CN115478210A - 1500 MPa-grade high-strength self-toughening protective steel plate and manufacturing method thereof - Google Patents
1500 MPa-grade high-strength self-toughening protective steel plate and manufacturing method thereof Download PDFInfo
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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
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
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- C21D6/00—Heat treatment of ferrous alloys
- C21D6/004—Heat treatment of ferrous alloys containing Cr and Ni
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- 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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- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
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- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
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- 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
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- 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
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- 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
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B1/00—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations
- B21B1/22—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling plates, strips, bands or sheets of indefinite length
- B21B2001/225—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling plates, strips, bands or sheets of indefinite length by hot-rolling
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- C21D2211/00—Microstructure comprising significant phases
- C21D2211/008—Martensite
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Abstract
The invention relates to a 1500 MPa-grade high-strength self-toughening protective steel plate which comprises the following chemical components in percentage by mass: c:0.20 to 0.60%, si:0.15 to 0.95%, mn:0.50 to 0.80%, al:0.10 to 0.40%, ti:0.01 to 0.05%, V:0.02 to 0.10%, ni:2 to 6%, cr:0.30 to 0.70%, mo:0.40 to 0.90 percent, 8.4 percent to (Ni +8Cr + 10Mo) to 16.4 percent, and the balance of Fe and inevitable impurities. The manufacturing method comprises the following steps: smelting, namely smelting by using the components of the 1500 MPa-grade high-strength self-toughening protective steel plate; casting; heating; rolling; and air cooling the steel plate. In the air cooling process after rolling of the steel sheet, austenite in the steel undergoes martensite transformation accompanied by precipitation of carbides, and self-tempering is completed in the cooling process. The microstructure of the 1500 MPa-grade high-strength self-toughening steel plate is martensite, retained austenite and dispersed carbide, the yield strength is 900-1100 MPa, the tensile strength is 1400-1600 MPa, the elongation after fracture is more than 10-16%, the Charpy impact energy is 80-120J at minus 40 ℃, and the thickness range which can be manufactured by the steel plate is 4-25 mm.
Description
Technical Field
The invention belongs to the technical field of metallurgy, and particularly relates to a 1500 MPa-grade high-strength self-strength and self-toughness protective steel plate and a manufacturing method thereof.
Background
Armor materials are the material basis for armor protection systems. Since the advent of armor protection concepts, humans have continued to research and manufacture high performance armor materials suitable for use in making armor. In armor protection systems, the simplest and most effective structural unit is homogeneous armor steel. Armor steel has been developed for over 100 years since its 1915 application to the first tank in the world. The performance of the armor steel adopted by various countries is greatly different from the traditional armor steel, so the steel is called as modern armor steel. The application range of modern armored steel is wide, such as armored vehicles like main battle tanks, light tanks, infantry chariot and the like. With the continuous development of modern anti-armor weapons, the armor-breaking level of novel armor-piercing bombs, armor-breaking bombs, explosive-shaped projectiles and the like is continuously improved, the threat to armor protection platforms is increased, and the requirement on the armor protection level is increased. Therefore, the ultra-high strength and high performance armor steel is always the focus of attention of experts and scholars at home and abroad.
With the improvement of the performance of armor steel plates and the overall design level of the whole automobile, the thickness of a matrix armor bears the descending trend. Table 1 shows the change in the thickness of the armor on the tank of the world famous home war. As can be seen from the table, the thickness of the armor is continuously reduced, and the reduction of the thickness of the steel plate is more convenient for improving the anti-elasticity performance of the armor, improving the process performance and reducing the cost. Compared with a thick plate, the thin plate can more easily obtain a high-strength homogeneous armor steel plate with better comprehensive mechanical properties, thereby improving the bulletproof performance of the armor. Three major process difficulties in the processing of armor steels, particularly high hardness armor steels, are straightening, cutting, and welding. The thin armor plate is easy to align and cut, has high blanking precision, and can replace cutting processing by shearing and flame cutting processes. The steel sheet is easier to be quenched, so the total alloy content is lower, the carbon equivalent is also low, and the hot working process performances of welding, heat treatment and the like of the steel sheet are favorably improved. Meanwhile, compared with a thick plate, the alloy content of the thin steel plate is reduced, so that the cost of the steel plate is greatly reduced. Therefore, modern high strength high performance armor plates are characterized by high strength and hardness, thin gauge, excellent weldability and machinability.
