CN111020353B - High-strength steel plate for car doorsill reinforcing plate and production method thereof - Google Patents

High-strength steel plate for car doorsill reinforcing plate and production method thereof Download PDF

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CN111020353B
CN111020353B CN201911326912.7A CN201911326912A CN111020353B CN 111020353 B CN111020353 B CN 111020353B CN 201911326912 A CN201911326912 A CN 201911326912A CN 111020353 B CN111020353 B CN 111020353B
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steel plate
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heating
strength steel
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CN111020353A (en
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王立辉
孙力
罗扬
王健
董伊康
刘需
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HBIS Co Ltd
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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C33/00—Making ferrous alloys
    • C22C33/04—Making ferrous alloys by melting
    • 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
    • C21D6/00—Heat treatment of ferrous alloys
    • C21D6/002—Heat treatment of ferrous alloys containing Cr
    • 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
    • C21D6/00—Heat treatment of ferrous alloys
    • C21D6/005—Heat treatment of ferrous alloys containing Mn
    • C—CHEMISTRY; METALLURGY
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    • 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
    • C21D6/00—Heat treatment of ferrous alloys
    • C21D6/008—Heat treatment of ferrous alloys containing Si
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    • 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
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    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C21D9/0081—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for slabs; for billets
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    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/002—Ferrous alloys, e.g. steel alloys containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
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    • C22C38/00—Ferrous alloys, e.g. steel alloys
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    • C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
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    • C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
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    • 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
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    • 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
    • C22C38/24—Ferrous alloys, e.g. steel alloys containing chromium with vanadium
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    • 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
    • C22C38/26—Ferrous alloys, e.g. steel alloys containing chromium with niobium or tantalum
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    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
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    • 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
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    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
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    • 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
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    • 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
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    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
    • C23C2/04—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor characterised by the coating material
    • C23C2/06—Zinc or cadmium or alloys based thereon
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
    • C23C2/34—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor characterised by the shape of the material to be treated
    • C23C2/36—Elongated material
    • C23C2/40—Plates; Strips
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    • C21—METALLURGY OF IRON
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    • 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

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Abstract

A high-strength steel plate for a car threshold reinforcing plate and a production method thereof are disclosed, wherein the steel plate comprises the following chemical components: c: 0.09-0.11%, Si: 0.05 to 0.07%, Mn: 2.11-2.21%, P0.010-0.017%, S not more than 0.008%, Al: 0.03-0.06%, Cr: 0.59-0.65%, Mo: 0.31 to 0.51%, Nb: 0.041-0.049%, Ti: 0.013-0.017%, V: 0.010-0.017%, B: 0.001-0.002%, Pr 0.01-0.05%, Ce 0.01-0.05%, Pr + Ce 0.02% or more and 0.06% or less, and the balance Fe and inevitable impurities. The production method comprises the working procedures of smelting, casting, heating, hot rolling, cold rolling and hot galvanizing. The steel plate has high strength and good platability.

Description

High-strength steel plate for car doorsill reinforcing plate and production method thereof
Technical Field
The invention belongs to the technical field of metallurgy, and particularly relates to a high-strength steel plate for a car doorsill reinforcing plate and a production method thereof.
Background
Increasingly stringent safety regulations for the entire automobile and increasing functional requirements of the automobile for consumers require that automobile designers continuously add various accessories to meet the requirements of safety, comfort, reliability, intellectualization and the like. Passenger car body sills are required to have high strength and good formability, and are therefore basically manufactured from high-strength steel sheets.
Comparative example 1: the invention discloses a cold-rolled dual-phase steel with the chemical components in percentage by weight (wt%) as follows, which is disclosed by the invention patent application with the application number of 201710364087.4 and the name of 'ultra-low yield ratio 980MPa grade cold-rolled dual-phase steel and a manufacturing method thereof': c: 0.13 to 0.18, Si: 0.3 to 0.6, Mn: 1.7-2.4, Als: 0.03 to 0.06, Nb: 0-0.05, Cr: 0.3-0.5, and the balance of Fe and inevitable impurities; the dual-phase steel structure is ferrite, island martensite and a small amount of residual austenite, the tensile strength is more than or equal to 980MPa, the yield ratio is less than 0.50, and the elongation A50Not less than 14 percent. Although the cold-rolled dual-phase steel can be used for automobile anti-collision parts, structural parts and inner plate materials, the process requirement is very high for obtaining the microstructure from the aspect of the components, the retained austenite is difficult to stably obtain, and simultaneously, due to the three-phase structure, the steel plate is easy to rebound in the deformation process.
