WO2021175318A1 - Three-layer composite structure high-strength steel plate and manufacturing method therefor - Google Patents

Three-layer composite structure high-strength steel plate and manufacturing method therefor Download PDF

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WO2021175318A1
WO2021175318A1 PCT/CN2021/079355 CN2021079355W WO2021175318A1 WO 2021175318 A1 WO2021175318 A1 WO 2021175318A1 CN 2021079355 W CN2021079355 W CN 2021079355W WO 2021175318 A1 WO2021175318 A1 WO 2021175318A1
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layer
composite structure
strength steel
steel sheet
steel plate
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French (fr)
Chinese (zh)
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朱晓东
薛鹏
李伟
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宝山钢铁股份有限公司
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    • 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
    • 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
    • C21D3/00—Diffusion processes for extraction of non-metals; Furnaces therefor
    • C21D3/02—Extraction of non-metals
    • C21D3/04—Decarburising
    • 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
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or 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
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
    • C21D8/0226—Hot rolling
    • 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
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
    • C21D8/0236—Cold rolling
    • 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
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0247—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment
    • C21D8/0257—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment with diffusion of elements, e.g. decarburising, nitriding
    • 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
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
    • 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
    • C22C38/12—Ferrous alloys, e.g. steel alloys containing tungsten, tantalum, molybdenum, vanadium, or niobium
    • 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
    • C22C38/14—Ferrous alloys, e.g. steel alloys containing titanium or zirconium
    • 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
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • 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
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/22—Ferrous alloys, e.g. steel alloys containing chromium with molybdenum or tungsten
    • 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
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/28—Ferrous alloys, e.g. steel alloys containing chromium with titanium or zirconium
    • 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
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/32—Ferrous alloys, e.g. steel alloys containing chromium with boron
    • 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
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/34—Ferrous alloys, e.g. steel alloys containing chromium with more than 1.5% by weight of 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
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/38—Ferrous alloys, e.g. steel alloys containing chromium with more than 1.5% by weight of manganese
    • 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
    • C21D2211/002—Bainite
    • 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
    • C21D2211/005—Ferrite
    • 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
    • C21D2211/008—Martensite

Definitions

  • the invention relates to a steel plate and a manufacturing method thereof, in particular to a high-strength steel plate and a manufacturing method thereof.
  • the laminated composite structure steel plate is an effective attempt to solve this problem, which can compensate to a certain extent for the decrease in formability and toughness caused by the increase in the strength of the steel plate.
  • the so-called layered composite structure refers to a multi-layer steel plate with distinct structures, strength and hardness layers in the thickness direction of the steel plate.
  • Rolling composite technology is a traditional technology for manufacturing laminated composite steel sheets.
  • cold-rolled steel sheets with a multi-layer composite structure in the prior art generally adopt three or more sets of steel plates with different compositions and structures.
  • three-layer or multi-layer steel plates with different structures are obtained.
  • the process of rolling and compounding is complicated and requires interface cleaning, and the three-layer steel plate needs to be processed to a specific thickness and then rolled and compounded.
  • the cost is high, and defects of poor bonding at the steel plate interface are prone to occur.
  • the publication number is CN102015423B
  • the publication date is October 1, 2014
  • the Chinese patent document titled "Application of Metal Composite Materials in Motor Vehicle Structures” discloses a coilable multi-layer fabricated by a roll method.
  • Metal composite materials can be effectively used for body structure.
  • the composite material of the invention is composed of three layers of different steel plates through hot-rolling and compounding to form three layers of composite steel plates with different structures, wherein at least one layer is a high-strength or very high-strength alloy steel.
  • the process of rolling and compounding is complicated and costly, and defects of poor bonding at the steel plate interface may occur.
  • One of the objectives of the present invention is to provide a three-layer composite structure high-strength steel plate.
  • the obtained three-layer composite structure high-strength steel plate has three layers of different tissue regions from top to bottom.
  • the reasonable distribution of the different tissues makes the high-strength steel plate have soft surface and internal Hard and other characteristics.
  • the low-hardness structure of the surface layer of the steel plate has good shape and toughness, and the high-strength structure of the inner layer is conducive to ensuring high strength and effectively improving the formability and toughness of ultra-high-strength steel.
  • the present invention provides a three-layer composite structure high-strength steel sheet, which has an upper surface layer, a lower layer, and a center layer located between the upper surface layer and the lower layer in the thickness direction of the steel plate; wherein the upper surface layer and The microstructure of the lower layer is a complete ferrite structure or a structure with a phase ratio (volume ratio) of ferrite> 50%, preferably ⁇ 70%; the microstructure of the center layer includes martensite and bainite At least one of; wherein the ferrite content of the central layer is less than the ferrite content of the upper and lower layers.
  • the steel plate has three layers of different tissue regions from top to bottom, and the strengths of different regions are different.
  • the reasonable distribution of different tissues makes the high-strength steel plate of the present invention have the characteristics of soft surface and hard inside, as well as high strength and excellent formability. It can be used to manufacture automobile safety parts and structural parts, improve the bending formability of high-strength steel plates and the deformation and energy absorption performance of the finished parts, which is beneficial to the safety protection of the finished parts.
  • the microstructure of the central layer is martensite, bainite or martensite with a phase ratio (volume ratio) ⁇ 50%, preferably ⁇ 70% Body + Bainite.
  • the microstructure of the center layer also includes: ferrite, carbide, and metastable austenite with a phase ratio (volume ratio) ⁇ 50% At least one of them.
  • the ferrite structure of the upper surface layer and the lower layer further contains carbides.
  • the three-layer composite structure high-strength steel sheet of the present invention is a cold-rolled steel sheet with a thickness of 0.5-2.5 mm.
  • the three-layer composite structure high-strength steel sheet of the present invention is a hot-rolled steel sheet with a thickness of 1.0-3.0 mm.
  • the thickness of the upper surface layer is 5-100 micrometers; and/or the thickness of the lower surface layer is 5-100 micrometers.
  • the thickness of the upper surface layer is greater than 100 microns; and/or the thickness of the lower surface layer is greater than 100 microns.
  • the ultra-high-strength steel not only has high strength, but also has good formability and toughness. It is necessary to rationally design each chemical element to ensure that the obtained three-layer composite structure high-strength steel plate has excellent performance.
  • the three-layer composite structure high-strength steel sheet of the present invention contains the following chemical elements: C: 0.08-0.35%; Si: 0.01-2.5%; Mn: 0.5-3.0%.
  • the mass percentage content of each chemical element is: C: 0.08-0.35%; Si: 0.01-2.5%; Mn: 0.5-3.0%; the balance It is Fe and other unavoidable impurities.
  • C In the three-layer composite structure high-strength steel sheet of the present invention, C can increase the strength of the steel by affecting the martensite hardness. If the carbon content in the steel is too low, the strength of the steel after quenching will be lower, the formability and toughness will be better, and the effect of the layered composite structure will be less obvious; the higher the carbon content in the steel, the stronger the strength of the steel after quenching. High, the more obvious the effect of the lamellar structure in the steel of the present invention. Compared with the general ultra-high-strength steel with a tensile strength of 980 MPa or more, the present invention has obvious effects.
  • the mass percentage of C is controlled to be between 0.08-0.35%, so that after quenching, a high-strength steel sheet with a tensile strength of 980 MPa or more can be obtained, and excellent performance can be obtained. improve.
  • Si is a common element in phase-change strengthening ultra-high-strength steel, which can play a role in solid solution strengthening, changing the phase transformation kinetic curve, and changing the type of structure. Effectively used to improve the performance of a variety of advanced high-strength steels. Therefore, similar to the addition amount of Si in common high-strength steels, in the three-layer composite structure high-strength steel sheet of the present invention, the mass percentage of Si is controlled to be between 0.01-2.5%. In some embodiments, the mass percentage of Si is controlled to be between 0.1% and 1.5%, preferably between 0.3% and 1.0%.
  • Mn is the main element that improves the hardenability of the steel.
  • the content of Mn needs to match the cooling capacity of the selected cooling method.
  • the mass percentage of Mn is controlled to be between 0.5-3.0%. In some embodiments, the mass percentage of Mn is controlled to be between 1.0-2.5%, preferably between 1.5-2.5%.
  • the three-layer composite structure high-strength steel sheet of the present invention also contains at least one of Cr, Mo, and B; wherein, when B ⁇ 0.0005%, Cr+Mn+Mo ⁇ 3%; When B is 0.0005 to 0.0035%, Cr+Mn+Mo ⁇ 2.3% or ⁇ 2.0%.
  • the Cr, Mn, and Mo in the formula all represent their mass percentages.
  • the mass percentage of Cr is controlled to be 0.05-0.20%, preferably 0.10-0.15%
  • the mass percentage of Mo is controlled to be 0.05-0.20%, preferably 0.05-0.10%
  • the mass percentage of B is ⁇ 0.0035%
  • the content of Cr+Mn+Mo meets the above requirements.
  • an appropriate amount of alloying elements such as Cr, Mo, B can be effectively combined with manganese, so as to improve the hardenability effect, so that the hardenability of the steel and the rapid cooling section
  • the cooling capacity is matched to avoid the inability to harden or the carbon equivalent to be too high.
  • the three-layer composite structure high-strength steel sheet of the present invention it further contains at least one of V, Ti, and Nb, and V+Ti+Nb ⁇ 0.15%, preferably ⁇ 0.12%.
  • the V, Ti, and Nb in the formula all represent their mass percentages.
  • the mass percentage of control V is 0.01-0.10%, preferably 0.03-0.08%
  • the mass percentage of Ti is 0.01-0.05%
  • the mass percentage of Nb is 0.01-0.05%
  • V+Ti +Nb meets the above requirements.
  • the three-layer composite structure high-strength steel sheet of the present invention it further contains Al: 0.03-0.30%, preferably 0.04-0.25%.
  • the content of P, S and N as inevitable impurities is controlled as follows: P ⁇ 0.015%, S ⁇ 0.01%, and N ⁇ 0.03%.
  • the content of P, S, and N is: P, 0.005-0.015%; S, 0.001-0.005%; N, 0.001-0.025%.
  • the overall tensile strength of the three-layer composite structure high-strength steel sheet is between 980-1700 MPa, and the microhardness of the upper surface layer and the lower layer is HV ⁇ 250, preferably ⁇ 150, such as 100-150, and the microhardness HV of the intermediate layer is ⁇ 270, preferably ⁇ 300, such as 310-550.
  • the overall yield strength of the three-layer composite structure high-strength steel plate is ⁇ 600 MPa, such as 610-1350 MPa.
  • another object of the present invention is to provide a method for manufacturing a three-layer composite structure high-strength steel plate.
  • the three-layer composite structure high-strength steel plate obtained by the manufacturing method has three different organizational regions from top to bottom, and the surface layer has low hardness.
  • the shape and toughness of the structure are good, and the high-strength structure of the inner layer is conducive to ensuring high strength and realizing the improvement of the formability and toughness of ultra-high-strength steel.
  • the present invention proposes the above-mentioned three-layer composite structure high-strength steel plate manufacturing method, the method includes the steps of: steelmaking, continuous casting, rolling and high-temperature humidification and decarburization; wherein, the high-temperature humidification and decarburization
  • the process conditions of carbon are: the steel plate temperature is 750 ⁇ 900°C, the dew point is -15 ⁇ 15°C, and the reaction time is 40-160s.
  • the present invention can make the upper surface layer and the lower layer of the steel plate become decarburized layers with a thickness of more than 5 microns (that is, both the upper surface layer and the lower layer are decarburized layers) through high temperature humidification and decarburization.
  • the rolling includes hot rolling or cold rolling after hot rolling.
  • Pickling is carried out after hot rolling.
  • the hot rolling, pickling and cold rolling can be conventional hot rolling, pickling and cold rolling in this field, and suitable hot rolling, pickling and cold rolling processes can be selected according to the high-strength steel manufactured.
  • the high temperature humidification decarburization can be carried out in a high temperature humidification decarburization furnace or an annealing furnace, as long as the process parameters meet the high temperature humidification decarburization process conditions of the present invention.
  • the manufacturing method of the present invention includes steelmaking, continuous casting, rolling, high temperature humidification decarburization and continuous annealing in a high temperature humidification decarburization furnace, wherein high temperature can be performed in the continuous annealing step. Humidification and decarburization or no high temperature humidification and decarburization.
  • the manufacturing method of the present invention includes steelmaking, continuous casting, rolling, and continuous annealing, wherein high-temperature humidification and decarburization can be performed in the continuous annealing step.
  • the process conditions of the continuous annealing of the present invention include: the holding temperature is 750-900°C, and the holding time is 40-160s.
  • the continuous annealing process parameters also include: the rapid cooling start temperature is 650-780°C, the rapid cooling speed is 30-1500°C/s, and the rapid cooling termination temperature is 50-450°C, preferably 50-380°C; and/or, over-aging The temperature is 180-450°C, and the over-aging time is 200-600s.
  • Quick cooling can be carried out by conventional water cooling or gas cooling.
  • the cooling medium used for the exemplary gas cooling usually contains hydrogen and nitrogen.