The online search is carried out by taking the bulletproof steel or the armored steel as keywords. At present, the alloy components of high-strength steel for armor protection are mainly Cr, ni and Mo systems, and a small amount of microalloying elements are taken as a strengthening means. Generally, the production mode of the steel plate comprises smelting, rolling, quenching and tempering treatment, the strength of the steel plate is mostly about 1000MPa, and the high-strength thin-specification steel plate with the strength of more than 1500MPa can ensure the flatness of the steel plate after heat treatment only by a special quenching device, so that the ultrahigh-strength steel plate has certain limitation in application. Meanwhile, the steel plate is subjected to quenching and tempering processes after being rolled, so that the production efficiency of the steel plate is low and the cost is high. For example, patent publication No. CN105088090A discloses a bulletproof steel with 2000 MPa-level tensile strength and a manufacturing method thereof, the steel plate comprises the following components in percentage by weight: c:0.35 to 0.45 percent; si:0.80 to 1.60 percent; mn:0.3 to 1.0 percent; al:0.02 to 0.06 percent; ni:0.3 to 1.2 percent; cr:0.30 to 1.00 percent; mo:0.20 to 0.80 percent; cu:0.20 to 0.60 percent; ti:0.01 to 0.05 percent; b:0.001 to 0.003 percent; the balance being Fe and unavoidable impurities. The manufacturing method comprises the following steps: smelting and casting, heating, rolling, cooling, quenching and low-temperature tempering. The ultrahigh-strength bulletproof steel plate with the tensile strength of 2000MPa can be obtained through the method, and meanwhile, the Brinell hardness can reach 600 HBW. Patent publication No. CN106756495A discloses '1760 MPa ultrahigh-strength bullet-resistant steel and a manufacturing method thereof', the manufacturing process of the steel plate comprises the following steps: KR molten iron pretreatment; smelting in a converter; refining outside an LF furnace; secondary refining outside the RH vacuum degassing converter; continuously casting the plate blank; reheating the plate blank; rough rolling by a rough rolling mill; finish rolling by a finish rolling mill; and (6) quenching and tempering inspection. The 6-25mm ultrahigh-strength alloy steel plate produced by the method achieves excellent obdurability matching and excellent low-temperature impact toughness at minus 40 ℃. Through controlled rolling, quenching and tempering heat treatment, the metallographic structure of the steel plate is mainly tempered martensite, the tensile strength is more than or equal to 1760MPa, the yield strength is more than or equal to 1270MPa, the transverse low-temperature impact energy at minus 40 ℃ is more than or equal to 20J, and the surface Brinell hardness is more than or equal to 490HBW. Patent publication No. CN102776337A discloses a pressure quenching and processing method for 30MnCrNiMo armored steel plate parts, which aims at quenching and processing large, medium and small flat plate parts and bent parts which are manufactured by a middle-thickness 30MnCrNiMo armored steel plate and have or not have mechanical processing, and comprises the following steps: pressure quenching of a whole annealed armor steel plate entering a factory → low-temperature tempering → shot blasting cleaning and leveling → direct forming or subsequent processing forming of a single part or a plurality of parts by blanking in a combined manner. The method can effectively control the quenching deformation of the 30MnCrNiMo armored steel plate part and ensure the quenching quality.