Comparative example 2: the invention patent application with the application number of 201710191787.8 and the name of 980MPa cold-rolled dual-phase steel plate with excellent cold bending performance and a preparation method thereof discloses a steel plate which comprises the following chemical components in percentage by weight: c: 0.10 to 0.12, Si: 0.45-0.65, Mn: 2.4-2.6, Cr: 0.35 to 0.45, 0.05 to 0.075 of Nb, Ti: 0.06-0.10, Als: 0.055-0.075, P is less than or equal to 0.008, S is less than or equal to 0.002, N is less than or equal to 0.003, and the balance of Fe and inevitable impurities; the microstructure is martensite and ferrite dual-phase structure, the yield strength is 730-850 MPa, the tensile strength is over 980MPa, the elongation is 10-20%, the 180-degree cold bending property is less than or equal to 2a, and a is the plate thickness. The finished steel sheet is a cold rolled material, but has a high Si content in terms of its chemical composition, and since Si having a high content is easily combined with O and Mn during heat treatment, Si is formed2MnO4Is difficult to galvanize, andthe high-end car sill is basically made of a high-strength galvanized steel sheet, and therefore, the cold-rolled dual-phase steel sheet is difficult to be used for a high-end car sill part.
From the above, in order to meet the rapid development of the automobile industry, it is urgently required to develop a high-strength steel sheet for a car rocker gusset, which has good drawability, platability and formability.
Disclosure of Invention
In order to solve the technical problems, the invention provides a high-strength steel plate for a car doorsill reinforcing plate and a production method thereof. The invention adopts the following technical scheme:
a high-strength steel plate for a car threshold reinforcing plate comprises the following chemical components in percentage by mass: c: 0.09-0.11%, Si: 0.05 to 0.07%, Mn: 2.11-2.21%, P0.010-0.017%, S not more than 0.008%, Al: 0.03-0.06%, Cr: 0.59-0.65%, Mo: 0.31 to 0.51%, Nb: 0.041-0.049%, Ti: 0.013-0.017%, V: 0.010-0.017%, B: 0.001-0.002%, 0.01-0.05% of Pr, 0.01-0.05% of Ce, more than or equal to 0.02% and less than or equal to 0.06% of Pr and Ce, and the balance of Fe and inevitable impurities.
The high-strength steel plate is a ferrite and martensite dual-phase structure, wherein the ferrite accounts for 20-25%.
The high-strength steel plate disclosed by the invention has the yield strength of 665-685 MPa, the tensile strength of 985-1020 MPa, the elongation of 13-20%, the adhesion force of a zinc layer is less than or equal to 1.5 grade, the resilience angle is less than or equal to 3 degrees, the 180-degree cold bending property is less than or equal to 0.5a, and a is the thickness of the steel plate.
The invention also provides a production method of the high-strength steel plate for the car threshold reinforcing plate, which comprises the working procedures of smelting, casting, heating, hot rolling, cold rolling and hot galvanizing.
According to the smelting process, the tapping temperature of molten steel is 1668-1676 ℃.
In the heating process, the heating temperature is 1237-1257 ℃, and the heat preservation time is 147-165 min.
The hot rolling procedure is 7-pass rolling, and the thickness of the rolled plate is 3.0-5.0 mm; the rough rolling temperature is 1133-1153 ℃, the final rolling temperature is 917-937 ℃, and the coiling temperature is 576-599 ℃.
In the cold rolling step, the total rolling reduction rate is 60-64%, and the thickness of the plate after rolling is 1.2-1.8 mm.
The hot galvanizing process comprises the following steps: heating the cold-rolled steel plate to 810-830 ℃, wherein the process takes 200-220 s; keeping the temperature for 50-80 s, and then rapidly cooling to 465-475 ℃ at the speed of 57-69 ℃/s; under the condition that the temperature of a zinc solution is 455-465 ℃, after 5-9 s of dip plating, cooling to room temperature at the speed of 5-17 ℃/s; the weight percentage of Al in the zinc liquid is 0.20-0.36%.