  • the temperature of the steel sheet in the annealing furnace is controlled to be 750 ⁇ 900°C, the dew point is -15 ⁇ 15°C, and the reaction is carried out for 40-160s to complete the high temperature humidification. Decarbonization.
  • the upper and lower surface layers of the steel plate can become the thickness of each Decarburized layer above 100 microns.
  • the three-layer composite structure high-strength steel sheet when it is a hot-rolled steel sheet, it includes the steps of: steelmaking, continuous casting, hot rolling, pickling and continuous annealing; wherein high-temperature humidification is performed in the continuous annealing step.
  • Decarburization Under the condition of steel plate temperature of 750 ⁇ 900°C, the dew point in the annealing furnace is controlled to be -15 ⁇ 15°C, and the reaction time is 40-160s, so that the upper and lower layers of the steel plate have a thickness of 5-100 respectively. Micron decarburized layer (that is, the upper and lower layers are both decarburized layers).
  • the steel sheet with uniform composition and structure is then hot-rolled and pickled, and then heated at a high temperature in a continuous annealing furnace.
  • the decarburized layer on the surface maintains the structure of full ferrite or ferrite, and the undecarburized area in the core is rapidly cooled to form martensite and bainite. Or martensite + bainite-based organization.
  • the ferrite content of the core structure is significantly lower than the surface ferrite content, and the obtained three-layer composite structure high-strength steel plate has the characteristics of high strength and low surface hardness.
  • the reason for choosing a steel plate temperature of 750 to 900°C is that it is beneficial to the decarburization reaction of the steel plate. Too low steel plate temperature will lead to insufficient decarburization, and too high steel plate temperature will affect the plate shape.
  • the reason for choosing the dew point in the furnace to be between -15 and +15 °C is because the dew point is lower than -15 °C, the decarburization reaction of the steel plate is not obvious, higher than +15 °C, there is a risk of excessive oxidation of Fe.
  • the continuous annealing process parameters are controlled in the continuous annealing step to satisfy at least one of the following items:
  • the start temperature of rapid cooling is 650-780°C; the speed of rapid cooling is 30-1500°C/s; the end temperature of rapid cooling is 50-450°C, preferably 50-380°C;
  • the over-aging temperature is 180-450°C; the over-aging time is 200-600s.
  • the three-layer composite structure high-strength steel sheet of the present invention when the three-layer composite structure high-strength steel sheet is a hot-rolled steel sheet, it includes the steps of: steelmaking, continuous casting, hot rolling, pickling , High temperature humidification decarburization furnace decarburization and continuous annealing; among them, in the high temperature humidification decarburization furnace decarburization process, under the condition of the steel plate temperature of 750 ⁇ 900°C, the dew point in the annealing furnace is controlled to be -15 ⁇ 15°C, The reaction time is 40-160s, so that the upper and lower layers of the steel plate become decarburized layers with a thickness of 5-100 microns, respectively.
  • the decarburization process is carried out in an independent high-temperature humidification decarburization furnace.
  • the method of humidification in the furnace is used, Increase the content of water vapor in the furnace, control the dew point in the furnace between -15 ⁇ +15°C, and control the holding time between 40-160s.
  • Humidification at high temperatures enables water vapor to decarburize with carbon in the steel plate at high temperatures, thereby decarburizing the surface of the steel plate.
  • the continuous annealing furnace can choose not to humidify and decarburize, so as to maintain the thickness of the decarburization layer formed on the upper and lower layers of the steel sheet to be 5-100 microns.
  • the continuous annealing process parameters are controlled in the continuous annealing step to satisfy at least one of the following items:
  • the start temperature of rapid cooling is 650-780°C; the speed of rapid cooling is 30-1500°C/s; the end temperature of rapid cooling is 50-450°C, preferably 50-380°C;
  • the over-aging temperature is 180-450°C; the over-aging time is 200-600s.
  • the high-temperature humidification and decarburization is continued in the continuous annealing step: the dew point in the annealing furnace is controlled to be -15 under the condition of the steel sheet temperature of 750 to 900°C ⁇ 15°C, and the reaction time is 40-160s, so that the upper and lower layers of the steel plate become decarburized layers with a thickness of more than 100 microns, respectively.
  • the steel is hot-rolled and pickled, and after the high-temperature humidification and decarburization in the independent high-temperature humidification and decarburization furnace is completed, the high-temperature humidification and decarburization can be performed again in the continuous annealing step. Secondary humidification and decarburization are performed to obtain a thicker decarburized layer, so that the upper and lower layers of the steel sheet become decarburized layers with a thickness greater than 100 microns.
  • the three-layer composite structure high-strength steel sheet when the three-layer composite structure high-strength steel sheet is a cold-rolled steel sheet, it includes the steps of: steelmaking, continuous casting, hot rolling, and cold rolling. And continuous annealing; among them, high temperature humidification and decarburization is carried out in the continuous annealing step: under the condition of the steel plate temperature of 750 ⁇ 900°C, the dew point in the annealing furnace is controlled to be -15 ⁇ 15°C, and the reaction time is 40-160s to make The upper and lower layers of the steel plate become decarburized layers with a thickness of 5-100 microns, respectively.
  • the continuous annealing process parameters are controlled in the continuous annealing step to satisfy at least one of the following items:
  • the start temperature of rapid cooling is 650-780°C; the speed of rapid cooling is 30-1500°C/s; the end temperature of rapid cooling is 50-450°C, preferably 50-380°C;
  • the over-aging temperature is 180-450°C; the over-aging time is 200-600s.
  • the three-layer composite structure high-strength steel sheet when the three-layer composite structure high-strength steel sheet is a cold-rolled steel sheet, it includes the steps of: steelmaking, continuous casting, hot rolling, and cold rolling. , High temperature humidification decarburization furnace decarburization and continuous annealing; among them, in the high temperature humidification decarburization furnace decarburization process, under the condition of the steel plate temperature of 750 ⁇ 900°C, the dew point in the annealing furnace is controlled to be -15 ⁇ 15°C, The reaction time is 40-160s, so that the upper and lower layers of the steel plate become decarburized layers with a thickness of 5-100 microns, respectively.
  • the continuous annealing furnace can choose not to humidify the decarburization, so as to maintain the thickness of the decarburization layer formed on the upper and lower layers of the steel plate. 5-100 microns.
  • the continuous annealing process parameters are controlled in the continuous annealing step to satisfy at least one of the following items:
  • the start temperature of rapid cooling is 650-780°C; the speed of rapid cooling is 30-1500°C/s; the end temperature of rapid cooling is 50-450°C, preferably 50-380°C;
  • the dew point in the annealing furnace is controlled under the condition of the steel sheet temperature of 750 to 900°C
  • the temperature is -15 to 15°C
  • the reaction time is 40-160s, so that the upper and lower layers of the steel plate become decarburized layers with a thickness of more than 100 microns.
  • the core key process is continuous annealing or the control of the humidification and decarburization reaction in an independent high-temperature humidification and decarburization furnace.
  • only Moisturizing and decarburizing in a continuous annealing furnace is more conducive to reducing costs and improving competitiveness.
  • the three-layer composite structure high-strength steel plate of the present invention adopts a reasonable decarburization process, so that the high-strength steel plate has three layers of different tissue regions from top to bottom, and the reasonable distribution of the different structures makes the high-strength steel plate have a surface Soft and internal hard features.
  • the low-hardness structure of the surface of the steel plate has good shape and toughness, and the high-strength structure of the inner layer ensures the high strength of the steel plate, and realizes the improvement of the formability and toughness of the ultra-high-strength steel.
  • the three-layer composite structure high-strength steel sheet of the present invention has better performance than the existing traditional rolling composite prepared multi-layer composite steel sheet, and its overall tensile strength is between 980-1700 MPa, and the microhardness of the upper and lower layers is HV ⁇ 250, the microhardness of the middle layer HV ⁇ 270. It can be used in the manufacture of automobile safety parts and structural parts to improve the bending formability of high-strength steel plates and the deformation and energy absorption performance of the finished parts, thereby playing a role in facilitating the safety protection of the finished parts.
  • the manufacturing method of the present invention adopts the composition design and process parameter design of the three-layer composite structure high-strength steel plate, while reducing the production cost, obtains the overall tensile strength between 980-1700 MPa, high strength, and shaping, Composite structure steel plate with good toughness.
  • Fig. 1 shows the cross-sectional microstructure morphology of the three-layer composite structure high-strength steel plate described in Example 4 near the upper surface.
  • Figure 2 shows the cross-sectional microstructure morphology near the upper surface of the steel plate in Comparative Example 1 of the present invention.
  • Figure 3 shows the cross-sectional microstructure morphology near the upper surface of the three-layer composite structure high-strength steel sheet described in Example 3 of the present invention.
  • the three-layer composite structure high-strength steel plate of the present invention is prepared by the following steps:
  • Continuous annealing high-temperature humidification and decarburization are carried out in continuous annealing. Under the condition of steel plate temperature of 750 ⁇ 900°C, the dew point in the annealing furnace is controlled to be -15 ⁇ 15°C, and the reaction time is 40-160s.
  • the holding temperature is controlled to be 750-900°C, and the holding time is 40-160s; the starting temperature of rapid cooling is controlled to 650-780°C; the speed of rapid cooling is 30-1500°C/s; the end temperature of rapid cooling is 50-450°C ;
  • the over-aging temperature is 180-450°C; the over-aging time is 200-600s.
  • the three-layer composite structure high-strength steel plate of the present invention is prepared by the following steps:
  • High temperature humidification decarburization furnace decarburization in the decarburization process of high temperature humidification decarburization furnace, the dew point in the high temperature humidification decarburization furnace is controlled to be -15 ⁇ 15 under the condition of the steel plate temperature of 750 ⁇ 900°C °C, the reaction time is 40-160s,
  • Continuous annealing In continuous annealing, control the holding temperature to 780-900°C, control the dew point in the furnace to be lower than -20°C, control the holding time to 40-160s, control the fast cooling start temperature to 650-780°C, and control fast
  • the cooling rate is 30-1500°C/s
  • the termination temperature of rapid cooling is controlled to 50-450°C
  • the over-aging temperature is controlled to 180-450°C
  • the over-aging time is 200-600s.
  • the three-layer composite structure high-strength steel plate of the present invention is prepared by the following steps:
  • High temperature humidification decarburization furnace decarburization in the decarburization process of high temperature humidification decarburization furnace, under the condition of steel plate temperature of 750 ⁇ 900°C, control the dew point in the high temperature humidification decarburization furnace to -15 ⁇ 15 °C, the reaction time is 40-160s,
  • Continuous annealing in continuous annealing, high-temperature humidification and decarburization are carried out again, the temperature of the steel plate is controlled to be 750-900 °C, the dew point in the annealing furnace is controlled to be -15 to 15 °C, and the reaction time is 40-160s.
  • the holding temperature is controlled to be 780-900°C, and the holding time is 40-160s; the starting temperature of rapid cooling is controlled to 650-780°C; the speed of rapid cooling is 30-1500°C/s; the end temperature of rapid cooling is 50-450°C ;
  • the over-aging temperature is 180-450°C; the over-aging time is 200-600s.
  • the three-layer composite structure high-strength steel plate of the present invention is prepared by the following steps:
  • Continuous annealing high-temperature humidification and decarburization are carried out in continuous annealing. Under the condition of steel plate temperature of 750 ⁇ 900°C, the dew point in the annealing furnace is controlled to be -15 ⁇ 15°C, and the reaction time is 40-160s.
  • the holding temperature is controlled at 780-900°C, the holding time is 40-160s, the starting temperature of fast cooling is 650-780°C, the speed of fast cooling is 30-1500°C/s, and the end temperature of fast cooling is 50-450°C ,
  • the over-aging temperature is 180-450°C, and the over-aging time is 200-600s.
  • the three-layer composite structure high-strength steel plate of the present invention is prepared by the following steps:
  • High temperature humidification decarburization furnace decarburization in the decarburization process of high temperature humidification decarburization furnace, the dew point in the high temperature humidification decarburization furnace is controlled to be -15 ⁇ 15 under the condition of the steel plate temperature of 750 ⁇ 900°C °C, the reaction time is 40-160s,
  • Continuous annealing In continuous annealing, control the holding temperature to 780-900°C, control the dew point in the furnace to be lower than -20°C, control the holding time to 40-160s, control the fast cooling start temperature to 650-780°C, and control fast
  • the cooling rate is 30-1500°C/s
  • the termination temperature of rapid cooling is controlled to 50-450°C
  • the over-aging temperature is controlled to 180-450°C
  • the over-aging time is 200-600s.
  • the three-layer composite structure high-strength steel plate of the present invention is prepared by the following steps:
  • Continuous annealing in continuous annealing, high-temperature humidification and decarburization are carried out again, the temperature of the steel plate is controlled to be 750-900 °C, the dew point in the annealing furnace is controlled to be -15 to 15 °C, and the reaction time is 40-160s.
  • the holding temperature is controlled at 780-900°C, the holding time is 40-160s, the starting temperature of fast cooling is 650-780°C, the speed of fast cooling is 30-1500°C/s, and the end temperature of fast cooling is 50-450°C ,
  • the over-aging temperature is 180-450°C, and the over-aging time is 200-600s.