In view of the above patent of high strength bulletproof steel plate, the highest strength of the high strength bulletproof steel plate can reach 2000MPa, but for the high strength steel plate, quenching and tempering processes are adopted in the production process to heat treat the rolled steel plate. For high-strength steel plates, in order to ensure that the steel plates still maintain good plate shape during heat treatment, special heat treatment devices are generally required to restrain the steel plates (pieces) during the heat treatment, so that the production and manufacturing efficiency of the steel plates are low, the cost is high, and the difficulty in subsequent use is increased.
Therefore, there is a need to develop a high-strength steel for bulletproof purposes, which has a strength of 15000MPa (or more), a simple production process, and can ensure a thin steel plate shape, so as to meet the requirements of protective equipment on the high-strength steel for bulletproof purposes.
Disclosure of Invention
In order to solve the problems, the invention provides a 1500 MPa-grade high-strength self-toughness protective steel plate, the strength of which can reach 1500MPa, and the low-temperature toughness of which has remarkable advantages. The manufacturing method of the 1500 MPa-grade high-strength self-toughening protective steel plate is simple in production process and high in operability, the rolling efficiency of the steel plate is improved, the energy consumption in the production process is reduced, and the production and manufacturing cost is obviously reduced.
In order to achieve the aim, the invention provides a 1500 MPa-grade high-strength self-toughness protective steel plate which comprises the following chemical components in percentage by mass: c:0.20 to 0.60%, si:0.15 to 0.95%, mn:0.50 to 0.80%, al:0.10 to 0.40%, ti:0.01 to 0.05%, V:0.02 to 0.10%, ni:2 to 6%, cr:0.30 to 0.70%, mo: 0.40-0.90 percent, more than or equal to 8.4 percent (Ni +8Cr + 10Mo) less than or equal to 16.4 percent, and the balance of Fe and inevitable impurities.
In the composition design of the steel of the invention:
c, carbon C: can ensure the strength of the material and can separate out fine and dispersed carbide with micro alloy elements such as Nb, V, ti and the like. The low carbon content in the steel can cause the low carbon content of martensite in the steel plate, the volume fraction of precipitated carbide is small, and the effective strengthening effect cannot be achieved; however, when the carbon content in the steel is too high, twin martensite is formed in the steel plate during cooling, and the ductility and toughness are poor. Therefore, the carbon content of the invention is controlled between 0.20 and 0.60 percent.
Silicon Si: the silicon has the solid solution strengthening effect, the corrosion resistance and the high-temperature oxidation resistance of the steel can be improved, and the elastic modulus of the steel plate can be effectively improved by adding the Si; however, too high a content results in severe decarburization of the steel surface and a decrease in weldability. Therefore, the silicon content selected by the invention is 0.15-0.95%.
Manganese Mn: manganese is a main element for stabilizing austenite in steel, the high manganese content can ensure that the material matrix structure is a stable austenite structure, and the martensite transformation temperature of the steel can be reduced by about 35-50 ℃ per 1% of manganese. The small amount of manganese added is beneficial to the increase of the stability of austenite in the steel plate and postpones the temperature of the transformation from the austenite to pearlite ferrite in the steel; however, too high manganese content can significantly reduce the martensitic transformation problem of the steel sheet, so that the steel sheet still has more residual austenite at room temperature without martensitic transformation, and the strength of the steel sheet is reduced. The manganese content of the invention is controlled between 0.50 and 0.80 percent.
Aluminum Al: the aluminum can effectively prevent carbide in the steel, is beneficial to solid solution of carbon in austenite, improves the stability of the austenite in the cooling process, and is beneficial to improving the toughness of the steel plate. However, if the content of aluminum in the steel is too high, the difficulty of steel smelting and casting increases, the manufacturing cost increases, and excessive oxide formation deteriorates the quality of the steel sheet. In the present invention, the intermetallic compound precipitates in the steel by the composite addition of elements such as Al and Ni, and serves to improve the strength of the steel sheet. Therefore, the invention selects proper aluminum content in the range of 0.10-0.40%.
