Hot forming method of zinc-based coated steel plate, coated steel plate, hot forming part and hot forming system

Abstract

The invention provides a hot forming method of a zinc-based coated steel plate, the coated steel plate, a hot forming part and a hot forming system. According to the hot forming method of the zinc-based coated steel plate, cracking caused by brittleness of liquid metal on the surface of the coated steel plate is prevented through the uniform controlled cooling effect of the high-temperature spraying medium, and when the temperature of the steel plate is reduced, cracking caused by the brittleness of the liquid metal can be prevented; and the formed hot forming part is good in surface quality, the defects of piebald and chromatic aberration caused by non-uniform cooling are avoided, high-strength parts within the range of 500-2000 MPa can be formed, the strength of the formed steel plate is guaranteed, and the brittleness problem of liquid metal can be prevented.

Description

Technical Field

[0001] The invention belongs to the field of steel parts processing, and particularly relates to a hot forming method of a zinc-based coated steel plate, a coated steel plate, a hot forming component, and a hot forming system. Background Art

[0002] Hot stamping technology gives full play to the advantages of lightweight materials and advanced manufacturing processes, and has become a special forming technology for high-strength steel and ultra-high-strength steel. From the initial uncoated hot-formed steel to aluminum-silicon coated hot-formed steel and now zinc-based coated hot-formed steel, the entire development process has gradually solved a series of process problems such as cumbersome processes and poor corrosion resistance.

[0003] The overall process route of hot-formed steel forming technology is: "heating-insulation-quenching and forming". For zinc-based coated hot-formed steel, the forming process requires more precise temperature control. The coated steel plate needs to be heated to 880-920°C in the furnace, but the temperature of the steel plate after forming is only around 100°C. If the steel plate is quenched directly after heating, the liquid zinc on the surface faces the risk of liquid metal brittle cracking. During the pre-cooling process, if the zinc-based coated steel plate is directly exposed to the air for cooling, the air medium cannot guarantee the cooling rate of the steel plate in different areas, resulting in uneven cooling of the entire steel plate. In the subsequent quenching and forming process, there is still a risk of liquid metal brittleness problems.

[0004] Chinese patent CN106825177A discloses a method and equipment for hot stamping of galvanized steel sheets. The method provides a method and equipment for hot stamping of galvanized steel sheets. The galvanized steel sheets include a steel sheet body and a galvanized layer. Before the galvanized steel sheets are hot stamped, a heat absorbing layer is sprayed on the surface of the galvanized steel sheets, and the heat absorbing layer is evenly covered on the galvanized layer. The main steps are as follows: (1) uncoiling the steel coil; (2) punching the blank; (3) coating the heat absorbing layer; (4) heating and stamping; (5) pressure quenching. However, this method still cannot avoid the risk of brittle cracking of liquid metal.

[0005] Therefore, it is extremely important to develop a pre-cooling forming process that can uniformly control temperature and remove the surface oxide layer. Summary of the invention

[0006] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a hot forming method of zinc-based coated steel plate and its coated steel plate, hot forming parts, and hot forming system, which aims to uniformly control the forming temperature of coated steel plate parts, effectively prevent the occurrence of liquid metal brittle cracking, and remove the surface oxide layer to facilitate the subsequent coating process. Zinc-based coated hot formed steel parts have excellent corrosion resistance and coating performance.

[0007] The object of the invention is achieved in this way:

[0008] A hot forming method for a zinc-based coated steel plate comprises the following steps:

[0009] S1: Heat the zinc-based coated steel plate to make it reach a completely austenitized state, the heating temperature is 800-905℃, and the heating time is 3-10min; if the temperature is too low, the steel plate is not completely austenitized; if the temperature is too high and exceeds the evaporation point of zinc, the zinc-based coating will evaporate; if the heating time is less than 3 minutes, the austenitization is not sufficient; if the heating time exceeds 10 minutes, the zinc-based coating will be oxidized in large quantities, the austenite grains will be coarse, and the Fe-Zn intermetallic compound with good corrosion resistance will completely disappear and transform into α-Fe(Zn) phase.

[0010] S2: Air-cooling the zinc-based coated steel sheet to 750-780°C; the purpose is to eliminate or minimize the liquid phase in the zinc-based coating.

