrosion resistance. Due to the high melting point of aluminum, the aluminum alloy coating and the substrate can diffuse rapidly at high temperatures, thereby forming high melting point intermetallic compounds Fe-Al phase and Fe-Al-Si phase. Therefore, it can effectively solve the problem of a large amount of surface oxide scale generated on uncoated steel plates during heating, thereby extending the service life of the mold and improving production efficiency.

[0058] In the coating process of aluminum-plated steel sheets, pretreatment must be performed first, that is, a layer of chemical conversion film is formed on the surface of the aluminum-plated steel sheet to improve the adhesion performance, corrosion resistance and corrosion protection of the electrophoretic paint film. At present, phosphating is a relatively mature and widely used pretreatment technology. However, due to the following reasons, the phosphating performance of aluminum-plated steel sheets is poor: (1) The aluminum alloy coating after degreasing is very easy to be oxidized and easily forms a dense oxide film. At the same time, oxidants are added to the phosphating solution to further promote the formation of a dense oxide film; (2) Compared with steel phosphating film-forming substances such as zinc phosphate and zinc ferrous phosphate, aluminum phosphate is easier to precipitate, that is, it is easy to form slag rather than a phosphating film. Therefore, the adhesion of the paint surface of the components formed by hot stamping of aluminum alloy-plated steel materials in the subsequent preparation is completely guaranteed by the uneven structure of the component surface.

[0059] The present application intends to provide an aluminum-plated steel plate and a preparation method thereof, which improves the performance of hot forming and the coating and corrosion resistance of hot-formed components by thermally spraying zinc-containing metal powder on the aluminum alloy coating surface of the aluminum-plated steel plate to form a zinc-containing alloy layer or a zinc-containing oxide layer. The hot-formed component has a lower friction coefficient, better coating properties and better corrosion resistance, and is suitable for automotive safety parts, such as front / rear door anti-collision beams, bumpers, A / B column reinforcement plates, floor mid-channel and other safety structural parts.

[0060] An embodiment of the present application provides an aluminum-plated steel plate, which includes a substrate, an aluminum-containing coating and a zinc-containing layer, wherein the aluminum-containing coating is attached to the substrate, the zinc-containing layer is attached to a side of the aluminum-containing coating away from the substrate, and the zinc-containing layer includes a zinc-containing alloy layer and / or a zinc-containing oxide layer.

[0061] The aluminum-plated steel sheet has a zinc-containing layer consisting of a zinc-containing alloy layer and / or a zinc-containing oxide layer arranged on the aluminum-containing coating, which is beneficial for reducing the friction coefficient during the hot stamping process, thereby improving the problem that the current aluminum-plated steel sheet is prone to burring or damage to the mold during hot stamping; at the same time, it can improve the phosphating performance, which is beneficial for the subsequent electrophoretic corrosion resistance and adhesion performance, and is beneficial for the adhesion of the paint surface.

[0062] The mechanism by which the zinc-containing layer composed of a zinc-containing alloy layer and / or a zinc-containing oxide layer disposed on the aluminum-containing coating can provide coating performance is as follows: When the aluminum-coated steel sheet with a zinc-containing layer on the surface is immersed in a phosphating solution, the phosphoric acid in the phosphating solution dissociates to form H + and PO4 3- ; Zinc is etched by acid to form Zn 2+ , while H + is consumed, resulting in an increase in local pH; when Zn 2+ PO4 3-When the film-forming substances reach saturation, a phosphating film mainly composed of Zn3(PO4)2·4H2O is formed. The chemical reaction process is as follows:

[0063] Phosphoric acid dissociation: H3PO4 → 3H + +PO4 3- (1)

[0064] Zn→Zn 2+ +2e -

[0065] Acid etching: 2H + +2e - →H2↑(2)

[0066] Phosphate film deposition: 3Zn 2+ +2PO4 3- +4H2O→Zn3(PO4)2·4H2O(3)