Chromium Cr: chromium increases the hardenability of steel, and in steel grades with higher carbon content, chromium can also be a carbide with carbon-performance chromium, thereby improving the hardness and wear resistance of carbon steel without making the steel brittle, and also increasing the hot strength performance of the steel. Meanwhile, the addition of chromium can remarkably delay ferrite pearlite transformation, so that ferrite transformation cannot occur in the air cooling process after rolling of the steel plate, the steel plate avoids a pearlite ferrite transformation area in the air cooling process, and austenite is directly transformed into martensite. Therefore, the range of chromium addition in the present invention is 0.30 to 0.70%.
Nickel Ni: nickel increases the hardenability of steel, and the strength of steel increases with the increase of nickel content in steel, but ductility and toughness do not decrease significantly. In medium-high carbon steel, since nickel can reduce pearlite transformation temperature, pearlite is refined, and the strength of the steel sheet is improved but the toughness of the steel sheet is not significantly reduced. Meanwhile, nickel can also increase the low-temperature toughness of the steel plate. In the present invention, precipitation of an intermetallic compound of nickel and aluminum can further improve the strength and hardness of the steel sheet. In addition, nickel can also significantly improve the low-temperature toughness of the steel sheet. Therefore, in the present invention, the range of nickel addition is 2 to 6%.
Titanium Ti: titanium is a strong carbide former, and TiN can be formed in steel, and plays a role of refining austenite grains as a mass point of austenite nucleation. In the invention, a trace amount of Ti is added to mainly play a role in refining austenite grains, if the content of Ti is too high, tiC is precipitated, C in steel is consumed, the solid solubility of C in austenite is reduced, and the stability of austenite is reduced. Therefore, the range of Ti addition selected in the present invention is 0.01 to 0.05%.
V, V: vanadium is a strong carbide forming element and has the functions of precipitation strengthening and fine crystal strengthening in the material. Because the Mn content in the steel is too high, the crystal grains are easy to coarsen, and the addition of trace vanadium element is beneficial to refining the structure and improving the alloy strength. Meanwhile, the carbide precipitation of V has the effect of dispersion strengthening, and the strength of the steel can be further improved. Therefore, the range of the vanadium selected by the invention is 0.02-0.10%.
Molybdenum Mo: the molybdenum can improve the hardenability and the heat strength of the steel plate in the steel, so that the thick steel plate with a larger section can be deeply quenched and fully quenched. In high carbon steel, molybdenum can reduce the tendency of carbides to form a continuous network at grain boundaries, reduce retained austenite in the steel, and relatively increase the hardness and wear resistance of the steel sheet matrix. Also, molybdenum is a noble metal because of its high cost, and thus, in the present invention, molybdenum is added in the range of 0.40 to 0.90%.
Meanwhile, in the invention, the above elements also meet the requirement of less than or equal to 8.4 percent (Ni +8Cr + 10Mo) and less than or equal to 16.4 percent.
Furthermore, the matrix structure of the 1500 MPa-grade high-strength self-toughness protective steel plate provided by the invention is air-cooled martensite, retained austenite and dispersed carbide.
The air-cooled martensite refers to martensite formed in the air cooling process of the rolled steel plate, and is mainly supersaturated lath martensite; the retained austenite is austenite which is formed by enrichment of elements in the air cooling process and has high stability and does not have martensite transformation at room temperature; the dispersoid-precipitated carbides refer to carbides precipitated from martensite during the formation of martensite.
Furthermore, the 1500 MPa-grade high-strength self-toughness protective steel plate provided by the invention has the yield strength of 900-1100 MPa, the tensile strength of 1400-1600 MPa, the elongation after fracture of 10-16%, and the Charpy impact energy at-40 ℃ of 80-120J.
Furthermore, the 1500 MPa-grade high-strength self-strength-toughness protective steel plate provided by the invention has the thickness of 4-25 mm.
Further, the inevitable impurities in the 1500 MPa-grade high-strength self-toughness protective steel plate provided by the invention comprise: p: < 0.02%, S: is less than 0.02 percent.
