CN114645197A - Special steel for composite reinforced protection and manufacturing method thereof - Google Patents

Special steel for composite reinforced protection and manufacturing method thereof Download PDF

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Publication number
CN114645197A
CN114645197A CN202210181738.7A CN202210181738A CN114645197A CN 114645197 A CN114645197 A CN 114645197A CN 202210181738 A CN202210181738 A CN 202210181738A CN 114645197 A CN114645197 A CN 114645197A
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CN114645197B (en
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郝燕森
胡淑娥
孙卫华
车金锋
王振华
王兴
高龙永
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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
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/18—Hardening; Quenching with or without subsequent tempering
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D6/00—Heat treatment of ferrous alloys
    • C21D6/004—Heat treatment of ferrous alloys containing Cr and Ni
    • 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
    • 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
    • C21D6/008—Heat treatment of ferrous alloys containing Si
    • 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
    • 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
    • C22C33/06—Making ferrous alloys by melting using master alloys
    • 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
    • C22C38/005—Ferrous alloys, e.g. steel alloys containing rare earths, i.e. Sc, Y, Lanthanides
    • 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
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/44—Ferrous alloys, e.g. steel alloys containing chromium with nickel 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
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/46—Ferrous alloys, e.g. steel alloys containing chromium with nickel with vanadium
    • 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
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/50—Ferrous alloys, e.g. steel alloys containing chromium with nickel 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
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/54—Ferrous alloys, e.g. steel alloys containing chromium with nickel with boron
    • 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
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00—Technologies related to metal processing
    • Y02P10/20—Recycling

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Abstract

The invention relates to special steel for composite reinforcement protection and a manufacturing method thereof, belonging to the technical field of production of high-strength quenched and tempered steel plates. The special steel comprises the following components in percentage by weight: 0.27 to 0.35 percent of C, 0.30 to 0.45 percent of Si, 0.35 to 0.75 percent of Mn, less than or equal to 0.010 percent of P, less than or equal to 0.008 percent of S, 0.60 to 1.60 percent of Cr, 0.40 to 1.00 percent of Ni, 0.40 to 0.80 percent of Mo, 0.030 to 0.060 percent of V, 0.015 to 0.035 percent of Ti, 0.010 to 0.030 percent of RE, 0.025 to 0.045 percent of Alt, 0.0018 to 0.0026 percent of B, less than or equal to 20ppm of [ O ], less than or equal to 20ppm of [ N ], less than or equal to 2ppm of [ H ], and the balance of Fe and inevitable impurities. Compared with the prior art, the invention adds a certain amount of rare earth elements on the Cr-Ni-Mo component system, can reduce the whole addition amount of alloy elements such as Cr, Ni, Mn, Mo, V, Ti and the like, and simultaneously can ensure that the performance is not lower than that of products with the same grade and the same specification, thereby reducing the whole manufacturing cost.

Description

Special steel for composite reinforced protection and manufacturing method thereof
Technical Field
The invention belongs to the technical field of production of high-strength quenched and tempered steel plates, and particularly relates to special steel for composite reinforcement protection and a manufacturing method thereof.
Background
Data statistics shows that the annual demand of the high-strength special steel for protection is more than 30 ten thousand tons, the high-strength special steel can be used in the fields of military protection, civil protection, engineering machinery and the like, and the function and the status are very important. The steel plate needs to have ultrahigh strength and hardness, and also needs to have good plasticity, toughness and crack arrest performance so as to ensure that the steel plate does not generate through cracking under the condition of being impacted by external force, effectively reduce the impact force borne by a support behind the bulletproof steel plate and further play a due role in protecting an object.
Chinese patent CN111455289A provides a high-strength hot-rolled bulletproof steel plate and a manufacturing method thereof, the main alloy elements of the steel plate are 0.80-1.30% of Cr, 1.00-1.80% of Ni and 0.15-0.50% of Mo, and V is 0.05-0.20% and Re0.005% -0.06% are used for strengthening treatment; the steel plate production process needs a strict controlled rolling and cooling process, then the steel plate is subjected to off-line quenching treatment and tempering treatment, the thickness of the prepared product is only 4.0-6.0 mm, and in order to improve the mechanical performance of the steel plate, the surface of the steel plate needs to be subjected to sand blasting treatment.
