High collision energy absorption 550MPa level zinc-based coated steel plate, manufacturing method thereof, hot forming method and component

Abstract

The invention provides a high collision energy absorption 550MPa grade zinc-based coated steel plate which comprises a base plate and a coating, the base plate comprises the following components in percentage by weight: 0.05%-0.09% of C, 0.15%-0.45% of Si, 1.20%-2.50% of Mn, less than or equal to 0.02% of P, less than or equal to 0.02% of S, 0.03%-0.06% of Al, 0.02%-0.10% of Nb, 0.02%-0.10% of Ti, 0.15%-0.60% of Cr, and Fe and other inevitable impurities; and the plating layer comprises the following components in percentage by mass: 0.15%-3.50% of Al and the balance of Zn. The invention further provides a manufacturing method of the 550MPa-grade zinc-based coated steel plate with the high collision energy absorption. The manufacturing method comprises the steps of smelting, casting, hot rolling and hot dipping. The invention further discloses a hot stamping method of the 550MPa-grade zinc-based coated steel plate with the high collision energy absorption. The hot stamping method comprises the steps of steel plate heating, steel plate cooling and hot stamping. According to the hot stamping forming part produced through the method, the tensile strength is larger than 550 MPa, the yield strength is larger than 370 MPa, liquid-phase brittleness and liquid-phase cracks do not exist, and the hot stamping forming part has good obdurability, excellent corrosion resistance and high collision energy absorption performance.

Description

Technical Field

[0001] This invention relates to a coated steel sheet, and more particularly to a high-impact energy absorption 550MPa grade zinc-based coated steel sheet, its manufacturing method, hot forming method, and components. Background Technology

[0002] One of the development trends in hot-formed steel parts is integral forming, such as single-door rings, double-door rings, and rear floor beams. Some integrally formed parts require ultra-high strength, necessitating the use of materials with a strength of 1500MPa or higher, while others require good deformability, sufficient strength, and other comprehensive mechanical properties. 550MPa grade hot-formed steel possesses good deformability and a good combination of strength and toughness, meeting the basic requirements for soft areas in integrally formed hot-stamped parts.

[0003] Since hot forming is carried out at high temperatures, steel sheets inevitably oxidize, requiring subsequent methods such as sandblasting and pickling to remove the iron oxide scale. To address this issue, aluminum-silicon coated hot-formed steel sheets have been developed. The aluminum-silicon coating can provide protection for the steel sheet at high temperatures, preventing the formation of iron oxide scale. However, the aluminum-iron intermetallic compound formed by the reaction between the coating and the steel substrate during hot stamping is a brittle and hard phase and cannot provide electrochemical protection for the substrate.

[0004] Therefore, zinc-based coated hot-formed steel sheets were proposed. Compared with traditional aluminum-silicon coated hot-formed steel sheets, zinc-based coated hot-formed steel sheets have better corrosion resistance. However, due to the low melting point of iron-zinc compounds, liquid phase embrittlement can occur during the stamping process, leading to cracking and failure of parts.

[0005] To address these issues, this invention provides a hot stamping method for 550MPa grade zinc-based coated steel sheets and a zinc-based coated hot-formed steel sheet. The formed parts possess the protective effect of the pure zinc coating on the steel sheet, while simultaneously solving the problem of liquid phase corrosion of the steel substrate by the pure zinc coating. It also exhibits good impact energy absorption properties and can be used as a soft area material for integral hot-formed parts. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the purpose of this invention is to provide a high-impact energy absorption 550MPa grade zinc-based coated steel sheet, its manufacturing method, hot forming method, and components. The hot-stamped parts produced by the method of this invention do not exhibit liquid phase brittleness or liquid phase cracks, and possess good strength and toughness, while also exhibiting excellent corrosion resistance and high impact energy absorption performance.