  • Table 1 lists the mass percentage ratios of various chemical elements of the steel types used in the various examples and comparative examples of the present invention.
  • Table 2 lists the specific process parameters of the three-layer composite structure high-strength steel plate of Examples 1-16 and the steel plate of Comparative Example 1.
  • Table 3 lists the three-layer composite structure high-strength steel plates of Examples 1-16 and the relevant performance parameters of the steel plates of Comparative Example 1.
  • the three-layer composite structure high-strength steel plate treated by the manufacturing method of the present invention in Examples 1-6 of this case is decarburized
  • the hardness of the layer is significantly reduced, and the surface layer has a low-hardness structure with good toughness and excellent performance.
  • the three-layer composite structure high-strength steel sheet of the present invention has a soft surface layer and a hard inner layer, which can effectively improve the formability and toughness of the ultra-high-strength steel.
  • the high-strength steel plate have better performance than the existing traditional rolling composite multi-layer composite steel plate.
  • Its overall tensile strength is between 985-1700 MPa, and the microhardness of the upper and lower layers is between 985 and 1700 MPa.
  • Fig. 1 shows the cross-sectional microstructure morphology of the three-layer composite structure high-strength steel plate described in Example 4 near the upper surface. It can be seen from Figure 1 that the three-layer composite structure high-strength steel plate in this embodiment has a decarburized layer mainly composed of ferrite structure on the upper surface layer, which is significantly different from the center layer mainly composed of martensite structure. Organization morphology.
  • Figure 2 shows the cross-sectional microstructure morphology near the upper surface of the steel plate in Comparative Example 1 of the present invention. It can be seen from Fig. 2 that the conventional structure of the high-strength steel plate in this comparative example is a martensitic structure with substantially uniform surface layer and central area, which is obviously different from the layered composite structure in the high-strength steel plate of Example 4 in Fig. 1.
  • Fig. 3 shows the cross-sectional microstructure morphology near the upper surface of the three-layer composite structure high-strength steel sheet described in Example 3 of the present invention. It can be seen from Figure 3 that the three-layer composite structure high-strength steel plate in this embodiment has obtained a decarburized layer mainly composed of ferrite structure on the upper surface layer, and a center layer mainly composed of martensite + bainite structure. Presents a significantly different organization morphology.
  • the volume percentage of martensite in the center layer is about 40%, the volume percentage of bainite is about 30%, and there is about 30% ferrite.

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Abstract

Disclosed is a three-layer composite structure high-strength steel plate provided with an upper surface layer, a lower surface layer and a central layer located between the upper surface layer and the lower surface layer in a thickness direction of the steel plate, wherein microstructures of the upper surface layer and the lower surface layer are complete ferrite structures or structures in which a phase proportion of ferrite is greater than 50%; a microstructure of the central layer comprises at least one of martensite and bainite; and the ferrite content of the central layer is less than the ferrite content of the upper surface layer and the lower surface layer. In addition, further disclosed in the present invention is a manufacturing method for a three-layer composite structure high-strength steel plate. The three-layer composite structure high-strength steel plate of the present invention has the features of a soft surface and a hard interior, a low-hardness structure of the surface layer is good in terms of shaping and toughness, and the high strength of the inner-layer high-strength structure is favorable for ensuring a high strength, such that the formability and toughness of the ultrahigh-strength steel are improved by simple means.

Description

一种三层复合组织高强钢板及其制造方法Three-layer composite structure high-strength steel plate and manufacturing method thereof 技术领域Technical field
本发明涉及一种钢板及其制造方法，尤其涉及一种高强钢板及其制造方法。The invention relates to a steel plate and a manufacturing method thereof, in particular to a high-strength steel plate and a manufacturing method thereof.
背景技术Background technique
随着汽车制造业的发展，节能和安全成为了汽车制造业的主要发展方向。汽车工业出于减重和安全性的需要，需要使用更高强度的钢板，但高强钢随着强度的增加，塑性、韧性和成形性会降低，这些相互矛盾的性能关系，制约了高强钢的应用。层状复合组织钢板是解决这一问题的有效尝试，可以在一定程度上弥补钢板强度增加带来的成形性和韧性的下降。所谓层状复合组织是指在钢板厚度方向上存在有明显的不同组织和强度、硬度层的多层状钢板。轧制复合技术是制造层状复合组织钢板的传统技术。With the development of the automobile manufacturing industry, energy conservation and safety have become the main development directions of the automobile manufacturing industry. For the needs of weight reduction and safety, the automobile industry needs to use higher-strength steel plates. However, as the strength of high-strength steel increases, plasticity, toughness and formability will decrease. These conflicting performance relationships restrict the development of high-strength steels. application. The laminated composite structure steel plate is an effective attempt to solve this problem, which can compensate to a certain extent for the decrease in formability and toughness caused by the increase in the strength of the steel plate. The so-called layered composite structure refers to a multi-layer steel plate with distinct structures, strength and hardness layers in the thickness direction of the steel plate. Rolling composite technology is a traditional technology for manufacturing laminated composite steel sheets.
目前，现有技术中多层复合组织冷轧钢板一般采用的都是采用三组或多组不同成分和组织的钢板，通过轧制复合的方式，获得组织不同的三层或多层钢板，其轧制复合过程工艺复杂，需要进行界面清理，并且需要将三层钢板分别加工成为特定的厚度再进行轧制复合、成本很高，容易出现钢板界面处结合不良的缺陷。At present, cold-rolled steel sheets with a multi-layer composite structure in the prior art generally adopt three or more sets of steel plates with different compositions and structures. Through rolling and compounding, three-layer or multi-layer steel plates with different structures are obtained. The process of rolling and compounding is complicated and requires interface cleaning, and the three-layer steel plate needs to be processed to a specific thickness and then rolled and compounded. The cost is high, and defects of poor bonding at the steel plate interface are prone to occur.
例如：公开号为CN102015423B，公开日为2014年10月01日，名称为“金属复合材料在机动车结构中的应用”的中国专利文献公开了一种通过轧辊方式制造的可卷取的多层金属复合材料，可以有效用于车身结构。该发明复合材料是由三层不同的钢板通过热轧轧制复合，组成三层组织不同的复合钢板，其中至少一层为高强度或非常高强度的合金钢。但轧制复合过程工艺复杂，成本较高，可能出现钢板界面处结合不良的缺陷。For example: the publication number is CN102015423B, the publication date is October 1, 2014, and the Chinese patent document titled "Application of Metal Composite Materials in Motor Vehicle Structures" discloses a coilable multi-layer fabricated by a roll method. Metal composite materials can be effectively used for body structure. The composite material of the invention is composed of three layers of different steel plates through hot-rolling and compounding to form three layers of composite steel plates with different structures, wherein at least one layer is a high-strength or very high-strength alloy steel. However, the process of rolling and compounding is complicated and costly, and defects of poor bonding at the steel plate interface may occur.
又例如：公开号为特开平7-275938，公开日为1995年10月24日，名称为“形状冻结性优异的复合高强度钢板”的日本专利文献公开了一种有利于改善回弹的复合高强度钢板，该复合钢板表层为500-1000MPa高强钢，内部为强度较低的250-400MPa的低强度钢。采用轧制复合制造复合钢板。但该发明成本略高。Another example: Publication No. 7-275938, publication date of October 24, 1995, Japanese patent document titled "Composite high-strength steel sheet with excellent shape freezing property" discloses a composite material that is beneficial to improve springback. High-strength steel plate, the surface layer of the composite steel plate is 500-1000MPa high-strength steel, and the inner part is low-strength low-strength steel of 250-400MPa. The composite steel plate is manufactured by rolling and compounding. But the cost of this invention is slightly higher.
发明内容Summary of the invention
本发明的目的之一在于提供一种三层复合组织高强钢板，所得的三层复合组织高强钢板从上到下有三层不同的组织区域，通过不同组织的合理分布使得高强钢板具有表面软，内部硬等特点。钢板的表层低硬度组织的塑形和韧性好，内层高强度组织有利于保证高强度，有效实现超高强度钢的成形性、韧性的提高。One of the objectives of the present invention is to provide a three-layer composite structure high-strength steel plate. The obtained three-layer composite structure high-strength steel plate has three layers of different tissue regions from top to bottom. The reasonable distribution of the different tissues makes the high-strength steel plate have soft surface and internal Hard and other characteristics. The low-hardness structure of the surface layer of the steel plate has good shape and toughness, and the high-strength structure of the inner layer is conducive to ensuring high strength and effectively improving the formability and toughness of ultra-high-strength steel.
为了实现上述目的，本发明提供了一种三层复合组织高强钢板，其在钢板的厚度方向上具有上表层、下表层和位于上表层和下表层之间的中心层；其中所述上表层和所述下表层的微观组织为完全铁素体组织或者铁素体的相比例(体积比)＞50％、优选≥70％的组织；所述中心层的微观组织包括马氏体和贝氏体的至少其中之一；其中所述中心层的铁素体含量少于上表层和下表层的铁素体含量。In order to achieve the above object, the present invention provides a three-layer composite structure high-strength steel sheet, which has an upper surface layer, a lower layer, and a center layer located between the upper surface layer and the lower layer in the thickness direction of the steel plate; wherein the upper surface layer and The microstructure of the lower layer is a complete ferrite structure or a structure with a phase ratio (volume ratio) of ferrite> 50%, preferably ≥ 70%; the microstructure of the center layer includes martensite and bainite At least one of; wherein the ferrite content of the central layer is less than the ferrite content of the upper and lower layers.
在本发明所述的技术方案中，钢板从上到下有三层不同的组织区域，不同区域的强度不同。不同组织的合理分布使得本发明的高强钢板具有表面软，内部硬的特点，同时还具有高强度和优异的成形性。可以用于制造汽车安全件和结构件，提高高强度钢板的弯曲成形性和制成零件的变形吸能性能，有利于制成零件安全保护的作用。In the technical scheme of the present invention, the steel plate has three layers of different tissue regions from top to bottom, and the strengths of different regions are different. The reasonable distribution of different tissues makes the high-strength steel plate of the present invention have the characteristics of soft surface and hard inside, as well as high strength and excellent formability. It can be used to manufacture automobile safety parts and structural parts, improve the bending formability of high-strength steel plates and the deformation and energy absorption performance of the finished parts, which is beneficial to the safety protection of the finished parts.
优选地，在本发明所述的三层复合组织高强钢板中，所述中心层的微观组织为相比例(体积比)≥50％、优选≥70％的马氏体、贝氏体或马氏体+贝氏体。Preferably, in the three-layer composite structure high-strength steel sheet of the present invention, the microstructure of the central layer is martensite, bainite or martensite with a phase ratio (volume ratio) ≥50%, preferably ≥70% Body + Bainite.
进一步地，在本发明所述的三层复合组织高强钢板中，所述中心层的微观组织还包括：相比例(体积比)＜50％的铁素体、碳化物、亚稳奥氏体的至少其中之一。Further, in the three-layer composite structure high-strength steel sheet of the present invention, the microstructure of the center layer also includes: ferrite, carbide, and metastable austenite with a phase ratio (volume ratio) <50% At least one of them.
进一步地，在本发明所述的三层复合组织高强钢板中，所述上表层和所述下表层的铁素体组织中还含有碳化物。Further, in the three-layer composite structure high-strength steel sheet of the present invention, the ferrite structure of the upper surface layer and the lower layer further contains carbides.
进一步地，在本发明所述的三层复合组织高强钢板中，所述三层复合组织高强钢板为冷轧钢板，其厚度为0.5-2.5mm。Further, in the three-layer composite structure high-strength steel sheet of the present invention, the three-layer composite structure high-strength steel sheet is a cold-rolled steel sheet with a thickness of 0.5-2.5 mm.
进一步地，在本发明所述的三层复合组织高强钢板中，所述三层复合组织高强钢板为热轧钢板，其厚度为1.0-3.0mm。Further, in the three-layer composite structure high-strength steel sheet of the present invention, the three-layer composite structure high-strength steel sheet is a hot-rolled steel sheet with a thickness of 1.0-3.0 mm.
进一步地，在本发明所述的三层复合组织高强钢板中，所述上表层的厚度为5-100微米；并且/或者所述下表层的厚度为5-100微米。Further, in the three-layer composite structure high-strength steel sheet of the present invention, the thickness of the upper surface layer is 5-100 micrometers; and/or the thickness of the lower surface layer is 5-100 micrometers.
进一步地，所述上表层的厚度＞100微米；并且/或者所述下表层的厚度大于100 微米。Further, the thickness of the upper surface layer is greater than 100 microns; and/or the thickness of the lower surface layer is greater than 100 microns.
为了使超高强度钢在具有高强度的同时还具有良好的成形性和韧性。需要通过对各化学元素的进行合理设计，从而保证所得三层复合组织高强钢板具有优异的性能。In order to make the ultra-high-strength steel not only has high strength, but also has good formability and toughness. It is necessary to rationally design each chemical element to ensure that the obtained three-layer composite structure high-strength steel plate has excellent performance.