[0011] S3: Use high-pressure jet cooling to further cool the zinc-based coated steel plate to 500-700℃, and clean the oxide layer on the surface of the coating at the same time. The jet pressure is 0.1-1.0MPa. If the temperature is too low, the steel plate cannot maintain the austenitization state. If the temperature is too high, it will cause metal liquid phase brittleness and serious oxidation on the surface of the steel plate, which is not conducive to improving the surface quality. The reason for using high-temperature gas is to ensure the uniformity of cooling. The purpose of using high-pressure gas is to clean the oxide layer on the surface of the zinc-based coating, which can reduce or even eliminate the subsequent sandblasting process, save costs and improve efficiency.

[0012] S4: Transfer the cooled zinc-coated steel sheet to the stamping forming device for final forming; the downward pressure of the steel sheet during the forming process is 80-400kN; the steel sheet is cooled to 80-150℃ while being formed. Ensure full contact between the mold and the steel sheet to ensure full and uniform quenching. The stamping forming device has a cooling function, so that the zinc-coated steel sheet is cooled to 80-150℃ while being formed, and "quenching + forming" is completed simultaneously; the purpose of cooling to this temperature is to produce self-baking of the steel parts, improve plastic toughness, and use its own heat to dry the surface moisture, which can also reduce the holding time and improve stamping efficiency.

[0013] Furthermore, the jet cooling medium is one of high-temperature steam, high-temperature water mist, high-temperature air, and high-temperature nitrogen; and the high-temperature steam is pure water vapor.

[0014] Furthermore, the steam temperature of the jet cooling process is 100-150°C, and the jet pressure is 0.1-1.0MPa; the high-temperature water mist temperature is 90-100°C, and the jet pressure is 0.1-1.0MPa; the high-temperature air and high-temperature nitrogen temperature is 100-200°C, and the jet pressure is 0.1-1.0MPa.

[0015] Technical solution 2 of the present invention provides a hot forming system for a hot forming method of a zinc-based coated steel plate, including an induction heating device and a stamping forming device; the induction heating device and the stamping forming device also include a clamping transfer device, a jet cooling device, and a clamping transfer device in sequence.

[0016] The induction heating device is used to heat the zinc-based coated steel sheet to an austenitized state;

[0017] The clamping transfer device is used to transfer the zinc-based coated steel plate to the jet cooling device;

[0018] The jet cooling device includes a nozzle and a water storage tank. The nozzle is connected to an external jet medium through a pipeline, and the jet pressure is controlled by a valve. It is used for the pre-cooling process of the zinc-based coated steel plate. The water storage tank is placed under the nozzle to store the liquid generated during the cooling process; the clamping transfer device is used to transfer the zinc-based coated steel plate to the stamping forming device; the stamping forming device is used to stamp the zinc-based coated steel plate into a final shape.

[0019] The jet cooling device is the core device of this forming method. The jet medium is placed in a gas storage tank, connected to the nozzle through a pipeline and a valve, and the jet pressure is controlled by a valve, which is used for the pre-cooling process of the zinc-based coated steel plate; the clamping transfer device is used to transfer the zinc-based coated steel plate to the stamping forming device; the stamping forming device is used to stamp the zinc-based coated steel plate into a final shape.

[0020] Technical solution three of the present invention provides a coated steel plate for use in a hot forming method of zinc-based coated steel plate parts, comprising a steel plate substrate and a coating.

[0021] The chemical composition range of the steel plate matrix includes: C: 0.05-0.42wt%, Si: 0.05-0.55wt%, Mn: 0.5-3.5wt%, P≤0.02wt%, S≤0.02wt%, Al: 0.02-1.20%, Nb: 0.02-0.15wt%, V: 0.05-0.15wt%, Ti: 0.02-0.10wt%, Cr≤0.8wt%, Mo≤0.5wt%, B: 0.001-0.005wt%, and the balance is Fe.

[0022] The composition design reasons of the steel plate matrix of the present invention are as follows:

[0023] C: 0.05%-0.42wt%. C, as the main alloying element, contributes the most to the strength of quenching martensitic steel, provides strength, and can expand the austenite phase region and improve the strength of martensite. If the C content is less than 0.05wt%, it cannot meet the strength level requirements. If the content is too high, the strength of the steel is too high, the toughness decreases, and the welding performance decreases.