The invention also provides a manufacturing method of the 1500 MPa-grade high-strength self-toughness protective steel plate, which comprises the following steps: smelting, casting, heating, rolling and air cooling of steel plates.
The method comprises the following steps:
s1: and smelting, namely smelting by using the components of the 1500 MPa-grade high-strength self-toughness protective steel plate.
S2: and casting to form steel ingots or continuous casting billets.
S3: heating, steel ingot or casting blank heating.
S4: rolling, namely rolling the steel ingot after cogging; and directly rolling the continuous casting billet.
S5: and air cooling the steel plate.
Adopt above-mentioned scheme, to rolling to the steel sheet of finished product thickness, need not pass through online or off-line heat treatment, the direct air cooling of rolling state steel sheet is to room temperature, practices thrift heat treatment resources, improves the production efficiency of steel sheet simultaneously, reduces the manufacturing cost of super high strength steel sheet. The 1500 MPa-grade high-strength self-toughening protective steel plate and the manufacturing method thereof can be used for manufacturing the steel plate with the thickness of 4-25 mm, the yield strength of 900-1100 MPa at room temperature, the tensile strength of 1400-1600 MPa, the elongation after fracture of more than 10-16 percent, and the Charpy impact energy of 80-120J at minus 40 ℃.
Further, the rolled steel sheet was air-cooled to room temperature.
Specifically, after the steel plate is air-cooled to room temperature, the added carbon, manganese, nickel, chromium and molybdenum in the steel have the functions of delaying pearlite transformation and improving the stability of austenite, and the martensite transformation temperature Ms of the steel plate is between 200 and 300 ℃. Meanwhile, it can be determined from the calculation result of the continuous cooling transformation curve of the steel sheet that pearlite transformation does not occur in the steel during the air cooling of the rolled steel sheet, and austenite in the steel is directly transformed into lath martensite structure during the cooling. Since the cooling method of the steel sheet is air cooling, the cooling rate is slow, and after martensite is formed, carbon in the steel precipitates from supersaturated martensite and diffuses into surrounding untransformed austenite, thereby promoting improvement in stability of the surrounding untransformed austenite, lowering the martensitic transformation temperature, and gradually increasing the volume fraction of martensite in the steel with a gradual decrease in temperature. Since the martensite transformation temperature of part of austenite is reduced to room temperature or lower due to the enrichment of carbon element, the steel sheet air-cooled to room temperature has part of retained austenite which is not subjected to martensite transformation. In addition, after the martensite transformation occurs, because supersaturated carbon cannot diffuse for a long distance at a low temperature (below the martensite transformation temperature, in the present invention, the martensite transformation temperature is 200 to 300 ℃), and this part of carbon precipitates as carbides on the martensite lath, because the carbide precipitation temperature is low and the driving force for carbide growth is insufficient, carbides which are dispersed in the steel are formed, and the precipitation strengthening effect is achieved to a certain extent, and the strength of the steel plate is improved.
Further, in the heating step, the heating temperature of the slab is 1150 to 1250 ℃.
Further, in the rolling step, the slab has a start rolling temperature of 1050 to 1200 ℃.
Further, in the rolling step, the rolling process includes a first stage rolling and a second stage rolling; wherein in the first stage of rolling, the initial rolling temperature is 1050-1200 ℃, and when the rolling is carried out to the first thickness, the temperature is kept to 850-900 ℃ on a roller way; in the second stage of rolling, the initial rolling temperature is 850-900 ℃, the final rolling temperature is 720-780 ℃, and the steel plate is rolled to a finished product steel plate with the second thickness.
Further, in two stages of the rolling step, the first thickness is 3 to 5 times the thickness of the finished steel plate; the second thickness is 4-25 mm.
In a preferable embodiment, the slab is heated to 1150-1250 ℃, taken out of the soaking furnace, rolled at 1050-1200 ℃, rolled on a roller bed when the temperature is 3-5 times of the thickness of the finished steel plate to 850-900 ℃, the final rolling temperature is controlled at 720-780 ℃, the thickness of the finished steel plate is 4-25 mm, and the rolled steel plate is directly air-cooled to room temperature.