In order to ensure that the comprehensive performance of the steel plate is excellent, the basic principle of limiting the content of each element is as follows:
c: is a solid solution strengthening element and is also a martensite forming element, and therefore, the invention adopts a control scheme of the content of C. If the C content is too low, the strength of the steel is difficult to ensure; too high a C content reduces the plasticity and impact properties of the steel and also affects the weldability.
Si: the steel can play a role in solid solution strengthening to improve the strength of the steel, the Si content is too low to play the role, the Si content is too high, the surface quality of the material is poor, and the galvanization is difficult.
Mn: the Mn-Mn alloy is a conventional strengthening and toughening element, the Mn element content is too high, on one hand, the cost is increased, and a hardened layer appears on a welding structure, so that crack sensitivity of a crack welding line and a heat affected zone is increased.
P: in the invention, P has the function of strengthening and toughening, but the welding performance is influenced by too high content.
S: the lower the content in the steel, the better, the adverse effect on the cracking and welding of the steel material of the present invention is avoided. In addition, the higher sulfur content may consume too much manganese, affect the strengthening and toughening effect of the steel, or increase the material cost.
Al: the deoxidation effect is realized in the steelmaking link; the Al content is too high, the stacking fault energy of austenite is increased, the martensite phase transformation is inhibited, and a crystallizer water gap in a steelmaking process can be seriously blocked in industrial production.
Cr, Mo and B are solid-solution strengthening elements and strong carbide-forming elements, which strongly improve hardenability of steel, but too high Cr content leads to an increase in cost and also deteriorates formability of steel.
Nb, Ti and V are strong carbonitride forming elements, are beneficial to precipitation strengthening, can prevent high-temperature austenite from excessively growing, but are easy to cause partial aggregation of carbonitride due to excessively high content, and have poor processability, and meanwhile, the material cost is increased.
Pr and Ce in the invention, the coating performance of the substrate is enhanced, the formation of intermetallic compounds is avoided, and the corrosion resistance is enhanced.
The invention solves the problems of high difficulty in galvanizing and low adhesion of a zinc layer of the traditional dual-phase steel. The reinforcing plate in the doorsill punched by the steel plate has low resilience, good drawability, platability and forming performance, wide market application prospect and remarkable social benefit and economic benefit.
Compared with the traditional high-strength steel plate, the high-strength steel plate has the following advantages:
(1) the invention has the advantages of unique chemical component composition and process matching, simple manufacturing process, easy control of process window and easy realization of products.
(2) The high-strength steel plate is a dual-phase structure of ferrite and martensite, wherein the ferrite accounts for 20-25%, and the high-strength steel plate can ensure enough strength and has certain plasticity.
(3) The adhesion force of the zinc layer is less than or equal to 1.5 grade, the galvanized layer of the steel plate is good in quality, the rebound angle of the reinforcing plate in the punched doorsill is less than or equal to 3 degrees, and the steel plate has good ductility.
Drawings
FIG. 1 is a structural view of a metallographic microstructure of a steel sheet according to example 1 of the present invention.
Detailed Description
The present invention will be described in further detail with reference to examples.
Example 1
The chemical components and mass percentage contents of the high-strength steel plate of the embodiment are shown in table 1, and the mechanical properties thereof are shown in table 2.
The production method of the high-strength steel plate for the car threshold reinforcing plate comprises the working procedures of smelting, casting, heating, hot rolling, cold rolling and hot galvanizing. The steps of each process are as follows:
smelting: the tapping temperature of the molten steel is 1670 ℃;
a heating procedure: heating at 1239 deg.C for 150 min;
a hot rolling procedure: 7-pass rolling is carried out, and the thickness of the rolled plate is 3.0 mm; the rough rolling temperature is 1137 ℃, the final rolling temperature is 922 ℃ and the coiling temperature is 599 ℃;
a cold rolling procedure: the total reduction rate is 60 percent, and the thickness of the rolled plate is 1.2 mm;
hot galvanizing procedure: heating the cold-rolled steel plate to 812 ℃, wherein the process takes 210 s; keeping the temperature for 55s, and rapidly cooling to 468 ℃ at the speed of 58 ℃/s; under the condition that the temperature of zinc liquid is 461 ℃, after dip plating is carried out for 7s, cooling to room temperature at the speed of 12 ℃/s; the weight percentage of Al in the zinc liquid is 0.36 percent.