[0024] Si: 0.05% to 0.55wt%. Si mainly inhibits the appearance of cementite and ensures the existence of austenite. At the same time, silicon can exist at the interface between the steel matrix and the coating, slowing down the diffusion of Zn elements in the coating into the steel matrix, slowing down the speed at which Fe atoms in the steel matrix and the coating elements form Fe-Zn alloys, and reducing the liquid phase brittleness of zinc-based hot-formed steel; at the same time, Si can also improve the hardenability of steel and strengthen the steel matrix. When the Si content is lower than 0.05%, the above effects cannot be achieved. When the silicon content is higher than 0.55%, selective oxidation will occur on the surface during the continuous annealing process before hot dip plating to generate silicon oxide or silicon-manganese composite oxides, affecting the hot dip plating performance.

[0025] Mn: 0.5%-3.5wt%. The main function of Mn is to expand the austenite phase area, so that the zinc-based hot-formed steel plate can be hot stamped in a lower temperature range and can also obtain martensite structure; improve the strength of the steel matrix through solid solution strengthening, improve the hardenability of the steel, refine the grains, and improve the toughness of the steel; when the Mn content is lower than 0.5%, the austenite phase area of ​​the steel is small and cannot meet the requirements of low-temperature hot stamping. When the Mn content is higher than 3.50%, selective oxidation will occur on the surface during the continuous annealing process before hot dip plating to generate manganese oxide or silicon-manganese composite oxide, affecting the hot dip plating performance.

[0026] Al: 0.02% to 1.20%. The addition of Al can inhibit the formation of cementite, which is similar to the effect of Si element, and can reduce the deterioration of hot-dip coating performance caused by Si, Mn and other elements. Al content below 0.02% will not have a good deoxidation effect, and Al content above 1.20% will cause problems such as nozzle floccules during continuous casting, while increasing costs.

[0027] Nb: 0.02-0.15wt%, V: 0.05-0.15wt%, Ti: 0.02-0.10wt%. The addition of Ti, V and Nb can form fine dispersed precipitates such as TiN, TiC, NbC, VC, etc. in the steel, forming hydrogen traps during service and improving the delayed fracture resistance of the steel. The addition of Nb can strengthen the steel matrix and refine the grains. Ti can improve hardenability.

[0028] Cr≤0.8wt%. Cr is added to ensure hardenability. During continuous annealing, Cr will migrate to the surface of the steel plate due to selective oxidation and accumulate on the surface of the steel plate. Due to the solute drag effect, it can slow down the erosion of liquid Zn on the grain boundary of the steel matrix and reduce liquid phase brittleness. Cr above 0.8% will increase hardenability, affect the stable existence of austenite at lower temperatures, deteriorate hot dip performance, and increase the cost of steel.

[0029] Mo≤0.5wt%. The addition of Mo has the effect of strengthening the steel matrix and refining the grains.

[0030] B: 0.001-0.005wt%. To ensure hardenability, element B is added. The addition of B can improve the grain boundary strength of steel. B gathers at the grain boundary, reduces the local enrichment of H at the grain boundary, reduces the tendency of hydrogen-induced cracking, improves the toughness of steel, and can also improve the hardenability of steel.

[0031] Furthermore, the chemical composition of the coating is in the range of 0.1-1.0wt.% Al, the balance is Zn. The weight of the coating on the steel plate is 60-240g / m 2 .

[0032] The coating contains a certain amount of Al, and when heated and kept warm, an Al2O3 protective film will be formed on the surface of the coating to reduce the oxidation of Zn in the coating and improve the bonding between the coating and the steel substrate. The weight of the coating on the steel plate surface is 60-240g / m 2 If the coating is too thin, the corrosion resistance will be insufficient. If the coating is too thick, a too thick α-Fe(Zn) phase layer will be produced, reducing the strength of the steel plate. Within the target weight range, it can provide good corrosion resistance and control the α-Fe(Zn) phase layer within a good range, which does not reduce the strength of the steel plate and can provide good toughness.