Specifically, the two-stage rolling is adopted mainly because the rolling is carried out at 1050-1200 ℃, the temperature is higher than the recrystallization temperature of the material, and the material is fully deformed in the temperature range, so that the dynamic recrystallization of the steel plate can be completed in the rolling deformation process, and the effect of refining grains can be achieved. As the rolling pass progresses, the temperature of the steel sheet is also decreasing, and the degree of dynamic recrystallization thereof gradually decreases. When the thickness of the finished steel plate is 3-5 times of the thickness of the finished steel plate, the temperature of the plate blank is heated to 850-900 ℃, and partial deformed grains which are not fully subjected to dynamic recrystallization can be subjected to recovery and recrystallization processes of austenite grains in the temperature-waiting process, so that the austenite grains before finish rolling are fully refined. The second stage of rolling is started at 850-900 c because at this temperature the recrystallization of the deformed austenite grains of the steel sheet does not substantially occur any more, i.e. the deformation of the steel sheet at this stage is such as to retain the deformed austenite grains until the end of rolling. In addition, the deformation temperature is lower than that of the first-stage rolling, the dynamic recovery speed of dislocation is reduced, and the dislocation density is further improved compared with that of the first-stage rolling. In the second-stage rolling, the defects in austenite are increased by increasing deformation and inhibiting recovery, so that sufficient nucleation positions are provided for the subsequent transformation from austenite to martensite, the martensite lath is refined, and the strength of the steel plate is improved. The reason why the finishing temperature is controlled to be above 720 ℃ is that the temperature is higher than Ac of the steel sheet 3 At this temperature, the steel sheet is always subjected to rolling deformation in the austenite region, and the composition in the steel sheet can be always kept uniform because no transformation occurs.
The beneficial effects of the invention are:
1. through reasonable design of chemical components, more stable austenite is added into steel, the element for pearlite ferrite transformation is delayed, the rolled steel plate does not generate pearlite ferrite transformation in the process of air cooling to room temperature, martensite phase transformation occurs when the steel plate is cooled to below the martensite transformation temperature, the slow cooling process in the air cooling process is utilized, the self-tempering effect is exerted on the steel plate, the precipitated carbide generates the strengthening effect on the steel plate, the internal stress of the high-strength steel plate is reduced, and the problems of deformation, cracking and the like caused by quenching are solved.
2. The steel plate is air-cooled to room temperature after being rolled, and the finished steel plate does not need to be subjected to traditional heat treatment such as quenching, tempering and the like, so that the rolling efficiency of the steel plate is improved, the energy consumption in the production process is reduced, and the production and manufacturing cost is obviously reduced.
3. Because the components and the process design are reasonable, the steel plate is directly air-cooled to room temperature after being rolled, the production process is simple, and the operability is strong. From the implementation effect, the method is suitable for stable batch production in medium and thick plate production lines.
4. The 1500 MPa-grade high-strength self-strengthening and self-toughening protective steel plate has a matrix structure of air-cooled martensite, residual austenite and dispersed carbide at room temperature, has the yield strength of 900-1100 MPa, the tensile strength of 1400-1600 MPa, the elongation after fracture of more than 10-16 percent, the Charpy impact energy of 80-120J at the temperature of minus 40 ℃, and can be produced to have the thickness of 4-25 mm.
Detailed Description
The following description of the embodiments of the present invention is provided for illustrative purposes, and other advantages and effects of the present invention will become apparent to those skilled in the art from the present disclosure. While the invention will be described in conjunction with the preferred embodiments, it is not intended that features of the invention be limited to these embodiments. On the contrary, the invention has been described in connection with the embodiments for the purpose of covering alternatives or modifications as may be extended based on the claims of the invention. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. The invention may be practiced without these particulars. Moreover, some of the specific details have been left out of the description in order to avoid obscuring or obscuring the focus of the present invention. It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict.
