CN115627416A - Low-cost hot-rolled steel plate for 700 MPa-level heavy-load axle after heat treatment machining and forming and preparation method thereof - Google Patents

Low-cost hot-rolled steel plate for 700 MPa-level heavy-load axle after heat treatment machining and forming and preparation method thereof Download PDF

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Publication number
CN115627416A
CN115627416A CN202211202623.8A CN202211202623A CN115627416A CN 115627416 A CN115627416 A CN 115627416A CN 202211202623 A CN202211202623 A CN 202211202623A CN 115627416 A CN115627416 A CN 115627416A
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steel plate
rolled steel
percent
equal
hot
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李相前
张志男
单修迎
郭朝海
贾崇雪
李贺
文雄
李恒
马强
董苗翠
胡华东
刘飞
杨西亚
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SD Steel Rizhao Co Ltd
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SD Steel Rizhao 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
    • 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
    • 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
    • C21D8/0205—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips of ferrous alloys
    • 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
    • C21D8/0247—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment
    • C21D8/0263—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment following hot rolling
    • 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
    • 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
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/26—Ferrous alloys, e.g. steel alloys containing chromium with niobium or tantalum
    • 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
    • C22C38/38—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
    • 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
    • C21D2211/009—Pearlite
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/80—Technologies aiming to reduce greenhouse gasses emissions common to all road transportation technologies
    • Y02T10/86—Optimisation of rolling resistance, e.g. weight reduction 

Abstract

The invention relates to the technical field of steel for heavy-duty vehicle axles, in particular to a low-cost hot-rolled steel plate for 700MPa heavy-duty vehicle axles after heat treatment processing forming and a preparation method thereof. The hot rolled steel plate comprises the following chemical components in percentage by weight: 0.15 to 0.26 percent of C, 0.15 to 0.40 percent of Si, 0.8 to 1.8 percent of Mn, less than or equal to 0.020 percent of P, less than or equal to 0.020 percent of S, 0.007 to 0.020 percent of Nb, 0.010 to 0.040 percent of Ti, 0.10 to 0.30 percent of Cr, 0.015 to 0.050 percent of Als, and the balance of Fe and other inevitable impurities. The invention has simple components and low alloy cost, the prepared hot rolled steel plate has excellent physical properties after being processed and formed by heat treatment, and the C content in the chemical component design is low, thereby improving the welding performance of the steel plate.

Description

Low-cost hot-rolled steel plate for 700 MPa-level heavy-load axle after heat treatment processing forming and preparation method thereof
Technical Field
The invention relates to the technical field of steel for heavy-duty axles, in particular to a low-cost hot-rolled steel plate for 700MPa heavy-duty axles after heat treatment, machining and molding and a preparation method thereof.
Background
The lightweight design of the heavy truck becomes a new direction for research and development and design of a plurality of vehicle enterprises, and the light truck can cover the whole body from a frame, a carriage and wheels. The reduction in weight of the truck core is also adopted in each of the large-sized vehicles. Through optimizing the axle structure, reduce the thickness of casing, utilize novel material and new technology to reduce the weight of axle to reach the lightweight purpose. Due to the requirements of commercial vehicle manufacturing for light weight development and energy conservation and weight reduction, particularly for a support frame and a rear drive axle, a large amount of hot rolled steel plates are used for manufacturing a punching welded axle shell, and a cast axle shell with complex manufacturing process, low production efficiency, heaviness and higher cost is replaced. The axle shell is formed by stamping the half axle housing from a steel plate and then assembling and welding the half axle housing, the axle package and the axle head, and the steel plate is required to have high strength, good cold bending and drawing formability and excellent weldability and fatigue resistance by combining the shape and the structural characteristics of the axle housing.
