WO2022017138A1 - 一种热镀锌钢板的制造方法、钢板及车用构件 - Google Patents

一种热镀锌钢板的制造方法、钢板及车用构件 Download PDF

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WO2022017138A1
WO2022017138A1 PCT/CN2021/103136 CN2021103136W WO2022017138A1 WO 2022017138 A1 WO2022017138 A1 WO 2022017138A1 CN 2021103136 W CN2021103136 W CN 2021103136W WO 2022017138 A1 WO2022017138 A1 WO 2022017138A1
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steel sheet
atmosphere
heating
soaking
hot
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PCT/CN2021/103136
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English (en)
French (fr)
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金鑫焱
钟勇
陈孟
李旭飞
王利
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宝山钢铁股份有限公司
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Priority to US18/017,057 priority Critical patent/US20230295758A1/en
Priority to JP2023504450A priority patent/JP2023534861A/ja
Priority to EP21846555.7A priority patent/EP4186986A4/en
Priority to CA3186254A priority patent/CA3186254A1/en
Priority to KR1020237005437A priority patent/KR20230043138A/ko
Publication of WO2022017138A1 publication Critical patent/WO2022017138A1/zh

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    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
    • C23C2/04—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor characterised by the coating material
    • C23C2/06—Zinc or cadmium or alloys based thereon
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B15/00—Layered products comprising a layer of metal
    • B32B15/01—Layered products comprising a layer of metal all layers being exclusively metallic
    • B32B15/013—Layered products comprising a layer of metal all layers being exclusively metallic one layer being formed of an iron alloy or steel, another layer being formed of a metal other than iron or aluminium
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/26—Methods of annealing
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/74—Methods of treatment in inert gas, controlled atmosphere, vacuum or pulverulent material
    • C21D1/76—Adjusting the composition of the atmosphere
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C21D9/46—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for sheet metals
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
    • C23C2/02—Pretreatment of the material to be coated, e.g. for coating on selected surface areas
    • C23C2/022—Pretreatment of the material to be coated, e.g. for coating on selected surface areas by heating
    • C23C2/0222—Pretreatment of the material to be coated, e.g. for coating on selected surface areas by heating in a reactive atmosphere, e.g. oxidising or reducing atmosphere
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
    • C23C2/02—Pretreatment of the material to be coated, e.g. for coating on selected surface areas
    • C23C2/022—Pretreatment of the material to be coated, e.g. for coating on selected surface areas by heating
    • C23C2/0224—Two or more thermal pretreatments
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
    • C23C2/26—After-treatment
    • C23C2/28—Thermal after-treatment, e.g. treatment in oil bath
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
    • C23C2/34—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor characterised by the shape of the material to be treated
    • C23C2/36—Elongated material
    • C23C2/40—Plates; Strips
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/001—Austenite