[0007] The objective of this invention is achieved as follows:

[0008] This invention provides a high-impact energy absorption 550MPa grade zinc-based coated steel sheet, comprising a substrate and a coating, as detailed below:

[0009] The zinc-based plated steel plate substrate, in terms of mass percentage, comprises the following chemical components: C: 0.05% to 0.09%, Si: 0.15% to 0.45%, Mn: 1.20% to 2.50%, P≤0.02%, S≤0.02%, Al: 0.03% to 0.06%, Nb: 0.02 to 0.10%, Ti: 0.02 to 0.10%, Cr: 0.15% to 0.60%, and Fe and other inevitable impurities.

[0010] Further, the substrate components further comprise one or more of the following elements: B≤0.005%, Mo≤1.00%, Cu≤0.50%, Ni≤1.00%;

[0011] Further, the zinc-based plated steel plate substrate, in terms of mass percentage, comprises the following chemical components: C: 0.05% to 0.09%, Si: 0.15% to 0.45%, Mn: 1.20% to 2.50%, P≤0.02%, S≤0.02%, Al: 0.03% to 0.06%, Nb: 0.02 to 0.10%, Ti: 0.02 to 0.10%, Cr: 0.15% to 0.60%, and Fe and other inevitable impurities.

[0012] Further, the zinc-based plated steel plate substrate, in terms of mass percentage, comprises the following chemical components: C: 0.05% to 0.09%, Si: 0.15% to 0.45%, Mn: 1.20% to 2.50%, P≤0.02%, S≤0.02%, Al: 0.03% to 0.06%, Nb: 0.02 to 0.10%, Ti: 0.02 to 0.10%, Cr: 0.15% to 0.60%, and Fe and other inevitable impurities.

[0013] The component design reasons of the elements in the steel plate substrate are as follows:

[0014] C: 0.05% to 0.09%

[0015] C, as the main alloying element, contributes most to the strength of the quenched martensitic steel, provides strength, and forms precipitates with Nb and Ti elements in the steel to improve strength and refine grains; when the content is lower than 0.05%, sufficient martensite, bainite and other low-temperature transformation phases cannot be formed after hot forming; when the content is higher than 0.09%, the hardenability of the steel is improved, the strength of the steel after hot forming is much greater than 550 MPa, and the plasticity and toughness of the steel decrease, which cannot provide sufficient impact energy absorption.

[0016] Si: 0.15% to 0.45%

[0017] Si mainly inhibits the appearance of cementite, ensures that austenite does not undergo pearlite transformation during the cooling process, and exists at a relatively low temperature; at the same time, it solid solution strengthens the steel matrix to improve the strength. When the content of Si is lower than 0.15%, the stability of austenite during hot stamping is not enough, and pearlite transformation is prone to occur; when the content of Si is higher than 0.45%, selective oxidation occurs during continuous hot dipping, forming Si oxides on the surface of the steel plate, which affects the hot dipping performance of the steel.

[0018] Mn: 1.20% to 2.50%

[0019] The main role of Mn is to expand the austenite phase region, so that the zinc-based plated hot forming steel plate can be hot stamped at a lower temperature range, and martensite structure can also be obtained, while solid solution strengthening the steel matrix to improve the strength. When the content of Mn is lower than 1.20%, the strength of the steel is lower, and the austenite state cannot be maintained at the hot stamping temperature. When the content of Mn is higher than 2.50%, the austenite content is too high during the hot stamping process, and the strength of the steel is higher than the requirement of 550 MPa grade.

[0020] Al: 0.03% to 0.06%

[0021] The addition of Al can inhibit the formation of cementite.

[0022] Ti: 0.02 to 0.10%, Cr: 0.15% to 0.60%, B≤0.005%

[0023] In order to ensure the hardenability, Ti, Cr and B are added. Cr and Si elements can prevent the erosion of the liquid Zn coating on the steel matrix during the hot stamping heating and holding process, reduce the liquid phase brittleness, and thus improve the performance of the zinc-based plated hot forming steel plate.

[0024] Cu≤0.50%

[0025] The addition of Cu improves the corrosion resistance of the steel, thereby preventing the penetration of H and improving the resistance to delayed fracture of the steel.

[0026] Mo≤1.00%, Nb: 0.02 to 0.10%

[0027] The addition of Mo and Nb strengthens the steel matrix and refines the grain.