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be further described according to specific embodiments. However, the present invention is not limited to the following embodiments, and various modifications thereof should fall within the scope of the present invention.
The compositions of the examples of the invention are shown in Table 1, and Table 2 shows the performance parameters of the examples of the steel of the invention.
Examples
Example 1
1) Smelting the alloy by adopting an electric furnace or a converter, and casting the alloy into a steel ingot or a continuous casting billet; the weight percentages of the components are shown in table 1;
2) Heating the steel ingot or the plate blank to 1250 ℃, rolling the steel plate at the first stage at the initial rolling temperature of 1200 ℃ to 3 times of the thickness of the finished steel plate,
3) Cooling to 860 ℃ and starting the second-stage rolling, wherein the final rolling temperature is 730 ℃, rolling to a finished steel plate with the thickness of 15mm, and air cooling the rolled steel plate to the room temperature.
Example 2
1) Smelting the alloy by adopting an electric furnace or a converter, and casting into a steel ingot or a continuous casting blank; the weight percentages of the components are shown in table 1;
2) Heating the steel ingot or the plate blank to 1230 ℃, wherein the initial rolling temperature of the first stage rolling of the steel plate is 1180 ℃, and the initial rolling temperature is 5 times of the thickness of the finished steel plate;
3) Cooling to 900 ℃, starting the second-stage rolling, wherein the final rolling temperature is 760 ℃, rolling to a finished steel plate with the thickness of 10mm, and air cooling the rolled steel plate to the room temperature.
Example 3
1) Smelting the alloy by adopting an electric furnace or a converter, and pouring the alloy into a steel ingot or a continuous casting blank; the weight percentages of the components are shown in table 1;
2) Heating a steel ingot or a plate blank to 1200 ℃, rolling the steel plate to 4 times of the thickness of a finished steel plate, wherein the initial rolling temperature of the first stage rolling of the steel plate is 1150 ℃;
3) Cooling to 860 ℃ and starting the second stage of rolling, wherein the final rolling temperature is 750 ℃, rolling to a finished steel plate with the thickness of 20mm, and air cooling the rolled steel plate to the room temperature.
Example 4
1) Smelting the alloy by adopting an electric furnace or a converter, and pouring the alloy into a steel ingot or a continuous casting blank; the weight percentages of the components are shown in table 1;
2) Heating a steel ingot or a plate blank to 1180 ℃, wherein the initial rolling temperature of the first stage rolling of the steel plate is 1100 ℃, and rolling to 4 times of the thickness of the finished steel plate;
3) Cooling to 870 ℃, starting the second-stage rolling, wherein the final rolling temperature is 740 ℃, rolling to a finished steel plate with the thickness of 12mm, and cooling the steel plate to room temperature in air after rolling.
Example 5
1) Smelting the alloy by adopting an electric furnace or a converter, and pouring the alloy into a steel ingot or a continuous casting blank; the weight percentages of the components are shown in table 1;
2) Heating a steel ingot or a plate blank to 1210 ℃, rolling the steel plate to 5 times of the thickness of a finished steel plate, wherein the initial rolling temperature of the first stage rolling of the steel plate is 1150 ℃;
3) Cooling to 880 ℃, starting the second-stage rolling, wherein the final rolling temperature is 720 ℃, rolling to a finished steel plate with the thickness of 18mm, and cooling the steel plate to room temperature in air after rolling.
Table 1 chemical composition (wt.%) of steel sheets of inventive examples 1-5
EXAMPLES results
The 1500MPa grade high strength self-toughness protective steel plates of the embodiments 1 to 5 of the invention are tested for the properties of yield strength, tensile strength, elongation after fracture, charpy impact energy at-40 ℃ and the like, wherein the tensile test result is an average value of two samples, the impact energy test result is an average value of three samples, and the test results are shown in the following table 2.