Definitions

  • the invention relates to a metal processing method and a product thereof, in particular to a manufacturing method of a hot-dip galvanized steel sheet, a steel sheet and a vehicle component.
  • the demand for hot-dip galvanized steel sheets in the fields of automobiles, home appliances, and building materials has greatly increased.
  • the reduction annealing stage the individual oxidation points of the steel sheet are reduced, and the steel sheet forms an austenite structure at high temperature and retains part of the austenite (ie retained austenite) after annealing to improve the fracture elongation of the steel sheet.
  • the immersion plating stage a pure zinc coating is formed on the steel sheet.
  • the Zn of the coating and the Fe of the steel sheet diffuse each other, so that the coating obtains sufficient Fe content to form a zinc-iron alloy coating.
  • the alloying temperature is increased or the alloying time is prolonged to ensure the Fe content of the coating, the stability of the retained austenite will be destroyed, the ratio of the retained austenite in the structure of the hot-dip galvanized steel sheet will be reduced, and the fracture extension of the hot-dip galvanized steel sheet will be reduced. rate decreased.
  • Patent document CN101809182B provides a method for preparing a hot dip galvanized annealed steel sheet, the method comprising the steps of: - oxidizing the steel sheet to form an iron oxide layer on the surface of the steel sheet, and forming a layer selected from the following Internal oxides of at least one oxide of the group: Si oxides, Mn oxides, Al oxides, complex oxides containing Si and Mn, complex oxides containing Si and Al, complex oxides containing Al and Mn and a composite oxide comprising Si, Mn and Al; reducing the oxidized steel sheet to reduce the iron oxide layer; - hot-dip galvanizing the reduced steel sheet to form a zinc-based coated steel sheet and subjecting the zinc-based coated steel sheet to an alloying process to form a zinc-coated annealed steel sheet.
  • the Fe content of the steel sheet is insufficient or the elongation at break of the steel sheet is too low.
  • the iron oxide layer formed by the existing method has a certain effect on inhibiting the enrichment of Si and Mn alloy elements on the surface of the steel plate, but this method brings a new problem, the iron oxide layer and the reduced iron layer. They form interfaces with the base steel plate respectively, and the internal oxides formed by Si and Mn alloy elements will be enriched at the interface between the iron oxide layer and the base steel plate and at the interface between the reduced iron layer and the base steel plate.
  • the range of iron diffusion includes both the surface of the steel sheet and the interface between the reduced iron layer and the base steel sheet, which affects the alloying speed, resulting in insufficient Fe content in the coating of the steel sheet or too low elongation at break of the steel sheet.
  • the purpose of the present invention is to provide a method for producing a hot-dip galvanized steel sheet, which can not only suppress the enrichment of Si and Mn alloy elements on the surface of the steel sheet, but also suppress the Si and Mn alloy elements in the iron oxide and the base steel sheet.
  • the interface and the interface between the reduced iron and the base steel plate are enriched, so that when the hot-dip galvanized steel plate uses a steel plate with high Si and Mn content as the base material, after the alloying treatment step, it can have both sufficient Fe content in the coating and high content. Elongation at break.
  • the inventor In order to solve the above-mentioned problems, the inventor repeatedly conducted research, and found in the process that the level of dew point can affect the degree of enrichment of Si and Mn alloy elements at the interface between iron oxide and base steel plate and at the interface between reduced iron and base steel plate. Raising the dew point can suppress this enrichment. Therefore, the inventor proposes that in the process of first passing oxygen to the steel plate for oxidation and then passing hydrogen to reduce it, controlling the dew point ⁇ -20 °C at the same time can not only effectively suppress the enrichment on the surface of the steel plate, but also effectively suppress the interface between the iron oxide and the base steel plate. and the enrichment at the interface of the reduced iron and the base steel plate, thus completing the present invention.
  • the present invention provides a method for manufacturing a hot-dip galvanized steel sheet, which comprises the steps of heat treatment, hot dip plating and alloying treatment on a base steel sheet containing more than 0.5% Si and more than 0.5% Mn by mass, and the heat treatment
  • the steps include a first heating stage and a soaking stage, wherein, the first heating atmosphere in the first heating stage contains 0.01-0.5% volume fraction of O 2 , and the balance is N 2 and inevitable impurities, and soaking in the soaking stage
  • the atmosphere contains more than 0.5% H 2 by volume fraction, the balance is N 2 and inevitable impurities, and the dew point of the first heating atmosphere and the soaking atmosphere is controlled to be ⁇ -20°C.
  • the heat treatment step further includes a second heating stage, the second heating atmosphere in the second heating stage contains H 2 with a volume fraction of more than 0.5%, and the balance is N 2 and inevitable impurities, and the control of the second heating atmosphere. Dew point ⁇ -20°C.
  • the base steel sheet contains 0.1-0.3% by mass of C, 0.5-3.0% of Si, 0.5-4.0% of Mn, and the balance is Fe and inevitable impurities.
  • the base steel sheet contains 0.1-0.3% by mass of C, 0.5-1.8% of Si, 2.0-4.0% of Mn, with the balance being Fe and inevitable impurities.
  • the temperature of the steel plate when entering the zinc pot is 450-520°C
  • the temperature of the plating solution is 450-500°C
  • the plating solution contains 0.10-0.15% Al by mass
  • the balance is Zn and Inevitable impurities
  • the amount of galvanized adhesion on each side of the steel sheet after the hot-dip plating step is 30-90 g/m 2 .
  • the temperature of the steel sheet when entering the zinc pot is 450-500°C.
  • the temperature of the steel plate in the alloying treatment step is controlled to be ⁇ 500°C, and the alloying treatment time is ⁇ 25 seconds.
  • the temperature of the steel plate in the control alloying treatment step is ⁇ 460°C, and the alloying treatment time is ⁇ 5 seconds.
  • the steel plate temperature of the alloying treatment step is 460-500°C, and the alloying treatment time is 5-25 seconds.
  • the outlet temperature of the first heating stage is controlled to be 570-750°C.
  • the temperature of the steel plate in the soaking stage is controlled to be 750-930° C., and the soaking time is 30-300 seconds.
  • the O 2 volume fraction of the first heating atmosphere is 0.03-0.3%.
  • the H 2 volume fraction of the second heating atmosphere and the soaking atmosphere is ⁇ 10%.
  • the dew points of the first heating atmosphere, the second heating atmosphere, and the soaking atmosphere are controlled to be ⁇ 30°C.
  • the dew points of the first heating atmosphere, the second heating atmosphere and the soaking atmosphere are controlled to be ⁇ -10°C.
  • the dew points of the first heating atmosphere, the second heating atmosphere, and the soaking atmosphere are controlled to be ⁇ 0°C.
  • the second object of the present invention is to provide a hot-dip galvanized steel sheet, so that the hot-dip galvanized steel sheet with high Si and Mn content as the base material can have both sufficient coating Fe content and High elongation at break.
  • the present invention also provides a hot-dip galvanized steel sheet prepared by the above-mentioned manufacturing method.
  • the steel plate includes a zinc-iron alloy coating and an inner oxide layer from the outside to the inside, the zinc-iron alloy coating contains 7-13% Fe by mass, the proportion of retained austenite in the structure is greater than or equal to 5%, and the tensile strength of the steel plate is greater than or equal to 980MPa. , elongation at break ⁇ 20%.
  • the third object of the present invention is to provide a vehicle component that meets the performance requirements of the vehicle component.
  • the present invention also provides a vehicle component, which is made of the above hot-dip galvanized steel sheet.
  • the present invention provides a method for manufacturing a hot-dip galvanized steel sheet.
  • the enrichment of Si and Mn alloy elements on the surface of the steel sheet is suppressed, and the presence of Si and Mn alloy elements in the iron oxide and the base steel sheet is suppressed.
  • the interface of galvanized steel and the interface between the reduced iron and the base steel plate are enriched, so that when the steel plate with high Si and Mn content is used as the base material for the hot-dip galvanized steel plate, the appropriate temperature and time of the steel plate can be selected in the alloying treatment step, which is conducive to obtaining Sufficient coating Fe content and high elongation at break.
  • FIG. 1 is a schematic diagram of a temperature control curve of the manufacturing method provided by the present invention.
  • FIG. 2 is a schematic cross-sectional view of the steel plate after each step of the manufacturing method provided by the present invention.
  • FIG. 3 is a cross-sectional metallographic photograph of the hot-dip galvanized steel sheet obtained in Example 1.
  • Base material steel plate 1'. Base steel plate; 2. Internal oxide layer; 3. Iron oxide; 4. Reduced iron; 5. Pure zinc coating; 6. Zinc-iron alloy coating.
  • the present invention provides a method for manufacturing a hot-dip galvanized steel sheet, which includes a heat treatment step, a hot dip plating step, and an alloying treatment step on a base steel sheet containing more than 0.5% Si and more than 0.5% Mn by mass.
  • Heat treatment refers to a metal thermal processing process in which the material is in a solid state by means of heating, heat preservation and cooling to obtain the desired structure and properties.
  • Hot dip plating is a process method in which the plated piece is immersed in molten metal liquid to form a metal coating on the surface. In this technical solution, it is specifically referred to that the steel plate is immersed in the zinc liquid to form a pure zinc coating on the surface.
  • the alloying treatment of this technical solution refers to maintaining the steel sheet at a certain temperature, which is the temperature of the steel sheet in the alloying treatment step, and the holding time is the time of the alloying treatment step.
  • the zinc element in the alloy diffuses with each other, so that the pure zinc coating becomes a zinc-iron alloy coating.
  • the heat treatment step includes a first heating stage and a soaking stage.
  • the first heating stage is a stage in which the steel plate is heated from the ambient temperature to a certain temperature, which is the outlet temperature of the first heating stage, and the heating atmosphere in the first heating stage is called
  • the soaking stage is a stage in which the steel plate is kept at a certain temperature, which is the temperature of the steel plate in the soaking stage, and the soaking time is the time of the soaking stage.
  • the first heating atmosphere of the first heating stage contains 0.01-0.5% volume fraction of O 2
  • the balance is N 2 and inevitable impurities
  • the soaking atmosphere of the soaking stage contains more than 0.5% volume fraction of H 2 , the balance being N 2 and unavoidable impurities, controlling the first heating and soaking the atmosphere and the dew point of the atmosphere ⁇ -20 °C.
  • the dew point is the temperature at which the air is cooled to saturation under the condition that the water vapor content in the atmosphere remains unchanged and the air pressure is kept constant, that is, the temperature at which the water vapor and water reach equilibrium.
  • the O 2 oxidizes the steel sheet base material of the first layer of the heating atmosphere of the iron oxide is formed on the surface thereof, so that Si, Mn alloying elements within the oxide layer is formed substantially only in the bottom of the iron oxide, thereby suppressing
  • the alloy elements of Si and Mn are enriched on the surface of the steel plate in the first heating stage and soaking stage.