As can be seen from fig. 1, the high-strength steel sheet of this example has a dual-phase structure of ferrite and martensite, wherein the ferrite content is 23%, and it is able to ensure sufficient strength and have a certain plasticity (the microstructure of the steel sheets of the other examples is similar to that of fig. 1, and therefore, it is omitted).
Example 2
The chemical components and mass percentage contents of the high-strength steel plate of the embodiment are shown in table 1, and the mechanical properties thereof are shown in table 2.
The production method of the high-strength steel plate for the car threshold reinforcing plate comprises the working procedures of smelting, casting, heating, hot rolling, cold rolling and hot galvanizing. The steps of each process are as follows:
smelting: the tapping temperature of the molten steel is 1674 ℃;
a heating procedure: heating at 1254 deg.C for 148 min;
a hot rolling procedure: 7-pass rolling is carried out, and the thickness of the rolled plate is 4.0 mm; the rough rolling temperature is 1153 ℃, the final rolling temperature is 937 ℃, and the coiling temperature is 595 ℃;
a cold rolling procedure: the total reduction rate is 60 percent, and the thickness of the rolled plate is 1.6 mm;
hot galvanizing procedure: heating the cold-rolled steel plate to 820 ℃, wherein the process is used for 202 s; after preserving heat for 52s, rapidly cooling to 471 ℃ at the speed of 66 ℃/s; under the condition that the temperature of a zinc solution is 464 ℃, after immersion plating is carried out for 6s, cooling to the room temperature at the speed of 7 ℃/s; the weight percentage of Al in the zinc liquid is 0.22 percent.
Example 3
The chemical components and mass percentage contents of the high-strength steel plate of the embodiment are shown in table 1, and the mechanical properties thereof are shown in table 2.
The production method of the high-strength steel plate for the car threshold reinforcing plate comprises the working procedures of smelting, casting, heating, hot rolling, cold rolling and hot galvanizing. The steps of each process are as follows:
smelting: the tapping temperature of the molten steel is 1676 ℃;
a heating procedure: the heating temperature is 1240 ℃, and the heat preservation time is 160 min;
a hot rolling procedure: 7-pass rolling is carried out, and the thickness of the rolled plate is 4.5 mm; the rough rolling temperature is 1135 ℃, the final rolling temperature is 933 ℃, and the coiling temperature is 577 ℃;
a cold rolling procedure: the total reduction rate is 62%, and the thickness of the rolled plate is 1.7 mm;
hot galvanizing procedure: heating the cold-rolled steel plate to 815 ℃, wherein the process takes 220 s; keeping the temperature for 80s, and rapidly cooling to 470 ℃ at the speed of 68 ℃/s; under the condition that the temperature of zinc liquid is 460 ℃, after immersion plating is carried out for 9s, cooling to room temperature at the speed of 17 ℃/s; the weight percentage of Al in the zinc liquid is 0.35 percent.
Example 4
The chemical components and mass percentage contents of the high-strength steel plate of the embodiment are shown in table 1, and the mechanical properties thereof are shown in table 2.
The production method of the high-strength steel plate for the car threshold reinforcing plate comprises the working procedures of smelting, casting, heating, hot rolling, cold rolling and hot galvanizing. The steps of each process are as follows:
smelting: the tapping temperature of the molten steel is 1669 ℃;
a heating procedure: heating at 1252 deg.C for 165 min;
a hot rolling procedure: 7-pass rolling is carried out, and the thickness of the rolled plate is 4.7 mm; the rough rolling temperature is 1140 ℃, the final rolling temperature is 920 ℃, and the coiling temperature is 582 ℃;
a cold rolling procedure: the total reduction rate is 64 percent, and the thickness of the rolled plate is 1.7 mm;
hot galvanizing procedure: heating the cold-rolled steel plate to 823 ℃, wherein the process takes 214 s; keeping the temperature for 68s, and rapidly cooling to 465 ℃ at the speed of 60 ℃/s; under the condition that the temperature of the zinc liquid is 459 ℃, after dip plating is carried out for 8s, cooling to the room temperature at the speed of 9 ℃/s; the weight percentage of Al in the zinc liquid is 0.28 percent.
Example 5
The chemical components and mass percentage contents of the high-strength steel plate of the embodiment are shown in table 1, and the mechanical properties thereof are shown in table 2.