TABLE 2 Properties of Steel sheets of inventive examples 1-5
As can be seen from tables 1 and 2, the high-hardness steel plate for protection produced by the method for manufacturing the 1500 MPa-grade high-strength self-toughness protection steel plate has the yield strength of 900-1100 MPa at room temperature, the tensile strength of 1400-1600 MPa, the elongation after fracture of more than 10-16 percent, and the Charpy impact energy of 80-120J at-40 ℃. Compared with other steel plates subjected to air cooling after rolling, the steel plate has obvious advantages in strength; in the quenched and tempered high-strength steel plate with the same strength grade, the low-temperature toughness of the steel plate also has remarkable advantages, and the steel plate is directly air-cooled to room temperature after being rolled without heat treatment of quenching and tempering, so that the production period is shortened, and the production cost is reduced.
While the invention has been described with reference to certain preferred embodiments thereof, it will be understood by those skilled in the art that the foregoing is a more particular description of the invention than is possible with reference to the specific embodiments, which are not to be construed as limiting the invention. Various changes in form and detail, including simple deductions or substitutions, may be made by those skilled in the art without departing from the spirit and scope of the invention.
Claims (10)
1. A1500 MPa-grade high-strength self-toughening protective steel plate is characterized by comprising the following chemical components in percentage by mass: c:0.20 to 0.60%, si:0.15 to 0.95%, mn:0.50 to 0.80%, al:0.10 to 0.40%, ti:0.01 to 0.05%, V:0.02 to 0.10%, ni:2 to 6%, cr:0.30 to 0.70%, mo: 0.40-0.90 percent, more than or equal to 8.4 percent (Ni +8Cr + 10Mo) less than or equal to 16.4 percent, and the balance of Fe and inevitable impurities.
2. The 1500 MPa-grade high-strength self-strengthening and self-toughening protective steel plate as claimed in claim 1, wherein the yield strength is 900-1100 MPa, the tensile strength is 1400-1600 MPa, the elongation after fracture is 10-16%, and the Charpy impact energy at-40 ℃ is 80-120J.
3. The 1500 MPa-grade high-strength self-strengthening and self-toughening protective steel plate according to claim 1, wherein the matrix structure is air-cooled martensite, retained austenite and dispersed carbide.
4. The 1500MPa grade high-strength self-strength and self-toughness protective steel plate as claimed in claim 1, wherein the thickness is 4-25 mm.
5. The high-strength self-strengthening and self-toughening armor plate of claim 1, wherein the inevitable impurities include: p: < 0.02%, S: is less than 0.02 percent.
6. A manufacturing method of a 1500 MPa-grade high-strength self-toughness protective steel plate is characterized by comprising the following steps:
smelting, namely smelting by using the components of the 1500MPa grade high-strength self-toughening protection steel plate according to any one of claims 1 to 4;
casting;
heating;
rolling;
and air cooling the steel plate.
7. The method of claim 6, wherein the rolled steel sheet is air cooled to room temperature.
8. The manufacturing method of the 1500MPa grade high-strength self-toughening protective steel plate according to claim 6,
in the heating step, the heating temperature of the plate blank is 1150-1250 ℃;
in the rolling step, the initial rolling temperature of the plate blank is 1050-1200 ℃.
9. The method for manufacturing the 1500MPa grade high-strength self-toughness protective steel plate as claimed in claim 8, wherein in the rolling step, the rolling process comprises a first stage rolling and a second stage rolling; wherein
In the first stage of rolling, the initial rolling temperature is 1050-1200 ℃, and when the rolling is carried out to the first thickness, the temperature is kept to 850-900 ℃ on a roller way;
and in the second stage of rolling, the initial rolling temperature is 850-900 ℃, the final rolling temperature is 720-780 ℃, and the steel plate is rolled to a finished product steel plate with a second thickness.
10. The method of manufacturing a 1500 MPa-level high-strength self-toughening armor plate according to claim 9, wherein in the rolling step, the first thickness is 3 to 5 times the thickness of the finished steel plate, and the second thickness is 4 to 25mm.
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