  • the high dew point makes the internal oxide layer formed by Si and Mn alloy elements basically only appear in the base steel plate under the iron oxide, rather than on the interface between the iron oxide and the base steel plate, thus inhibiting the Si and Mn alloy elements in the first heating stage. It is enriched at the interface between iron oxide and the base steel plate, and the high dew point also has a certain promotion effect on inhibiting the surface enrichment of the steel plate.
  • the iron oxide is soaking atmosphere H 2 reduction of the reduced iron.
  • the inner oxide layer formed by Si and Mn alloy elements basically only appears below the iron oxide that has not been reduced and the reduced iron obtained from the reduction of iron oxide, thereby inhibiting the Si and Mn alloys.
  • the elements are enriched on the surface of the steel sheet in the soaking stage, which maintains the effect of inhibiting the enrichment on the surface of the steel sheet in the first heating stage and prepares for the subsequent hot dip plating.
  • the high dew point makes the thickness of the inner oxide layer in the base steel plate increase towards the inside of the base steel plate, rather than towards the interface (where the interface includes the interface between the iron oxide and the base steel plate and the interface between the reduced iron and the base steel plate) direction.
  • the enrichment at the interface is inhibited, the effect of inhibiting the interface enrichment of iron oxide and the base steel plate in the first heating stage is maintained, and the high dew point also has a certain promotion effect on inhibiting the enrichment on the surface of the steel plate.
  • the volume fraction of O 2 is less than 0.01%, the oxidation degree of the base metal steel plate is too low, and it cannot sufficiently inhibit the enrichment of the steel plate surface; when the volume fraction of O 2 > 0.5%, the oxidation degree of the base metal steel plate Too high is not conducive to subsequent reduction and coating adhesion. Therefore, the volume fraction of O 2 that defines the first heating atmosphere is 0.01-0.5%.
  • H 2 is the volume fraction of ⁇ 0.5%, reducing effect is insufficient, it is not conducive to the subsequent hot dipping.
  • the hot atmosphere of H 2 are the volume fraction of ⁇ 0.5%, when the volume fraction of ⁇ 2% H 2, better reducing effect, and therefore the volume fraction of H 2 were hot atmosphere is preferably ⁇ 2%.
  • the dew point of the atmosphere When the dew point of the atmosphere is less than -20°C, it can hardly inhibit the enrichment of iron oxide and the base steel plate and the interface between the reduced iron and the base steel plate in the first heating stage and soaking stage. Therefore, the first heating atmosphere and soaking temperature are limited.
  • the dew point of the atmosphere is ⁇ -20°C.
  • the heat treatment step further includes a second heating stage.
  • the second heating stage is a stage in which the steel plate is heated from the outlet temperature of the first heating stage to the steel plate temperature of the soaking stage, which is called the second heating stage.
  • the heating atmosphere is the second heating atmosphere, the second heating atmosphere in the second heating stage contains more than 0.5% volume fraction of H 2 , the balance is N 2 and inevitable impurities, and the dew point of the second heating atmosphere is controlled ⁇ -20 °C.
  • the manufacturing method of hot-dip galvanized steel sheet also includes a first cooling stage and a second cooling stage, the first cooling stage is to cool the steel sheet from the temperature of the steel sheet in the soaking stage to the temperature of the steel sheet when entering the zinc pot, and the second cooling stage is to cool the steel sheet. Cool down from the steel sheet temperature in the alloying treatment step to ambient temperature.
  • the cross section of the steel plate changes from that shown in Fig. 2(a) to that shown in Fig. 2(b), because the O 2 in the first heating atmosphere will oxidize the base metal steel plate 1 on its surface A layer of iron oxide 3 is formed, so that the inner oxide layer 2 formed by Si and Mn alloy elements basically only appears under the iron oxide 3, thereby inhibiting the Si and Mn alloy elements in the first heating stage, the second heating stage and the soaking stage. enriched on the surface of the steel plate.
  • the high dew point makes the inner oxide layer 2 formed by Si and Mn alloy elements basically only appear in the base steel plate 1' below the iron oxide 3, rather than on the interface between the iron oxide 3 and the base steel plate 1', thereby inhibiting the Si,
  • the enrichment of Mn alloy elements at the interface between the iron oxide 3 and the base steel plate 1 ′ in the first heating stage, and the high dew point also has a certain promotion effect on inhibiting the enrichment on the surface of the steel plate.
  • the steel sheet cross-sectional FIG. 2 (b) becomes as shown in 2 (c)
  • the iron oxide 3 is a second heating atmosphere and soaking atmosphere H 2 reduction of the reduced iron FIG. 4.
  • the inner oxide layer 2 formed by Si and Mn alloy elements basically only appears on the iron oxide 3 that has not been reduced and the reduced iron 4 obtained from the reduction of iron oxide 3. In this way, the enrichment of Si and Mn alloy elements on the surface of the steel sheet in the second heating stage and the soaking stage is suppressed, the effect of suppressing the surface enrichment of the steel sheet in the first heating stage is maintained, and preparations for subsequent hot dip plating are prepared.
  • the high dew point makes the thickness of the inner oxide layer 2 in the base steel sheet 1' increase toward the inside of the base steel sheet 1', rather than toward the interface (here the interface includes the interface between the iron oxide 3 and the base steel sheet 1' and the reduced iron 4 and the The interface of the base steel sheet 1') direction increases, that is, the enrichment at the interface is suppressed, and the effect of suppressing the interface enrichment of iron oxide 3 and the base steel sheet 1' in the first heating stage is maintained.
  • Surface enrichment also has a certain promoting effect.
  • the volume fraction of O 2 is less than 0.01%, the oxidation degree of the base metal steel plate 1 is too low, and the effect of inhibiting the surface enrichment of the steel plate cannot be sufficiently achieved; when the volume fraction of O 2 > 0.5%, the base metal steel plate 1 The degree of oxidation is too high, which is not conducive to subsequent reduction and coating adhesion. Therefore, the volume fraction of O 2 that defines the first heating atmosphere is 0.01-0.5%.
  • the H 2 volume fraction of the second heating atmosphere and soaking atmosphere is limited to ⁇ 0.5%.
  • the H 2 volume fraction of the second heating atmosphere and soaking atmosphere is preferably ⁇ 2%.
  • the dew point of the atmosphere When the dew point of the atmosphere is less than -20°C, it can hardly inhibit the enrichment of iron oxide 3 and the base steel plate 1' and the interface between the reduced iron 4 and the base steel plate 1' in the first heating stage, the second heating stage and the soaking stage. Therefore, the dew points of the first heating atmosphere, the second heating atmosphere and the soaking atmosphere are defined to be ⁇ -20°C.
  • the base steel sheet 1 contains 0.1-0.3% by mass of C, 0.5-3.0% of Si, 0.5-4.0% of Mn, and the balance is Fe and inevitable impurities.
  • the mass fraction of the base material steel sheet 1 When the C mass fraction of the base material steel sheet 1 is less than 0.1%, the tensile strength of the steel sheet is insufficient, and when the C mass fraction of the base material steel sheet 1 is greater than 0.3%, the weldability of the steel sheet deteriorates, so the mass fraction of C is limited to 0.1- 0.3%.
  • the Si mass fraction of the base steel sheet 1 When the Si mass fraction of the base steel sheet 1 is less than 0.5%, the tensile strength and elongation at break of the steel sheet are insufficient.
  • the Si mass fraction of the base steel sheet 1 When the Si mass fraction of the base steel sheet 1 is greater than 3.0%, the high-temperature plasticity of the steel sheet is insufficient, and defects during processing are increased. Therefore, the mass fraction of Si is limited to 0.5-3.0%.
  • the mass fraction of Si in the base steel sheet is 0.5-1.8%.
  • the Mn mass fraction of the base steel sheet 1 is less than 0.5%, the tensile strength and elongation at break of the steel sheet are insufficient.
  • the Mn mass fraction of the base steel sheet 1 is greater than 4.0%, the hardenability of the steel sheet is too high, which is unfavorable for the microstructure. The fine control of Mn thus limits the mass fraction of Mn to 0.5-4.0%. In some embodiments, the mass fraction of Mn in the base steel sheet is 2.0-4.0%.
  • the temperature of the steel plate when entering the zinc pot is 450-520°C
  • the temperature of the plating solution is 450-500°C
  • the plating solution contains 0.10-0.15% Al by mass
  • the balance is Zn and Inevitable impurities
  • the amount of galvanized adhesion on each side of the steel sheet after the hot-dip plating step is 30-90 g/m 2 .
  • the cross section of the steel sheet is changed from that shown in FIG. 2( c ) to that shown in FIG. 2( d ), and a pure zinc coating 5 is formed on the steel sheet.
  • the temperature of the steel plate and the temperature of the plating solution when entering the zinc pot affect the reaction between the steel plate and the plating solution
  • the reaction speed is slow and the efficiency is reduced.
  • the temperature and the temperature of the bath are too high, the reaction speed is too fast, and an "explosive structure" will be formed, which is not conducive to the control of the Fe content of the coating in the subsequent alloying process.
  • the temperature of the steel plate when entering the zinc pot for hot-dip plating is limited to 450-520 °C, and the temperature of the plating solution is 450-500 °C. , the reaction speed is moderate, so it is preferred that the temperature of the steel plate is 470-500°C and the temperature of the plating solution is 460-480°C when entering the zinc pot.
  • the plating solution contains 0.10-0.15% Al by mass, preferably 0.10-0.12% Al.
  • the corrosion resistance is poor, zinc coating weight per one surface of> 90g / m 2, the formability of zinc-iron alloy plating layer 6 Poor, easy to pulverize and fall off, and affect the alloying process, which is not conducive to the steel plate to have both sufficient Fe content of the coating and high elongation at break. Therefore, the amount of galvanized adhesion on each side of the steel plate after the hot-dip plating step is limited to 30-90g /m 2 .
  • the temperature of the steel plate in the alloying treatment step is controlled to be ⁇ 500°C, and the time is ⁇ 25 seconds.
  • the cross-section of the steel plate is changed from that shown in Figure 2(d) to that shown in Figure 2(e).
  • a zinc-iron alloy plating layer 6 is formed. Because the temperature and time of the steel plate in the alloying treatment step will affect the stability of the retained austenite and the Fe content of the coating, when the temperature of the steel plate is greater than 500 °C or the time is greater than 25 seconds, the stability of the retained austenite in the steel plate will decrease, and the retained austenite will decrease. The proportion of body to phase is reduced, thereby reducing the elongation at break of the steel sheet, and it will also lead to excessive zinc-iron diffusion, which will deteriorate the anti-powdering performance of the zinc-iron alloy coating 6.
  • the temperature of the steel sheet in the alloying treatment step is limited to ⁇ 500 °C and the time ⁇ 25 seconds, because the temperature of the steel plate is less than or equal to 480 °C, and the time is less than or equal to 20 seconds, the proportion of retained austenite in the steel plate is higher, and the elongation at break of the steel plate is higher, so the temperature of the steel plate in the alloying treatment step is preferably ⁇ 480 °C, The time is preferably ⁇ 20 seconds.
  • the temperature of the steel plate in the alloying treatment step is controlled to be ⁇ 460°C, and the time is ⁇ 5 seconds.
  • the temperature and time of the steel plate in the alloying treatment step will affect the Fe content of the coating layer.
  • the temperature is less than 460°C or the time is less than 5 seconds, the diffusion of zinc and iron will be insufficient, and the Fe content of the coating layer will be insufficient. Therefore, the steel plate temperature in the alloying treatment step is limited to ⁇ 460 °C, time ⁇ 5 seconds.