Chinese patent CN109852779A provides a heat treatment method for civil bulletproof steel, the main alloy elements of the steel plate are Cr 0.75% -1.1%, Ni 1.8% -2.2%, Mo 0.25% -0.45%, and V0.15% -0.25%, Nb0.015% -0.025%, Re 0-0.01% for composite strengthening treatment; the steel plate needs to be subjected to complex procedures such as high-temperature forging, high-temperature rolling, quenching treatment, tempering treatment and the like during production, the yield strength is 1350-1480 MPa, the tensile strength is 1550-1750 MPa, the elongation is 12-14%, the low-temperature impact energy (u-shaped notch) at minus 40 ℃ is 30-38J, and the Brinell hardness HBS is 450-550.
Chinese patent CN103993235A provides a method for manufacturing a high-strength hot-rolled bulletproof steel plate, the main alloy elements are 0.7-1.8% of Si, 1.30-1.80% of Mn, 0.3-1.0% of Cr and 0.0015% -0.0025% of B, meanwhile, Ti + Nb is added in the steel plate to be less than or equal to 0.2%, the yield strength of the steel plate prepared by the method is more than 1120MPa, the tensile strength is more than 1485MPa, the elongation is more than 8%, the hardness is more than 475HBW, but the thickness of the steel plate is only 2-3 mm.
Chinese patent CN105088090A provides a bulletproof steel plate with 2000MPa level tensile strength and a manufacturing method thereof, and the main alloy elements comprise 0.30-1.00% of Cr, 0.3-1.2% of Ni, 0.20-0.80% of Mo, 0.20-0.60% of Cu, 0.01-0.05% of Ti and 0.001-0.0035% of B; the tensile strength of the steel plate can reach 2000MPa, the Brinell hardness can reach 600, and the thickness range of the steel plate is 6-22 mm.
At present, more alloying elements such as Cr, Ni, Mo and the like are added into an alloy component system of the steel for protection, and a certain amount of Nb, V and Ti microalloying elements are also added in the research and development process for further improving the performance, so that the overall production and manufacturing cost is higher. The rare earth element has the name of industrial vitamin, is a strategic dominant resource owned by China, and has the functions of refining metamorphic inclusions, deeply purifying molten steel, strongly microalloying and the like, thereby improving the toughness and plasticity, the wear resistance, the corrosion resistance, the heat resistance and the like of the steel plate. Therefore, the addition of a certain amount of rare earth can improve the performance of the steel plate and reduce the addition of other alloy elements, but the addition of the rare earth elements in the conventional protective steel is low, and the application research is less.
Disclosure of Invention
Aiming at the problems of low addition amount of rare earth elements in the steel for protection, less application research and the like in the prior art, the invention provides the special steel for composite reinforcement protection and the manufacturing method thereof, so as to solve the problems. According to the invention, RE 0.01-0.03% is added to the medium carbon and V, Ti composite reinforced alloy component system, and the high-quality high-strength special steel plate for protection of 10-30 mm can be produced and prepared by an online controlled rolling and offline heat treatment coupling process.
The technical scheme of the invention is as follows:
the special steel for composite reinforced protection comprises the following components in percentage by weight: 0.27 to 0.35 percent of C, 0.30 to 0.45 percent of Si, 0.35 to 0.75 percent of Mn, less than or equal to 0.010 percent of P, less than or equal to 0.008 percent of S, 0.60 to 1.60 percent of Cr, 0.40 to 1.00 percent of Ni0, 0.40 to 0.80 percent of Mo, 0.030 to 0.060 percent of V, 0.015 to 0.035 percent of Ti, 0.010 to 0.030 percent of RE, 0.025 to 0.045 percent of Alt, 0.0018 to 0.0026 percent of B, less than or equal to 20ppm of [ O ], less than or equal to 20ppm of [ N ], less than or equal to 2ppm of [ H ], and the balance of Fe and inevitable impurities.