[0028] The addition of Mo, Ti and Nb can form fine and dispersed precipitates such as TiN, TiC and NbC in the steel, which form hydrogen traps during service and improve the resistance to delayed fracture of the steel.

[0029] Ni≤1.00%

[0030] The addition of Ni can improve the toughness of the steel, improve the corrosion resistance of the steel, reduce the diffusion rate of H, and improve the resistance to delayed fracture.

[0031] The reasons for the composition design of the elements in the zinc-based plated steel plate are as follows:

[0032] Al: 0.15% to 3.50%

[0033] The addition of Al can generate aluminum trioxide covering the surface of the plated layer during the heating and holding process of the hot forming of the steel plate, forming a protective layer to prevent further oxidation of the plated layer. An Fe-Al phase is formed at the interface between the plated layer and the steel substrate, and the presence of the Fe-Al phase can delay the erosion of the liquid phase of the zinc layer relative to the steel substrate (especially the grain boundary of the steel) during the heating and holding process of the hot stamping, reduce the brittleness of the liquid phase, and improve the forming performance and bending performance of the steel. When the aluminum content is less than 0.15%, an Fe-Al inhibiting layer cannot be formed to ensure the adhesion of the plated layer, and when the aluminum content is greater than 3.50%, a thick aluminum trioxide covering layer is formed on the surface, which affects the later coating pretreatment.

[0034] Mg: 1.0% to 2%

[0035] The addition of Mg can greatly improve the corrosion resistance of the plated layer, and the magnesium oxide generated by the oxidation of Mg can also cover the surface of the plated layer to form a protective layer to prevent further oxidation of the plated layer.

[0036] Si: 0.05% to 0.50%

[0037] Si is enriched in the intermetallic compound layer, which hinders the mutual diffusion of Fe and Zn atoms through the liquid phase channel, can form a compact inhibiting layer structure, thereby reducing or even eliminating the liquid phase erosion of the plated layer on the steel substrate, and can refine the structure of the plated layer and improve the performance of the plated layer.

[0038] Ti: 0.03% to 0.50%

[0039] The addition of Ti can improve the corrosion resistance of the plated layer, and in addition, Ti can form a protective film of titanium oxide, which has strong bonding force with the substrate, good protection performance, and can repair damage by itself. The addition of Si and Ti together can generate a more compact inhibiting layer to improve the ability of the steel plate to resist liquid phase corrosion. Ti can form intermetallic compounds with Al to improve the hardness of the plated layer,

[0040] Re: 0.01% to 0.10%

[0041] The addition of Re can improve the corrosion resistance of the plated layer, refine the grains, and facilitate the formation of a dense oxide film on the surface of the plated layer to provide protection during the hot stamping process.

[0042] Mn: 0.5% to 3.0%

[0043] The addition of Mn can improve the corrosion resistance of the plated layer, refine the grains, and improve the hardness of the plated layer.

[0044] The second technical scheme of the present application provides a manufacturing method of a 550MPa grade zinc-based plated steel plate with high collision energy absorption, which comprises smelting, casting, hot rolling, pickling and cold rolling, and hot dip plating.

[0045] Hot rolling process:

[0046] 1220±40℃ heating, holding for 180±90 minutes, 1100±40℃ rough rolling, 1060±40℃ finish rolling, 870±40℃ final rolling, 450-750℃ coiling;

[0047] 1220±40℃ heating, holding for 180±90 minutes, ensuring uniform composition of the cast blank, sufficient dissolution of Nb, Ti and other precipitates, 1100±40℃ rough rolling, ensuring sufficient deformation capacity, 1060±40℃ finish rolling, ensuring good phosphorus removal performance, 870±40℃ final rolling, conducive to obtaining relatively uniform and fine grain structure, 450-750℃ coiling, reducing the thickness of the iron oxide scale, facilitating pickling, forming fine and uniformly distributed second phase precipitates, ensuring uniform distribution of C, Mn and other elements in the steel, ensuring consistency of steel properties.

[0048] Pickling and cold rolling:

[0049] The iron oxide scale is completely removed by pickling, and the cold rolling reduction is 30%-70%, greater than 70% rolling is difficult, and less than 30% grain refinement is not obvious.