[0067] At the same time, even if the zinc in the zinc-containing layer is oxidized to zinc oxide during the heat treatment process, a phosphating film mainly composed of Zn3(PO4)2·4H2O will be generated due to the action of phosphoric acid in the phosphoric acid solution. The chemical reaction process is as follows:

[0068] Phosphate film deposition: 3ZnO+2H3PO4+H2O→Zn3(PO4)2·4H2O(4)

[0069] It can be seen that compared with traditional aluminum alloy coated steel, when a zinc-containing layer is prepared on its surface, since Zn or ZnO are easier to phosphate, the phosphating performance of the aluminum-coated steel plate will be improved to a certain extent, which is beneficial to the subsequent electrophoretic corrosion resistance and adhesion performance, and is beneficial to the adhesion of the paint surface.

[0070] In some embodiments, there is a diffusion bonding layer between the zinc-containing layer and the aluminum-containing coating. The zinc-containing layer is prepared by spraying zinc-containing particles during the preparation process of the aluminum-containing coating (i.e., when the aluminum-containing plating solution is not solidified). In this process, zinc can diffuse to form a diffusion bonding layer, which is beneficial to improving the bonding force between the zinc-containing layer and the aluminum-containing coating.

[0071] In some embodiments, the area coverage of the zinc content of the zinc-containing layer on one side of the aluminum-plated steel plate is greater than 0.5%; the depth of the zinc-containing layer ranges from 0.4 μm to 29 μm; the zinc content of the zinc-containing layer is 0.1 g / m 2 ~8g / m 2 .

[0072] In some embodiments, the aluminum-containing coating comprises an alloy coating containing an Al-Fe-Si system.

[0073] In some embodiments, the aluminum-containing coating includes a plurality of alloy phases and intermetallic compound phases.

[0074] In some embodiments, the aluminum-containing coating has a thickness of 4 μm to 50 μm.

[0075] In some embodiments, the single-sided loading of the aluminum-containing coating is 10 g / m 2 ~100g / m 2 .

[0076] In some embodiments, the chemical composition of the aluminum-containing coating includes, in percentage by mass: Si: 7% to 12%, Fe: 1% to 3%, and the remainder is Al and other inevitable impurities. When the Si content is too large, the roughness of the hot-stamped component obtained based on the aluminum-plated steel plate is too small, and it is not suitable for electrophoretic coating. When the Si content is too small, the coating of the hot-stamped component obtained based on the aluminum-plated steel plate is more likely to crack, resulting in reduced corrosion resistance. Controlling the Si content to 7% to 12% can achieve excellent comprehensive performance of the aluminum alloy coating. At the same time, if the Fe element content is too small, it is easy to cause the dissolution of the steel strip during the hot dip plating process, increasing the risk of strip breakage, while if the Fe element content is too large, it is easy to cause a large amount of aluminum slag to be generated, which will affect the surface quality of the aluminum-plated steel plate.

[0077] In some embodiments, the chemical composition of the substrate includes, by mass percentage, C: 0.05% to 0.4%, Si: 0.05% to 0.3%, Mn: 0.8% to 2%, P≤0.03%, S≤0.01%, Al≤0.5%, N: ≤0.01%, B: 0.0005% to 0.005%, Cr: 0.10% to 0.5%, Ni: 0.001% to 0.5%, Mo: 0.001% to 0.5%, and one or more of Ti0.01% to 0.10%, Nb 0.01% to 0.10% and V 0.02% to 0.15%, and the rest is Fe and unavoidable impurities; the relationship of the chemical composition of the substrate by mass percentage satisfies: 1.5%≤(Cr+Mn+Ni+Mo)≤2.5% and

[0078] 0.5×Mn+Cr+0.5×Ni>0.7%; 0.03%≤(Ti+Nb+V)≤0.30%.

[0079] Generally, when the tensile strength of the substrate is 500MPa to 1200MPa, the mass percentage of the chemical composition of the C element of the substrate is: 0.05% to 0.12%; when the tensile strength of the substrate is 1200MPa to 2200MPa (excluding 1200MPa), the mass percentage of the chemical composition of the C element of the substrate is: 0.18% to 0.40%.