[0033] Furthermore, the type of coating includes one of GI coating and GA coating.

[0034] A zinc-based coated steel plate component is made from the above-mentioned zinc-based coated steel plate, wherein the component coating structure is, from the surface to the steel substrate, a surface oxide layer, a Fe-Zn intermetallic compound layer, an α-Fe(Zn) phase layer, and a martensite phase layer.

[0035] Furthermore, within the time and temperature range specified in the present invention, the zinc-based coating structure from the surface to the steel substrate is: surface oxide layer, Fe-Zn intermetallic compound layer, α-Fe (Zn) phase layer, and martensite phase layer. The coating surface is an extremely thin oxide film with a thickness of 0.1 to 2 μm; under the oxide film is the Fe-Zn intermetallic compound, whose thickness varies between 3 μm and 25 μm depending on the coating thickness and the hot forming process; under the Fe-Zn intermetallic compound is the α-Fe (Zn) phase, whose thickness is between 5 μm and 20 μm; under the α-Fe (Zn) phase is the martensitic steel substrate. Both the Fe-Zn intermetallic compound and the α-Fe (Zn) phase have good corrosion resistance and coating performance, so the steel plate parts have excellent corrosion resistance and coating performance.

[0036] The beneficial effects of the present invention are:

[0037] 1. The hot forming device and hot forming method of coated steel plate parts provided by the present invention are to prevent cracking caused by the brittleness of liquid metal on the surface of the coated steel plate through the uniform controlled cooling effect of the high-temperature spray medium. When the temperature of the steel plate is reduced, the liquid zinc coating on the surface of the steel plate is converted into a semi-solid state, thereby preventing cracking caused by the brittleness of the liquid metal; the slight pressure in the high-temperature spray medium mode can remove the thin oxide layer on the surface of the steel plate.

[0038] 2. The hot forming method of the zinc-based coated steel plate parts provided by the present invention has good surface quality after forming and will not produce spots and color defects caused by uneven cooling.

[0039] 3. The hot forming method of zinc-based coated steel plate parts provided by the present invention has a wide range of forming strengths, and can form high-strength parts in the range of 500-2000MPa. Zinc-based coated hot-formed steel parts have excellent corrosion resistance and coating performance.

[0040] 4. The hot forming method of zinc-based coated steel plate parts provided by the present invention is characterized by diversified spraying medium selectivity, high operability and convenient implementation.

[0041] 5. The zinc-based coated hot-formed steel of the present invention ensures the feasibility of the low-temperature quenching forming process by adjusting the steel plate matrix composition, that is, the steel plate is pre-cooled from the heating temperature to 500-650°C before quenching and forming. This can ensure the strength of the steel plate after forming and prevent the occurrence of liquid metal brittleness problems. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 It is a structural schematic diagram of a hot forming system of a hot forming method for a zinc-based coated steel plate component of the present invention, Figure 1 middle:

[0043] 1-induction heating device; 2-robotic arm clamping and transferring device; 3-condensation water tank; 4-cooling nozzle; 5-robotic arm clamping and transferring device; 6-stamping device. DETAILED DESCRIPTION

[0044] The present invention will be further described below by way of examples.

[0045] A hot forming method for a zinc-based coated steel plate comprises the following steps:

[0046] Step 1: Place the zinc-based coated steel sheet in an induction heating furnace for heating to achieve a complete austenitization state, the heating temperature is 800-905°C, and the heating time is 3-10 minutes;

[0047] If the temperature is too low, the steel plate will not be completely austenitized; if the temperature is too high and exceeds the evaporation point of zinc, the zinc-based coating will evaporate; if the heating time is less than 3 minutes, the austenitization will not be sufficient; if the heating time exceeds 10 minutes, the zinc-based coating will be oxidized in large quantities, the austenite grains will be coarse, and the Fe-Zn intermetallic compounds with good corrosion resistance will completely disappear and transform into α-Fe(Zn) phase.

[0048] Step 2: Air cool the zinc-based coated steel plate to 750-780°C;

[0049] The purpose is to eliminate or minimize the liquid phase in the zinc-based coating.