  • the outlet temperature of the first heating stage is controlled to be 570-750°C.
  • the outlet temperature affects the oxidation degree of the base metal steel plate 1.
  • the temperature is less than 570 °C, the oxidation degree of the base metal steel plate 1 is too low, and the effect of inhibiting the surface enrichment of the steel plate cannot be fully achieved.
  • the temperature is greater than 750 °C, The degree of oxidation of the base metal steel plate 1 is too high, which is not conducive to subsequent reduction and coating adhesion, so the outlet temperature of the first heating stage is limited to 570-750°C.
  • the outlet temperature is 600-720°C, the degree of oxidation is moderate.
  • the outlet temperature of a heating stage is preferably 600-720°C.
  • the temperature of the steel plate in the soaking stage is controlled to be 750-930° C., and the time is 30-300 seconds.
  • the temperature of the steel plate in the soaking stage affects the formation of austenite.
  • the temperature of the steel plate is less than 750 °C, the austenitization of the steel plate is not sufficient.
  • the temperature of the steel plate is greater than 930 °C, the steel plate will form coarse austenite grains.
  • the performance is unfavorable, so the temperature of the steel plate in the soaking stage is limited to 750-930 °C. Because the time of soaking stage is less than 30 seconds, the austenitization of the steel sheet is insufficient, and when the time of soaking stage is greater than 300 seconds, the production efficiency is affected, so the time of soaking stage is limited to 30-300 seconds.
  • the O 2 volume fraction of the first heating atmosphere is 0.03-0.3%.
  • the O 2 volume fraction of the first heating atmosphere is 0.03-0.3%
  • the oxidation degree of the base steel sheet 1 is more moderate, so the O 2 volume fraction of the first heating atmosphere is preferably 0.03-0.3%.
  • the H 2 volume fraction of the second heating atmosphere and the soaking atmosphere is ⁇ 10%.
  • the H 2 volume fraction of the second heating atmosphere and soaking atmosphere is greater than 10%, the reduction effect on iron oxide 3 will no longer increase. From an economical point of view, the H 2 volume fraction of the second heating atmosphere and soaking atmosphere is limited to ⁇ 10%.
  • the H 2 volume fraction defining the second heating atmosphere and soaking atmosphere is 0.5-10%, preferably 2-10%.
  • the dew points of the first heating atmosphere, the second heating atmosphere, and the soaking atmosphere are controlled to be ⁇ 30°C.
  • the inhibitory effect on the enrichment at the interface of iron oxide 3 and base steel plate 1' and at the interface of reduced iron 4 and base steel plate 1' is no longer increased, so the first heating atmosphere and the second heating atmosphere are limited.
  • the dew point of the hot atmosphere is less than or equal to 30°C.
  • the dew points of the first heating atmosphere, the second heating atmosphere and the soaking atmosphere are controlled to be ⁇ -10°C.
  • the dew point of the atmosphere is greater than or equal to -10°C, the effect of inhibiting the interface enrichment of iron oxide 3 and base steel plate 1' and reduced iron 4 and base steel plate 1' is obvious. Therefore, the dew point of the first heating atmosphere, the second heating atmosphere and the soaking atmosphere Preferably it is ⁇ -10°C.
  • the dew points of the first heating atmosphere, the second heating atmosphere, and the soaking atmosphere are controlled to be ⁇ 0°C.
  • the dew point of the atmosphere is greater than or equal to 0°C, the effect of inhibiting the interface enrichment of iron oxide 3 and base steel plate 1' and reduced iron 4 and base steel plate 1' is more obvious. Therefore, the dew points of the first heating atmosphere, the second heating atmosphere and the soaking atmosphere are more obvious. More preferably, it is ⁇ 0°C.
  • the dew points of the first heating atmosphere, the second heating atmosphere, and the soaking atmosphere are -20°C to 30°C. In some embodiments, the dew points of the first heating atmosphere, the second heating atmosphere, and the soaking atmosphere are -10°C to 30°C. In some embodiments, the dew points of the first heating atmosphere, the second heating atmosphere, and the soaking atmosphere are 0°C to 30°C.
  • the present invention also provides a hot-dip galvanized steel sheet prepared by the above manufacturing method.
  • the steel plate includes a zinc-iron alloy coating 6 and an inner oxide layer 2 from the outside to the inside.
  • the zinc-iron alloy coating 6 contains 7-13% Fe by mass, and the proportion of retained austenite in the structure is greater than or equal to 5%.
  • the present invention also provides a vehicle component, which is made of the above hot-dip galvanized steel sheet.
  • the base material steel sheets whose components are shown in Table 1 were selected, and the hot-dip galvanized steel sheets of Examples 1-11 and Comparative Examples 1-6 were manufactured by the following manufacturing method.
  • the first cooling stage Cool the steel sheet from the temperature of the steel sheet in the soaking stage to the temperature of the steel sheet when it enters the zinc pot, and the cooling rate is ⁇ 10°C/s.
  • Hot-dip plating The steel sheet is immersed in the plating solution, the plating solution is maintained at the temperature of the plating solution, and contains Al and the balance of Zn and inevitable impurities, and the amount of galvanized adhesion on each side of the hot-dipped steel plate is 30%. -90g/m 2 .
  • Alloying treatment The steel sheet after hot-dip plating is controlled at the temperature of the steel sheet in the alloying treatment step for heat preservation to form a zinc-iron alloy coating.
  • Second cooling stage the steel sheet is cooled from the steel sheet temperature in the alloying treatment step to ambient temperature.
  • the galvanized steel sheet of Comparative Example 7 was produced by the following production method by selecting the base material steel sheet having the composition shown in Table 1.
  • heating a first heating stage and the second stage heating the base steel sheet temperature of the steel sheet from ambient temperature to the soaking stage, the atmosphere is an atmosphere of H 2, N 2 balance and inevitable impurities, and the dew point to be control.
  • a disc with a diameter of 50 mm made of a steel plate was selected as the sample to be tested, and a 10% by volume hydrochloric acid solution added with a hexamethylene tetramine corrosion inhibitor was used to dissolve the coating, and the Fe content was determined by ICP-AES method. .
  • each phase was identified and quantitatively analyzed by scanning electron microscope backscatter diffraction (EBSD), and the phase ratio of retained austenite was calculated.
  • EBSD scanning electron microscope backscatter diffraction
  • the results are shown in Table 1. It can be seen from Examples 1-11 that the tensile strength of the hot-dip galvanized steel sheet obtained by the manufacturing method of the present invention is greater than or equal to 980Mpa, the Fe content of the coating is within the range of 7-13% by mass, and the elongation at break is greater than or equal to 20%.
  • the high tensile strength is obtained by using the steel sheet with high Si and Mn content as the base material, and at the same time, sufficient Fe content of the coating and high elongation at break are obtained.
  • Fig. 3 is the metallographic photograph of the cross-section of the hot-dip galvanized steel sheet obtained in Example 1.
  • the zinc-iron alloy coating is fully alloyed, and the inner oxide layer formed by the Si and Mn alloy elements is thicker, indicating that the surface of the steel sheet and the iron oxide are closely related to the The interface of the base steel plate and the interface between the reduced iron and the base steel plate are less enriched.
  • the O 2 content was insufficient in the first heating stage, resulting in insufficient oxidation degree of the base metal steel plate, and iron oxide had a poor inhibitory effect on the enrichment of Si and Mn alloy elements on the surface of the steel plate. Continuous oxides are formed on the surface of the steel plate, which affects the alloying speed. Therefore, the alloying temperature is increased to 550 °C and the alloying time is extended to 30s, which reduces the austenite content and the elongation at break of the steel plate is only 17%.
  • the dew point of the first heating stage is too low, which is -30°C, which leads to the deterioration of the dew point's inhibitory effect on the enrichment of Si and Mn alloy elements, especially the interface enrichment of iron oxide and the base steel plate. Poor, Si and Mn alloying elements form continuous oxides at this interface, which affects the alloying speed, so the alloying temperature is increased to 530 ° C, which reduces the austenite content, the elongation at break of the steel plate is only 14.7%, and the iron content of the coating is Still only 3.7%.
  • the O 2 content is excessively high in the first heating stage, resulting in the degree of oxidation of the base steel sheet is too high, the subsequent reduction is not complete, the coating adhesion is poor, and the step of hot-dip coating bath temperature is too low, only the When the temperature is 360 °C, the reaction between the plating solution and the steel plate is not good, and the alloying temperature is increased to 510 °C, which reduces the austenite content.
  • the elongation at break of the steel plate is only 18.8%, and the iron content of the coating is still only 2.5%.
  • the dew point of the second heating stage is too low, which is -25°C, resulting in the dew point's poor inhibitory effect on the enrichment of Si and Mn alloy elements, especially for the interface (here the interface includes the difference between the iron oxide and the base steel plate).
  • the interface and the interface between the reduced iron and the base steel plate) have a poor inhibitory effect on enrichment, and Si and Mn alloy elements form continuous oxides at the interface, which affect the alloying speed, so the iron content of the coating is only 3.4%.
  • the dew point in the soaking stage is too low, at -25°C, resulting in the dew point's poor inhibitory effect on the enrichment of Si and Mn alloy elements, especially for the interface (here the interface includes the interface between the iron oxide and the base steel plate)
  • the interface includes the interface between the iron oxide and the base steel plate
  • the effect of inhibiting the enrichment of the interface between the reduced iron and the base steel plate becomes poor, and the Si and Mn alloy elements form continuous oxides at the interface, which affects the alloying speed, so the iron content of the coating is only 2.8%.
  • Comparative Example 7 the first heating stage as H 2 O 2 atmosphere rather than an atmosphere, so that the iron oxide layer is not formed, and the base steel sheet more iron or reduced iron interface does not exist, and therefore, the rich Si, Mn alloying elements The aggregation is not inhibited and affects the alloying speed, so the alloying temperature is increased to 550 ° C, so that the austenite content is reduced, the elongation at break of the steel plate is only 16%, and the iron content of the coating is still only 2.3%.
  • Figure 4 is the metallographic photo of the cross-section of the hot-dip galvanized steel sheet obtained in Comparative Example 7. It can be seen that the alloying of the zinc-iron alloy coating is insufficient, and the inner oxide layer formed by the Si and Mn alloy elements is relatively thin, indicating that the surface enrichment degree of the steel sheet is relatively high. Heavy.
  • the present invention provides a method for manufacturing a hot-dip galvanized steel sheet, which not only suppresses the enrichment of Si and Mn alloy elements on the surface of the hot-dip galvanized steel sheet, but also suppresses the atmosphere control in the heating and soaking stages.
  • Si and Mn alloying elements are enriched at the interface between iron oxide and base steel plate and at the interface between reduced iron and base steel plate, so that when hot-dip galvanized steel plate uses steel plate with high Si and Mn content as the base material, the alloying treatment step can Selecting the appropriate temperature and time of the steel plate is conducive to obtaining sufficient Fe content of the coating and high elongation at break, which is suitable for automotive components.