[0080] The functions of each chemical component in the substrate are as follows:

[0081] C is the most effective and cheapest solid solution strengthening element, which can effectively ensure the strength level of hot stamping steel (substrate). At the same time, C is an austenite stabilizing element and can most effectively stabilize austenite.

[0082] When the tensile strength of the substrate is 500MPa-1200MPa, the mass percentage of the chemical composition of the C element of the substrate is: 0.05%-0.12%; at this time, the strength requirement is relatively low, and the toughness can be improved by adding trace amounts of alloy elements.

[0083] When the tensile strength of the substrate is 1200MPa to 2200MPa (excluding 1200MPa), the mass percentage of the chemical composition of the C element of the substrate is: 0.18% to 0.40%. If the mass content of the chemical composition of the C element of the substrate exceeds 0.40%, it is not conducive to obtaining toughness and plasticity; if the mass content of the chemical composition of the C element of the substrate is less than 0.18%, it is not conducive to forming sufficient strengthening effect to obtain stable high dislocation martensite and improve the strength of the substrate.

[0084] Mn is used to increase the austenite region and lower the austenitizing temperature, thereby improving the hardenability of the substrate.

[0085] Cr can significantly increase hardenability and reduce severe oxidation on the high-temperature surface, but it will promote the formation of bainite, so the mass percentage of Cr in the substrate should not be too high.

[0086] Ni can effectively improve hardenability and low-temperature toughness. On the one hand, it can greatly improve the strength of the substrate, and on the other hand, it can always keep the toughness of the substrate at a high level, and the brittle temperature is low. When Ni is combined with Cr and Mo, the hardenability can be increased. Nickel-molybdenum steel also has a higher fatigue limit.

[0087] Mo can refine the grains of steel and improve hardenability. However, the addition of Mo element will increase the cost, so the mass percentage of the chemical composition of Mo element in the substrate can be ≤0.5%.

[0088] Among them, in order to ensure that the substrate has sufficiently high strength, the mass percentage of alloy elements affecting the strength of the substrate can be limited to satisfy (Cr+Mn+Ni+Mo)≥1.5%. In order to take into account the toughness, the mass percentage of alloy elements affecting the hardenability of the substrate can be limited to satisfy (Cr+Mn+Ni+Mo)≤2.5%. At the same time, in order to avoid excessive carbide formation of Cr, the composition design is mainly based on the addition of Mn and Ni to improve their influence factors.

[0089] P is easy to form micro segregation when the steel liquid solidifies, and then segregates to the grain boundary when heated at the austenite post-temperature, which significantly increases the brittleness of the steel and increases the sensitivity to hydrogen-induced delayed fracture. Therefore, the mass percentage of P should be controlled below 0.01%.

[0090] S is an unavoidable impurity. The formation of MnS inclusions and segregation at grain boundaries will deteriorate the toughness of the steel, thereby reducing the toughness and plasticity of the substrate and increasing the sensitivity to hydrogen-induced delayed fracture. Therefore, the mass percentage of S should be controlled below 0.01%.

[0091] N combines with Al, Ti, Nb, V, etc. to form compounds, thereby refining the grains and reducing the sensitivity to hydrogen-induced delayed fracture, but it will also segregate at the grain boundaries and reduce the grain boundary strength. Therefore, the mass percentage of N should be controlled at ≤0.01%.

[0092] Nb, Ti, V combine with C and N to form precipitates, which are mainly used to refine austenite grains. The present application adds a specific component of V element to its alloy composition, so that during the hot stamping process (full austenitization heating temperature range of 850℃~950℃), a certain amount of VC or (V, Ti / Nb)C composite carbides will precipitate at the grain boundaries. Because the second phase particles added to the material effectively pin the austenite grains, the original austenite grains will be refined. If (Ti+Nb+V)>0.3%, it may lead to the coarsening of the precipitate phase, which is not conducive to obtaining a nano-scale dispersed precipitate phase. In addition, after (Ti+Nb+V)>0.0.3%, the precipitation strengthening effect is not significantly improved and the cost is increased. If (Ti+Nb+V)<0.03%, it is insufficient to form sufficient precipitation phases to obtain precipitation strengthening and fine grain strengthening. In addition, the number of H traps formed by the precipitates is also insufficient, and the toughness is reduced.