CN 111534758A discloses 'an axle housing steel for controlling strength reduction after hot forming and a preparation method thereof', the steel plate comprises the following chemical components: c:0.26 to 0.30%, si:0 to 0.1%, mn: 1.8-2.2%, P is less than or equal to 0.010%, S is less than or equal to 0.005%, V:0.01 to 0.03%, N:0 to 0.003%, cu:0.20 to 0.60%, al:0.02 to 0.05 percent, and the balance of Fe and inevitable impurities; the axle housing steel with yield strength more than 600MPa, tensile strength more than 700MPa and elongation more than 20% is obtained through the production of a hot continuous rolling process. The production method related to the patent has high element content, influences the welding performance of the material, and has high content of the added alloy V element and high cost; meanwhile, the performance of the material after hot forming is reduced, so that the strength of the subsequent material meets the requirement, the strength design of the initial material is high, and the load on a rolling mill is large.
CN110106444A discloses 'a drive axle housing 700 MPa-grade hot-rolled plate coil and a preparation method thereof', wherein the steel comprises the following components in percentage by mass: c:0.10 to 0.30 percent; si:0.10 to 0.25 percent; mn:1.0 to 2.5 percent; p: less than or equal to 0.02 percent; s: less than or equal to 0.010 percent; cr:0.1 to 0.8 percent; nb: 0.005-0.10%; and (3) Alt:0.02 to 0.35 percent; ti:0.01 to 0.05 percent; the balance of Fe and inevitable impurities. The axle steel with the tensile strength of 700MPa is obtained by adopting the design of a C-Mn-Cr-Nb component system and combining the controlled rolling and controlled cooling technology. The production method related to the patent has high cost of the whole alloy.
CN 108588550A discloses a 'steel plate for a hot-rolled stamping axle housing and a production method thereof', the steel comprises the following components by mass percent: c:0.14 to 0.20%, si: 0.15-0.60%, mn 1.40-1.60%, P: less than or equal to 0.030 percent, S: less than or equal to 0.020%, cr:0.040 to 0.10%, nb:0.020 to 0.090%, ti: 0.004-0.022%, alt: 0.020-0.060%, the rest is Fe and inevitable impurities. The hot stamping axle with yield strength of more than or equal to 450MPa, tensile strength of more than or equal to 580MPa and elongation of more than or equal to 14 percent is produced by adopting the working procedures of converter smelting, LF refining, slab continuous casting, slab heating, high-pressure water descaling, controlled rolling and controlled cooling. The production method related to the patent adopts niobium-vanadium-titanium composite reinforcement, so that the alloy cost is high, and the strength is lower.
Disclosure of Invention
Aiming at the technical problems of high cost, low strength, poor welding performance and the like, the invention provides a low-cost hot-rolled steel plate for a 700 MPa-level heavy-load axle after heat treatment processing forming and a preparation method thereof, and the low-cost hot-rolled steel plate has the advantages of low cost, high strength, good welding performance and the like.
In a first aspect, the invention provides a low-cost hot-rolled steel plate for a 700 MPa-grade heavy-load axle after heat treatment, processing and forming, which is characterized by comprising the following chemical components in percentage by weight: 0.15 to 0.26 percent of C, 0.15 to 0.40 percent of Si, 0.8 to 1.8 percent of Mn0.020 percent, less than or equal to 0.020 percent of P, less than or equal to 0.020 percent of S, 0.007 to 0.020 percent of Nb, 0.010 to 0.040 percent of Ti, 0.10 to 0.30 percent of Cr, 0.015 to 0.050 percent of Als, and the balance of Fe and other inevitable impurities.
Further, the physical properties of the hot rolled steel sheet are as follows: the thickness of the steel plate is 10-16 mm, the yield strength is more than or equal to 400MPa, the tensile strength is more than or equal to 550MPa, and the elongation is more than or equal to 22 percent; the metallographic structure of the hot rolled steel plate is ferrite plus pearlite.
Further, the physical properties of the hot rolled steel plate after heat treatment and forming are as follows: the yield strength is more than or equal to 600MPa, the tensile strength is more than or equal to 700MPa, and the elongation after fracture is more than or equal to 20 percent; the metallographic structure of the hot-rolled steel plate is a tempered sorbite after the hot-rolled steel plate is processed and formed by heat treatment.