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Abstract

本发明提供一种热镀锌钢板的制造方法，包括对高Si、Mn含量的钢板进行热处理步骤、热浸镀步骤和合金化处理步骤，热处理步骤包括第一加热阶段和均热阶段，第一加热阶段的第一加热气氛含有0.01-0.5％体积分数的O 2，余量为N 2和不可避免的杂质，均热阶段的均热气氛含有0.5％以上体积分数的H 2，余量为N 2和不可避免的杂质，控制第一加热气氛和均热气氛的露点≥-20℃。本发明还提供一种热镀锌钢板和车用构件。本发明通过对热处理气氛进行控制，抑制了Si、Mn合金元素在钢板表面及氧化铁与基体钢板的界面、还原铁与基体钢板的界面富集，使得热镀锌钢板选用高Si、Mn含量的钢板作为母材时，经历合金化处理步骤后，可以兼得足够的镀层Fe含量和高断裂延伸率。

Description

一种热镀锌钢板的制造方法、钢板及车用构件 技术领域
本发明涉及金属加工方法及其产品，尤其涉及一种热镀锌钢板的制造方法、钢板及车用构件。
背景技术
近年来，热镀锌钢板在汽车、家电、建材等领域的需求大大增加，其制造方法为依次对钢板进行还原退火、热浸镀、合金化处理。在还原退火阶段，还原钢板的个别氧化点，且使钢板在高温时形成奥氏体结构并在退火结束后保留部分奥氏体(即残余奥氏体)以提高钢板的断裂延伸率，在热浸镀阶段钢板上形成纯锌镀层，在合金化处理阶段，镀层的Zn和钢板的Fe相互扩散，使镀层获得足够的Fe含量，形成锌铁合金镀层。热镀锌钢板经过合金化处理后，以不易脱落的镀层获得可靠优异的防锈性，从而获得广泛且大量的应用。
目前，为提高热镀锌钢板的抗拉强度，提出使用高Si、Mn含量的钢板作为热镀锌钢板的母材，但Si、Mn合金元素在还原退火加工过程中会以连续氧化物的形式在钢板表面富集，阻碍锌铁扩散，从而影响合金化速度。如合金化温度、时间不变，则使得合金化后的钢板镀层Fe含量不足。如为保证镀层Fe含量提高合金化温度或者延长合金化时间，则会破坏残余奥氏体的稳定性，使得热镀锌钢板组织中的残余奥氏体相比例降低，热镀锌钢板的断裂延伸率降低。
专利文献CN101809182B提供了一种制备热浸锌镀层退火的钢片材的方法，该方法包括如下步骤：-氧化钢片材以便在钢片材的表面上形成铁氧化物层，以及形成选自下组中至少一种氧化物的内部氧化物：Si氧化物、Mn氧化物、Al氧化物、包含Si和Mn的复合氧化物、包含Si和Al的复合氧化物、包含Al和Mn的复合氧化物以及包含Si、Mn和Al的复合氧化物；还原该氧化的钢片材，以便还原铁氧化物层；-对该还原的钢片材进行热浸镀锌以形成锌基涂覆的钢片材；和使该锌基涂覆的钢片材经受合金化处理从而形成锌镀层退火的钢片材。其钢片材的镀层Fe含量不足或钢片材的断裂延伸率过低。
综上所述，现有技术中存在热镀锌钢板选用高Si、Mn含量的钢板作为母材时，经过 合金化处理后，难以兼得足够的镀层Fe含量和高断裂延伸率的问题。
发明内容
发明人发现，现有的方法形成的铁氧化物层对抑制Si、Mn合金元素在钢板表面富集有一定作用，但这种方法带来了一个新的问题，铁氧化物层和还原铁层分别与基体钢板形成界面，Si、Mn合金元素形成的内部氧化物会在铁氧化物层与基体钢板的界面处以及还原铁层与基体钢板的界面处富集，而在合金化过程中，锌铁扩散的范围既包括钢板表面又包括还原铁层与基体钢板的界面，从而影响了合金化速度，使得钢片材的镀层Fe含量不足或钢片材的断裂延伸率过低。
鉴于上述问题，本发明的目的在于提供一种热镀锌钢板的制造方法，不仅可以抑制Si、Mn合金元素在钢板表面的富集，还可以抑制Si、Mn合金元素在氧化铁与基体钢板的界面处以及还原铁与基体钢板的界面处富集，使得热镀锌钢板选用高Si、Mn含量的钢板作为母材时，在经历合金化处理步骤后，可以兼得足够的镀层Fe含量和高断裂延伸率。
发明人为了解决上述问题，反复进行研究，在该过程中发现，露点的高低可以影响Si、Mn合金元素在氧化铁与基体钢板的界面处以及还原铁与基体钢板的界面处的富集程度，提高露点可以抑制该富集。因此，发明人提出，在对钢板先通氧气氧化再通氢气还原的过程中，同时控制露点≥-20℃，不仅可以有效抑制钢板表面的富集还可有效抑制氧化铁与基体钢板的界面处以及还原铁与基体钢板的界面处的富集，从而完成了本发明。
本发明提供了一种热镀锌钢板的制造方法，包括对以质量计含有0.5％以上的Si和0.5％以上的Mn的母材钢板进行热处理步骤、热浸镀步骤和合金化处理步骤，热处理步骤包括第一加热阶段和均热阶段，其中，第一加热阶段的第一加热气氛含有0.01-0.5％体积分数的O 2，余量为N 2和不可避免的杂质，均热阶段的均热气氛含有0.5％以上体积分数的H 2，余量为N 2和不可避免的杂质，以及控制第一加热气氛和均热气氛的露点≥-20℃。
可选地，热处理步骤还包括第二加热阶段，第二加热阶段的第二加热气氛含有0.5％以上体积分数的H 2，余量为N 2和不可避免的杂质，以及控制第二加热气氛的露点≥-20℃。
可选地，母材钢板以质量计含有0.1-0.3％的C、0.5-3.0％的Si、0.5-4.0％的Mn，余量为Fe和不可避免的杂质。在一些实施方案中，母材钢板以质量计含有0.1-0.3％的C、0.5-1.8％的Si、2.0-4.0％的Mn，余量为Fe和不可避免的杂质。
可选地，热浸镀步骤中，入锌锅时钢板温度为450-520℃，镀液温度为450-500℃，镀液中以质量计含有0.10-0.15％的Al，余量为Zn及不可避免的杂质，完成热浸镀步骤的钢 板每单面镀锌附着量为30-90g/m 2。在一些实施方案中，热浸镀步骤中，入锌锅时钢板温度为450-500℃。
可选地，控制合金化处理步骤的钢板温度≤500℃，合金化处理时间≤25秒。
可选地，控制合金化处理步骤的钢板温度≥460℃，合金化处理时间≥5秒。
在一些实施方案中，合金化处理步骤的钢板温度为460-500℃，合金化处理时间为5-25秒。
可选地，控制第一加热阶段的出口温度为570-750℃。
可选地，控制均热阶段的钢板温度为750-930℃，均热时间为30-300秒。
可选地，第一加热气氛的O 2体积分数为0.03-0.3％。
可选地，第二加热气氛、均热气氛的H 2体积分数≤10％。
可选地，控制第一加热气氛、第二加热气氛、均热气氛的露点≤30℃。
可选地，控制第一加热气氛、第二加热气氛、均热气氛的露点≥-10℃。
可选地，控制第一加热气氛、第二加热气氛、均热气氛的露点≥0℃。
本发明的第二个目的在于提供一种热镀锌钢板，使得以高Si、Mn含量的钢板作为母材的热镀锌钢板在经历合金化处理步骤后，可以兼得足够的镀层Fe含量和高断裂延伸率。
为了实现上述目的，本发明还提供了一种由上述制造方法制备的热镀锌钢板。
可选地，钢板由外向内包括锌铁合金镀层、内氧化层，锌铁合金镀层以质量计含有7-13％的Fe，组织中残余奥氏体相比例≥5％，钢板的抗拉强度≥980MPa，断裂延伸率≥20％。
本发明的第三个目的在于提供一种车用构件，满足车用构件的性能需求。
为了实现上述目的，本发明还提供了一种车用构件，由上述热镀锌钢板制成。
本发明提供的一种热镀锌钢板的制造方法，通过对热处理气氛进行控制，既抑制了Si、Mn合金元素在钢板表面的富集，又抑制了Si、Mn合金元素在氧化铁与基体钢板的界面处以及还原铁与基体钢板的界面处富集，使得热镀锌钢板选用高Si、Mn含量的钢板作为母材时，在合金化处理步骤可以选择合适的钢板温度、时间，从而利于获得足够的镀层Fe含量和高断裂延伸率。
附图说明
图1为本发明提供的制造方法的温度控制曲线示意图。
图2为本发明提供的制造方法的各步骤后的钢板截面示意图。
图3为实施例1得到的热镀锌钢板的截面金相照片。
图4为对比例7得到的热镀锌钢板的截面金相照片。
附图标记
(a).未进行任何步骤；(b).第一加热阶段后；(c).第二加热阶段及均热阶段后；(d).热浸镀步骤后；(e).合金化处理步骤后。
1.母材钢板；1’.基体钢板；2.内氧化层；3.氧化铁；4.还原铁；5.纯锌镀层；6.锌铁合金镀层。
具体实施方式
以下由特定的具体实施例说明本发明的实施方式，本领域技术人员可由本说明书所揭示的内容轻易地了解本发明的其他优点及功效。虽然本发明的描述将结合较佳实施例一起介绍，但这并不代表此发明的特征仅限于该实施方式。恰恰相反，结合实施方式作发明介绍的目的是为了覆盖基于本发明的权利要求而有可能延伸出的其它选择或改造。为了提供对本发明的深度了解，以下描述中将包含许多具体的细节。本发明也可以不使用这些细节实施。此外，为了避免混乱或模糊本发明的重点，有些具体细节将在描述中被省略。