[0093] The presence of a small amount of B can ensure that the substrate has sufficiently good hardenability.

[0094] Figure 1 A flow chart of the method provided in the embodiment of the present application is as follows: Figure 1 As shown, based on a general inventive concept, an embodiment of the present application also provides a method for preparing an aluminum-plated steel sheet, wherein the aluminum-plated steel sheet is the aluminum-plated steel sheet provided above.

[0095] This method is used for preparing the above-mentioned aluminum-plated steel plate. The specific content of the aluminum-plated steel plate can refer to the above-mentioned embodiment. Since this method adopts part or all of the technical solutions of the above-mentioned embodiment, it at least has all the beneficial effects brought by the technical solutions of the above-mentioned embodiment, which will not be repeated here one by one.

[0096] In some embodiments, the method comprises:

[0097] S1. Rolling the steel billet to obtain a substrate;

[0098] Specifically, in this embodiment, a steel billet with required components is smelted and cast, and then hot rolled, pickled, and cold rolled to obtain a substrate.

[0099] S2. Immersing the substrate in an aluminum-containing plating solution to perform aluminum plating to form an aluminum-containing coating, and spraying zinc-containing particles during the solidification process of the plating solution to form a zinc-containing layer to obtain an aluminum-plated steel sheet, wherein the zinc-containing layer includes a zinc-containing alloy layer and / or a zinc-containing oxide layer.

[0100] Zinc particles are sprayed through the circulation pipeline at high temperature and attached to the surface of the aluminum coating that has not been completely solidified. Figure 2 As shown, it is helpful to reduce the friction coefficient during hot stamping. By forming a zinc-containing layer in a local area on the surface of the aluminum-containing coating, lubricity during hot stamping can be ensured, thereby improving the problem that the aluminum-coated steel sheet is prone to burring or damage to the mold during hot stamping.

[0101] Specifically, in this embodiment, the substrate is continuously annealed and then immersed in an aluminum-containing plating solution to obtain a strip steel having the aluminum-containing coating on the surface. During the solidification process of the aluminum-containing plating solution, zinc-containing particles such as Zn powder or Zn alloy powder are sprayed on the high-temperature aluminum-containing coating, thereby forming a zinc-containing layer attached to the side of the aluminum-containing coating away from the substrate to obtain an aluminum-coated steel sheet. Generally, the following operations can also be performed: the aluminum-coated steel sheet is sequentially straightened, skin-finished and coiled to obtain a steel coil; when it is needed, the steel coil can be uncoiled and blanked to obtain a steel sheet blank.

[0102] In some embodiments, the zinc-containing particles include at least one of zinc powder and zinc alloy powder, and the mass content of zinc in the zinc-containing particles is ≥50%; the particle size of the zinc-containing particles is 300 mesh to 1200 mesh.

[0103] In some embodiments, the zinc-containing layer on a single side of the substrate has an area coverage of ≥80% with a zinc content of greater than 0.5% by mass.

[0104] In some embodiments, the number of zinc-containing particles sprayed on a single surface of the substrate satisfies 10 particles / cm 2 ~500

[0105] / cm 2 If the number of zinc-containing particles sprayed is too small, it is difficult to achieve effective results. If the number of zinc-containing particles sprayed is too large, the zinc oxide content will increase, affecting the surface roughness of the aluminum-coated steel plate, which is not conducive to the coating performance of the aluminum-coated steel plate, and causing defects such as electrophoretic pinholes in the electrophoretic coating.