Furthermore, the heat treatment processing and forming process comprises the steps of quenching and tempering the hot-rolled steel plate after local hot processing and stretching forming of the welded pipe.
In a second aspect, the invention provides a preparation method of a low-cost hot-rolled steel plate for a 700 MPa-level heavy-load axle after heat treatment, processing and forming, which comprises the following steps: molten iron KR desulfurization pretreatment → converter smelting → refining → continuous casting → casting blank heating → rough rolling → finish rolling → cooling → coiling → stacking and slow cooling.
Furthermore, oxygen content in steel is controlled during smelting, molten steel peroxidation is avoided, a sliding plate is adopted for slag stopping and tapping, and the slag discharging amount during tapping is strictly controlled; the refining adopts an LF single refining process, and the treatment period and the soft blowing time are strictly controlled, wherein the treatment period is more than or equal to 25min, and the soft blowing time is more than or equal to 10min.
Furthermore, the continuous casting adopts the full-flow argon protection pouring, the standing time before the continuous casting machine is arranged on the machine is more than or equal to 5min, the superheat degree is controlled to be 15-35 ℃, the fluctuation of the liquid level of the crystallizer is controlled to be less than or equal to +/-3 mm, and the purity of the molten steel is improved so as to improve the quality of casting blanks.
Furthermore, the heating tapping temperature of the casting blank is controlled to be 1150-1220 ℃, the heating time is more than or equal to 165min, and in order to ensure that the slab is fully heated in the heating furnace, the time of the casting blank in the soaking section is more than or equal to 30min.
Further, rough rolling adopts full-pass descaling, the descaling pressure is more than or equal to 25MPa, the temperature of R2DT is strictly controlled, and the temperature of a last-pass outlet is 980-1060 ℃; the descaling is fully opened between the frames of the finishing mill, and the finishing temperature of the finish rolling is 800-860 ℃. The hot rolling production process is simple, has low requirements on rolling line equipment, and is suitable for large-scale popularization.
Further, the cooling adopts a conventional sparse cooling mode, and the coiling temperature is 500-580 ℃; the slow cooling time of the stack is more than or equal to 24 hours.
The invention has the beneficial effects that:
(1) The invention adopts Nb + Cr + Ti element composite alloying design, has simple components and low alloy cost, and the thickness of the prepared steel plate is 10-16 mm, thus being suitable for producing thick axle housing steel plates;
(2) The hot rolled steel plate prepared by the invention is processed and formed by heat treatment, the yield strength is more than or equal to 600MPa, the tensile strength is more than or equal to 700MPa, the elongation after fracture is more than or equal to 20 percent, and the physical property is excellent;
(3) The hot rolled steel plate prepared by the method is easy to machine and form, the performance is quickly improved after heat treatment, the structure is uniform, the fatigue is strong, and meanwhile, the content of C in the chemical composition design is low, so that the welding performance of the steel plate is improved.
Drawings
In order to more clearly illustrate the embodiments or technical solutions in the prior art of the present invention, the drawings used in the description of the embodiments or prior art will be briefly described below, and it is obvious for those skilled in the art that other drawings can be obtained based on these drawings without creative efforts.
FIG. 1 is a metallographic structure of a hot rolled steel sheet obtained in example 1 according to an embodiment of the present invention.
FIG. 2 is a metallographic structure diagram of steel for an axle according to example 1 of the present invention.
Detailed Description
In order to make those skilled in the art better understand the technical solution of the present invention, the technical solution in the embodiment of the present invention will be clearly and completely described below with reference to the drawings in the embodiment of the present invention, and it is obvious that the described embodiment is only a part of the embodiment of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Example 1
And (3) producing a 1 furnace 1 mm 3mm 1500mm hot rolled steel plate order according to design requirements by combining the order, wherein the average chemical composition of the casting time is as follows (in wt%): 0.19% of C, 0.22% of Si, 1.25% of Mn, 0.013% of P, 0.003% of S, 0.012% of Nb, 0.032% of Ti, 0.21% of Cr, 0.035% of Als, and the balance of Fe and inevitable impurities.