本发明提供了一种热镀锌钢板的制造方法，包括对以质量计含有0.5％以上的Si和0.5％以上的Mn的母材钢板进行热处理步骤、热浸镀步骤和合金化处理步骤。热处理是指材料在固态下，通过加热、保温和冷却的手段，以获得预期组织和性能的一种金属热加工工艺。热浸镀是把被镀件浸入到熔融的金属液体中使其表面形成金属镀层的一种工艺方法，在本技术方案中特指，钢板浸入到锌液中使其表面形成纯锌镀层。本技术方案的合金化处理是指，将钢板在某一温度下保温，该温度即合金化处理步骤的钢板温度，保温时间即合金化处理步骤的时间，通过钢板中的铁元素和纯锌镀层中的锌元素相互扩散，使纯锌镀层成为锌铁合金镀层。热处理步骤包括第一加热阶段和均热阶段，第一加热阶段为将钢板从环境温度加热到某一温度的阶段，该温度即第一加热阶段的出口温度，称第一加热阶段的加热气氛为第一加热气氛，均热阶段为将钢板在某一温度下保温的阶段，该温度即均热阶段的钢板温度，保温时间即均热阶段的时间。其中，第一加热阶段的第一加热气氛含有0.01-0.5％体积分数的O 2，余量为N 2和不可避免的杂质，均热阶段的均热气氛含有0.5％以上体积分数的H 2，余量为N 2和不可避免的杂质，以及控制第一加热气氛和均热气氛的露点≥-20℃。
露点为，在气氛中水汽含量不变，保持气压一定的情况下，使空气冷却达到饱和时的温度，即水蒸气与水达到平衡状态的温度。
经过第一加热阶段后，由于第一加热气氛的O 2会氧化母材钢板在其表面形成一层氧化铁，使得Si、Mn合金元素形成的内氧化层基本只出现在氧化铁下方，从而抑制了Si、Mn合金元素在第一加热阶段及均热阶段的钢板表面富集。同时，高露点使得Si、Mn合金元素形成的内氧化层基本只出现在氧化铁下方的基体钢板中，而不是氧化铁与基体钢板的界面上，从而抑制Si、Mn合金元素在第一加热阶段于氧化铁与基体钢板的界面处富集，且高露点对抑制钢板表面富集也有一定促进作用。
经过均热阶段后，氧化铁被均热气氛的H 2还原为还原铁。在均热阶段的过程中，Si、Mn合金元素形成的内氧化层基本只出现在还未被还原的氧化铁和由氧化铁被还原得来的还原铁的下方，从而抑制了Si、Mn合金元素在均热阶段的钢板表面富集，维持了第一加热阶段中抑制钢板表面富集的效果，并为后续热浸镀做准备。同时，高露点使得基体钢板中的内氧化层厚度向基体钢板内部的方向增加，而不是向界面(此处界面包括氧化铁与基体钢板的界面和还原铁与基体钢板的界面)方向增加，即抑制了于该界面处的富集，维持了第一加热阶段中抑制氧化铁与基体钢板的界面富集的效果，且高露点对抑制钢板表面富集也有一定促进作用。
当O 2的体积分数＜0.01％时，母材钢板的氧化程度太低，起不到充分的抑制钢板表面富集的作用；当O 2的体积分数＞0.5％时，母材钢板的氧化程度太高，不利于后续还原以及镀层附着性。因此限定第一加热气氛的O 2体积分数为0.01-0.5％。
当H 2的体积分数＜0.5％时，还原效果不足，不利于后续热浸镀。因此限定均热气氛的H 2体积分数≥0.5％，当H 2体积分数≥2％时，还原效果更佳，因此均热气氛的H 2体积分数优选为≥2％。
气氛露点＜-20℃时，其在第一加热阶段及均热阶段几乎起不到抑制氧化铁与基体钢板及还原铁与基体钢板界面处富集的作用，因此限定第一加热气氛及均热气氛的露点≥-20℃。
可选地，如图1所示，热处理步骤还包括第二加热阶段，第二加热阶段为将钢板从第一加热阶段的出口温度加热到均热阶段的钢板温度的阶段，称第二加热阶段的加热气氛为第二加热气氛，第二加热阶段的第二加热气氛含有0.5％以上体积分数的H 2，余量为N 2和不可避免的杂质，以及控制第二加热气氛的露点≥-20℃。
热镀锌钢板的制造方法还包括第一冷却阶段和第二冷却阶段，第一冷却阶段为将钢板从均热阶段的钢板温度冷却到入锌锅时的钢板温度，第二冷却阶段为将钢板从合金化处理步骤的钢板温度冷却到环境温度。
如图2所示，经过第一加热阶段后，钢板截面由图2(a)所示变为图2(b)所示，由于第一加热气氛的O 2会氧化母材钢板1在其表面形成一层氧化铁3，使得Si、Mn合金元素形成的内氧化层2基本只出现在氧化铁3下方，从而抑制了Si、Mn合金元素在第一加热阶段、第二加热阶段及均热阶段的钢板表面富集。同时，高露点使得Si、Mn合金元素形成的内氧化层2基本只出现在氧化铁3下方的基体钢板1’中，而不是氧化铁3与基体钢板1’的界面上，从而抑制了Si、Mn合金元素在第一加热阶段的于氧化铁3与基体钢板1’的界面处的富集，且高露点对抑制钢板表面富集也有一定促进作用。
经过第二加热阶段及均热阶段后，钢板截面由图2(b)所示变为图2(c)所示，氧化铁3被第二加热气氛及均热气氛的H 2还原为还原铁4。在第二加热阶段及均热阶段的过程中，Si、Mn合金元素形成的内氧化层2基本只出现在还未被还原的氧化铁3和由氧化铁3被还原得来的还原铁4的下方，从而抑制了Si、Mn合金元素在第二加热阶段及均热阶段的钢板表面富集，维持了第一加热阶段中抑制钢板表面富集的效果，并为后续热浸镀做准备。同时，高露点使得基体钢板1’中的内氧化层2厚度向基体钢板1’内部的方向增加，而不是向界面(此处界面包括氧化铁3与基体钢板1’的界面和还原铁4与基体钢板1’的界面)方向增加，即抑制了于该界面处的富集，维持了第一加热阶段中抑制氧化铁3与基体钢板1’的界面富集的效果，且高露点对抑制钢板表面富集也有一定促进作用。
当O 2的体积分数＜0.01％时，母材钢板1的氧化程度太低，起不到充分的抑制钢板表面富集的作用；当O 2的体积分数＞0.5％时，母材钢板1的氧化程度太高，不利于后续还原以及镀层附着性。因此限定第一加热气氛的O 2体积分数为0.01-0.5％。
当H 2的体积分数＜0.5％时，还原效果不足，不利于后续热浸镀。因此限定第二加热气氛及均热气氛的H 2体积分数≥0.5％，当H 2体积分数≥2％时，还原效果更佳，因此第二加热气氛及均热气氛的H 2体积分数优选为≥2％。
气氛露点＜-20℃时，其在第一加热阶段、第二加热阶段及均热阶段几乎起不到抑制氧化铁3与基体钢板1’及还原铁4与基体钢板1’界面处富集的作用，因此限定第一加热气氛、第二加热气氛及均热气氛的露点≥-20℃。
可选地，母材钢板1以质量计含有0.1-0.3％的C、0.5-3.0％的Si、0.5-4.0％的Mn，余量为Fe和不可避免的杂质。
当母材钢板1的C质量分数＜0.1％时，钢板的抗拉强度不足，当母材钢板1的C质量分数＞0.3％时，钢板的焊接性能恶化，因此限定C的质量分数为0.1-0.3％。当母材钢板1的Si质量分数＜0.5％时，钢板的抗拉强度及断裂延伸率不足，当母材钢板1的Si质量 分数＞3.0％时，钢板的高温塑性不足，增加加工时的缺陷发生率，因此限定Si的质量分数为0.5-3.0％。在一些实施方案中，母材钢板中Si的质量分数为0.5-1.8％。当母材钢板1的Mn质量分数＜0.5％时，钢板的抗拉强度及断裂延伸率不足，当母材钢板1的Mn质量分数＞4.0％时，钢板的淬透性过高，不利于组织的精细控制，因此限定Mn的质量分数为0.5-4.0％。在一些实施方案中，母材钢板中Mn的质量分数为2.0-4.0％。
可选地，热浸镀步骤中，入锌锅时钢板温度为450-520℃，镀液温度为450-500℃，镀液中以质量计含有0.10-0.15％的Al，余量为Zn及不可避免的杂质，完成热浸镀步骤的钢板每单面镀锌附着量为30-90g/m 2。
经过热浸镀后，钢板截面由图2(c)所示变为图2(d)所示，钢板上形成纯锌镀层5。因入锌锅时的钢板温度和镀液温度影响钢板和镀液之间的反应，入锌锅时的钢板温度和镀液温度过低时，反应速度慢，降低效率，入锌锅时的钢板温度和镀液温度过高时，反应速度太快，会形成“爆发组织”，不利于后续合金化过程中的镀层Fe含量控制。故限定热浸镀的入锌锅时钢板温度为450-520℃，镀液温度为450-500℃，当入锌锅时的钢板温度为470-500℃，镀液温度为460-480℃时，反应速度适中，因此优选为入锌锅时钢板温度为470-500℃，镀液温度为460-480℃。镀液中以质量计含有0.10-0.15％Al，优选为0.10-0.12％Al。因完成热浸镀步骤的钢板每单面镀锌附着量＜30g/m 2时，耐蚀性较差，每单面镀锌附着量为＞90g/m 2时，锌铁合金镀层6的成形性较差，易粉化脱落，且影响合金化进程，不利于钢板兼得足够的镀层Fe含量和高断裂延伸率，故限定完成热浸镀步骤的钢板每单面镀锌附着量为30-90g/m 2。
可选地，控制合金化处理步骤的钢板温度≤500℃，时间≤25秒。
经过合金化处理后，钢板截面由图2(d)所示变为图2(e)所示，合金化处理过程中，纯锌镀层5的Zn和基体钢板1’的Fe相互扩散，钢板上形成锌铁合金镀层6。因合金化处理步骤的钢板温度、时间都会影响残余奥氏体的稳定性和镀层Fe含量，钢板温度＞500℃或者时间＞25秒时，钢板中残余奥氏体的稳定性下降，残余奥氏体相比例减少，从而降低钢板的断裂延伸率，而且也会导致锌铁扩散程度过高，恶化锌铁合金镀层6的抗粉化性能，故限定合金化处理步骤的钢板温度≤500℃，时间≤25秒，因钢板温度≤480℃，时间≤20秒时，钢板中的残余奥氏体相比例更高，钢板的断裂延伸率更高，因此合金化处理步骤的钢板温度优选为≤480℃，时间优选为≤20秒。
可选地，控制合金化处理步骤的钢板温度≥460℃，时间≥5秒。
合金化处理步骤的钢板温度、时间都会影响镀层Fe含量，温度＜460℃或者时间＜5 秒时，会导致锌铁扩散不充分，镀层Fe含量不足，故限定合金化处理步骤的钢板温度≥460℃，时间≥5秒。