[0106] In some embodiments, the temperature of the aluminum-containing plating solution is 650°C to 680°C; during the process of spraying the zinc-containing particles, the temperature of the substrate is 550°C to 640°C. By controlling the plating solution temperature to 650°C to 680°C, it is beneficial to ensure that the surface temperature of the aluminum-silicon coated strip steel is 550°C to 640°C during the spraying of the zinc-containing particles. If the temperature of the aluminum-containing plating solution and the substrate is high, it is easy to cause the zinc-containing gold particles to evaporate, affecting the final effect; if the temperature of the aluminum-containing plating solution and the substrate is too low, it is easy to cause the zinc-containing metal particles to fail to diffuse with the aluminum-containing coating, resulting in reduced adhesion of the paint surface of the aluminum-plated steel plate.

[0107] Based on a general inventive concept, an embodiment of the present application further provides a component, the material of which includes the aluminum-plated steel plate provided above.

[0108] This component is prepared based on the above-mentioned aluminum-plated steel plate. The specific content of the aluminum-plated steel plate can refer to the above-mentioned embodiment. Since this component adopts part or all of the technical solutions of the above-mentioned embodiment, it at least has all the beneficial effects brought by the technical solutions of the above-mentioned embodiment, which will not be repeated here one by one.

[0109] The components may be automobile safety parts, such as front / rear door anti-collision beams, bumpers, A / B pillar reinforcement plates, floor mid-channels and other safety structural parts.

[0110] In some embodiments, the method of preparing a component includes:

[0111] S1. heat treating the aluminum-coated steel plate;

[0112] During the hot stamping process, the aluminum-containing coating is highly brittle and will produce cracks, which will reduce the corrosion resistance of the formed component after painting. When the hot stamping forming temperature is higher than 650°C, the forming resistance of the aluminum-plated steel plate can be effectively reduced, and the risk of cracking of the aluminum-containing coating in the aluminum-plated steel plate can be reduced. As the holding time of hot stamping increases, the ratio of iron-aluminum alloy phase on the surface of the aluminum-plated steel plate will increase, resulting in a decrease in roughness. Therefore, the upper limit of the holding temperature and holding time of hot stamping is limited to 960°C / 500s. In some embodiments, the heat treatment includes a first heat treatment and a second heat treatment, the temperature of the first heat treatment is 650°C to 900°C, and the time of the first heat treatment is 30s to 150s; the temperature of the second heat treatment is 900°C to 960°C, and the time of the second heat treatment is 200s to 400s.

[0113] In some embodiments, the heating rate of the heat treatment does not exceed 15°C / s; the time in the furnace for the heat treatment is 250s to 500s. By limiting the heating rate of the heat treatment or the time for alloying, the Fe element in the substrate can enter the aluminum-containing coating at a lower temperature, increase the melting point of the aluminum-containing coating and reduce the emissivity. If the heating efficiency at high temperature is increased and the heating rate is too fast, it is easy to cause the evaporation of zinc-containing particles.

[0114] Specifically, in this embodiment, the aluminum-coated steel plate is placed in a heating furnace for heating and insulation in the heat treatment step of the manufacturing process of the hot-formed parts, including but not limited to a box furnace or a tunnel roller hearth furnace. During the heating process of the heating furnace, the aluminum-coated steel plate is heated in a furnace at 650°C to 900°C for 30s to 150s, and the heating rate does not exceed 15°C / s; then it continues to stay at a furnace temperature of 900°C to 960°C for 200s to 400s, and the total time in the furnace is 250 to 500s.

[0115] During the above heat treatment process, the atmosphere in the heating furnace is dry air or nitrogen. The total heat treatment time in the furnace is controlled to be 250s to 500s, and the maximum temperature of the heat treatment is controlled to be 960°C, which can ensure the roughness of the finished aluminum-plated steel plate and ensure that the components have a sufficient degree of austenitization. If the temperature is too high, it is easy to cause cracks in the aluminum-plated steel plate, thereby reducing the corrosion resistance of the stamped components after painting. If the heat treatment time is too long, it is easy to cause an increase in the proportion of the iron-aluminum alloy phase on the surface of the aluminum-plated steel plate, which in turn leads to a decrease in the roughness of the aluminum-plated steel plate.