The preparation method of the hot rolled steel plate comprises the following steps: molten iron KR desulfurization pretreatment → converter smelting → refining → continuous casting → casting blank heating → rough rolling → finish rolling → cooling → coiling → stacking and slow cooling, which specifically comprises the following steps:
(1) Smelting in a converter after KR desulfurization pretreatment of molten iron, controlling the oxygen content in steel during smelting, avoiding molten steel peroxidation, and carrying out slag stopping and tapping by adopting a sliding plate, wherein the slag discharging amount during tapping is strictly controlled; the refining adopts an LF single refining process, the treatment period is more than or equal to 25min, and the soft blowing time is more than or equal to 10min;
(2) The continuous casting adopts the full-process argon protection pouring, the superheat degree is controlled at 20 ℃, and the fluctuation of the liquid level of the crystallizer is controlled to be less than or equal to +/-3 mm;
(3) The average heating time of the casting blank is 182min, the average tapping temperature is 1206 ℃, and the average soaking time of the casting blank is 40min;
(4) Heating the casting blank out of the furnace, then, conducting high-pressure descaling-fixed width pressing on the casting blank to 1520mm, conducting rough rolling, and conducting full-pass descaling, wherein the descaling pressure is not less than 25MPa, the 1-pass rough rolling mill conducts 1-pass rolling, the 2-pass rough rolling mill conducts 5-pass rolling, the average R2DT 1058 ℃ of rough rolling outlets is realized, and the thickness of an intermediate blank is 52mm; hot rolling with an average inlet temperature of 1028 ℃, finish rolling for 7 passes, descaling and full opening among frames of a finish rolling mill, finish rolling with an average outlet temperature of FDT 844 ℃, cooling with an average cooling rate of ultrafast cooling and ordinary laminar flow rapid cooling to 560 ℃ at a rapid cooling rate of 20 ℃ for 2s, and then coiling at 550 ℃ to form a coil; stacking and slowly cooling for 28h to obtain the finished hot rolled steel plate.
The hot rolled steel plate sample prepared in the embodiment is taken for physical property detection, and the specific result is as follows: the yield strength of the steel plate is 485MPa, the tensile strength is 596MPa, the elongation A is 22.5%, the metallographic structure diagram of the hot rolled steel plate prepared in the embodiment is shown in figure 1, and it can be seen that the metallographic structure of the hot rolled steel plate is ferrite + pearlite.
The finished hot rolled steel plate manufactured by the embodiment is subjected to heat treatment, machining and forming to manufacture the steel for the heavy load vehicle bridge, wherein the heat treatment, machining and forming process comprises the steps of quenching and tempering after the hot rolled steel plate is subjected to local hot working, stretching and forming of a welded pipe. The yield strength of the prepared steel for the bridge is 600MPa, the tensile strength is 707MPa, the elongation A is 20.5 percent, and fig. 2 shows a metallographic structure diagram of the steel for the bridge prepared by the embodiment, and it can be seen that the metallographic structure of the steel for the bridge is a tempered sorbite.
Example 2
According to design requirements, a 1 furnace 16mm 1500mm hot-rolled steel plate order is produced by combining the order, and the average value of the chemical composition of the pouring time is as follows (in wt%): 0.15% of C, 0.15% of Si, 0.8% of Mn, 0.012% of P, 0.004% of S, 0.007% of Nb, 0.033% of Ti, 0.11% of Cr, 0.04% of Als, and the balance of Fe and inevitable impurities.
