CN115478210B - 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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- C21D6/004—Heat treatment of ferrous alloys containing Cr and Ni
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- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
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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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- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
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- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
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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
- C22C38/50—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
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- 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-level high-strength self-toughening protective steel plate, which comprises the following chemical components in percentage by mass: c:0.20 to 0.60 percent of Si:0.15 to 0.95 percent of Mn:0.50 to 0.80 percent of Al:0.10 to 0.40 percent of Ti:0.01 to 0.05 percent, V:0.02 to 0.10 percent of Ni: 2-6%, cr:0.30 to 0.70 percent of Mo:0.40 to 0.90 percent, and 8.4 percent to less than or equal to (Ni+8Cr+10Mo) to less than or equal to 16.4 percent, and the balance being Fe and unavoidable impurities. The manufacturing method comprises the following steps: smelting, namely smelting the components of the 1500 MPa-level high-strength self-toughening protective steel plate; casting; heating; rolling; and (5) air cooling the steel plate. In the air cooling process after the rolling of the steel plate, austenite in the steel undergoes martensitic transformation accompanied by precipitation of carbide, and self-tempering is completed in the cooling process. The microstructure of the 1500 MPa-level high-strength self-toughening steel plate is martensite, retained austenite and carbide which is diffused and precipitated, the yield strength is 900-1100 MPa, the tensile strength is 1400-1600 MPa, the elongation after fracture exceeds 10-16%, the Charpy impact energy at minus 40 ℃ is 80-120J, and the manufacturable thickness range of 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-level high-strength self-toughening protection steel plate and a manufacturing method thereof.
Background
Armor materials are the material basis for armor protection systems. Since the advent of the armor protection concept, humans have been continually researching and manufacturing high performance armor materials suitable for use in the manufacture of armor. While in armor protection systems the simplest and most effective structural element is homogeneous armor steel. Armor steel has been developed over 100 years since 1915 was applied to the first tank in the world today. Armor steel currently used in various countries has been greatly different in performance from traditional armor steel and is referred to as "modern armor steel". The application range of the modern armored steel is very wide, such as armored vehicles like main battle tanks, light tanks, infantry battle cars and the like. With the continuous development of modern anti-armor weapons, the armor breaking level of novel armor piercing bullets, armor breaking bullets, explosion forming bullets and the like is continuously improved, the threat to armor protection platforms is larger and larger, and the requirement on the armor protection level is higher and higher. Therefore, the ultrahigh-strength high-performance armor steel is always the focus of attention of expert students at home and abroad.
With the improvement of the performance of the armor steel plate and the overall design level of the whole vehicle, the thickness of the matrix armor tends to decrease. Table 1 shows the change in armor thickness over the first part of a well known main battle tank in the world. As can be seen from the table, the thickness of the armor is continuously reduced, and the thickness of the steel plate is reduced, so that the armor is more convenient to improve the elastic resistance, the technological performance and the cost. Compared with a thick plate, the high-strength homogeneous armor plate with better comprehensive mechanical properties is easier to obtain by the thin plate, so that the elastic resistance of the armor is improved. Three major process difficulties in the machining of armor steel, particularly high hardness armor steel, are straightening, cutting and welding. The thin armor plate is easy to straighten and cut, has higher blanking precision, and can replace cutting by shearing and flame cutting processes. The thin steel plate is easier to quench, so the total alloy content is lower, the carbon equivalent is also low, and the improvement of the thermal processing performances of welding, heat treatment and the like of the steel plate is facilitated. 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, the development characteristics of the modern high-strength high-performance armor plate are high-strength hardness, thin specification, excellent welding performance and machining use performance.
On-line searching was performed using "ballistic steel" or "armor steel" as keywords. At present, the alloy components of the high-strength steel for armor protection mainly comprise Cr, ni and Mo systems, and a small amount of microalloying elements are used as strengthening means. The production mode of the steel plate generally comprises smelting, rolling, quenching and tempering treatment, the strength of the steel plate is about 1000MPa, and the high-strength thin-specification steel plate exceeding 1500MPa can ensure the flatness of the steel plate after heat treatment by a special quenching device, so that the ultra-high-strength steel plate has certain limitation in application. Meanwhile, the steel plate is required to be 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. As disclosed in patent publication No. CN105088090a, "a bulletproof steel with a tensile strength of 2000MPa level and a manufacturing method thereof", the steel plate comprises the following components in percentage: 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 patent can obtain the ultra-high strength bulletproof steel plate with the tensile strength of 2000MPa, and the Brinell hardness can reach 600 HBW. Patent publication No. CN106756495A discloses "a 1760MPa ultra-high strength anti-spring steel and a manufacturing method thereof", and 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 an RH vacuum degassing converter; continuously casting a plate blank; reheating the slab; rough rolling by a roughing mill; finish rolling by a finishing mill; and (5) quenching and tempering inspection. The 6-25mm ultrahigh-strength alloy steel plate produced by the method achieves excellent toughness matching and excellent low-temperature impact toughness at minus 40 ℃. The metallurgical 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-40 ℃ is more than or equal to 20J, and the Brinell hardness of the surface is more than or equal to 490HBW through controlling rolling, quenching and tempering heat treatment. Patent publication No. CN102776337a discloses a "method for pressure quenching and processing of 30MnCrNiMo armor plate parts", which is directed to quenching and processing of large, medium and small plate members and bending members with or without machining in the manufacture of 30MnCrNiMo armor plates with a medium thickness, comprising the steps of: the method comprises the steps of pressure quenching of a whole annealed armor plate entering a factory, low-temperature tempering, shot blasting and leveling, and direct forming or subsequent processing and forming of single part or multiple parts 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-mentioned patent situation of high-strength bulletproof steel sheet, the current high-strength bulletproof steel sheet can reach the strength level of 2000MPa at the highest, but for the high-strength steel sheet, the quenching and tempering processes are adopted to heat treat the rolled steel sheet in the production and manufacturing process. For high-strength grade steel plates, special heat treatment devices are usually required to restrain the steel plates (pieces) in the heat treatment process in order to ensure that the steel plates still maintain good plate shape in the heat treatment process, so that the production and manufacturing efficiency of the steel plates are low, the cost is high, and the subsequent difficulty in use is increased.