[0050] Hot dipping process:

[0051] The composition of the plating solution is: Al: 0.15-3.50%, the rest is Zn; it can also include one or more of Mg: 1.0-2%, Si: 0.05-0.50%, Ti: 0.03-0.50%, Re: 0.01-0.10%, Mn: 0.5-3.0%;

[0052] The hot dipping heating temperature is controlled at 750-900℃, and the zinc pot temperature is 450-520℃. The steel plate is pre-oxidized during heating, specifically at a temperature range of 600-750℃, using an oxidizing atmosphere (such as a high dew point furnace atmosphere above zero degrees, a high oxygen content furnace atmosphere) to pre-oxidize the surface of the steel plate, forming an oxide film mainly composed of iron oxide on the surface of the steel plate, which is reduced to active iron during subsequent heating and holding. The active iron is easy to react with aluminum in the zinc pot to produce an alloy layer mainly composed of aluminum-iron, inhibiting the formation of Si and Mn oxides, and improving the platability of the steel.

[0053] The third technical solution of the present application provides a hot forming method for a high-impact energy-absorbing 550MPa grade zinc-based plated steel plate, including steel plate heating, steel plate cooling, and hot stamping.

[0054] 1) Steel sheet heating: the zinc-based plated hot-formed steel sheet is fed into a heating furnace, the total heating and holding time is 180 seconds to 600 seconds, the heating temperature is 800-930 °C, preferably 850-890 °C; less than 180 seconds, the austenitization of the steel sheet is not sufficient, and the reaction between the coating and the steel substrate is not sufficient, which cannot be completely converted into Fe-Zn intermetallic compound, more than 600 seconds, which will cause the austenite grain to be coarsened, which will deteriorate the performance of the steel, at the same time, the Fe-Zn intermetallic compound in the coating will be completely converted into α-Fe(Zn) solid solution, which will reduce the corrosion resistance of the steel, and a very thick α-Fe layer will be formed, which will greatly reduce the strength of the steel. Less than 800 °C, the austenitization cannot be achieved, and the alloying of the coating is not sufficient. More than 930 °C, the effect is the same as the holding time being too long.

[0055] 2) Steel sheet cooling: after the holding of the steel sheet is completed, the steel sheet is cooled to the hot stamping temperature to start stamping, the target temperature range for cooling is 500-850 °C, preferably 600-720 °C, and the cooling speed is greater than 10 °C / s; the target temperature for cooling is less than 500 °C, which will cause the decomposition of austenite, and the target temperature for cooling is higher than 850 °C, the Fe-Zn intermetallic compound is in a liquid state, which will cause liquid brittleness, which can be completely avoided below 720 °C. The purpose of the cooling speed greater than 10 °C / s is to ensure that there is austenite in the steel.

[0056] 3) Hot stamping: the steel sheet is immediately subjected to hot stamping after being cooled to the hot stamping temperature, the cooling speed of the hot stamping is greater than 15 °C / s, and the cooling end temperature is controlled at 120-280 °C, preferably 150-200 °C. The cooling end temperature is controlled above 120 °C, which can utilize the residual heat to perform aging treatment on the part after the stamping is completed, which will improve the toughness of the part to a certain extent; the cooling end temperature is controlled below 280 °C, because above 280 °C, the transformation of martensite is not complete, and the residual heat aging temperature is too high, which will reduce the strength of the steel.

[0057] Further, the heating temperature in the steel sheet heating process is 850-890 °C; the target temperature range for cooling in the steel sheet cooling process is 600-720 °C; and the cooling end temperature in the hot stamping process is 150-200 °C.

[0058] The fourth technical scheme of the present application provides a hot formed part made of the high-impact energy 550MPa grade zinc-based plated steel sheet, the steel base structure of the part is composed of ferrite + martensite + residual austenite + bainite, the content of the martensite is 10% to 30%, the content of the bainite is 5% to 20%, the residual austenite is less than 5%, and the rest is ferrite. The microstructure of the surface of the part has four layers (from the surface to the steel base body in turn), the first layer is a surface oxide layer: aluminum oxide + zinc oxide + iron oxide + manganese oxide and other oxides; the second layer is an iron-zinc intermetallic compound layer; the third layer is an α-Fe(Zn) solid solution layer, the content of Zn is greater than 5%, and the thickness ranges from 10um to 50um; and the fourth layer is a steel base body layer.