[0116] S2. The aluminum-plated steel sheet after heat treatment is subjected to stamping to obtain a component.

[0117] In some embodiments, the temperature of the stamping forming is ≥650°C; the holding pressure of the stamping forming is ≥5MPa; the holding time of the stamping forming is >5s; and the end temperature of the stamping forming is ≤160°C.

[0118] Specifically, in this embodiment, the heat-treated blank is transferred to the mold within 3s to 15s after being taken out of the furnace, and the hot stamping forming temperature is ≥650℃; the holding pressure of the sheet during stamping is ≥5MPa, and the holding time is ≥5s; the component temperature is ≤160℃ after the mold is opened.

[0119] After heat treatment, the yield strength of the component is 350MPa-1400MPa, the tensile strength is 500-2200MPa, and the elongation is ≥4%; when the component is used for automobile structural parts, after the white body is painted and baked, the yield strength is 400-1600MPa, the tensile strength is 450MPa-2100MPa, and the elongation is ≥5%.

[0120] After painting, the component has no cracking or peeling on the paint surface, and the cupping and other properties meet the requirements; the corrosion resistance is good, there is no blistering or peeling, and the paint adhesion meets the requirements. It is suitable for automotive safety parts, such as front / rear door anti-collision beams, bumpers, A / B column reinforcement plates, floor mid-channels and other safety structural parts.

[0121] The present application will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are intended only to illustrate the present application and are not intended to limit the scope of the present application. The experimental methods for which specific conditions are not specified in the following examples are usually measured according to national standards. If there is no corresponding national standard, then the conditions recommended by the manufacturer are followed.

[0122] Examples and Comparative Examples

[0123] A component, the preparation process of which is as follows:

[0124] (1) A steel billet with the required composition is smelted and cast, and then hot-rolled, pickled, and cold-rolled to obtain a substrate; the chemical composition of the substrates of each embodiment and comparative example is shown in the following table:

[0125]

[0126] In the table, “-” means that the substance is not contained.

[0127] In the table, the chemical composition of the substrate includes Fe and unavoidable impurities, the remainder of which is not shown.

[0128] (2) After continuous annealing, the substrate is immersed in an aluminum-containing plating solution to obtain a steel strip (substrate) having an aluminum-containing coating on the surface. During the solidification process of the aluminum-containing plating solution, zinc-containing Zn powder is sprayed onto the high-temperature substrate. The chemical composition of the plating solution and the parameter control of the Zn powder in each embodiment and comparative example are shown in the following table:

[0129]

[0130] In the table, “-” means not to perform the operation.

[0131] (3) straightening, skin-passing and coiling the aluminum-coated steel strip in sequence to obtain a steel coil; uncoiling and blanking the steel coil to obtain a steel plate blank;

[0132] (4) heat treating the blank; quickly transferring the heat treated blank to a mold for cooling and stamping to obtain a hot formed component. The heat treatment and stamping parameters of each embodiment and comparative example are shown in the following table:

[0133]

[0134]

[0135] In the table, “-” means not to perform the operation.

[0136] The performance of the components provided in each embodiment and comparative example was tested, and the results are shown in the following table.

[0137]

[0138] In the table, “-” means that the operation is not performed or the structural layer is not included.

[0139] As can be seen from the above table, the high temperature friction coefficient of the components provided by Examples 1 to 4 is lower than that of the components provided by Comparative Examples 1 to 2 without zinc powder spraying, and the quality of the phosphating film is significantly improved. The maximum corrosion width at the cross-section of the electrophoretic paint film of Comparative Example 2 is low after 1000h of neutral salt spray test, but the coating thickness is thick, which seriously affects the welding performance and easily causes spatter.