可选地，控制第一加热阶段的出口温度为570-750℃。
出口温度影响母材钢板1的氧化程度，当该温度＜570℃时，母材钢板1的氧化程度太低，起不到充分的抑制钢板表面富集的作用，当该温度＞750℃时，母材钢板1的氧化程度太高，不利于后续还原以及镀层附着性，故限定第一加热阶段的出口温度为570-750℃，当出口温度为600-720℃时，氧化程度适中，因此第一加热阶段的出口温度优选为600-720℃。
可选地，控制均热阶段的钢板温度为750-930℃，时间为30-300秒。
均热阶段的钢板温度影响奥氏体的形成，当钢板温度＜750℃时，钢板的奥氏体化不充分，当钢板温度＞930℃时，钢板会形成粗大奥氏体晶粒，对钢板性能不利，故限定均热阶段的钢板温度为750-930℃。因，均热阶段的时间＜30秒时，钢板的奥氏体化不充分，均热阶段的时间＞300秒时，影响生产效率，故限定均热阶段的时间为30-300秒。
可选地，第一加热气氛的O 2体积分数为0.03-0.3％。
当第一加热气氛的O 2体积分数为0.03-0.3％时，母材钢板1的氧化程度更加适中，因此第一加热气氛的O 2体积分数优选为0.03-0.3％。
可选地，第二加热气氛、均热气氛的H 2体积分数≤10％。
第二加热气氛、均热气氛的H 2体积分数＞10％后，对氧化铁3的还原作用不再增加，从经济角度考虑，故限定第二加热气氛、均热气氛的H 2体积分数≤10％。
在一些实施方案中，限定第二加热气氛及均热气氛的H 2体积分数为0.5-10％，优选为2-10％。
可选地，控制第一加热气氛、第二加热气氛、均热气氛的露点≤30℃。
露点＞30℃后，对氧化铁3与基体钢板1’界面处、还原铁4与基体钢板1’界面处富集的抑制作用不再增加，故限定第一加热气氛、第二加热气氛、均热气氛的露点≤30℃。
可选地，控制第一加热气氛、第二加热气氛、均热气氛的露点≥-10℃。
当气氛露点≥-10℃时，抑制氧化铁3与基体钢板1’及还原铁4与基体钢板1’界面富集的作用明显，因此第一加热气氛、第二加热气氛、均热气氛的露点优选为≥-10℃。
可选地，控制第一加热气氛、第二加热气氛、均热气氛的露点≥0℃。
当气氛露点≥0℃时，抑制氧化铁3与基体钢板1’及还原铁4与基体钢板1’界面富集的作用更加明显，因此第一加热气氛、第二加热气氛、均热气氛的露点更优选为≥0℃。
在一些实施方案中，第一加热气氛、第二加热气氛及均热气氛的露点为-20℃到30℃。在一些实施方案中，第一加热气氛、第二加热气氛及均热气氛的露点为为-10℃到30℃。在一些实施方案中，第一加热气氛、第二加热气氛及均热气氛的露点为0℃到30℃。
本发明还提供了一种由上述制造方法制备的热镀锌钢板。
可选地，钢板由外向内包括锌铁合金镀层6、内氧化层2，锌铁合金镀层6以质量计含有7-13％的Fe，组织中残余奥氏体相比例≥5％，钢板的抗拉强度≥980MPa，断裂延伸率≥20％。
本发明还提供了一种车用构件，由上述热镀锌钢板制成。
实施例
实施例1-11和对比例1-6
选择成分如表1所示的母材钢板，通过下述制造方法，制造实施例1-11和对比例1-6的热镀锌钢板。
(1)第一加热阶段：将母材钢板从环境温度加热到出口温度，气氛为O 2气氛，余量为N 2和不可避免的杂质，并对露点加以控制。
(2)第二加热阶段：将钢板从出口温度加热到均热阶段的钢板温度，气氛为H 2气氛，余量为N 2和不可避免的杂质，并对露点加以控制。
(3)均热阶段：将钢板进行保温，气氛为H 2气氛，余量为N 2和不可避免的杂质，并对露点加以控制。
(4)第一冷却阶段：将钢板从均热阶段的钢板温度冷却到入锌锅时的钢板温度，冷却速度≥10℃/s。
(5)热浸镀：将钢板浸入镀液，镀液维持在镀液温度，且含有Al以及余量为Zn和不可避免的杂质，完成热浸镀的钢板每单面镀锌附着量为30-90g/m 2。
(6)合金化处理：将热浸镀后的钢板控制在合金化处理步骤的钢板温度进行保温，形成锌铁合金镀层。
(7)第二冷却阶段：将钢板从合金化处理步骤的钢板温度冷却到环境温度。
对比例7
选择成分如表1所示的母材钢板，通过下述制造方法，制造对比例7的热镀锌钢板。
(1)第一加热阶段及第二加热阶段：将母材钢板从环境温度加热到均热阶段的钢板 温度，气氛为H 2气氛，余量为N 2和不可避免的杂质，并对露点加以控制。
(2)-(6)与实施例1-11和对比例1-6的制造方法的(3)-(7)相同。
性能测试方法：
按照下述测试方法中的记载，对热镀锌钢板进行性能测试，各项测试结果示于表1：
(1)抗拉强度(MPa)
使用万能拉伸试验机，依GB/T 228.1-2010所述方法测试。
(2)断裂延伸率(％)
使用万能拉伸试验机，依GB/T 228.1-2010所述方法测试。
(3)镀层Fe含量(％)
选用钢板冲制成的直径为50mm的圆片为待测样品，使用添加六次甲基四胺缓蚀剂的以体积计10％的盐酸溶液将镀层溶下，采用ICP-AES法测定Fe含量。
(4)奥氏体相比例(％)
制备截面金相后，采用扫描电镜背散射衍射装置(EBSD)对各相进行鉴别和定量分析，计算残余奥氏体的相比例。
金相照片拍摄方法：
按照下述拍摄方法中的记载，对热镀锌钢板进行金相拍摄，照片示于附图3、4。
制备截面金相后，采用金相显微镜拍摄。
Figure PCTCN2021103136-appb-000001
结果如表1所示。由实施例1-11可知，本发明的制造方法得到的热镀锌钢板抗拉强度≥980Mpa，镀层Fe含量以质量计在7-13％的范围内，断裂延伸率≥20％。在使用高Si、Mn含量的钢板作为母材得到高抗拉强度的同时，兼得了足够的镀层Fe含量和高断裂延伸率。图3为实施例1得到的热镀锌钢板的截面金相照片，可以看出，锌铁合金镀层合金化充分，且Si、Mn合金元素形成的内氧化层较厚，说明钢板表面及氧化铁与基体钢板的界面、还原铁与基体钢板的界面富集程度较轻。
关于对比例1，其在第一加热阶段中O 2含量不足，导致母材钢板的氧化程度不足，氧化铁对Si、Mn合金元素在钢板表面富集的抑制作用差，Si、Mn合金元素在钢板表面形成连续的氧化物，影响合金化速度，故提高合金化温度至550℃，延长合金化时间至30s，使得奥氏体含量降低，钢板断裂延伸率仅为17％。
关于对比例2，第一加热阶段的露点过低，为-30℃，导致露点对Si、Mn合金元素富集的抑制作用变差，尤其是对于氧化铁与基体钢板的界面富集抑制作用变差，Si、Mn合金元素在该界面形成连续的氧化物，影响合金化速度，故提高合金化温度至530℃，使得奥氏体含量降低，钢板断裂延伸率仅为14.7％，且镀层铁含量仍仅为3.7％。
关于对比例3，第一加热阶段的出口温度过低，仅为550℃，导致母材钢板的氧化程度不足，氧化铁对Si、Mn合金元素在钢板表面富集的抑制作用差，Si、Mn合金元素在钢板表面形成连续的氧化物，影响合金化速度，镀层铁含量仅为5.2％。
关于对比例4，其在第一加热阶段中O 2含量过高，导致母材钢板的氧化程度过高，后续还原不彻底，镀层附着性差，而热浸镀步骤的镀液温度过低，仅为360℃，使得镀液和钢板的反应不佳，且合金化温度提高至510℃，使得奥氏体含量降低，钢板断裂延伸率仅为18.8％，镀层铁含量仍仅为2.5％。
关于对比例5，第二加热阶段的露点过低，为-25℃，导致露点对Si、Mn合金元素富集的抑制作用变差，尤其是对于界面(此处界面包括氧化铁与基体钢板的界面和还原铁与基体钢板的界面)富集的抑制作用变差，Si、Mn合金元素在该界面形成连续的氧化物，影响合金化速度，故镀层铁含量仅为3.4％。
关于对比例6，均热阶段的露点过低，为-25℃，导致露点对Si、Mn合金元素富集的抑制作用变差，尤其是对于界面(此处界面包括氧化铁与基体钢板的界面和还原铁与基体钢板的界面)富集的抑制作用变差，Si、Mn合金元素在该界面形成连续的氧化物，影响合金化速度，故镀层铁含量仅为2.8％。
关于对比例7，第一加热阶段为H 2气氛而不是O 2气氛，故未形成铁的氧化层，更不存在基体钢板与氧化铁或还原铁的界面，因此，Si、Mn合金元素的富集不受抑制，影响合金化速度，故提高合金化温度至550℃，使得奥氏体含量降低，钢板断裂延伸率仅为16％，且镀层铁含量仍仅为2.3％。图4为对比例7得到的热镀锌钢板的截面金相照片，可以看出，锌铁合金镀层合金化不充分，Si、Mn合金元素形成的内氧化层较薄，说明钢板表面富集程度较重。
综上所述，本发明提供的一种热镀锌钢板的制造方法，通过加热和均热阶段的气氛控制，既抑制了Si、Mn合金元素在热镀锌钢板表面的富集，又抑制了Si、Mn合金元素在氧化铁与基体钢板的界面处以及还原铁与基体钢板的界面处富集，使得热镀锌钢板选用高Si、Mn含量的钢板作为母材时，在合金化处理步骤可以选择合适的钢板温度、时间，从而利于获得足够的镀层Fe含量和高断裂延伸率，适用于车用构件。
上述实施例仅例示性说明本发明的原理及其功效，而非用于限制本发明。任何熟悉此技术的人士皆可在不违背本发明的精神及范畴下，对上述实施例进行修饰或改变。因此，举凡所属技术领域中具有通常知识者在未脱离本发明所揭示的精神与技术思想下所完成的一切等效修饰或改变，仍应由本发明的权利要求所涵盖。