进一步地，在本发明所述的三层复合组织高强钢板中，其含有下述各项化学元素：C：0.08-0.35％；Si：0.01-2.5％；Mn：0.5-3.0％。Further, in the three-layer composite structure high-strength steel sheet of the present invention, it contains the following chemical elements: C: 0.08-0.35%; Si: 0.01-2.5%; Mn: 0.5-3.0%.
进一步地，在本发明所述的三层复合组织高强钢板中，其各化学元素质量百分含量为：C：0.08-0.35％；Si：0.01-2.5％；Mn：0.5-3.0％；余量为Fe和其他不可避免的杂质。Further, in the three-layer composite structure high-strength steel sheet of the present invention, the mass percentage content of each chemical element is: C: 0.08-0.35%; Si: 0.01-2.5%; Mn: 0.5-3.0%; the balance It is Fe and other unavoidable impurities.
在本发明所述的三层复合组织高强钢板中，各化学元素设计原理具体情况如下所述：In the three-layer composite structure high-strength steel sheet of the present invention, the specific conditions of the design principles of each chemical element are as follows:
C：在本发明所述的三层复合组织高强钢板中，C可以通过影响马氏体硬度来提高钢的强度。若钢中含碳量过低，则淬火后钢的强度较低，成形性和韧性较好，层状复合组织的作用不太明显；而钢中含碳量越高，淬火后钢的强度越高，本发明钢中的层状组织的作用就越明显。本发明相对于一般抗拉强度980MPa以上的超高强度钢效果明显。因此，在本发明所述的三层复合组织高强钢板中，控制C的质量百分比在0.08-0.35％之间，从而在淬火后可以得到980MPa以上抗拉强度的高强钢板，并能获得优良的性能改善。C: In the three-layer composite structure high-strength steel sheet of the present invention, C can increase the strength of the steel by affecting the martensite hardness. If the carbon content in the steel is too low, the strength of the steel after quenching will be lower, the formability and toughness will be better, and the effect of the layered composite structure will be less obvious; the higher the carbon content in the steel, the stronger the strength of the steel after quenching. High, the more obvious the effect of the lamellar structure in the steel of the present invention. Compared with the general ultra-high-strength steel with a tensile strength of 980 MPa or more, the present invention has obvious effects. Therefore, in the three-layer composite structure high-strength steel sheet of the present invention, the mass percentage of C is controlled to be between 0.08-0.35%, so that after quenching, a high-strength steel sheet with a tensile strength of 980 MPa or more can be obtained, and excellent performance can be obtained. improve.
Si：本发明所述的三层复合组织高强钢板中，Si是相变强化超高强度钢中的常用元素，可以起到固溶强化、改变相变动力学曲线和改变组织类型的作用，可以有效用于改善多种先进高强钢的性能。因此，类似于常见高强钢中Si的添加量，在本发明所述的三层复合组织高强钢板中，控制Si的质量百分比在0.01-2.5％之间。在一些实施方案中，控制Si的质量百分比在0.1-1.5％之间，优先在0.3-1.0％之间。Si: In the three-layer composite structure high-strength steel sheet of the present invention, Si is a common element in phase-change strengthening ultra-high-strength steel, which can play a role in solid solution strengthening, changing the phase transformation kinetic curve, and changing the type of structure. Effectively used to improve the performance of a variety of advanced high-strength steels. Therefore, similar to the addition amount of Si in common high-strength steels, in the three-layer composite structure high-strength steel sheet of the present invention, the mass percentage of Si is controlled to be between 0.01-2.5%. In some embodiments, the mass percentage of Si is controlled to be between 0.1% and 1.5%, preferably between 0.3% and 1.0%.
Mn：在本发明所述的三层复合组织高强钢板中，Mn是提高钢的淬硬性的主要元素，Mn的含量需要和选取的冷却方式的冷却能力相匹配，当Mn的含量过低时，钢板无法淬硬，从而无法得到较高强度，而若Mn含量过高，则对碳当量不利。因此综合考虑Mn对三层复合组织高强钢板的性能改善效果和不利影响，在本发明所述的三层复合组织高强钢板中，控制Mn的质量百分比在0.5-3.0％之间。在一些实施方案中，控制Mn的质量百分比在1.0-2.5％之间，优选在1.5-2.5％之间。Mn: In the three-layer composite structure high-strength steel sheet of the present invention, Mn is the main element that improves the hardenability of the steel. The content of Mn needs to match the cooling capacity of the selected cooling method. When the content of Mn is too low, The steel plate cannot be hardened, so that higher strength cannot be obtained, and if the Mn content is too high, it is detrimental to the carbon equivalent. Therefore, comprehensively considering the performance improvement effect and adverse effects of Mn on the three-layer composite structure high-strength steel sheet, in the three-layer composite structure high-strength steel sheet of the present invention, the mass percentage of Mn is controlled to be between 0.5-3.0%. In some embodiments, the mass percentage of Mn is controlled to be between 1.0-2.5%, preferably between 1.5-2.5%.
进一步地，在本发明所述的三层复合组织高强钢板中，其还含有Cr、Mo、B的至少其中之一；其中，当B＜0.0005％时，Cr+Mn+Mo≤3％；当B为0.0005-0.0035％时，Cr+Mn+Mo≤2.3％或≤2.0％。式中的Cr、Mn、Mo均表示其质量百分含量。优选地，当含有时，控制Cr的质量百分比为0.05-0.20％、优选0.10-0.15％，控制Mo的质量百分比为0.05-0.20％、优选0.05-0.10％，控制B的质量百分比≤0.0035％，且Cr+Mn+Mo的含量满足上述要求。Further, in the three-layer composite structure high-strength steel sheet of the present invention, it also contains at least one of Cr, Mo, and B; wherein, when B<0.0005%, Cr+Mn+Mo≤3%; When B is 0.0005 to 0.0035%, Cr+Mn+Mo≤2.3% or≤2.0%. The Cr, Mn, and Mo in the formula all represent their mass percentages. Preferably, when contained, the mass percentage of Cr is controlled to be 0.05-0.20%, preferably 0.10-0.15%, the mass percentage of Mo is controlled to be 0.05-0.20%, preferably 0.05-0.10%, and the mass percentage of B is ≤0.0035%, And the content of Cr+Mn+Mo meets the above requirements.
在本发明所述的三层复合组织高强钢板中，适量的Cr、Mo、B等合金元素可以有效配合锰，从而起到提高淬透性的效果，以使钢的淬透性和快冷段冷却能力相匹配，避免无法淬硬或者碳当量过高。In the three-layer composite structure high-strength steel sheet of the present invention, an appropriate amount of alloying elements such as Cr, Mo, B can be effectively combined with manganese, so as to improve the hardenability effect, so that the hardenability of the steel and the rapid cooling section The cooling capacity is matched to avoid the inability to harden or the carbon equivalent to be too high.
进一步地，在本发明所述的三层复合组织高强钢板中，其还含有V、Ti、Nb的至少其中之一，并且V+Ti+Nb≤0.15％，优选≤0.12％。式中的V、Ti、Nb均表示其质量百分含量。优选地，当含有时，控制V的质量百分比为0.01-0.10％、优选0.03-0.08％，控制Ti的质量百分比为0.01-0.05％，控制Nb的质量百分比为0.01-0.05％，且V+Ti+Nb满足上述要求。Further, in the three-layer composite structure high-strength steel sheet of the present invention, it further contains at least one of V, Ti, and Nb, and V+Ti+Nb≤0.15%, preferably≤0.12%. The V, Ti, and Nb in the formula all represent their mass percentages. Preferably, when contained, the mass percentage of control V is 0.01-0.10%, preferably 0.03-0.08%, the mass percentage of Ti is 0.01-0.05%, the mass percentage of Nb is 0.01-0.05%, and V+Ti +Nb meets the above requirements.
进一步地，在本发明所述的三层复合组织高强钢板中，其还含有Al：0.03-0.30％，优选0.04-0.25％。Further, in the three-layer composite structure high-strength steel sheet of the present invention, it further contains Al: 0.03-0.30%, preferably 0.04-0.25%.
进一步，在本发明所述的三层复合组织高强钢板中，作为不可避免的杂质的P、S和N，其含量控制为：P≤0.015％，S≤0.01％，N≤0.03％。在一些实施方案中，P、S和N的含量为：P，0.005-0.015％；S，0.001-0.005％；N，0.001-0.025％。Furthermore, in the three-layer composite structure high-strength steel sheet of the present invention, the content of P, S and N as inevitable impurities is controlled as follows: P≤0.015%, S≤0.01%, and N≤0.03%. In some embodiments, the content of P, S, and N is: P, 0.005-0.015%; S, 0.001-0.005%; N, 0.001-0.025%.
进一步地，在本发明所述的三层复合组织高强钢板中，所述三层复合组织高强钢板的整体拉伸强度为980-1700MPa之间，所述上表层和下表层的显微硬度HV≤250、优选≤150，如100-150，所述中间层的显微硬度HV≥270、优选≥300，如310-550。优选地，所述三层复合组织高强钢板的整屈服强度为≥600MPa，如610-1350MPa。Further, in the three-layer composite structure high-strength steel sheet of the present invention, the overall tensile strength of the three-layer composite structure high-strength steel sheet is between 980-1700 MPa, and the microhardness of the upper surface layer and the lower layer is HV≤ 250, preferably ≤150, such as 100-150, and the microhardness HV of the intermediate layer is ≥270, preferably ≥300, such as 310-550. Preferably, the overall yield strength of the three-layer composite structure high-strength steel plate is ≥600 MPa, such as 610-1350 MPa.
相应地，本发明的另一目的在于提供一种三层复合组织高强钢板的制造方法，采用该制造方法所获得的三层复合组织高强钢板从上到下有三层不同的组织区域，表层低硬度组织的塑形和韧性好，内层高强度组织有利于保证高强度，实现了超高强度钢的成形性、韧性的提高。Correspondingly, another object of the present invention is to provide a method for manufacturing a three-layer composite structure high-strength steel plate. The three-layer composite structure high-strength steel plate obtained by the manufacturing method has three different organizational regions from top to bottom, and the surface layer has low hardness. The shape and toughness of the structure are good, and the high-strength structure of the inner layer is conducive to ensuring high strength and realizing the improvement of the formability and toughness of ultra-high-strength steel.
为了实现上述目的，本发明提出了上述的三层复合组织高强钢板的制造方法， 所述方法包括步骤：炼钢、连铸、轧制和高温增湿脱碳；其中，所述高温增湿脱碳的工艺条件为：钢板温度为750～900℃，露点为-15～15℃，反应时间为40-160s。本发明通过高温增湿脱碳，可使得钢板的上表层和下表层分别成为厚度为5微米以上的脱碳层(即上表层和下表层均为脱碳层)。所述轧制包括热轧、或热轧后冷轧。热轧后进行酸洗。热轧、酸洗和冷轧可以是本领域常规的热轧、酸洗和冷轧，可根据所制造的高强钢选择合适的热轧、酸洗和冷轧工艺。In order to achieve the above object, the present invention proposes the above-mentioned three-layer composite structure high-strength steel plate manufacturing method, the method includes the steps of: steelmaking, continuous casting, rolling and high-temperature humidification and decarburization; wherein, the high-temperature humidification and decarburization The process conditions of carbon are: the steel plate temperature is 750～900℃, the dew point is -15～15℃, and the reaction time is 40-160s. The present invention can make the upper surface layer and the lower layer of the steel plate become decarburized layers with a thickness of more than 5 microns (that is, both the upper surface layer and the lower layer are decarburized layers) through high temperature humidification and decarburization. The rolling includes hot rolling or cold rolling after hot rolling. Pickling is carried out after hot rolling. The hot rolling, pickling and cold rolling can be conventional hot rolling, pickling and cold rolling in this field, and suitable hot rolling, pickling and cold rolling processes can be selected according to the high-strength steel manufactured.
本发明中，所述高温增湿脱碳可在高温增湿脱碳炉中进行，也可在退火炉内进行，只要其工艺参数满足本发明所述的高温增湿脱碳的工艺条件即可。在一些实施方案中，本发明的制造方法包括炼钢、连铸、轧制、高温增湿脱碳炉内进行高温增湿脱碳和连续退火，其中，在所述连续退火步骤中可进行高温增湿脱碳或不进行高温增湿脱碳。在另外一些实施方案中，本发明的制造方法包括炼钢、连铸、轧制和连续退火，其中，在所述连续退火步骤中可进行高温增湿脱碳。本发明的连续退火的工艺条件包括：保温温度为750-900℃，保温时间为40-160s。连续退火工艺参数还包括：快冷开始温度为650-780℃，快冷速度为30-1500℃/s，快冷终止温度为50-450℃、优选50-380℃；和/或，过时效温度为180-450℃，过时效时间为200-600s。快冷可采用常规的水冷或气体冷却进行。示例性的气体冷却所用的冷却介质通常含有氢气和氮气。In the present invention, the high temperature humidification decarburization can be carried out in a high temperature humidification decarburization furnace or an annealing furnace, as long as the process parameters meet the high temperature humidification decarburization process conditions of the present invention. . In some embodiments, the manufacturing method of the present invention includes steelmaking, continuous casting, rolling, high temperature humidification decarburization and continuous annealing in a high temperature humidification decarburization furnace, wherein high temperature can be performed in the continuous annealing step. Humidification and decarburization or no high temperature humidification and decarburization. In other embodiments, the manufacturing method of the present invention includes steelmaking, continuous casting, rolling, and continuous annealing, wherein high-temperature humidification and decarburization can be performed in the continuous annealing step. The process conditions of the continuous annealing of the present invention include: the holding temperature is 750-900°C, and the holding time is 40-160s. The continuous annealing process parameters also include: the rapid cooling start temperature is 650-780°C, the rapid cooling speed is 30-1500°C/s, and the rapid cooling termination temperature is 50-450°C, preferably 50-380°C; and/or, over-aging The temperature is 180-450℃, and the over-aging time is 200-600s. Quick cooling can be carried out by conventional water cooling or gas cooling. The cooling medium used for the exemplary gas cooling usually contains hydrogen and nitrogen.