Preferably, the RE is a compound of La and Ce, wherein the mass ratio of La to Ce is 0.4-0.6: 1.
A manufacturing method of special steel for composite reinforcement protection comprises the following steps: (1) smelting and pouring; (2) slowly cooling the plate blank; (3) heating and rolling; (4) cooling the steel plate; (5) and (4) carrying out heat treatment on the steel plate.
Preferably, in the step (1), RE is a bulk La/Ce composite with the size of 20-50 mm, and is added in a batch-wise dispersing manner in the early stage of the RH stage, wherein before the rare earth is added, the [ O ] is less than 20 ppm.
Preferably, in the step (2), the plate blank is cut, immediately taken off line and sent into a slow cooling pit, the pit entry temperature is more than or equal to 400 ℃, the pit exit temperature is less than or equal to 100 ℃, the average temperature drop rate per hour is less than 2 ℃, and stacking is continued after the plate blank exits the pit, so that the position of a tuyere is avoided.
Preferably, in the step (2), the thickness of the slab is 110-300 mm.
Preferably, in the step (4), the steel plate is cooled by stacking and slowly cooling in a mode of laying a cover below a hot steel plate with the temperature of more than or equal to 400 ℃ and avoiding the position of the tuyere.
Preferably, in the step (5), the steel plate heat treatment comprises high-temperature quenching and low-temperature tempering, wherein the high-temperature quenching temperature is 850-910 ℃, the charging mode is to warm charging, and the heating coefficient is 1.4-1.8 mm/min; the low-temperature tempering temperature is 200-270 ℃, the charging mode is to warm charging, and the heating coefficient is 2.6-3.0 mm/min.
Preferably, the time interval between the high-temperature quenching and the low-temperature tempering treatment is less than or equal to 36 h.
The invention has the beneficial effects that:
compared with the prior art, the invention adds a certain amount of rare earth elements on the Cr-Ni-Mo component system, can reduce the whole addition amount of alloy elements such as Cr, Ni, Mn, Mo, V, Ti and the like, and simultaneously can ensure that the performance is not lower than that of products with the same grade and the same specification, thereby reducing the whole manufacturing cost. By adding the rare earth elements, the segregation phenomenon of alloy elements in the macrostructure of the plate blank is obviously improved, even the phenomenon of the central black line of the plate blank caused by impurities is eliminated, the size of the impurities in the microstructure of the hot-rolled steel plate is reduced, and simultaneously, the spheroidization of the long-strip-shaped impurities is promoted, and finally, the quality and the yield of the hot-rolled steel plate are improved. The method has strong operability in industrial production, can fill and expand the group of protective steel products, and is suitable for popularization and application in a large range in the technical field of production of the protective high-strength special steel plate.
Detailed Description
In order to make those skilled in the art better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments 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
A manufacturing method of special steel for composite reinforcement protection comprises the following steps:
(1) smelting according to the following chemical components: 0.27 percent of C, 0.38 percent of Si, 0.65 percent of Mn, less than or equal to 0.008 percent of P, less than or equal to 0.005 percent of S, 0.90 percent of Cr, 0.50 percent of Ni, 0.40 percent of Mo, 0.035 percent of V, 0.019 percent of Ti, 0.025 percent of RE (La/Ce, La: Ce is equal to 1:2), 0.026 percent of Alt, 0.0020 percent of B, less than or equal to 15ppm of [ O ], lessthan or equal to 20ppm of [ N ], lessthan or equal to 2ppm of [ H ], and the balance of Fe and inevitable impurities.
(2) Pouring to obtain a slab with the thickness of 100mm, feeding the slab into a slow cooling pit, wherein the pit entry temperature is about 418 ℃, the pit exit temperature is about 98 ℃, the average temperature drop rate per hour is about 1.5 ℃, and continuously stacking the slab after pit exit to avoid the position of an air port.