[0059] The second layer of intermetallic compound and the third layer of α-Fe(Zn) solid solution layer will preferentially corrode the base body electrochemically, and play a cathodic protection role on the base body. The α-Fe(Zn) solid solution layer has good plasticity and toughness, can reduce or even eliminate the generation and expansion of microcracks, and improve the toughness of the product.

[0060] The present application has the beneficial effects that:

[0061] The present application adopts high manganese component design combined with low temperature hot stamping process design, so that the steel sheet hot formed part has excellent impact energy absorption performance, and the specific performance parameters are as follows:

[0062] 1. The tensile strength of the hot formed part is greater than 550MPa, the complementary yield strength, and the elongation is greater than 20%.

[0063] 2. The plating layer is completely converted into a zinc-iron alloy layer, there is no plating layer evaporation phenomenon, no liquid phase corrosion phenomenon, and no hard Fe-Al intermetallic compound.

[0064] 3. The part of the present application has good deformation capacity and can meet the requirement of 180 degree bending.

[0065] 4. The steel base structure of the hot formed part of the present application is ferrite + martensite + residual austenite + bainite, the content of the martensite is 10% to 30%, the content of the bainite is 5% to 20%, the residual austenite is less than 5%, and the rest is ferrite. DETAILED DESCRIPTION

[0066] The present application will be further described below through examples.

[0067] A manufacturing method of a high-impact energy 550MPa grade zinc-based plated steel sheet, comprising smelting, casting, hot rolling, and hot dip plating.

[0068] Hot rolling process:

[0069] 1220±40℃ heating, holding for 180±90 minutes, 1100±40℃ rough rolling, 1060±40℃ finish rolling, 870±40℃ final rolling, 450-750℃ coiling;

[0070] hot-dip plating process:

[0071] The plating solution composition is Al: 0.15-3.50%, the rest is Zn; and further includes one or more of Mg: 1.0-2%, Si: 0.05-0.50%, Ti: 0.03-0.50%, Re: 0.01-0.10%, Mn: 0.5-3.0%;

[0072] The hot-dip plating heating temperature is 750-900℃, the zinc pot temperature is 450-520℃; the steel plate is pre-oxidized during heating, specifically, the steel plate surface is pre-oxidized using an oxidizing atmosphere at a temperature range of 600-750℃.

[0073] A hot stamping method of a high-impact energy 550MPa grade zinc-based plated steel plate, comprising steel plate heating, steel plate cooling, hot stamping,

[0074] Steel plate heating:

[0075] The zinc-based plated hot-formed steel plate is sent into a heating furnace for heating, the total heating and holding time is 180-600 seconds, and the heating temperature is 800-930℃.

[0076] Steel plate cooling:

[0077] After the steel plate holding is completed, the steel plate is cooled to the hot stamping temperature to start stamping, the target temperature range of the cooling is 500-850℃, and the cooling speed is greater than 10℃ / s.

[0078] Hot stamping: the hot stamping is immediately performed after the steel plate is cooled to the hot stamping temperature, the hot stamping cooling speed is greater than 15℃ / s, and the cooling end temperature is between 120-280℃.

[0079] Further, the heating temperature during the steel plate heating is preferably 850-890℃; the target temperature range of the cooling during the steel plate cooling is preferably 600-720℃; and the cooling end temperature during the hot stamping is preferably 150-200℃.

[0080] A part made by the hot stamping method of a high-impact energy 550MPa grade zinc-based plated steel plate, the steel base structure of the part is composed of ferrite + martensite + residual austenite + bainite, wherein the martensite content is 10%-30%, the bainite content is 5%-20%, the residual austenite is less than 5%, and the rest is ferrite.