应理解，当在退火炉内进行高温增湿脱碳时，控制退火炉内钢板温度为750～900℃，露点为-15～15℃，并进行40-160s的反应，即可完成高温增湿脱碳。在进行两次高温增湿脱碳处理的情况下，即先后在高温增湿脱碳炉和退火炉内进行高温增湿脱碳炉的情况下，钢板的上表层和下表层可分别成为厚度在100微米以上的脱碳层。It should be understood that when high-temperature humidification and decarburization are performed in the annealing furnace, the temperature of the steel sheet in the annealing furnace is controlled to be 750～900℃, the dew point is -15～15℃, and the reaction is carried out for 40-160s to complete the high temperature humidification. Decarbonization. In the case of two high-temperature humidification decarburization treatments, that is, in the case of high-temperature humidification decarburization furnace and annealing furnace successively, the upper and lower surface layers of the steel plate can become the thickness of each Decarburized layer above 100 microns.
在一些实施方案中，当所述三层复合组织高强钢板为热轧钢板时，其包括步骤：炼钢、连铸、热轧、酸洗和连续退火；其中在连续退火步骤中进行高温增湿脱碳：在钢板温度为750～900℃的条件下，控制退火炉内露点为-15～15℃，反应时间为40-160s，以使得钢板的上表层和下表层分别成为厚度为5-100微米的脱碳层(即上表层和下表层均为脱碳层)。In some embodiments, when the three-layer composite structure high-strength steel sheet is a hot-rolled steel sheet, it includes the steps of: steelmaking, continuous casting, hot rolling, pickling and continuous annealing; wherein high-temperature humidification is performed in the continuous annealing step. Decarburization: Under the condition of steel plate temperature of 750～900℃, the dew point in the annealing furnace is controlled to be -15～15℃, and the reaction time is 40-160s, so that the upper and lower layers of the steel plate have a thickness of 5-100 respectively. Micron decarburized layer (that is, the upper and lower layers are both decarburized layers).
在本发明所述的三层复合组织高强钢板的制造方法中，钢经过炼钢、连铸后，制成的成分和组织均一的钢板再经热轧酸洗后，在连续退火炉的高温加热和保温阶 段，控制钢板温度为750～900℃，利用炉内增湿的方法，提高退火炉内水蒸气的含量，控制炉内露点在-15～+15℃之间，保持时间控制在40-160s，使水蒸气在高温下和钢板中的碳进行脱碳反应(如反应式：C+H 2O＝CO+H 2；C+2H 2O＝CO 2+2H 2，和其他不限于此的脱碳反应)，从而使钢板表层发生部分或完全脱碳，最终在钢板上下表层可以获得5-100微米的脱碳层深度。从而使钢板在后续冷却过程中，表面的脱碳层保持为全铁素体或铁素体为主的组织形态，而心部未脱碳区域经快速冷却，形成以马氏体、贝氏体或马氏体+贝氏体为主的组织。心部组织的铁素体含量明显低于表面的铁素体含量，得到的三层复合组织高强钢板具有高强度和表面低硬度的特点。 In the manufacturing method of the three-layer composite structure high-strength steel sheet of the present invention, after the steel is made and continuously cast, the steel sheet with uniform composition and structure is then hot-rolled and pickled, and then heated at a high temperature in a continuous annealing furnace. In the heat preservation stage, control the temperature of the steel plate to 750～900℃, use the method of humidification in the furnace to increase the content of water vapor in the annealing furnace, control the dew point in the furnace between -15～+15℃, and control the holding time at 40- 160s, make the water vapor decarburize reaction with the carbon in the steel plate at high temperature (such as reaction formula: C+H 2 O=CO+H 2 ; C+2H 2 O=CO 2 +2H 2 , and others are not limited to this Decarburization reaction), so that the surface layer of the steel plate is partially or completely decarburized, and finally the depth of the decarburization layer of 5-100 microns can be obtained on the lower layer of the steel plate. So that in the subsequent cooling process of the steel plate, the decarburized layer on the surface maintains the structure of full ferrite or ferrite, and the undecarburized area in the core is rapidly cooled to form martensite and bainite. Or martensite + bainite-based organization. The ferrite content of the core structure is significantly lower than the surface ferrite content, and the obtained three-layer composite structure high-strength steel plate has the characteristics of high strength and low surface hardness.
此外，选择钢板温度为750～900℃的原因是有利于钢板的脱碳反应，钢板温度过低会导致脱碳不足，钢板温度过高则会影响板形。而选择炉内露点在-15～+15℃之间的原因是因为露点低于-15℃，钢板的脱碳反应不明显，高于+15℃则有使Fe过度氧化的风险。In addition, the reason for choosing a steel plate temperature of 750 to 900°C is that it is beneficial to the decarburization reaction of the steel plate. Too low steel plate temperature will lead to insufficient decarburization, and too high steel plate temperature will affect the plate shape. The reason for choosing the dew point in the furnace to be between -15 and +15 ℃ is because the dew point is lower than -15 ℃, the decarburization reaction of the steel plate is not obvious, higher than +15 ℃, there is a risk of excessive oxidation of Fe.
进一步地，在本发明所述的三层复合组织高强钢板的制造方法中，其中在连续退火步骤中控制连续退火工艺参数至少满足下列各项的至少其中一项：Further, in the method for manufacturing a high-strength steel sheet with a three-layer composite structure according to the present invention, the continuous annealing process parameters are controlled in the continuous annealing step to satisfy at least one of the following items:
控制保温温度为750-900℃、优选780-900℃，保温时间为40-160s；Control the holding temperature at 750-900℃, preferably 780-900℃, and the holding time at 40-160s;
快冷开始温度为650-780℃；快冷速度为30-1500℃/s；快冷终止温度为50-450℃、优选50-380℃；The start temperature of rapid cooling is 650-780℃; the speed of rapid cooling is 30-1500℃/s; the end temperature of rapid cooling is 50-450℃, preferably 50-380℃;
过时效温度为180-450℃；过时效时间为200-600s。The over-aging temperature is 180-450℃; the over-aging time is 200-600s.
进一步地，在本发明所述的三层复合组织高强钢板的制造方法中，当所述三层复合组织高强钢板为热轧钢板时，其包括步骤：炼钢、连铸、热轧、酸洗、高温增湿脱碳炉脱碳和连续退火；其中在高温增湿脱碳炉脱碳过程中，在钢板温度为750～900℃的条件下，控制退火炉内露点为-15～15℃，反应时间为40-160s，以使得钢板的上表层和下表层分别成为厚度为5-100微米的脱碳层。Further, in the manufacturing method of the three-layer composite structure high-strength steel sheet of the present invention, when the three-layer composite structure high-strength steel sheet is a hot-rolled steel sheet, it includes the steps of: steelmaking, continuous casting, hot rolling, pickling , High temperature humidification decarburization furnace decarburization and continuous annealing; among them, in the high temperature humidification decarburization furnace decarburization process, under the condition of the steel plate temperature of 750～900℃, the dew point in the annealing furnace is controlled to be -15～15℃, The reaction time is 40-160s, so that the upper and lower layers of the steel plate become decarburized layers with a thickness of 5-100 microns, respectively.
在本发明所述的技术方案中，钢经热轧酸洗后，在独立高温增湿脱碳炉内进行脱碳过程，通过控制钢板温度为750～900℃，利用炉内增湿的方法，提高炉内水蒸气的含量，控制炉内露点在-15～+15℃之间，保持时间控制在40-160s。在高温下增湿，实现水蒸气在高温下和钢板中的碳进行脱碳反应，从而使钢板表面脱碳。需要说明的是，高温增湿脱碳炉脱碳完成后，在连续退火炉内可以选择不增湿脱碳，从而维持钢板的上表层和下表层形成的脱碳层厚度为5-100微米。In the technical scheme of the present invention, after the steel is hot-rolled and pickled, the decarburization process is carried out in an independent high-temperature humidification decarburization furnace. By controlling the temperature of the steel plate to 750-900°C, the method of humidification in the furnace is used, Increase the content of water vapor in the furnace, control the dew point in the furnace between -15～+15℃, and control the holding time between 40-160s. Humidification at high temperatures enables water vapor to decarburize with carbon in the steel plate at high temperatures, thereby decarburizing the surface of the steel plate. It should be noted that after the decarburization in the high-temperature humidification decarburization furnace is completed, the continuous annealing furnace can choose not to humidify and decarburize, so as to maintain the thickness of the decarburization layer formed on the upper and lower layers of the steel sheet to be 5-100 microns.
进一步地，在上述三层复合组织高强钢板的制造方法中，其中在连续退火步骤中控制连续退火工艺参数至少满足下列各项的至少其中一项：Further, in the above-mentioned method for manufacturing a high-strength steel sheet with a three-layer composite structure, the continuous annealing process parameters are controlled in the continuous annealing step to satisfy at least one of the following items:
控制保温温度为750-900℃、优选780-900℃，保温时间为40-160s；Control the holding temperature at 750-900℃, preferably 780-900℃, and the holding time at 40-160s;
快冷开始温度为650-780℃；快冷速度为30-1500℃/s；快冷终止温度为50-450℃、优选50-380℃；The start temperature of rapid cooling is 650-780℃; the speed of rapid cooling is 30-1500℃/s; the end temperature of rapid cooling is 50-450℃, preferably 50-380℃;
过时效温度为180-450℃；过时效时间为200-600s。The over-aging temperature is 180-450℃; the over-aging time is 200-600s.
进一步地，在上述三层复合组织高强钢板的制造方法中，其中在连续退火步骤中继续进行高温增湿脱碳：在钢板温度为750～900℃的条件下，控制退火炉内露点为-15～15℃，反应时间为40-160s，以使得钢板的上表层和下表层分别成为厚度大于100微米的脱碳层。Further, in the above-mentioned three-layer composite structure high-strength steel sheet manufacturing method, the high-temperature humidification and decarburization is continued in the continuous annealing step: the dew point in the annealing furnace is controlled to be -15 under the condition of the steel sheet temperature of 750 to 900°C ~15°C, and the reaction time is 40-160s, so that the upper and lower layers of the steel plate become decarburized layers with a thickness of more than 100 microns, respectively.
在本发明所述的技术方案中，钢经热轧酸洗，在独立高温增湿脱碳炉内高温增湿脱碳完成后，还可以在连续退火步骤中再次进行高温增湿脱碳，采取二次增湿脱碳来获得更厚的脱碳层，以使得钢板的上表层和下表层分别成为厚度大于100微米的脱碳层。In the technical solution of the present invention, the steel is hot-rolled and pickled, and after the high-temperature humidification and decarburization in the independent high-temperature humidification and decarburization furnace is completed, the high-temperature humidification and decarburization can be performed again in the continuous annealing step. Secondary humidification and decarburization are performed to obtain a thicker decarburized layer, so that the upper and lower layers of the steel sheet become decarburized layers with a thickness greater than 100 microns.
进一步地，在本发明所述的三层复合组织高强钢板的制造方法中，当所述三层复合组织高强钢板为冷轧钢板时，其包括步骤：炼钢、连铸、热轧、冷轧和连续退火；其中在连续退火步骤中进行高温增湿脱碳：在钢板温度为750～900℃的条件下，控制退火炉内露点为-15～15℃，反应时间为40-160s，以使得钢板的上表层和下表层分别成为厚度为5-100微米的脱碳层。Further, in the method for manufacturing a three-layer composite structure high-strength steel sheet of the present invention, when the three-layer composite structure high-strength steel sheet is a cold-rolled steel sheet, it includes the steps of: steelmaking, continuous casting, hot rolling, and cold rolling. And continuous annealing; among them, high temperature humidification and decarburization is carried out in the continuous annealing step: under the condition of the steel plate temperature of 750～900℃, the dew point in the annealing furnace is controlled to be -15～15℃, and the reaction time is 40-160s to make The upper and lower layers of the steel plate become decarburized layers with a thickness of 5-100 microns, respectively.