The production method of the high-strength steel plate for the car threshold reinforcing plate comprises the working procedures of smelting, casting, heating, hot rolling, cold rolling and hot galvanizing. The steps of each process are as follows:
smelting: the tapping temperature of the molten steel is 1671 ℃;
a heating procedure: heating at 1255 deg.C for 162 min;
a hot rolling procedure: 7-pass rolling is carried out, and the thickness of the rolled plate is 3.7 mm; the rough rolling temperature is 1133 ℃, the final rolling temperature is 928 ℃, and the coiling temperature is 590 ℃;
a cold rolling procedure: the total reduction rate is 62%, and the thickness of the rolled plate is 1.4 mm;
hot galvanizing procedure: heating the cold-rolled steel plate to 830 ℃, wherein the time is 217 s; keeping the temperature for 60s, and then rapidly cooling to 473 ℃ at the speed of 57 ℃/s; under the condition that the temperature of a zinc solution is 462 ℃, after immersion plating is carried out for 7s, cooling to room temperature at the speed of 14 ℃/s; the weight percentage of Al in the zinc liquid is 0.25 percent.
Example 6
The chemical components and mass percentage contents of the high-strength steel plate of the embodiment are shown in table 1, and the mechanical properties thereof are shown in table 2.
The production method of the high-strength steel plate for the car threshold reinforcing plate comprises the working procedures of smelting, casting, heating, hot rolling, cold rolling and hot galvanizing. The steps of each process are as follows:
smelting: the tapping temperature of the molten steel is 1675 ℃;
a heating procedure: heating at 1237 deg.C for 155 min;
a hot rolling procedure: 7-pass rolling is carried out, and the thickness of the rolled plate is 5.0 mm; the rough rolling temperature is 1150 ℃, the final rolling temperature is 925 ℃ and the coiling temperature is 585 ℃;
a cold rolling procedure: the total reduction rate is 64 percent, and the thickness of the rolled plate is 1.8 mm;
hot galvanizing procedure: heating the cold-rolled steel plate to 825 deg.C for 200 s; keeping the temperature for 50s, and rapidly cooling to 469 ℃ at the speed of 62 ℃/s; under the condition that the temperature of zinc liquid is 465 ℃, after 5s of dip plating, cooling to room temperature at the speed of 10 ℃/s; the weight percentage of Al in the zinc liquid is 0.33 percent.
Example 7
The chemical components and mass percentage contents of the high-strength steel plate of the embodiment are shown in table 1, and the mechanical properties thereof are shown in table 2.
The production method of the high-strength steel plate for the car threshold reinforcing plate comprises the working procedures of smelting, casting, heating, hot rolling, cold rolling and hot galvanizing. The steps of each process are as follows:
smelting: the tapping temperature of the molten steel is 1668 ℃;
a heating procedure: the heating temperature is 1250 ℃, and the heat preservation time is 153 min;
a hot rolling procedure: 7-pass rolling is carried out, and the thickness of the rolled plate is 3.5 mm; the rough rolling temperature is 1133 ℃, the final rolling temperature is 918 ℃, and the coiling temperature is 576 ℃;
a cold rolling procedure: the total reduction rate is 63 percent, and the thickness of the rolled plate is 1.3 mm;
hot galvanizing procedure: heating the cold-rolled steel plate to 829 ℃ for 211 s; keeping the temperature for 69s, and then rapidly cooling to 472 ℃ at the speed of 63 ℃/s; under the condition that the temperature of the zinc liquid is 455 ℃, after dip plating is carried out for 7s, cooling to room temperature at the speed of 15 ℃/s; the weight percentage of Al in the zinc liquid is 0.31 percent.
Example 8
The chemical components and mass percentage contents of the high-strength steel plate of the embodiment are shown in table 1, and the mechanical properties thereof are shown in table 2.
The production method of the high-strength steel plate for the car threshold reinforcing plate comprises the working procedures of smelting, casting, heating, hot rolling, cold rolling and hot galvanizing. The steps of each process are as follows:
smelting: the tapping temperature of the molten steel is 1670 ℃;
a heating procedure: heating at 1239 deg.C for 158 min;
a hot rolling procedure: 7-pass rolling is carried out, and the thickness of the rolled plate is 4.1 mm; the rough rolling temperature is 1140 ℃, the final rolling temperature is 930 ℃, and the coiling temperature is 588 ℃;
a cold rolling procedure: the total reduction rate is 63 percent, and the thickness of the rolled plate is 1.5 mm;
hot galvanizing procedure: heating the cold-rolled steel plate to 810 ℃, wherein the process takes 205 s; keeping the temperature for 51s, and rapidly cooling to 470 ℃ at the speed of 69 ℃/s; under the condition that the temperature of a zinc solution is 463 ℃, after dip plating is carried out for 6s, cooling to room temperature at the speed of 13 ℃/s; the weight percentage of Al in the zinc liquid is 0.30 percent.