Claims (15)

  1. 一种热镀锌钢板的制造方法，包括对以质量计含有0.5％以上的Si和0.5％以上的Mn的母材钢板依次进行热处理步骤、热浸镀步骤和合金化处理步骤，其特征在于，
    所述热处理步骤包括第一加热阶段和均热阶段，其中，
    所述第一加热阶段的第一加热气氛含有0.01-0.5％体积分数、优选0.03-0.3％体积分数的O 2，余量为N 2和不可避免的杂质，所述均热阶段的均热气氛含有0.5％以上体积分数的H 2，余量为N 2和不可避免的杂质，以及控制所述第一加热气氛和所述均热气氛的露点≥-20℃。
  2. 根据权利要求1所述的制造方法，其特征在于，所述热处理步骤还包括第二加热阶段，所述第二加热阶段的第二加热气氛含有0.5％以上体积分数的H 2，余量为N 2和不可避免的杂质，以及控制所述第二加热气氛的露点≥-20℃。
  3. 根据权利要求1所述的制造方法，其特征在于，所述母材钢板以质量计含有0.1-0.3％的C、0.5-3.0％的Si、0.5-4.0％的Mn，余量为Fe和不可避免的杂质。
  4. 根据权利要求1-3中任一项所述的制造方法，其特征在于，所述热浸镀步骤中，入锌锅时钢板温度为450-520℃，镀液温度为450-500℃，镀液中以质量计含有0.10-0.15％的Al，余量为Zn及不可避免的杂质，完成所述热浸镀步骤的钢板每单面镀锌附着量为30-90g/m 2。
  5. 根据权利要求1-3中任一项所述的制造方法，其特征在于，控制所述合金化处理步骤的钢板温度≤500℃，合金化处理时间≤25秒。
  6. 根据权利要求5所述的制造方法，其特征在于，控制所述合金化处理步骤的钢板温度≥460℃，合金化处理时间≥5秒。
  7. 根据权利要求1-3中任一项所述的制造方法，其特征在于，控制所述第一加热阶段的出口温度为570-750℃。
  8. 根据权利要求1-3中任一项所述的制造方法，其特征在于，控制所述均热阶段的钢板温度为750-930℃，时间为30-300秒。
  9. 根据权利要求2所述的制造方法，其特征在于，所述第二加热气氛、所述均热气氛的H 2体积分数≤10％。
  10. 根据权利要求2所述的制造方法，其特征在于，控制所述第一加热气氛、所述第 二加热气氛、所述均热气氛的露点≤30℃。
  11. 根据权利要求2所述的制造方法，其特征在于，控制所述第一加热气氛、所述第二加热气氛、所述均热气氛的露点≥-10℃。
  12. 根据权利要求2所述的制造方法，其特征在于，控制所述第一加热气氛、所述第二加热气氛、所述均热气氛的露点≥0℃。
  13. 一种热镀锌钢板，由权利要求1-12中任一项所述的制造方法制备。
  14. 根据权利要求13所述的热镀锌钢板，其特征在于，所述钢板由外向内包括锌铁合金镀层、内氧化层，所述锌铁合金镀层以质量计含有7-13％的Fe，组织中残余奥氏体相比例≥5％，所述钢板的抗拉强度≥980MPa，断裂延伸率≥20％。
  15. 一种车用构件，由权利要求13-14中任一项所述的热镀锌钢板制成。
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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2024053544A1 (ja) * 2022-09-07 2024-03-14 Ｊｆｅスチール株式会社 高強度溶融亜鉛めっき鋼板およびその製造方法

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101809182A (zh) 2007-06-29 2010-08-18 安赛乐米塔尔法国公司 通过dff调节制造锌镀层退火的钢片材的方法
JP2010215998A (ja) * 2009-03-19 2010-09-30 Jfe Steel Corp 高強度溶融亜鉛めっき鋼板および高強度合金化溶融亜鉛めっき鋼板の製造方法
CN103597102A (zh) * 2011-06-01 2014-02-19 杰富意钢铁株式会社 材质稳定性、加工性和镀层外观优良的高强度热镀锌钢板的制造方法
CN103814148A (zh) * 2011-09-20 2014-05-21 杰富意钢铁株式会社 涂装后耐腐蚀性优良的合金化热镀锌钢板
CN104245996A (zh) * 2012-04-17 2014-12-24 杰富意钢铁株式会社 镀层密合性和滑动特性优良的合金化热镀锌钢板的制造方法
CN110878386A (zh) * 2018-09-06 2020-03-13 本钢板材股份有限公司 一种低成本热镀锌相变诱导塑性钢及其制备方法

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102012101018B3 (de) * 2012-02-08 2013-03-14 Thyssenkrupp Nirosta Gmbh Verfahren zum Schmelztauchbeschichten eines Stahlflachprodukts
EP2940176B1 (en) * 2013-03-04 2019-03-27 JFE Steel Corporation High-strength steel sheet, method for manufacturing same, high-strength molten-zinc-plated steel sheet, and method for manufacturing same
JP5799996B2 (ja) * 2013-09-12 2015-10-28 Ｊｆｅスチール株式会社 外観性とめっき密着性に優れる溶融亜鉛めっき鋼板および合金化溶融亜鉛めっき鋼板ならびにそれらの製造方法
MX2016007518A (es) * 2013-12-13 2016-09-13 Jfe Steel Corp Metodo para la produccion de laminas de acero recocidas despues de galvanizadas de alta resistencia.
JP5842942B2 (ja) * 2014-02-03 2016-01-13 Ｊｆｅスチール株式会社 めっき密着性に優れた合金化溶融亜鉛めっき鋼板およびその製造方法
US10570474B2 (en) * 2014-07-02 2020-02-25 Jfe Steel Corporation Method for manufacturing high-strength galvanized steel sheet
CN106350731B (zh) * 2016-08-30 2018-08-10 宝山钢铁股份有限公司 一种具有优良磷化性能和成形性的冷轧高强度钢板及其制造方法
EP3502300B1 (en) * 2016-10-25 2021-01-13 JFE Steel Corporation Method for producing high strength hot-dip galvanized steel sheet
CN106987790A (zh) * 2017-04-10 2017-07-28 唐山钢铁集团有限责任公司 高硅高锰镀锌钢带的连续镀锌方法

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101809182A (zh) 2007-06-29 2010-08-18 安赛乐米塔尔法国公司 通过dff调节制造锌镀层退火的钢片材的方法
JP2010215998A (ja) * 2009-03-19 2010-09-30 Jfe Steel Corp 高強度溶融亜鉛めっき鋼板および高強度合金化溶融亜鉛めっき鋼板の製造方法
CN103597102A (zh) * 2011-06-01 2014-02-19 杰富意钢铁株式会社 材质稳定性、加工性和镀层外观优良的高强度热镀锌钢板的制造方法
CN103814148A (zh) * 2011-09-20 2014-05-21 杰富意钢铁株式会社 涂装后耐腐蚀性优良的合金化热镀锌钢板
CN104245996A (zh) * 2012-04-17 2014-12-24 杰富意钢铁株式会社 镀层密合性和滑动特性优良的合金化热镀锌钢板的制造方法
CN110878386A (zh) * 2018-09-06 2020-03-13 本钢板材股份有限公司 一种低成本热镀锌相变诱导塑性钢及其制备方法

Cited By (1)

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WO2024053544A1 (ja) * 2022-09-07 2024-03-14 Ｊｆｅスチール株式会社 高強度溶融亜鉛めっき鋼板およびその製造方法

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