进一步地，在上述三层复合组织高强钢板的制造方法中，其中在连续退火步骤中控制连续退火工艺参数至少满足下列各项的至少其中一项：Further, in the above-mentioned method for manufacturing a high-strength steel sheet with a three-layer composite structure, the continuous annealing process parameters are controlled in the continuous annealing step to satisfy at least one of the following items:
控制保温温度为750-900℃、优选780-900℃，保温时间为40-160s；Control the holding temperature at 750-900℃, preferably 780-900℃, and the holding time at 40-160s;
快冷开始温度为650-780℃；快冷速度为30-1500℃/s；快冷终止温度为50-450℃、优选50-380℃；The start temperature of rapid cooling is 650-780℃; the speed of rapid cooling is 30-1500℃/s; the end temperature of rapid cooling is 50-450℃, preferably 50-380℃;
过时效温度为180-450℃；过时效时间为200-600s。The over-aging temperature is 180-450℃; the over-aging time is 200-600s.
进一步地，在本发明所述的三层复合组织高强钢板的制造方法中，当所述三层复合组织高强钢板为冷轧钢板时，其包括步骤：炼钢、连铸、热轧、冷轧、高温增湿脱碳炉脱碳和连续退火；其中在高温增湿脱碳炉脱碳过程中，在钢板温度为750～900℃的条件下，控制退火炉内露点为-15～15℃，反应时间为40-160s，以使得钢板的 上表层和下表层分别成为厚度为5-100微米的脱碳层。Further, in the method for manufacturing a three-layer composite structure high-strength steel sheet of the present invention, when the three-layer composite structure high-strength steel sheet is a cold-rolled steel sheet, it includes the steps of: steelmaking, continuous casting, hot rolling, and cold rolling. , High temperature humidification decarburization furnace decarburization and continuous annealing; among them, in the high temperature humidification decarburization furnace decarburization process, under the condition of the steel plate temperature of 750～900℃, the dew point in the annealing furnace is controlled to be -15～15℃, The reaction time is 40-160s, so that the upper and lower layers of the steel plate become decarburized layers with a thickness of 5-100 microns, respectively.
在上述方案中，需要说明的是，高温增湿脱碳炉脱碳完成后，在连续退火炉内可以选择不增湿脱碳，从而维持钢板的上表层和下表层形成的脱碳层厚度为5-100微米。In the above scheme, it should be noted that after the decarburization of the high-temperature humidification decarburization furnace is completed, the continuous annealing furnace can choose not to humidify the decarburization, so as to maintain the thickness of the decarburization layer formed on the upper and lower layers of the steel plate. 5-100 microns.
进一步地，在上述三层复合组织高强钢板的制造方法中，其中在连续退火步骤中控制连续退火工艺参数至少满足下列各项的至少其中一项：Further, in the above-mentioned method for manufacturing a high-strength steel sheet with a three-layer composite structure, the continuous annealing process parameters are controlled in the continuous annealing step to satisfy at least one of the following items:
控制保温温度为750-900℃、优选780-900℃，保温时间为40-160s；Control the holding temperature at 750-900℃, preferably 780-900℃, and the holding time at 40-160s;
快冷开始温度为650-780℃；快冷速度为30-1500℃/s；快冷终止温度为50-450℃、优选50-380℃；The start temperature of rapid cooling is 650-780℃; the speed of rapid cooling is 30-1500℃/s; the end temperature of rapid cooling is 50-450℃, preferably 50-380℃;
进一步地，在本发明所述的三层复合组织高强钢板的制造方法中，在连续退火过程中继续进行高温增湿脱碳：在钢板温度为750～900℃的条件下，控制退火炉内露点为-15～15℃，反应时间为40-160s，以使得钢板的上表层和下表层分别成为厚度大于100微米的脱碳层。Further, in the method for manufacturing a high-strength steel sheet with a three-layer composite structure of the present invention, high-temperature humidification and decarburization are continued during the continuous annealing process: the dew point in the annealing furnace is controlled under the condition of the steel sheet temperature of 750 to 900°C The temperature is -15 to 15°C, and the reaction time is 40-160s, so that the upper and lower layers of the steel plate become decarburized layers with a thickness of more than 100 microns.
在本发明所述的三层复合组织高强钢板的制造方法中，核心关键工序在于连续退火或独立高温增湿脱碳炉内的增湿脱碳反应的控制，在优选的实施方式中，可以仅在连续退火的退火炉中进行增湿脱碳，从而更有利于降低成本，提高竞争力。In the manufacturing method of the three-layer composite structure high-strength steel sheet of the present invention, the core key process is continuous annealing or the control of the humidification and decarburization reaction in an independent high-temperature humidification and decarburization furnace. In a preferred embodiment, only Moisturizing and decarburizing in a continuous annealing furnace is more conducive to reducing costs and improving competitiveness.
相较于现有技术，本发明所述的三层复合组织高强钢板通过合理的脱碳工艺，使高强钢板从上到下有三层不同的组织区域，不同组织的合理分布，使得高强钢板具有表面软，内部硬的特点。钢板的表层低硬度组织塑形、韧性好，内层高强度组织保证了钢板的高强度，实现了超高强度钢的成形性、韧性的提高。本发明所述三层复合组织高强钢板较现有传统的轧制复合制备多层复合钢板具有更优的性能，其整体拉伸强度为980-1700MPa之间，上表层和下表层的显微硬度HV≤250，中间层的显微硬度HV≥270。可用于汽车安全件和结构件的制造，提高高强度钢板的弯曲成形性和制成零件的变形吸能性能，从而起到有利于制成零件安全保护的作用。Compared with the prior art, the three-layer composite structure high-strength steel plate of the present invention adopts a reasonable decarburization process, so that the high-strength steel plate has three layers of different tissue regions from top to bottom, and the reasonable distribution of the different structures makes the high-strength steel plate have a surface Soft and internal hard features. The low-hardness structure of the surface of the steel plate has good shape and toughness, and the high-strength structure of the inner layer ensures the high strength of the steel plate, and realizes the improvement of the formability and toughness of the ultra-high-strength steel. The three-layer composite structure high-strength steel sheet of the present invention has better performance than the existing traditional rolling composite prepared multi-layer composite steel sheet, and its overall tensile strength is between 980-1700 MPa, and the microhardness of the upper and lower layers is HV≤250, the microhardness of the middle layer HV≥270. It can be used in the manufacture of automobile safety parts and structural parts to improve the bending formability of high-strength steel plates and the deformation and energy absorption performance of the finished parts, thereby playing a role in facilitating the safety protection of the finished parts.
相应地，本发明所述的制造方法通过三层复合组织高强钢板的成分设计及工艺参数设计，在降低生产成本的同时，获得整体拉伸强度在980-1700MPa之间，强度高，塑形、韧性好的复合组织钢板。Correspondingly, the manufacturing method of the present invention adopts the composition design and process parameter design of the three-layer composite structure high-strength steel plate, while reducing the production cost, obtains the overall tensile strength between 980-1700 MPa, high strength, and shaping, Composite structure steel plate with good toughness.
附图说明Description of the drawings
图1显示了实施例4所述的三层复合组织高强钢板上表面附近的截面微观组织形貌。Fig. 1 shows the cross-sectional microstructure morphology of the three-layer composite structure high-strength steel plate described in Example 4 near the upper surface.
图2显示了本发明对比例1中钢板上表面附近的截面微观组织形貌。Figure 2 shows the cross-sectional microstructure morphology near the upper surface of the steel plate in Comparative Example 1 of the present invention.
图3显示了本发明实施例3所述的所述的三层复合组织高强钢板上表面附近的截面微观组织形貌。Figure 3 shows the cross-sectional microstructure morphology near the upper surface of the three-layer composite structure high-strength steel sheet described in Example 3 of the present invention.
具体实施方式Detailed ways
下面将结合具体的实施例和说明书附图对本发明所述的三层复合组织高强钢板及其制造方法做进一步的解释和说明，然而该解释和说明并不对本发明的技术方案构成不当限定。In the following, the three-layer composite structure high-strength steel plate of the present invention and its manufacturing method will be further explained and described in conjunction with specific embodiments and the accompanying drawings. However, the explanation and description do not improperly limit the technical solution of the present invention.
实施例1-6以及对比例1Examples 1-6 and Comparative Example 1
本发明所述的三层复合组织高强钢板采用以下步骤制得：The three-layer composite structure high-strength steel plate of the present invention is prepared by the following steps:
(1)炼钢：铁水经过转炉进行冶炼；(1) Steelmaking: molten iron is smelted through a converter;
(2)连铸：连铸制得板坯；(2) Continuous casting: slab produced by continuous casting;
(3)热轧、酸洗；(3) Hot rolling and pickling;
(4)冷轧；(4) Cold rolling;
(5)连续退火：在连续退火中进行高温增湿脱碳，在钢板温度为750～900℃的条件下，控制退火炉内露点为-15～15℃，反应时间为40-160s。连续退火中控制保温温度为750-900℃，保温时间为40-160s；控制快冷开始温度为650-780℃；快冷速度为30-1500℃/s；快冷终止温度为50-450℃；过时效温度为180-450℃；过时效时间为200-600s。(5) Continuous annealing: high-temperature humidification and decarburization are carried out in continuous annealing. Under the condition of steel plate temperature of 750～900℃, the dew point in the annealing furnace is controlled to be -15～15℃, and the reaction time is 40-160s. In continuous annealing, the holding temperature is controlled to be 750-900°C, and the holding time is 40-160s; the starting temperature of rapid cooling is controlled to 650-780°C; the speed of rapid cooling is 30-1500°C/s; the end temperature of rapid cooling is 50-450°C ; The over-aging temperature is 180-450℃; the over-aging time is 200-600s.
实施例7-8Example 7-8
本发明所述的三层复合组织高强钢板采用以下步骤制得：The three-layer composite structure high-strength steel plate of the present invention is prepared by the following steps:
(1)炼钢：铁水经过转炉进行冶炼；(1) Steelmaking: molten iron is smelted through a converter;
(2)连铸：连铸制得板坯；(2) Continuous casting: slab produced by continuous casting;
(3)热轧、酸洗；(3) Hot rolling and pickling;
(4)冷轧；(4) Cold rolling;
(5)高温增湿脱碳炉脱碳：在高温增湿脱碳炉脱碳过程中，在钢板温度为750～ 900℃的条件下，控制高温增湿脱碳炉内露点为-15～15℃，反应时间为40-160s，(5) High temperature humidification decarburization furnace decarburization: in the decarburization process of high temperature humidification decarburization furnace, the dew point in the high temperature humidification decarburization furnace is controlled to be -15～15 under the condition of the steel plate temperature of 750～900℃ ℃, the reaction time is 40-160s,
(6)连续退火：在连续退火中控制保温温度为780-900℃，控制炉内露点低于-20℃，控制保温时间为40-160s，控制快冷开始温度为650-780℃，控制快冷速度为30-1500℃/s，控制快冷终止温度为50-450℃，控制过时效温度为180-450℃，过时效时间为200-600s。(6) Continuous annealing: In continuous annealing, control the holding temperature to 780-900℃, control the dew point in the furnace to be lower than -20℃, control the holding time to 40-160s, control the fast cooling start temperature to 650-780℃, and control fast The cooling rate is 30-1500°C/s, the termination temperature of rapid cooling is controlled to 50-450°C, the over-aging temperature is controlled to 180-450°C, and the over-aging time is 200-600s.
实施例9-10Examples 9-10
本发明所述的三层复合组织高强钢板采用以下步骤制得：The three-layer composite structure high-strength steel plate of the present invention is prepared by the following steps:
(1)炼钢：铁水经过转炉进行冶炼；(1) Steelmaking: molten iron is smelted through a converter;
(2)连铸：连铸制得板坯；(2) Continuous casting: slab produced by continuous casting;
(3)热轧、酸洗；(3) Hot rolling and pickling;
(4)冷轧；(4) Cold rolling;
(5)高温增湿脱碳炉脱碳：在高温增湿脱碳炉脱碳过程中，在钢板温度为750～900℃的条件下，控制高温增湿脱碳炉内露点为-15～15℃，反应时间为40-160s，(5) High temperature humidification decarburization furnace decarburization: in the decarburization process of high temperature humidification decarburization furnace, under the condition of steel plate temperature of 750～900℃, control the dew point in the high temperature humidification decarburization furnace to -15～15 ℃, the reaction time is 40-160s,
(6)连续退火：在连续退火中再次进行高温增湿脱碳，控制钢板温度为750～900℃，控制退火炉内露点为-15～15℃，反应时间为40-160s。连续退火中控制保温温度为780-900℃，保温时间为40-160s；控制快冷开始温度为650-780℃；快冷速度为30-1500℃/s；快冷终止温度为50-450℃；过时效温度为180-450℃；过时效时间为200-600s。(6) Continuous annealing: in continuous annealing, high-temperature humidification and decarburization are carried out again, the temperature of the steel plate is controlled to be 750-900 ℃, the dew point in the annealing furnace is controlled to be -15 to 15 ℃, and the reaction time is 40-160s. In continuous annealing, the holding temperature is controlled to be 780-900°C, and the holding time is 40-160s; the starting temperature of rapid cooling is controlled to 650-780°C; the speed of rapid cooling is 30-1500°C/s; the end temperature of rapid cooling is 50-450°C ; The over-aging temperature is 180-450℃; the over-aging time is 200-600s.