[0140] After the aluminum-coated steel plate has passed through the first heat treatment, the second heat treatment and the stamping forming treatment, a certain amount of mutual diffusion will occur between the aluminum-containing coating and the substrate to form a coating alloy layer mainly including aluminum and iron. The thickness of the coating alloy layer in the embodiment of the present application can be 6μm~8μm; the formation of the coating alloy layer reduces the thickness of the substrate and increases the total coating thickness (the sum of the aluminum-containing coating and the coating alloy layer). The total coating thickness in the embodiment of the present application can be 20μm~28μm; a certain amount of mutual diffusion will also occur between the zinc-containing layer and the aluminum-containing coating to form a diffusion bonding layer; the zinc-containing layer containing a zinc-containing alloy layer and / or a zinc-containing oxide layer diffuses into the aluminum-containing coating, thereby increasing the thickness of the zinc-containing layer. The thickness of the zinc-containing layer in the embodiment of the present application can be 12μm~24.5μm.

[0141] Detailed description of the attached drawings:

[0142] Figures 3 to 6 They are the SEM images and energy spectrum diagrams of the aluminum-plated steel plate before and after hot stamping provided in Example 1. It can be seen from the figures that before stamping, mainly zinc powder particles are attached to the surface of the coating, and a certain degree of mutual diffusion occurs, which can improve the bonding strength.

[0143] Figure 7 This is the GDS diagram of the aluminum-plated steel plate before and after hot stamping provided in Example 1 of the present application. It can be seen from the figure that the thickness of the zinc-containing alloy layer and / or zinc-containing oxide layer on the surface of the aluminum-containing coating of the aluminum-plated steel plate before stamping is about 16 μm. The thickness of the zinc-containing alloy layer and / or zinc-containing oxide layer on the surface of the aluminum-containing coating of the component obtained after stamping of the aluminum-plated steel plate is about 12 μm.

[0144] Figures 8 to 9 They are respectively the morphology and energy spectrum of the phosphate film of the aluminum-plated steel plate after heat treatment provided in Example 1, Fig.10 and Fig.11The surface P signal diagrams of the aluminum-plated steel plates after phosphating provided in Example 1 and Comparative Example 1 respectively show that the components can form a good phosphorus film, which is beneficial to the adhesion of the paint surface.

[0145] Various embodiments of the present application may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be understood as a rigid limitation on the scope of the present application; therefore, the range description should be considered to have specifically disclosed all possible sub-ranges and single numerical values ​​within the range. For example, the range description from 1 to 6 should be considered to have 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., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which apply regardless of the range. In addition, whenever a numerical range is indicated herein, it is meant to include any cited number (fractional or integer) within the indicated range.

[0146] In the present application, in the absence of any contrary description, the directional words used, such as "upper" and "lower", are specifically the directions of the drawings in the accompanying drawings. In addition, in the description of the present specification, the terms "including", "comprising", etc. refer to "including but not limited to". In this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. In this article, "and / or" describes the association relationship of the associated objects, indicating that there may be three relationships, for example, A and / or B, which can represent: A exists alone, A and B exist at the same time, and B exists alone. Wherein A, B can be singular or plural. In this article, "at least one" refers to one or more, and "plural" refers to 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 singular 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 single or multiple.

[0147] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. An aluminum-plated steel plate, characterized in that: The steel plate includes a substrate, an aluminum-containing coating and a zinc-containing layer, wherein the aluminum-containing coating is attached to the substrate, the zinc-containing layer is attached to a side of the aluminum-containing coating away from the substrate, and the zinc-containing layer includes a zinc-containing alloy layer and / or a zinc-containing oxide layer.

2. The aluminum-plated steel sheet according to claim 1, characterized in that: A diffusion bonding layer exists between the zinc-containing layer and the aluminum-containing coating layer.

3. The aluminum-plated steel sheet according to claim 1, characterized in that: The zinc-containing layer on one side of the steel plate has an area coverage of more than 80% by mass of zinc content greater than 0.5%; and / or The depth of the zinc-containing layer ranges from 0.4 μm to 29 μm; and / or The zinc content of the zinc-containing layer is 0.1 g / m 2 ~8g / m 2 .