[0081] Further, the microstructure of the component surface has four layers from the surface to the steel substrate, and the four layers are layer 1, layer 2, layer 3 and layer 4 in sequence, the layer 1 is a surface oxide layer, the layer 2 is an iron-zinc intermetallic compound layer, the layer 3 is an alpha-Fe(Zn) solid solution layer, the content of Zn is greater than 5%, and the thickness ranges from 10um to 50um, and the layer 4 is a steel substrate layer.

[0082] Further, the tensile strength of the component is greater than 550MPa, the yield strength is greater than 370MPa, and the elongation is greater than 20%, and the component has good deformation capacity and can meet the requirement of 180-degree bending.

[0083] The embodiment of the present application is shown in Tables 1, 2, 3, 4 and 5

[0084] Table 1: Chemical element composition of the plated layer of the embodiment

[0085] Al Mg Ti Si Mn Re Zn 1 0.20 1.0 balance 2 0.22 0.4 0.09 balance 3 0.17 1.0 balance 4 2.15 1.5 0.05 0.20 balance 5 1.41 0.10 2.8 balance 6 0.18 0.05 balance 7 3.33 1.2 0.30 balance 8 0.22 2.0 0.50 0.07 balance 9 0.2 0.80 balance 10 0.15 balance

[0086] Table 2: Chemical composition of the steel of the embodiment

[0087] C Si Mn P S Al Ni Cu Cr Mo B Nb Ti Fe 1 0.05 0.45 1.8 0.010 0.008 0.03 0.35 0.5 0.001 0.037 0.03 balance 2 0.06 0.39 1.5 0.011 0.005 0.04 0.3 0.3 0.03 0.035 balance 3 0.07 0.30 1.4 0.010 0.004 0.05 0.25 0.55 0.002 0.031 0.04 balance 4 0.08 0.25 1.3 0.013 0.010 0.06 0.25 0.02 0.08 balance 5 0.09 0.15 1.2 0.010 0.012 0.03 0.35 0.08 0.02 balance 6 0.05 0.27 2.4 0.015 0.006 0.04 0.45 0.3 0.5 0.05 0.03 balance 7 0.06 0.22 1.8 0.010 0.009 0.05 0.5 0.15 0.2 0.04 0.038 balance 8 0.07 0.24 1.6 0.017 0.007 0.06 0.4 0.2 0.04 0.07 balance 9 0.08 0.20 1.7 0.010 0.005 0.03 0.4 0.002 0.05 0.02 balance 10 0.09 0.4 2.0 0.008 0.003 0.04 0.3 0.45 0.02 0.05 balance

[0088] Table 3: Partial data of the steel manufacturing method of the embodiment

[0089]

[0090] Table 4: Process parameters and properties of the steel of the embodiment

[0091]

[0092] Table 5: Microstructure and plated layer of the hot-formed component

[0093]

[0094] As can be seen from the above, the tensile strength of the steel plate of the present application is greater than 550MPa, and the elongation is greater than 20%. The plated layer is completely converted into a zinc-iron alloy layer, and there is no plated layer evaporation phenomenon, no liquid phase erosion phenomenon, and no hard Fe-Al intermetallic compound. The stamping temperature is in a large range of 400-750 degrees. The performance emphasizes good deformation capacity, and can meet the requirement of 180-degree bending.

[0095] In order to describe the present application, the above embodiment is described appropriately and sufficiently in the above embodiment, the above embodiment is only used for describing the present application, and is not limited to the present application. Any modification, equivalent replacement, improvement and the like made by ordinary skilled in the art without departing from the spirit and scope of the present application should be included in the protection scope of the present application, and the patent protection scope of the present application should be limited by the claims.

Claims

1. A high collision energy-absorbing 550 MPa-grade zinc-based plated steel sheet comprising a base sheet and a plated layer, characterized in that, The substrate includes the following components by weight percentage: C: 0.05% to 0.09%, Si: 0.15% to 0.45%, Mn: 1.20% to 2.50%, P ≤ 0.02%, S ≤ 0.02%, Al: 0.03% to 0.06%, Nb: 0.02% to 0.10%, Ti: 0.02% to 0.10%, Cr: 0.15% to 0.60%, and Fe and other inevitable impurities.