The preparation method of the hot rolled steel plate comprises the following steps: molten iron KR desulfurization pretreatment → converter smelting → refining → continuous casting → casting blank heating → rough rolling → finish rolling → cooling → coiling → stacking and slow cooling, which specifically comprises the following steps:
(1) Smelting in a converter after KR desulfurization pretreatment of molten iron, controlling the oxygen content in steel during smelting, avoiding molten steel peroxidation, and carrying out slag stopping and tapping by adopting a sliding plate, wherein the slag discharging amount during tapping is strictly controlled; refining by adopting an LF single refining process, wherein the treatment period is more than or equal to 25min, and the soft blowing time is more than or equal to 10min;
(2) The continuous casting adopts the full-flow argon protection pouring, the superheat degree is controlled at 15 ℃, and the fluctuation of the liquid level of the crystallizer is controlled to be less than or equal to +/-3 mm;
(3) The average heating time of the casting blank in the furnace is 176min, the average tapping temperature is 1160 ℃, and the time of the casting blank in the soaking period is 36min;
(4) Heating the casting blank out of the furnace, then, conducting high-pressure descaling-fixed width pressing on the casting blank to 1520mm, conducting rough rolling, conducting full-pass descaling, wherein the descaling pressure is not less than 25MPa, 1-pass rolling is conducted by a 1# rough rolling machine, 5-pass rolling is conducted by a 2# rough rolling machine, the average R2DT 989 ℃ of a rough rolling outlet is achieved, and the thickness of an intermediate blank is 57mm; hot rolling at an average inlet temperature of 979 ℃, finish rolling for 7 passes, descaling and full opening between frames of a finish rolling mill, finish rolling at an average outlet temperature of FDT 806 ℃, cooling the outlet to 560 ℃ at a fast cooling rate of 20 ℃ for 2s at an average cooling rate of ultrafast cooling and ordinary laminar flow fast cooling, and then coiling at 500 ℃ to form a coil plate; stacking and slowly cooling for 26h to obtain the finished hot rolled steel plate.
The hot rolled steel plate sample prepared in the embodiment is taken for physical property detection, and the specific result is as follows: the steel sheet had a yield strength of 467MPa, a tensile strength of 586MPa, and an elongation A of 23.7%.
The finished hot rolled steel plate manufactured by the embodiment is subjected to heat treatment, machining and molding to manufacture the steel for the heavy-duty vehicle bridge, and the heat treatment, machining and molding process comprises the steps of performing local hot working, stretching and molding on the hot rolled steel plate through a welded pipe, and then performing quenching and tempering treatment. The yield strength of the prepared bridge steel is 611MPa, the tensile strength is 703MPa, and the elongation A is 20.3%.
Example 3
And (3) producing a 1 furnace 16mm x 1500mm hot rolled steel plate order according to design requirements by combining with the order, wherein the average chemical composition value of the pouring time is as follows (in wt%): 0.26% of C, 0.15% of Si, 1.8% of Mn, 0.009% of P, 0.005% of S, 0.02% of Nb, 0.038% of Ti, 0.28% of Cr, 0.048% of Als, and the balance of Fe and inevitable impurities.
The preparation method of the hot rolled steel plate comprises the following steps: molten iron KR desulfurization pretreatment → converter smelting → refining → continuous casting → casting blank heating → rough rolling → finish rolling → cooling → coiling → stacking and slow cooling, which specifically comprises the following steps:
(1) Smelting in a converter after KR desulfurization pretreatment of molten iron, controlling the oxygen content in steel during smelting, avoiding molten steel peroxidation, and carrying out slag stopping and tapping by adopting a sliding plate, wherein the slag discharging amount during tapping is strictly controlled; the refining adopts an LF single refining process, the treatment period is more than or equal to 25min, and the soft blowing time is more than or equal to 10min;
(2) The continuous casting adopts the full-flow argon protection pouring, the superheat degree is controlled at 35 ℃, and the fluctuation of the liquid level of the crystallizer is controlled to be less than or equal to +/-3 mm;
(3) The average heating time of the casting blank in the furnace is 191min, the average tapping temperature is 1220 ℃, and the average time of the casting blank in the soaking section is 46min;
(4) Heating the casting blank out of the furnace, then carrying out high-pressure descaling-fixed width pressing on the casting blank to 1520mm, carrying out rough rolling by adopting full-pass descaling, wherein the descaling pressure is more than or equal to 25MPa,1 pass is rolled by a 1# rough rolling mill, 5 passes is rolled by a 2# rough rolling mill, the average R2DT 1059 ℃ of a rough rolling outlet is formed, and the thickness of an intermediate blank is 56mm; hot rolling at mean inlet temperature of 1031 ℃, finish rolling at mean outlet temperature of FDT 860 ℃, finish rolling at 7 passes, descaling between frames of a finish rolling mill, cooling at mean cooling rate of 20 ℃ for 2s to 560 ℃ at the outlet through ultrafast cooling and common laminar flow rapid cooling, and then coiling at 580 ℃ to form a coiled plate; stacking and slowly cooling for 31h to obtain a finished hot rolled steel plate.