实施例11-12Examples 11-12
本发明所述的三层复合组织高强钢板采用以下步骤制得：The three-layer composite structure high-strength steel plate of the present invention is prepared by the following steps:
(1)炼钢：铁水经过转炉进行冶炼；(1) Steelmaking: molten iron is smelted through a converter;
(2)连铸：连铸制得板坯；(2) Continuous casting: slab produced by continuous casting;
(3)热轧；(3) Hot rolling;
(4)酸洗；(4) Pickling;
(5)连续退火：在连续退火中进行高温增湿脱碳，在钢板温度为750～900℃的条件下，控制退火炉内露点为-15～15℃，反应时间为40-160s。连续退火中控制保温温度为780-900℃，保温时间为40-160s，控制快冷开始温度为650-780℃，快冷速度 为30-1500℃/s，快冷终止温度为50-450℃，过时效温度为180-450℃，过时效时间为200-600s。(5) Continuous annealing: high-temperature humidification and decarburization are carried out in continuous annealing. Under the condition of steel plate temperature of 750～900℃, the dew point in the annealing furnace is controlled to be -15～15℃, and the reaction time is 40-160s. In continuous annealing, the holding temperature is controlled at 780-900℃, the holding time is 40-160s, the starting temperature of fast cooling is 650-780℃, the speed of fast cooling is 30-1500℃/s, and the end temperature of fast cooling is 50-450℃ , The over-aging temperature is 180-450℃, and the over-aging time is 200-600s.
实施例13-14Examples 13-14
本发明所述的三层复合组织高强钢板采用以下步骤制得：The three-layer composite structure high-strength steel plate of the present invention is prepared by the following steps:
(1)炼钢：铁水经过转炉进行冶炼；(1) Steelmaking: molten iron is smelted through a converter;
(2)连铸：连铸制得板坯；(2) Continuous casting: slab produced by continuous casting;
(3)热轧；(3) Hot rolling;
(4)酸洗；(4) Pickling;
(5)高温增湿脱碳炉脱碳；在高温增湿脱碳炉脱碳过程中，在钢板温度为750～900℃的条件下，控制高温增湿脱碳炉内露点为-15～15℃，反应时间为40-160s，(5) High temperature humidification decarburization furnace decarburization; in the decarburization process of high temperature humidification decarburization furnace, the dew point in the high temperature humidification decarburization furnace is controlled to be -15～15 under the condition of the steel plate temperature of 750～900℃ ℃, the reaction time is 40-160s,
(6)连续退火：在连续退火中控制保温温度为780-900℃，控制炉内露点低于-20℃，控制保温时间为40-160s，控制快冷开始温度为650-780℃，控制快冷速度为30-1500℃/s，控制快冷终止温度为50-450℃，控制过时效温度为180-450℃，过时效时间为200-600s。(6) Continuous annealing: In continuous annealing, control the holding temperature to 780-900℃, control the dew point in the furnace to be lower than -20℃, control the holding time to 40-160s, control the fast cooling start temperature to 650-780℃, and control fast The cooling rate is 30-1500°C/s, the termination temperature of rapid cooling is controlled to 50-450°C, the over-aging temperature is controlled to 180-450°C, and the over-aging time is 200-600s.
实施例15-16Examples 15-16
本发明所述的三层复合组织高强钢板采用以下步骤制得：The three-layer composite structure high-strength steel plate of the present invention is prepared by the following steps:
(1)炼钢：铁水经过转炉进行冶炼；(1) Steelmaking: molten iron is smelted through a converter;
(2)连铸：连铸制得板坯；(2) Continuous casting: slab produced by continuous casting;
(3)热轧；(3) Hot rolling;
(4)酸洗；(4) Pickling;
(5)高温增湿脱碳炉脱碳；在高温增湿脱碳炉脱碳过程中，在钢板温度为750～900℃的条件下，控制高温增湿脱碳炉内露点为-15～15℃，反应时间为40-160s，(5) High temperature humidification decarburization furnace decarburization; in the high temperature humidification decarburization furnace decarburization process, the dew point in the high temperature humidification decarburization furnace is controlled to be -15～15 under the condition of the steel plate temperature of 750～900℃ ℃, the reaction time is 40-160s,
(6)连续退火：在连续退火中再次进行高温增湿脱碳，控制钢板温度为750～900℃，控制退火炉内露点为-15～15℃，反应时间为40-160s。连续退火中控制保温温度为780-900℃，保温时间为40-160s，控制快冷开始温度为650-780℃，快冷速度为30-1500℃/s，快冷终止温度为50-450℃，过时效温度为180-450℃，过时效时间为200-600s。(6) Continuous annealing: in continuous annealing, high-temperature humidification and decarburization are carried out again, the temperature of the steel plate is controlled to be 750-900 ℃, the dew point in the annealing furnace is controlled to be -15 to 15 ℃, and the reaction time is 40-160s. In continuous annealing, the holding temperature is controlled at 780-900℃, the holding time is 40-160s, the starting temperature of fast cooling is 650-780℃, the speed of fast cooling is 30-1500℃/s, and the end temperature of fast cooling is 50-450℃ , The over-aging temperature is 180-450℃, and the over-aging time is 200-600s.
表1列出了本发明各实施例和对比例中所用钢种的各化学元素的质量百分配比。Table 1 lists the mass percentage ratios of various chemical elements of the steel types used in the various examples and comparative examples of the present invention.
表1.(wt％，余量为Fe和除了S、P、N以外其他不可避免的杂质)Table 1. (wt%, the balance is Fe and other inevitable impurities except S, P, N)
Figure PCTCN2021079355-appb-000001
Figure PCTCN2021079355-appb-000001
表2列出了实施例1-16的三层复合组织高强钢板以及对比例1钢板的具体工艺参数。Table 2 lists the specific process parameters of the three-layer composite structure high-strength steel plate of Examples 1-16 and the steel plate of Comparative Example 1.
表2.Table 2.
Figure PCTCN2021079355-appb-000002
Figure PCTCN2021079355-appb-000002
Figure PCTCN2021079355-appb-000003
Figure PCTCN2021079355-appb-000003
注：在退火炉内进行连续退火时，当退火炉保温段露点≤-20℃时，不会发生明显的脱碳反应。Note: When continuous annealing is performed in the annealing furnace, when the dew point of the annealing furnace insulation section is ≤-20℃, no obvious decarburization reaction will occur.
表3列出了实施例1-16的三层复合组织高强钢板以及对比例1钢板的相关性能参数。Table 3 lists the three-layer composite structure high-strength steel plates of Examples 1-16 and the relevant performance parameters of the steel plates of Comparative Example 1.
表3.table 3.
Figure PCTCN2021079355-appb-000004
Figure PCTCN2021079355-appb-000004
Figure PCTCN2021079355-appb-000005
Figure PCTCN2021079355-appb-000005
从表3可以看出，较之于保温段露点不在-15～15℃范围内的对比例1，本案实施例1-6中经本发明所述制造方法处理的三层复合组织高强钢板脱碳层硬度明显下降，表层低硬度组织塑形、韧性好，性能优异。从表3实施例1-6可以看出，本发明所述三层复合组织高强钢板表面层软，内部层硬，可以有效实现超高强度钢的成形性、韧性的提高。钢中不同组织的合理分布使得高强钢板较现有传统的轧制复合制备多层复合钢板具有更优的性能，其整体拉伸强度为985-1700MPa之间，上表层和下表层的显微硬度HV≤150，中间层的显微硬度HV≥310。可有效用于汽车安全件和结构件的制造，提高高强度钢板的弯曲成形性和制成零件的变形吸能性能，从而起到有利于制成零件安全保护的作用。It can be seen from Table 3 that compared to Comparative Example 1, where the dew point of the insulation section is not within the range of -15～15℃, the three-layer composite structure high-strength steel plate treated by the manufacturing method of the present invention in Examples 1-6 of this case is decarburized The hardness of the layer is significantly reduced, and the surface layer has a low-hardness structure with good toughness and excellent performance. It can be seen from Examples 1-6 in Table 3 that the three-layer composite structure high-strength steel sheet of the present invention has a soft surface layer and a hard inner layer, which can effectively improve the formability and toughness of the ultra-high-strength steel. The reasonable distribution of different structures in the steel makes the high-strength steel plate have better performance than the existing traditional rolling composite multi-layer composite steel plate. Its overall tensile strength is between 985-1700 MPa, and the microhardness of the upper and lower layers is between 985 and 1700 MPa. HV≤150, the microhardness of the middle layer HV≥310. It can be effectively used in the manufacture of automobile safety parts and structural parts, improve the bending formability of high-strength steel plates and the deformation and energy absorption performance of the finished parts, thereby playing a role in the safety protection of the finished parts.
图1显示了实施例4所述的三层复合组织高强钢板上表面附近的截面微观组织形貌。从图1中可以看出，本实施例中的三层复合组织高强钢板在上表层获得了以铁素体组织为主的脱碳层，和马氏体组织为主的中心层呈现明显不同的组织形貌。Fig. 1 shows the cross-sectional microstructure morphology of the three-layer composite structure high-strength steel plate described in Example 4 near the upper surface. It can be seen from Figure 1 that the three-layer composite structure high-strength steel plate in this embodiment has a decarburized layer mainly composed of ferrite structure on the upper surface layer, which is significantly different from the center layer mainly composed of martensite structure. Organization morphology.
图2显示了本发明对比例1中的钢板上表面附近的截面微观组织形貌。从图2中可以看出，本对比例中的高强钢板常规组织为表层和中心区域基本均匀的马氏体组织类型，和图1中实施例4高强钢板中的层状复合组织有明显区别。Figure 2 shows the cross-sectional microstructure morphology near the upper surface of the steel plate in Comparative Example 1 of the present invention. It can be seen from Fig. 2 that the conventional structure of the high-strength steel plate in this comparative example is a martensitic structure with substantially uniform surface layer and central area, which is obviously different from the layered composite structure in the high-strength steel plate of Example 4 in Fig. 1.
图3显示了本发明实施例3所述的三层复合组织高强钢板上表面附近的截面微观组织形貌。从图3中可以看出，本实施例中的三层复合组织高强钢板在上表层获得了以铁素体组织为主的脱碳层，与马氏体+贝氏体组织为主的中心层呈现明显不同的组织形貌。该中心层中马氏体的体积百分比约40％、贝氏体的体积百分比约为30％，还有大约30％的铁素体。Fig. 3 shows the cross-sectional microstructure morphology near the upper surface of the three-layer composite structure high-strength steel sheet described in Example 3 of the present invention. It can be seen from Figure 3 that the three-layer composite structure high-strength steel plate in this embodiment has obtained a decarburized layer mainly composed of ferrite structure on the upper surface layer, and a center layer mainly composed of martensite + bainite structure. Presents a significantly different organization morphology. The volume percentage of martensite in the center layer is about 40%, the volume percentage of bainite is about 30%, and there is about 30% ferrite.
需要注意的是，以上所列举实施例仅为本发明的具体实施例。显然本发明不局 限于以上实施例，随之做出的类似变化或变形是本领域技术人员能从本发明公开的内容直接得出或者很容易便联想到的，均应属于本发明的保护范围。It should be noted that the above-listed embodiments are only specific embodiments of the present invention. Obviously, the present invention is not limited to the above embodiments, and the subsequent similar changes or modifications are those skilled in the art can directly derive or easily associate from the disclosure of the present invention, and they should all fall within the protection scope of the present invention. .

Claims (15)

  1. 一种三层复合组织高强钢板，其特征在于，其在钢板的厚度方向上具有上表层、下表层和位于上表层和下表层之间的中心层；其中所述上表层和所述下表层的微观组织为完全铁素体组织或者铁素体的相比例＞50％的组织；所述中心层的微观组织包括马氏体和贝氏体的至少其中之一；其中所述中心层的铁素体含量少于上表层和下表层的铁素体含量。A three-layer composite structure high-strength steel sheet, characterized in that it has an upper surface layer, a lower layer and a center layer located between the upper surface layer and the lower layer in the thickness direction of the steel plate; wherein the upper surface layer and the lower layer The microstructure is a complete ferrite structure or a structure with a phase ratio of >50% of ferrite; the microstructure of the central layer includes at least one of martensite and bainite; wherein the ferrite of the central layer The body content is less than the ferrite content of the upper and lower layers.
  2. 如权利要求1所述的三层复合组织高强钢板，其特征在于，所述中心层的微观组织还包括：相比例＜50％的铁素体、碳化物、亚稳奥氏体的至少其中之一。The three-layer composite structure high-strength steel sheet according to claim 1, wherein the microstructure of the central layer further comprises: at least one of ferrite, carbide, and metastable austenite with a phase ratio of <50% one.
  3. 如权利要求1所述的三层复合组织高强钢板，其特征在于，所述上表层和所述下表层的铁素体组织中还含有碳化物。The three-layer composite structure high-strength steel sheet according to claim 1, wherein the ferrite structure of the upper surface layer and the lower layer further contains carbides.
  4. 如权利要求1所述的三层复合组织高强钢板，其特征在于，所述三层复合组织高强钢板为冷轧钢板，其厚度为0.5-2.5mm，或所述三层复合组织高强钢板为热轧钢板，其厚度为1.0-3.0mm。The three-layer composite structure high-strength steel plate of claim 1, wherein the three-layer composite structure high-strength steel plate is a cold-rolled steel plate with a thickness of 0.5-2.5mm, or the three-layer composite structure high-strength steel plate is a hot The thickness of the rolled steel plate is 1.0-3.0mm.