(3) The hot rolled steel plate with the thickness of 12mm is stacked and slowly cooled by a hot steel plate with the temperature of about 405 ℃ in a mode of covering the steel plate, and the position of a tuyere is avoided.
(4) And (3) keeping the temperature of the slowly cooled steel plate at 890 ℃ for 18min, then quenching, keeping the temperature at 270 ℃ for 30min after 28h, and then air cooling to prepare the finished steel plate.
(5) The yield strength of the finished steel plate is 1520MPa, the tensile strength is 1850MPa, the elongation after fracture is 15%, and the Brinell hardness is 552HBW, and the low-temperature toughness at minus 40 ℃ is more than or equal to 27J.
Example 2
A manufacturing method of special steel for composite reinforcement protection comprises the following steps:
(1) smelting according to the following chemical components: 0.28 percent of C, 0.43 percent of Si, 0.55 percent of Mn, less than or equal to 0.008 percent of P, less than or equal to 0.005 percent of S, 0.80 percent of Cr, 0.70 percent of Ni, 0.50 percent of Mo, 0.045 percent of V, 0.017 percent of Ti, 0.020 percent of RE (La/Ce, La: Ce is equal to 1:2), 0.030 percent of Alt, 0.0019 percent of B, less than or equal to 15ppm of [ O ], lessthan or equal to 20ppm of [ N ], lessthan or equal to 2ppm of [ H ], and the balance of Fe and inevitable impurities.
(2) And pouring to obtain a slab with the thickness of 200mm, feeding the slab into a slow cooling pit, keeping the temperature of the slab in the pit at about 420 ℃, keeping the temperature of the slab out of the pit at about 95 ℃, keeping the average temperature drop rate per hour at about 1.5 ℃, and continuously stacking the slab out of the pit to avoid the position of an air port.
(3) And stacking and slowly cooling the hot rolled steel plate with the thickness of 20mm by using a hot steel plate with the temperature of about 410 ℃ in a mode of covering the hot steel plate, and avoiding the position of a tuyere.
(4) And (3) keeping the temperature of the slowly cooled steel plate at 900 ℃ for 35min, then quenching, keeping the temperature at 260 ℃ for 55min after 20h, and then air cooling to prepare the finished steel plate.
(5) The yield strength of the finished steel plate is 1469MPa, the tensile strength is 1788MPa, the elongation after fracture is 14%, and the Brinell hardness is 536HBW, and the low-temperature toughness at minus 40 ℃ is more than or equal to 27J.
Example 3
A manufacturing method of special steel for composite reinforcement protection comprises the following steps:
(1) smelting according to the following chemical components: 0.30 percent of C, 0.35 percent of Si, 0.40 percent of Mn, less than or equal to 0.008 percent of P, less than or equal to 0.005 percent of S, 0.65 percent of Cr, 0.80 percent of Ni, 0.60 percent of Mo, 0.055 percent of V, 0.015 percent of Ti, 0.015 percent of RE (La/Ce, La: Ce is equal to 1:2), 0.028 percent of Alt, 0.0018 percent of B, less than or equal to 15ppm of [ O ], lessthan or equal to 20ppm of [ N ], lessthan or equal to 2ppm of [ H ], and the balance of Fe and inevitable impurities.
(2) And pouring to obtain a slab with the thickness of 300mm, feeding the slab into a slow cooling pit, keeping the temperature of the slab in the pit at about 420 ℃, keeping the temperature of the slab out of the pit at about 95 ℃, keeping the average temperature drop rate per hour at about 1.5 ℃, and continuously stacking the slab out of the pit to avoid the position of an air port.
(3) And stacking and slowly cooling the hot rolled steel plate with the thickness of 30mm by using a hot steel plate with the temperature of about 402 ℃ in a mode of covering the hot steel plate, and avoiding the position of a tuyere.
(4) And (3) keeping the temperature of the slowly cooled steel plate at 910 ℃ for 45min, then quenching, keeping the temperature at 255 ℃ for 95min after 30h, and then air cooling to prepare the finished steel plate.