The hot rolled steel plate sample prepared in the embodiment is taken for physical property detection, and the specific result is as follows: the steel plate had a yield strength of 471MPa, a tensile strength of 579MPa, and an elongation A of 22.9%.
The finished hot rolled steel plate manufactured by the embodiment is subjected to heat treatment, machining and molding to manufacture the steel for the heavy-duty vehicle bridge, and the heat treatment, machining and molding process comprises the steps of performing local hot working, stretching and molding on the hot rolled steel plate through a welded pipe, and then performing quenching and tempering treatment. The yield strength of the prepared bridge steel is 621MPa, the tensile strength is 707MPa, and the elongation A is 21.4%.
Although the present invention has been described in detail by referring to the drawings in connection with the preferred embodiments, the present invention is not limited thereto. Various equivalent modifications or substitutions can be made on the embodiments of the present invention by those skilled in the art without departing from the spirit and the spirit of the present invention, and these modifications or substitutions are within the scope of the present invention 2 any person skilled in the art can easily conceive of changes or substitutions within the technical scope of the present invention disclosed by the present invention, and are also within the scope of the present invention.

Claims (10)

1. A low-cost hot rolled steel plate for 700MPa heavy-load axles after heat treatment processing forming is characterized by comprising the following chemical components in percentage by weight: 0.15 to 0.26 percent of C, 0.15 to 0.40 percent of Si, 0.8 to 1.8 percent of Mn, less than or equal to 0.020 percent of P, less than or equal to 0.020 percent of S, 0.007 to 0.020 percent of Nb, 0.010 to 0.040 percent of Ti, 0.10 to 0.30 percent of Cr, 0.015 to 0.050 percent of Als, and the balance of Fe and other inevitable impurities.
2. The low-cost hot-rolled steel plate for 700MPa class heavy-load axles after heat treatment forming according to claim 1, characterized in that the physical properties of the hot-rolled steel plate are as follows: the thickness of the steel plate is 10-16 mm, the yield strength is more than or equal to 400MPa, the tensile strength is more than or equal to 550MPa, and the elongation is more than or equal to 22 percent; the metallographic structure of the hot rolled steel plate is ferrite plus pearlite.
3. The low-cost hot-rolled steel plate for 700MPa heavy-duty axles after heat treatment and machining as claimed in claim 2, wherein the physical properties of the hot-rolled steel plate after heat treatment and machining are as follows: the yield strength is more than or equal to 600MPa, the tensile strength is more than or equal to 700MPa, and the elongation after fracture is more than or equal to 20 percent; the metallographic structure of the hot-rolled steel plate is a tempered sorbite after the hot-rolled steel plate is processed and formed by heat treatment.
4. The low-cost hot-rolled steel plate for the 700 MPa-level heavy-load axle after the heat treatment processing forming of claim 3 is characterized in that the heat treatment processing forming process comprises the steps of performing local hot-working stretching forming on the hot-rolled steel plate through a welded pipe, and then performing quenching and tempering treatment.