[0050] Step 3: Use high-pressure jet cooling to further cool the zinc-based coated steel plate to 500-700°C, and at the same time clean the oxide layer on the surface of the zinc-based coating; the jet pressure is 0.1-1.0 MPa.

[0051] Step 4: Transfer the cooled zinc-based coated steel sheet to a stamping forming device for final forming. The downward pressure of the steel sheet during the forming process is 80 to 400 kN; the steel sheet is cooled to 80 to 150° C. while being formed.

[0052] Furthermore, the jet cooling medium is one of high-temperature steam, high-temperature water mist, high-temperature air, and high-temperature nitrogen; and the high-temperature steam is pure water vapor.

[0053] Furthermore, the steam temperature of the jet cooling process is 100-150°C, and the jet pressure is 0.1-1.0MPa; the high-temperature water mist temperature is 90-100°C, and the jet pressure is 0.1-1.0MPa; the high-temperature air and high-temperature nitrogen temperature is 100-200°C, and the jet pressure is 0.1-1.0MPa.

[0054] A hot forming system for a hot forming method of a zinc-based coated steel plate comprises an induction heating device 1 and a stamping forming device 6, wherein a clamping transfer device 2, an air jet cooling device, and a clamping transfer device 5 are sequentially provided between the induction heating device 1 and the stamping forming device 6.

[0055] The induction heating device 1 is used to heat the zinc-based coated steel sheet to an austenitized state;

[0056] The clamping transfer device 2 is used to transfer the zinc-based coated steel plate to the jet cooling device;

[0057] The jet cooling device includes a nozzle 4 and a water storage tank 3. The nozzle 4 is connected to an external jet medium through a pipeline, and the jet pressure is controlled by a valve. It is used for the pre-cooling process of the zinc-based coated steel plate. The water storage tank 3 is placed below the nozzle 4 and is used to store the liquid generated during the cooling process; the clamping transfer device 5 is used to transfer the zinc-based coated steel plate to the stamping forming device 6; the stamping forming device 6 is used to stamp the zinc-based coated steel plate into a final shape.

[0058] A hot forming system for a hot forming method of a zinc-based coated steel plate component comprises the following devices: an induction heating device 1, a clamping and transferring device 2, an air jet cooling device, a clamping and transferring device 5, and a stamping and forming device 6.

[0059] The induction heating device 1 is used to heat the coated steel plate to an austenitized state;

[0060] The clamping transfer device 2 is used to transfer the coated steel plate to the jet cooling device;

[0061] The jet cooling device includes a nozzle 4 and a water storage tank 3. The nozzle 4 is connected to an external jet medium through a pipeline, and the jet pressure is controlled by a valve. It is used for the pre-cooling process of the coated steel plate. The water storage tank 3 is placed under the nozzle 4 and is used to store the liquid generated during the cooling process; the clamping transfer device 5 is used to transfer the coated steel plate to the stamping forming device 6; the stamping forming device 6 is used to stamp the coated steel plate into a final shape.

[0062] A zinc-based coated steel plate component made from the above steel plate, wherein the coating structure of the component is, from the surface to the steel substrate, a surface oxide layer, a Fe-Zn intermetallic compound layer, an α-Fe(Zn) phase layer, and a martensite phase layer.

[0063] Furthermore, the surface oxide layer is an extremely thin oxide film with a thickness of 0.1 to 2 μm; the Fe-Zn intermetallic compound layer has a thickness of 3 μm to 25 μm; and the α-Fe(Zn) phase layer has a thickness of 5 μm to 20 μm.

[0064] The heating temperature and heating time of the zinc-based coated steel plate of the present invention are shown in Table 1, the various setting parameters of the hot water washing section are shown in Table 2, the various parameter settings of the stamping section are shown in Table 3, and the parameters of the drying process section are shown in Table 4.