(6) The yield strength of the finished steel plate is 1455MPa, the tensile strength is 1784MPa, the elongation after fracture is 13%, and the Brinell hardness is 523HBW, and the low-temperature toughness is more than or equal to 26J at minus 40 ℃.
Comparative example
The preparation of the special steel for protection strengthened by using the existing method comprises the following steps:
(1) smelting according to the following chemical components: 0.27 percent of C, 0.38 percent of Si, 0.65 percent of Mn, less than or equal to 0.008 percent of P, less than or equal to 0.005 percent of S, 0.90 percent of Cr, 0.50 percent of Ni, 0.40 percent of Mo, 0.035 percent of V, 0.019 percent of Ti, 0.026 percent of Alt, 0.0020 percent of B, less than or equal to 15ppm of [ O ], less than or equal to 20ppm of [ N ], less than or equal to 2ppm of [ H ], and the balance of Fe and inevitable impurities.
(2) Pouring to obtain a slab with the thickness of 100mm, feeding the slab into a slow cooling pit, wherein the pit entry temperature is about 420 ℃, the pit exit temperature is about 99 ℃, the average temperature drop rate per hour is about 1.5 ℃, and continuously stacking the slab after pit exit to avoid the position of an air port.
(3) The hot rolled steel plate with the thickness of 12mm is stacked and slowly cooled by a hot steel plate with the temperature of about 405 ℃ in a mode of covering the steel plate, and the position of a tuyere is avoided.
(4) And (3) keeping the temperature of the slowly cooled steel plate at 890 ℃ for 18min, then quenching, keeping the temperature at 270 ℃ for 30min after 28h, and then air cooling to prepare the finished steel plate.
(5) The yield strength of the finished steel plate is 1485MPa, the tensile strength is 1750MPa, the elongation after fracture is 12%, the Brinell hardness is 528HBW, and the low-temperature toughness at minus 40 ℃ is more than or equal to 12J.
Compared with the prior art, the special steel for composite reinforcement protection adds 0.01-0.03% of La/Ce composite rare earth element on a Cr-Ni-Mo component system, so that the addition amount of alloy elements is obviously reduced, the performance is not lower than that of the product with the same grade and specification, and the purposes of cost reduction and efficiency improvement are achieved. According to the invention, by controlling the conditions of the addition type, method, quantity and the like of the rare earth elements, the size and quantity of inclusions in molten steel are obviously reduced, the segregation phenomenon of alloy elements in the slab is improved, the central black line phenomenon of the slab caused by inclusions is even eliminated, and meanwhile, the spheroidization of long-strip inclusions in the hot-rolled steel plate is promoted, and finally, the quality and the yield of the hot-rolled steel plate are improved.
Although the present invention has been described in detail by way of 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 scope of the present invention, and these modifications or substitutions are within the scope of the present invention/any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims (9)

1. The special steel for composite reinforcement protection is characterized by comprising the following components in percentage by weight: 0.27 to 0.35 percent of C, 0.30 to 0.45 percent of Si, 0.35 to 0.75 percent of Mn, less than or equal to 0.010 percent of P, less than or equal to 0.008 percent of S, 0.60 to 1.60 percent of Cr0.40 to 1.00 percent of Ni, 0.40 to 0.80 percent of Mo, 0.030 to 0.060 percent of V, 0.015 to 0.035 percent of Ti0.010 to 0.030 percent of RE, 0.025 to 0.045 percent of Alt, 0.0018 to 0.0026 percent of B, less than or equal to 20ppm of [ O ], [ N ] less than or equal to 20ppm of [ H ], [ 2ppm of [ H ], and the balance of Fe and inevitable impurities.
2. The special steel for composite reinforcement protection as claimed in claim, wherein RE is a composite of La and Ce, and the mass ratio of La to Ce is 0.4-0.6: 1.