2. The high-impact energy-absorbing 550 MPa-grade zinc-based plated steel sheet according to claim 1, characterized by, The substrate components further include one or more of the following elements: B ≤ 0.005%, Mo ≤ 1.00%, Cu ≤ 0.50%, Ni ≤ 1.00%.

3. The high-impact energy-absorbing 550 MPa-grade zinc-based plated steel sheet according to claim 1, characterized by, The coating layer includes the following components by mass percentage: Al: 0.15% to 3.50%, and the rest is Zn.

4. The high-impact energy-absorbing 550 MPa-grade zinc-based plated steel sheet according to claim 3, characterized by, The coating layer components further include one or more of the following elements: Mg: 1.0% to 2%, Si: 0.05% to 0.50%, Ti: 0.03% to 0.50%, Re: 0.01% to 0.10%, Mn: 0.5% to 3.0%.

5. A method for manufacturing the high-impact energy 550 MPa grade zinc-based coated steel sheet according to any one of claims 1 to 4, comprising smelting, casting, hot rolling, pickling and cold rolling, hot dip coating, characterized in that, Hot rolling process: heating at 1220 ± 40 °C, holding for 180 ± 90 minutes, rough rolling at 1100 ± 40 °C, finish rolling at 1060 ± 40 °C, final rolling at 870 ± 40 °C, and coiling at 450-750 °C; pickling and cold rolling: cold rolling reduction of 30% to 70%; hot dip coating process: hot dip coating heating temperature is 750-900 °C, zinc pot temperature is 450-520 °C; the steel sheet is pre-oxidized during heating, specifically, the surface of the steel sheet is pre-oxidized using an oxidizing atmosphere at a temperature range of 600-750 °C.

6. A hot stamping method for the high-impact energy 550 MPa grade zinc-based coated steel sheet according to any one of claims 1 to 4, comprising steel sheet heating, steel sheet cooling, and hot stamping, characterized in that, steel sheet heating: the zinc-based coated hot-formed steel sheet is fed into a heating furnace for heating, the total heating and holding time is 180-600 seconds, and the heating temperature is 800-930 °C; steel sheet cooling: after the steel sheet holding is completed, the steel sheet is cooled to the hot stamping temperature and the stamping starts, the cooling speed is greater than 10 °C / s, and the hot stamping temperature range is 500-850 °C; hot stamping: the hot stamping is immediately performed after the steel sheet is cooled to the hot stamping temperature, the hot stamping cooling speed is greater than 15 °C / s, and the cooling end temperature is between 120-280 °C.

7. The hot stamping method of a high-impact energy-absorbing 550 MPa-grade zinc-based plated steel sheet according to claim 6, characterized by, the heating temperature during the steel sheet heating is 850-890 °C; the target temperature range during the steel sheet cooling is 600-720 °C; and the cooling end temperature during the hot stamping is 150-200 °C.

8. A part made by a hot stamping method of a high-impact energy-absorbing 550 MPa grade zinc-based plated steel sheet according to claim 6, characterized in that, The steel base structure of the component is composed of ferrite + martensite + residual austenite + bainite, wherein the martensite content is 10% to 30%, the bainite content is 5% to 20%, the residual austenite is less than 5%, and the rest is ferrite.

9. A part made by the hot stamping method of a high-impact energy-absorbing 550 MPa-grade zinc-based plated steel sheet according to claim 8, characterized by, The microstructure of the component surface has four layers from the surface to the steel base body, which are 1, 2, 3 and 4 layers in sequence, the first layer is a surface oxide layer; the second layer is an iron-zinc intermetallic compound layer; the third layer is an alpha-Fe(Zn) solid solution layer, the content of Zn is greater than 5%, and the thickness ranges from 10um to 50um; and the fourth layer is a steel base body layer.

10. A part made by the method of hot stamping of a high-impact energy-absorbing 550 MPa grade zinc-based plated steel sheet according to claim 8, characterized in that, The tensile strength of the component is greater than 550MPa, the yield strength is greater than 370MPa, the elongation is greater than 20%, and the deformation capacity meets the 180-degree bending requirement.

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