[0065] Table 1 Aluminum content and coating weight of zinc-based coated steel sheets

[0066] Aluminum content / wt% <![CDATA[Coating weight / g / m 2 > Example 1 0.10 130 Example 2 0.93 110 Example 3 0.82 150 Example 4 0.44 80 Example 5 0.5 140 Example 6 0.65 90 Example 7 0.72 220 Example 8 0.38 170 Example 9 0.25 180 Example 10 1.00 160

[0067] Table 2 Heating temperature and heating time of zinc-based coated steel sheet

[0068] Heating temperature / ℃ Heating time / s Example 1 800 10 Example 2 820 9.5 Example 3 835 9 Example 4 845 8 Example 5 850 7.5 Example 6 855 7 Example 7 865 6 Example 8 870 5.5 Example 9 880 4.5 Example 10 905 3

[0069] Table 3 Parameter settings of zinc-based coated steel plate in the spray cooling process section

[0070]

[0071] Table 4 Parameter settings of zinc-based coated steel plate in the quenching forming process

[0072] Down force / kN Temperature after quenching / ℃ Example 1 150 90 Example 2 300 125 Example 3 220 80 Example 4 140 100 Example 5 190 140 Example 6 320 150 Example 7 250 130 Example 8 170 115 Example 9 280 135 Example 10 360 100

[0073] Table 5 Chemical composition of the substrate in zinc-based coated steel sheet

[0074] C Si Mn P S Al Cr Mo B Nb V Ti Fe Example 1 0.05 0.45 1.8 0.01 - 0.03 0.5 - 0.001 0.037 0.06 0.03 margin Example 2 0.06 0.39 1.5 0.02 - 0.04 - 0.08 0.001 0.03 0.05 0.035 margin Example 3 0.07 0.30 1.4 0.01 - 0.05 - - 0.002 0.031 0.055 0.04 margin Example 4 0.08 0.44 2.5 0.01 0.005 0.03 0.5 - 0.004 0.037 0.05 0.03 margin Example 5 0.09 0.38 2.2 0.02 - 0.04 0.45 - 0.003 0.03 0.07 0.035 margin Example 6 0.10 0.31 2.0 0.01 - 0.05 0.40 0.07 0.002 0.031 0.06 0.04 margin Example 7 0.18 0.45 1.9 0.01 0.004 0.03 0.45 - 0.001 0.035 0.06 0.033 margin Example 8 0.19 0.39 1.6 0.02 - 0.05 0.40 - 0.003 0.032 0.055 0.036 margin Example 9 0.20 0.30 1.5 0.015 - 0.04 0.30 0.05 0.005 0.031 0.06 0.04 margin Example 10 0.21 0.25 1.7 0.013 - 0.26 0.50 - 0.004 0.025 0.05 0.08 margin

[0075] Table 6 Thickness of each coating layer in zinc-based coated steel plate parts

[0076] Surface oxide layer / μm Fe-Zn intermetallic compound / μm α-Fe(Zn) phase / μm Example 1 1.1 10.5 10.7 Example 2 1.3 5 9.6 Example 3 0.6 8.4 8.3 Example 4 0.7 7.8 14.6 Example 5 1.0 21.9 12.3 Example 6 1.2 6.9 17.4 Example 7 0.9 12.3 10.9 Example 8 0.8 18.1 12.8 Example 9 1.0 15.7 15 Example 10 0.7 8 11.1

[0077] Table 7 Performance table of parts after zinc-based coated steel plate forming

[0078] Yield strength / MPa Tensile strength / MPa Elongation A50 / % Example 1 334 563 24 Example 2 327 552 26 Example 3 306 571 25 Example 4 780 1050 7.2 Example 5 795 1120 6.8 Example 6 782 1074 6.5 Example 7 1076 1569 6.2 Example 8 1197 1582 5.9 Example 9 1253 1882 5.7 Example 10 1282 1950 6.0

[0079] As can be seen from the above, the hot forming method of zinc-coated steel plate parts provided by the present invention has a wide range of forming strengths, and can form high-strength parts in the range of 500-2000MPa. Zinc-coated hot-formed steel parts have excellent corrosion resistance and coating performance. The present invention prevents cracking caused by the brittleness of liquid metal on the surface of the zinc-coated steel plate through the uniform controlled cooling effect of high-temperature water flow; the flushing pressure in the flushing mode can remove the thin oxide layer on the surface of the steel plate, which is beneficial to ensure the surface quality of the parts.

[0080] In order to describe the present invention, the present invention is appropriately and fully illustrated by the examples in the above. The above implementation modes are only used to illustrate the present invention, but not to limit the present invention. Ordinary technicians in the relevant technical field can make various changes and modifications without departing from the spirit and scope of the present invention. Any modifications, equivalent substitutions, improvements, etc. made should be included in the protection scope of the present invention. The patent protection scope of the present invention should be defined by the claims.