  5. 如权利要求1所述的三层复合组织高强钢板，其特征在于，所述上表层的厚度为5-100微米，并且/或者所述下表层的厚度为5-100微米；或，所述上表层的厚度＞100微米；并且/或者所述下表层的厚度大于100微米。The three-layer composite structure high-strength steel sheet according to claim 1, wherein the thickness of the upper surface layer is 5-100 micrometers, and/or the thickness of the lower surface layer is 5-100 micrometers; or, the upper surface layer has a thickness of 5-100 micrometers; or The thickness of the surface layer is greater than 100 microns; and/or the thickness of the lower layer is greater than 100 microns.
  6. 如权利要求1所述的三层复合组织高强钢板，其特征在于，其含有下述各项化学元素：C：0.08-0.35％；Si：0.01-2.5％；Mn：0.5-3.0％。The three-layer composite structure high-strength steel sheet according to claim 1, characterized in that it contains the following chemical elements: C: 0.08-0.35%; Si: 0.01-2.5%; Mn: 0.5-3.0%.
  7. 如权利要求7所述的三层复合组织高强钢板，其特征在于，其各化学元素质量百分含量为：C：0.08-0.35％；Si：0.01-2.5％；Mn：0.5-3.0％；余量为Fe和其他不可避免的杂质。The three-layer composite structure high-strength steel sheet according to claim 7, wherein the mass percentage content of each chemical element is: C: 0.08-0.35%; Si: 0.01-2.5%; Mn: 0.5-3.0%; The amount is Fe and other unavoidable impurities.
  8. 如权利要求6或7所述的三层复合组织高强钢板，其特征在于，其还含有Cr、Mo、B的至少其中之一；其中，当B＜0.0005％时，Cr+Mn+Mo≤3％；当B为0.0005-0.0035％时，Cr+Mn+Mo≤2.3％。The three-layer composite structure high-strength steel sheet according to claim 6 or 7, characterized in that it also contains at least one of Cr, Mo, and B; wherein, when B<0.0005%, Cr+Mn+Mo≤3 %; when B is 0.0005 to 0.0035%, Cr+Mn+Mo≤2.3%.
  9. 如权利要求6或7所述的三层复合组织高强钢板，其特征在于，其还含有V、Ti、Nb的至少其中之一，并且V+Ti+Nb≤0.15％。The three-layer composite structure high-strength steel sheet according to claim 6 or 7, characterized in that it further contains at least one of V, Ti, and Nb, and V+Ti+Nb≤0.15%.
  10. 如权利要求1-9中任意一项所述的三层复合组织高强钢板，其特征在于，所述三层复合组织高强钢板的整体拉伸强度为980-1700MPa之间，所述上表层和 下表层的显微硬度HV≤250，所述中间层的显微硬度HV≥270。The three-layer composite structure high-strength steel plate according to any one of claims 1-9, wherein the overall tensile strength of the three-layer composite structure high-strength steel plate is between 980-1700 MPa, and the upper surface and the lower The microhardness of the surface layer is HV≤250, and the microhardness of the middle layer is HV≥270.
  11. 权利要求1-10中任一项所述的三层复合组织高强钢板的制造方法，其特征在于，所述方法包括步骤：炼钢、连铸、轧制和高温增湿脱碳；其中，所述高温增湿脱碳的工艺条件为：钢板温度为750～900℃，露点为-15～15℃，反应时间为40-160s；优选地，所述高温增湿脱碳在温增湿脱碳炉和/或退火炉中进行。The method for manufacturing a high-strength steel sheet with a three-layer composite structure according to any one of claims 1-10, wherein the method comprises the steps of: steelmaking, continuous casting, rolling, and high-temperature humidification and decarburization; The process conditions of the high temperature humidification decarburization are: the steel plate temperature is 750～900℃, the dew point is -15～15℃, and the reaction time is 40-160s; preferably, the high temperature humidification decarburization is in the temperature humidification decarburization Furnace and/or annealing furnace.
  12. 如权利要求11所述的三层复合组织高强钢板的制造方法，其特征在于，所述三层复合组织高强钢板为热轧钢板，所述方法包括步骤：炼钢、连铸、热轧、酸洗和连续退火，其中在连续退火步骤中进行所述高温增湿脱碳，以获得分别为厚5-100微米的脱碳层的钢板的上表层和下表层；或者，所述方法包括步骤：炼钢、连铸、热轧、酸洗、所述高温增湿脱碳炉脱碳和连续退火，以获得分别为厚5-100微米的脱碳层的钢板的上表层和下表层，或任选地，在所述连续退火步骤中继续进行所述高温增湿脱碳，以获得分别为厚度大于100微米的脱碳层的钢板的上表层和下表层。The method for manufacturing a three-layer composite structure high-strength steel sheet according to claim 11, wherein the three-layer composite structure high-strength steel sheet is a hot-rolled steel sheet, and the method includes the steps of: steelmaking, continuous casting, hot rolling, acid Washing and continuous annealing, wherein the high-temperature humidification decarburization is performed in the continuous annealing step to obtain the upper surface layer and the lower layer of the steel plate having a decarburized layer with a thickness of 5-100 microns; or, the method includes the steps: Steelmaking, continuous casting, hot rolling, pickling, decarburization and continuous annealing in the high-temperature humidification decarburization furnace to obtain the upper and lower layers of the steel plate with a decarburization layer of 5-100 microns thick, or any Optionally, the high-temperature humidification decarburization is continued in the continuous annealing step to obtain the upper surface layer and the lower layer of the steel sheet each having a decarburized layer with a thickness of greater than 100 microns.
  13. 如权利要求12所述的三层复合组织高强钢板的制造方法，其特征在于，其中在连续退火步骤中控制连续退火工艺参数至少满足下列各项的至少其中一项：The method for manufacturing a high-strength steel sheet with a three-layer composite structure according to claim 12, wherein the continuous annealing process parameters are controlled in the continuous annealing step to satisfy at least one of the following items:
    控制保温温度为750-900℃，保温时间为40-160s；Control the holding temperature to be 750-900℃, and the holding time to be 40-160s;
    快冷开始温度为650-780℃；快冷速度为30-1500℃/s；快冷终止温度为50-450℃；The start temperature of rapid cooling is 650-780℃; the speed of rapid cooling is 30-1500℃/s; the end temperature of rapid cooling is 50-450℃;
    过时效温度为180-450℃；过时效时间为200-600s。The over-aging temperature is 180-450℃; the over-aging time is 200-600s.
  14. 如权利要求11所述的三层复合组织高强钢板的制造方法，其特征在于，所述三层复合组织高强钢板为冷轧钢板，所述方法包括步骤：炼钢、连铸、热轧、酸洗、冷轧和连续退火，其中在连续退火步骤中进行所述高温增湿脱碳，以获得分别为厚5-100微米的脱碳层的钢板的上表层和下表层；或者，所述方法包括步骤：炼钢、连铸、热轧、酸洗、冷轧、所述高温增湿脱碳炉脱碳和连续退火，以获得分别为厚5-100微米的脱碳层的钢板的上表层和下表层，或任选地，在所述连续退火过程中继续进行所述高温增湿脱碳，以获得分别为厚度大于100微米的脱碳层的钢板的上表层和下表层。The method for manufacturing a three-layer composite structure high-strength steel sheet according to claim 11, wherein the three-layer composite structure high-strength steel sheet is a cold-rolled steel sheet, and the method includes the steps of: steelmaking, continuous casting, hot rolling, acid Washing, cold rolling, and continuous annealing, wherein the high-temperature humidification decarburization is performed in the continuous annealing step to obtain the upper surface layer and the lower layer of the steel sheet having a decarburized layer with a thickness of 5-100 microns, respectively; or, the method Including steps: steelmaking, continuous casting, hot rolling, pickling, cold rolling, decarburization in the high-temperature humidification decarburization furnace, and continuous annealing to obtain the upper surface layer of the steel plate with a decarburization layer of 5-100 microns thick. And the lower layer, or optionally, the high-temperature humidification decarburization is continued during the continuous annealing process to obtain the upper and lower layers of the steel sheet each having a decarburized layer with a thickness of greater than 100 microns.
  15. 如权利要求14所述的三层复合组织高强钢板的制造方法，其特征在于，其中在连续退火步骤中控制连续退火工艺参数至少满足下列各项的至少其中一项：The method for manufacturing a high-strength steel sheet with a three-layer composite structure according to claim 14, wherein the continuous annealing process parameters are controlled in the continuous annealing step to satisfy at least one of the following items:
    控制保温温度为750-900℃，保温时间为40-160s；Control the holding temperature to be 750-900℃, and the holding time to be 40-160s;
    快冷开始温度为650-780℃；快冷速度为30-1500℃/s；快冷终止温度为50-450℃；The start temperature of rapid cooling is 650-780℃; the speed of rapid cooling is 30-1500℃/s; the end temperature of rapid cooling is 50-450℃;
    过时效温度为180-450℃；过时效时间为200-600s。The over-aging temperature is 180-450℃; the over-aging time is 200-600s.
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Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007224416A (en) * 2006-01-24 2007-09-06 Jfe Steel Kk High-strength cold rolled steel sheet having excellent deep- drawability and ductility and production method, high-strength hot dip galvanized steel sheet using the cold rolled steel sheet and its production method
JP2008106351A (en) * 2006-09-29 2008-05-08 Nippon Steel Corp High strength cold rolled steel sheet excellent in workability and its production method
KR20080097587A (en) * 2007-05-02 2008-11-06 주식회사 포스코 High strength hot dip coated steel sheet having good formability and manufacturing method thereof
CN106244923A (en) * 2016-08-30 2016-12-21 宝山钢铁股份有限公司 A kind of phosphorus characteristic and the excellent cold rolling high strength steel plate of forming property and manufacture method thereof
CN107208222A (en) * 2015-01-28 2017-09-26 杰富意钢铁株式会社 High strength cold rolled steel plate, high intensity coated steel sheet and its manufacture method
CN109371325A (en) * 2018-11-30 2019-02-22 宝山钢铁股份有限公司 A kind of electrogalvanized thermoforming steel plate that cold-bending property is excellent or steel band and its manufacturing method
WO2019079763A1 (en) * 2017-10-19 2019-04-25 Cola Gary M Jr High strength steels, processes for making same and materials resulting therefrom
CN110073024A (en) * 2016-12-19 2019-07-30 Posco公司 The ultrahigh-strength steel plates and its manufacturing method of excellent in bending workability

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH07150252A (en) * 1993-11-25 1995-06-13 Sumitomo Metal Ind Ltd Production of cold rolled steel sheet for porcelain enameling by continuous annealing
TWI468534B (en) * 2012-02-08 2015-01-11 Nippon Steel & Sumitomo Metal Corp High-strength cold rolled steel sheet and manufacturing method thereof
EP3187614A1 (en) * 2012-05-31 2017-07-05 Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.) High strength cold-rolled steel sheet and manufacturing method therefor
CN106498307B (en) * 2016-10-26 2018-09-25 武汉钢铁有限公司 The good high-strength and high ductility lightweight steel of 780MPa grades of cold-forming properties and its manufacturing method
CN108504956B (en) * 2017-02-27 2020-07-28 宝山钢铁股份有限公司 High-formability cold-rolled ultrahigh-strength clad steel sheet and manufacturing method thereof
US10329639B2 (en) * 2017-08-04 2019-06-25 Gm Global Technology Operations Llc. Multilayer steel and method of reducing liquid metal embrittlement
CN110423953B (en) * 2019-08-21 2020-12-01 马鞍山钢铁股份有限公司 Hot forming member with excellent cold bending performance and tensile strength of more than 1800MPa and preparation method thereof

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007224416A (en) * 2006-01-24 2007-09-06 Jfe Steel Kk High-strength cold rolled steel sheet having excellent deep- drawability and ductility and production method, high-strength hot dip galvanized steel sheet using the cold rolled steel sheet and its production method
JP2008106351A (en) * 2006-09-29 2008-05-08 Nippon Steel Corp High strength cold rolled steel sheet excellent in workability and its production method
KR20080097587A (en) * 2007-05-02 2008-11-06 주식회사 포스코 High strength hot dip coated steel sheet having good formability and manufacturing method thereof
CN107208222A (en) * 2015-01-28 2017-09-26 杰富意钢铁株式会社 High strength cold rolled steel plate, high intensity coated steel sheet and its manufacture method
CN106244923A (en) * 2016-08-30 2016-12-21 宝山钢铁股份有限公司 A kind of phosphorus characteristic and the excellent cold rolling high strength steel plate of forming property and manufacture method thereof
CN110073024A (en) * 2016-12-19 2019-07-30 Posco公司 The ultrahigh-strength steel plates and its manufacturing method of excellent in bending workability
WO2019079763A1 (en) * 2017-10-19 2019-04-25 Cola Gary M Jr High strength steels, processes for making same and materials resulting therefrom
CN109371325A (en) * 2018-11-30 2019-02-22 宝山钢铁股份有限公司 A kind of electrogalvanized thermoforming steel plate that cold-bending property is excellent or steel band and its manufacturing method

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