Example 9
The chemical components and mass percentage contents of the high-strength steel plate of the embodiment are shown in table 1, and the mechanical properties thereof are shown in table 2.
The production method of the high-strength steel plate for the car threshold reinforcing plate comprises the working procedures of smelting, casting, heating, hot rolling, cold rolling and hot galvanizing. The steps of each process are as follows:
smelting: the tapping temperature of the molten steel is 1673 ℃;
a heating procedure: heating at 1245 deg.C for 161 min;
a hot rolling procedure: 7-pass rolling is carried out, and the thickness of the rolled plate is 4.8 mm; the rough rolling temperature is 1135 ℃, the final rolling temperature is 921 ℃, and the coiling temperature is 580 ℃;
a cold rolling procedure: the total reduction rate is 62%, and the thickness of the rolled plate is 1.8 mm;
hot galvanizing procedure: heating the cold-rolled steel plate to 817 ℃ for 220 s; keeping the temperature for 80s, and rapidly cooling to 474 ℃ at the speed of 65 ℃/s; under the condition that the temperature of zinc liquid is 457 ℃, after immersion plating is carried out for 9s, cooling to room temperature at the speed of 5 ℃/s; the weight percentage of Al in the zinc liquid is 0.27%.
Example 10
The chemical components and mass percentage contents of the high-strength steel plate of the embodiment are shown in table 1, and the mechanical properties thereof are shown in table 2.
The production method of the high-strength steel plate for the car threshold reinforcing plate comprises the working procedures of smelting, casting, heating, hot rolling, cold rolling and hot galvanizing. The steps of each process are as follows:
smelting: the tapping temperature of the molten steel is 1672 ℃;
a heating procedure: heating at 1247 deg.C for 147 min;
a hot rolling procedure: 7-pass rolling is carried out, and the thickness of the rolled plate is 4.5 mm; the rough rolling temperature is 1150 ℃, the final rolling temperature is 935 ℃ and the coiling temperature is 599 ℃;
a cold rolling procedure: the total reduction rate is 62%, and the thickness of the rolled plate is 1.7 mm;
hot galvanizing procedure: heating the cold-rolled steel plate to 820 ℃, wherein the process takes 209 s; keeping the temperature for 55s, and then rapidly cooling to 475 ℃ at the speed of 64 ℃/s; under the condition that the temperature of zinc liquid is 460 ℃, after immersion plating is carried out for 7s, cooling to room temperature at the speed of 6 ℃/s; the weight percentage of Al in the zinc liquid is 0.20 percent.
Example 11
The chemical components and mass percentage contents of the high-strength steel plate of the embodiment are shown in table 1, and the mechanical properties thereof are shown in table 2.
The production method of the high-strength steel plate for the car threshold reinforcing plate comprises the working procedures of smelting, casting, heating, hot rolling, cold rolling and hot galvanizing. The steps of each process are as follows:
smelting: the tapping temperature of the molten steel is 1668 ℃;
a heating procedure: heating at 1257 deg.C for 164 min;
a hot rolling procedure: 7-pass rolling is carried out, and the thickness of the rolled plate is 3.9 mm; the rough rolling temperature is 1151 ℃, the final rolling temperature is 917 ℃, and the coiling temperature is 593 ℃;
a cold rolling procedure: the total reduction rate is 62%, and the thickness of the rolled plate is 1.5 mm;
hot galvanizing procedure: heating the cold-rolled steel plate to 825 deg.C for 206 s; keeping the temperature for 51s, and rapidly cooling to 465 ℃ at the speed of 60 ℃/s; under the condition that the temperature of zinc liquid is 458 ℃, after immersion plating is carried out for 6s, cooling to room temperature at the speed of 5 ℃/s; the weight percentage of Al in the zinc liquid is 0.23 percent.
The chemical compositions of the steel sheets of the examples of the present invention and the comparative examples are shown in Table 1; the performance pair ratios are shown in table 2.