Claims

1. A hot forming method for a zinc-based coated steel sheet, characterized in that: The following steps are involved: S1: heating the zinc-based coated steel sheet to achieve a complete austenitization state, the heating temperature is 800-905°C, and the heating time is 3-10 minutes; S2: air-cooling the zinc-based coated steel sheet to 750-780°C; S3: Use high-pressure jet cooling to further cool the zinc-based coated steel sheet to 500-700°C, and at the same time clean the oxide layer on the surface of the coating, with a jet pressure of 0.1-1.0 MPa; S4: final forming of the cooled zinc-based coated steel sheet; The downward pressure of the steel plate during the forming process is 80 to 400 kN; the steel plate is cooled to 80 to 150° C. during the forming process.

2. The hot forming method of a zinc-based coated steel sheet according to claim 1, characterized in that: The jet cooling medium is one of high-temperature steam, high-temperature water mist, high-temperature air, and high-temperature nitrogen; the high-temperature steam is pure water vapor.

3. The hot forming method of a zinc-based coated steel sheet according to claim 2, characterized in that: The steam temperature of the jet cooling process is 100-150°C; the high-temperature water mist temperature is 90-100°C; and the high-temperature air and high-temperature nitrogen temperatures are 100-200°C.

4. A hot forming system for the hot forming method of the zinc-based coated steel sheet according to claim 1, comprising an induction heating device (1) and a stamping device (6), characterized in that: The induction heating device (1) and the stamping forming device (6) further include a clamping transfer device (2), an air jet cooling device, and a clamping transfer device (5) in sequence. The induction heating device (1) is used to heat the zinc-based coated steel sheet to an austenitized state; The clamping transfer device (2) is used to transfer the zinc-based coated steel plate to the jet cooling device; The jet cooling device comprises a nozzle (4) and a water storage tank (3), wherein the nozzle (4) is connected to an external jet medium via a pipeline, and the jet pressure is controlled by a valve, and is used for the pre-cooling process of the zinc-based coated steel plate; the water storage tank (3) is placed below the nozzle (4) and is used for storing liquid generated during the cooling process; the clamping transfer device (5) is used for transferring the zinc-based coated steel plate to the stamping forming device (6); and the stamping forming device (6) is used for stamping the zinc-based coated steel plate into a final shape.

5. A zinc-based coated steel sheet, characterized in that: The hot forming method of the zinc-based coated steel plate parts according to any one of claims 1 to 3 comprises a steel plate substrate and a coating, wherein the chemical composition range of the steel plate substrate, by mass percentage, consists of the following components: C: 0.05% to 0.42%, Si: 0.05% to 0.55%, Mn: 0.5% to 3.5%, P≤0.02%, S≤0.02%, Al: 0.02% to 1.20%, Nb: 0.02% to 0.15%, V: 0.05% to 0.15%, Ti: 0.02% to 0.10%, Cr≤0.8%, Mo≤0.5%, B: 0.001% to 0.005%, and the balance is Fe.

6. The zinc-based coated steel sheet according to claim 5, characterized in that: The chemical composition range of the coating is: 0.1wt.%~1.0wt.% Al, the balance is Zn; the weight of the coating on the steel plate surface is 60~240g / m 2 .

7. The zinc-based coated steel sheet according to claim 5, characterized in that: The coating type also includes one of GI coating and GA coating.

8. A zinc-based coated steel plate component, characterized in that: It is made from the zinc-based coated steel sheet described in claim 5, and the coating structure of the component is, from the surface to the steel substrate, a surface oxide layer, a Fe-Zn intermetallic compound layer, an α-Fe(Zn) phase layer, and a martensite phase layer.

9. The zinc-based coated steel plate component according to claim 8, characterized in that: The surface oxide layer is an extremely thin oxide film with a thickness of 0.1 to 2 μm; the Fe-Zn intermetallic compound layer has a thickness of 3 to 25 μm; and the α-Fe(Zn) phase layer has a thickness of 5 to 20 μm.

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