3. A method for manufacturing the special steel for composite reinforcement protection as claimed in claim 1, characterized by comprising the following steps: (1) smelting and pouring; (2) slowly cooling the plate blank; (3) heating and rolling; (4) cooling the steel plate; (5) and (4) carrying out heat treatment on the steel plate.
4. The method for manufacturing the special steel for composite reinforcement protection as claimed in claim 3, wherein in the step (1), RE is a bulk La/Ce composite with the size of 20-50 mm, and is added in batch-wise dispersing manner in the early stage of RH stage, and before rare earth is added, [ O ] < 20 ppm.
5. The method for manufacturing the special steel for composite reinforcement protection as claimed in claim 3, wherein in the step (2), the plate blank is cut, immediately taken off line and sent into a slow cooling pit, the pit entry temperature is not less than 400 ℃, the pit exit temperature is not more than 100 ℃, the average temperature drop rate per hour is less than 2 ℃, and stacking is continued after pit exit, so as to avoid the position of the tuyere.
6. The method for manufacturing the special steel for composite reinforcement protection as claimed in claim 3, wherein in the step (2), the thickness of the plate blank is 110-300 mm.
7. The method for manufacturing special steel for composite reinforcement protection as claimed in claim 3, wherein in the step (4), the stack slow cooling is performed by covering a hot steel plate with a temperature of more than or equal to 400 ℃ below the stack, and the tuyere position is avoided.
8. The manufacturing method of special steel for composite reinforcement protection as claimed in claim 3, wherein in the step (5), the steel plate heat treatment comprises high temperature quenching and low temperature tempering, wherein the high temperature quenching temperature is 850-910 ℃, the charging mode is to warm charging, and the heating coefficient is 1.4-1.8 mm/min; the low-temperature tempering temperature is 200-270 ℃, the charging mode is to warm charging, and the heating coefficient is 2.6-3.0 mm/min.
9. The method for manufacturing special steel for composite reinforced protection as claimed in claim 8, wherein the time interval between the high-temperature quenching and the low-temperature tempering treatment is less than or equal to 36 h.
CN202210181738.7A 2022-02-25 2022-02-25 Special steel for composite reinforced protection and manufacturing method thereof Active CN114645197B (en)

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Publication number Priority date Publication date Assignee Title
CN109402499A (en) * 2018-09-27 2019-03-01 首钢集团有限公司 A kind of protection steel and its production method
CN109930075A (en) * 2019-04-12 2019-06-25 贝斯山钢(山东)钢板有限公司 A kind of armoring armour plate and its manufacturing method
US20200087764A1 (en) * 2016-12-05 2020-03-19 Nippon Steel Corporation High-strength steel sheet
CN111394652A (en) * 2020-04-09 2020-07-10 钢铁研究总院淮安有限公司 Rare earth armor steel and manufacturing method thereof
CN111455289A (en) * 2020-06-09 2020-07-28 重庆钢铁研究所有限公司 High-strength hot-rolled bulletproof steel plate and manufacturing method thereof
US20200308666A1 (en) * 2019-03-28 2020-10-01 University Of Science And Technology Beijing Method for Manufacturing Lightweight Steel Plate with Ultrahigh Strength and High Toughness

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20200087764A1 (en) * 2016-12-05 2020-03-19 Nippon Steel Corporation High-strength steel sheet
CN109402499A (en) * 2018-09-27 2019-03-01 首钢集团有限公司 A kind of protection steel and its production method
US20200308666A1 (en) * 2019-03-28 2020-10-01 University Of Science And Technology Beijing Method for Manufacturing Lightweight Steel Plate with Ultrahigh Strength and High Toughness
CN109930075A (en) * 2019-04-12 2019-06-25 贝斯山钢(山东)钢板有限公司 A kind of armoring armour plate and its manufacturing method
CN111394652A (en) * 2020-04-09 2020-07-10 钢铁研究总院淮安有限公司 Rare earth armor steel and manufacturing method thereof
CN111455289A (en) * 2020-06-09 2020-07-28 重庆钢铁研究所有限公司 High-strength hot-rolled bulletproof steel plate and manufacturing method thereof

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