4. The aluminum-plated steel sheet according to claim 1, characterized in that: The aluminum-containing coating comprises an alloy coating containing an Al-Fe-Si system; and / or The aluminum-containing coating comprises a plurality of alloy phases and intermetallic compound phases; and / or The thickness of the aluminum-containing coating is 4 μm to 50 μm; and / or The single-sided loading of the aluminum-containing coating is 10 g / m 2 ~100g / m 2 ; and / or The chemical composition of the aluminum-containing coating includes, by mass percentage, Si: 7% to 12%, Fe: 1% to 3%, and the remainder is Al and other inevitable impurities.

5. The aluminum-plated steel sheet according to claim 1, characterized in that: The chemical composition of the substrate comprises, by mass percentage, C: 0.05% to 0.4%, Si: 0.05% to 0.3%, Mn: 0.8% to 2%, P≤0.03%, S≤0.01%, Al≤0.5%, N:≤0.01%, B: 0.0005% to 0.005%, Cr: 0.10% to 0.5%, Ni: 0.001% to 0.5%, Mo: 0.001% to 0.5%, and one or more of Ti 0.01% to 0.10%, Nb 0.01% to 0.10% and V 0.02% to 0.15%, and the rest is Fe and unavoidable impurities; and / or The chemical composition of the substrate, in terms of mass percentage, satisfies the following relationship: 1.5%≤(Cr+Mn+Ni+Mo)≤2.5% and 0.5×Mn+Cr+0.5×Ni>0.7%; 0.03%≤(Ti+Nb+V)≤0.30%.

6. A method for preparing an aluminum-plated steel plate, characterized in that: The aluminum-plated steel sheet is the aluminum-plated steel sheet according to any one of claims 1 to 5; the method comprises: Rolling the steel billet to obtain a base plate; The substrate is immersed in an aluminum-containing plating solution to perform aluminum plating to form an aluminum-containing coating, and zinc-containing particles are sprayed during the solidification process of the aluminum-containing plating solution to form a zinc-containing layer to obtain an aluminum-plated steel sheet, wherein the zinc-containing layer includes a zinc-containing alloy layer and / or a zinc-containing oxide layer.

7. The method for preparing an aluminum-plated steel sheet according to claim 6, characterized in that: The zinc-containing particles include at least one of zinc powder and zinc alloy powder, and / or The mass content of zinc in the zinc-containing particles is ≥ 50%; and / or The zinc-containing particles have a particle size of 300 to 1200 mesh; and / or The zinc-containing particles make the area coverage of the zinc-containing layer on one side of the substrate with a zinc content greater than 0.5% by mass greater than 80%; and / or The temperature of the aluminum-containing plating solution is 650° C. to 680° C.; and / or During the spraying of the zinc-containing particles, the temperature of the substrate is 550°C to 640°C.

8. A component, characterized in that: The material of the component includes the aluminum-plated steel sheet according to any one of claims 1 to 5.

9. A method for preparing a component, characterized in that: The method comprises: Obtaining the aluminum-plated steel sheet according to any one of claims 1 to 5; heat treating the aluminum-plated steel plate; The aluminum-plated steel sheet after heat treatment is stamped to obtain a component.

10. The method for preparing a component according to claim 9, characterized in that: The heat treatment includes a first heat treatment and a second heat treatment, wherein the temperature of the first heat treatment is 650°C to 900°C, and the time of the first heat treatment is 30s to 150s; the temperature of the second heat treatment is 900°C to 960°C, and the time of the second heat treatment is 200s to 400s; and / or The heating rate of the heat treatment does not exceed 15°C / s; and / or The heat treatment time in the furnace is 250s to 500s; and / or The stamping temperature is ≥ 650°C; and / or The holding pressure of the stamping forming is ≥5MPa; and / or The holding time of the stamping molding is ≥5s; and / or The final temperature of the stamping process is ≤160°C.

Images