TABLE 1. Steel plate chemical composition (wt%) of inventive example and comparative example
Figure DEST_PATH_IMAGE002
In table 1, the balance is Fe and inevitable impurities.
TABLE 2 comparison of the Properties of the Steel sheets of the examples of the invention with those of the comparative examples
Figure DEST_PATH_IMAGE004
As can be seen from Table 2, the high-strength steel plate provided by the invention has excellent comprehensive mechanical properties, zinc layer adhesion performance and application performance, and can meet various index requirements of white car body threshold parts of stamping cars.

Claims (6)

1. The high-strength steel plate for the car threshold reinforcing plate is characterized by comprising the following chemical components in percentage by mass: c: 0.09-0.11%, Si: 0.05 to 0.07%, Mn: 2.11-2.21%, P0.010-0.017%, S not more than 0.008%, Al: 0.03-0.06%, Cr: 0.59-0.65%, Mo: 0.31 to 0.51%, Nb: 0.041-0.049%, Ti: 0.013-0.017%, V: 0.010-0.017%, B: 0.001-0.002%, 0.01-0.05% of Pr, 0.01-0.05% of Ce, more than or equal to 0.02% and less than or equal to 0.06% of Pr and Ce, and the balance of Fe and inevitable impurities;
the high-strength steel plate is a ferrite and martensite dual-phase structure, wherein the ferrite accounts for 20-25%; the high-strength steel plate has the yield strength of 665-685 MPa, the tensile strength of 985-1020 MPa, the elongation of 13-20%, the adhesion force of a zinc layer is less than or equal to 1.5 grade, the resilience angle is less than or equal to 3 degrees, the 180-degree cold bending performance is less than or equal to 0.5a, and a is the thickness of the steel plate;
the high-strength steel plate is produced by the following method: the method comprises the working procedures of smelting, casting, heating, hot rolling, cold rolling and hot galvanizing; the hot rolling procedure is 7-pass rolling, and the thickness of the rolled plate is 3.0-5.0 mm; the rough rolling temperature is 1133-1153 ℃, the final rolling temperature is 917-937 ℃, and the coiling temperature is 576-599 ℃; the hot galvanizing process comprises the following steps: heating the cold-rolled steel plate to 810-830 ℃, preserving heat for 50-80 s, and rapidly cooling to 465-475 ℃ at the speed of 57-69 ℃/s; under the condition that the temperature of a zinc solution is 455-465 ℃, dip-plating is carried out for 5-9 s, and then cooling is carried out to room temperature at the speed of 5-17 ℃/s; the steel plate is heated to 810-830 ℃ for 200-220 s.
2. The production method of the high-strength steel plate for the car threshold reinforcing plate is characterized by comprising the working procedures of smelting, casting, heating, hot rolling, cold rolling and hot galvanizing;
the hot rolling procedure is 7-pass rolling, and the thickness of the rolled plate is 3.0-5.0 mm; the rough rolling temperature is 1133-1153 ℃, the final rolling temperature is 917-937 ℃, and the coiling temperature is 576-599 ℃;
the hot galvanizing process comprises the following steps: heating the cold-rolled steel plate to 810-830 ℃, preserving heat for 50-80 s, and rapidly cooling to 465-475 ℃ at the speed of 57-69 ℃/s; under the condition that the temperature of a zinc solution is 455-465 ℃, dip-plating is carried out for 5-9 s, and then cooling is carried out to room temperature at the speed of 5-17 ℃/s; the steel plate is heated to 810-830 ℃ for 200-220 s.
3. The method for producing the high-strength steel plate for the car sill reinforcing plate according to claim 2, wherein in the smelting process, the tapping temperature of molten steel is 1668-1676 ℃.
4. The production method of the high-strength steel plate for the car sill reinforcing plate according to claim 3, characterized in that in the heating step, the heating temperature is 1237-1257 ℃ and the heat preservation time is 147-165 min.
5. The method for producing a high-strength steel sheet for a car sill reinforcing plate according to claim 4, wherein in the cold rolling step, the total rolling reduction rate is 60 to 64%, and the thickness of the rolled sheet is 1.2 to 1.8 mm.
6. The method for producing a high-strength steel sheet for a car sill reinforcing plate according to any one of claims 2 to 5, wherein in the hot dip galvanizing step, the Al content in the molten zinc is 0.20 to 0.36% by weight.
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