5. The preparation method of the low-cost hot-rolled steel plate for the 700 MPa-level heavy-load axle after the heat treatment processing forming according to any one of claims 1 to 4 is characterized by comprising the following steps of: molten iron KR desulfurization pretreatment → converter smelting → refining → continuous casting → casting blank heating → rough rolling → finish rolling → cooling → coiling → stacking and slow cooling.
6. The method for preparing the low-cost hot-rolled steel plate for the 700 MPa-level heavy-load axle after the heat treatment forming according to claim 5, characterized in that a sliding plate is adopted for slag-stopping and tapping in smelting; the refining adopts an LF single-link refining process, the treatment period and the soft blowing time are strictly controlled, the treatment period is more than or equal to 25min, and the soft blowing time is more than or equal to 10min.
7. The method for preparing the low-cost hot-rolled steel plate for the 700 MPa-level heavy-load axle after the heat treatment processing forming according to claim 5, characterized in that the continuous casting adopts full-flow argon protection casting, the standing time before the continuous casting is put on a machine is more than or equal to 5min, the superheat degree is controlled at 15-35 ℃, and the fluctuation of the liquid level of a crystallizer is controlled to be less than or equal to +/-3 mm.
8. The method for preparing the low-cost hot-rolled steel plate for the 700 MPa-level heavy-duty axle after the heat treatment forming according to claim 5, is characterized in that the heating tapping temperature of the casting blank is controlled to be 1150-1220 ℃, the heating time is not less than 165min, and the time of the casting blank in a soaking section is not less than 30min.
9. The method for preparing the low-cost hot-rolled steel plate for the 700 MPa-grade heavy-duty axle after the heat treatment forming according to claim 5, wherein the rough rolling adopts full-pass descaling, the descaling pressure is more than or equal to 25MPa, the temperature of R2DT is strictly controlled, and the temperature of a final-pass outlet is 980-1060 ℃; the descaling is fully opened between the frames of the finishing mill, and the finishing temperature of the finish rolling is 800-860 ℃.
10. The method for preparing the low-cost hot-rolled steel plate for the 700MPa heavy-load axle after the heat treatment forming according to claim 5, wherein the cooling adopts a conventional sparse cooling mode, and the coiling temperature is 500-580 ℃; the slow cooling time of the stack is more than or equal to 24 hours.
CN202211202623.8A 2022-09-29 2022-09-29 Low-cost hot-rolled steel plate for 700 MPa-level heavy-load axle after heat treatment machining and forming and preparation method thereof Pending CN115627416A (en)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110106444A (en) * 2019-05-30 2019-08-09 首钢集团有限公司 A kind of driving axle housing 700MPa grades of hot-rolled sheet coils and preparation method thereof
CN111549288A (en) * 2020-05-22 2020-08-18 包头钢铁（集团）有限责任公司 Automobile girder steel with thickness of 12.0-16.0 mm and high toughness of 700MPa and production method thereof
CN112195403A (en) * 2020-09-28 2021-01-08 首钢集团有限公司 700 MPa-grade hot-formed axle housing steel and preparation method thereof
CN112195410A (en) * 2020-09-30 2021-01-08 首钢集团有限公司 Steel for automobile stamping part, preparation method of steel and automobile stamping part

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110106444A (en) * 2019-05-30 2019-08-09 首钢集团有限公司 A kind of driving axle housing 700MPa grades of hot-rolled sheet coils and preparation method thereof
CN111549288A (en) * 2020-05-22 2020-08-18 包头钢铁（集团）有限责任公司 Automobile girder steel with thickness of 12.0-16.0 mm and high toughness of 700MPa and production method thereof
CN112195403A (en) * 2020-09-28 2021-01-08 首钢集团有限公司 700 MPa-grade hot-formed axle housing steel and preparation method thereof
CN112195410A (en) * 2020-09-30 2021-01-08 首钢集团有限公司 Steel for automobile stamping part, preparation method of steel and automobile stamping part

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