Therefore, there is a need to develop a high-strength bulletproof steel having a strength of 15000MPa (or more), which is simple in production process and capable of securing a thin gauge steel plate shape to meet the demand of protective equipment for the high-strength bulletproof steel.
Disclosure of Invention
In order to solve the problems, the invention provides a 1500 MPa-grade high-strength self-toughening protective steel plate, the strength of which can reach 1500MPa grade, and the low-temperature toughness has remarkable advantages. The manufacturing method of the 1500 MPa-level high-strength self-toughening protective steel plate is simple in production process and high in operability, improves the rolling efficiency of the steel plate, reduces the energy consumption in the production process, and remarkably reduces the production and manufacturing cost.
In order to achieve the purpose, the invention provides a 1500 MPa-level high-strength self-toughening protective steel plate, which comprises the following chemical components in percentage by mass: c:0.20 to 0.60 percent of Si:0.15 to 0.95 percent of Mn:0.50 to 0.80 percent of Al:0.10 to 0.40 percent of Ti:0.01 to 0.05 percent, V:0.02 to 0.10 percent of Ni: 2-6%, cr:0.30 to 0.70 percent of Mo:0.40 to 0.90 percent, and 8.4 percent to less than or equal to (Ni+8Cr+10Mo) to less than or equal to 16.4 percent, and the balance being Fe and unavoidable impurities.
In the composition design of the steel of the invention:
carbon C: the strength of the material can be ensured, and fine and dispersed carbide can be separated out with micro-alloy elements such as Nb, V, ti and the like. The low carbon content in the steel can lead to low carbon content of martensite in the steel plate, and the volume fraction of precipitated carbide is small, so that the steel cannot play an effective strengthening role; however, when the carbon content in the steel is too high, the steel plate forms twin martensite during cooling, and the plasticity and toughness are poor. Therefore, the carbon content of the present invention is controlled to be 0.20 to 0.60%.
Silicon Si: silicon has the function of solid solution strengthening, can improve the corrosion resistance and high-temperature oxidation resistance of steel, and the addition of Si can effectively improve the elastic modulus of the steel plate; however, too high a content may result in serious decarburization of the steel surface, degrading the welding performance. Therefore, the silicon content selected in the invention is 0.15-0.95%.
Manganese Mn: manganese is the main element of stable austenite in steel, and the higher manganese content can ensure that the matrix structure of the material is a stable austenite structure, and each 1% of manganese can reduce the martensitic transformation temperature of the steel by about 35-50 ℃. The addition of a small amount of manganese element is beneficial to the increase of the stability of austenite in the steel plate and delays the transformation temperature of the austenite in the steel to pearlite ferrite; however, the excessive manganese content can remarkably reduce the martensitic transformation problem of the steel plate, so that the steel plate still has more retained austenite at room temperature and does not generate martensitic transformation, and the strength of the steel plate 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 from forming in steel, is beneficial to solid solution of carbon in austenite, improves the stability of austenite in the cooling process, and is greatly beneficial to improving the toughness of the steel plate. However, if the aluminum content in the steel is too high, the difficulty of smelting and pouring the steel is increased, the manufacturing cost is increased, and excessive oxide is formed to deteriorate the quality of the steel plate. In the present invention, the intermetallic compound is precipitated in the steel by the composite addition of elements such as Al and Ni, and the effect of improving the strength of the steel sheet is obtained. Therefore, the invention selects proper aluminum content range of 0.10-0.40%.
Chromium Cr: chromium can increase the hardenability of steel, and in the steel grade with higher carbon content, chromium can also be used as carbide of chromium with carbon property, so that the hardness and wear resistance of carbon steel are improved without embrittling the steel, and the heat strength of the steel can be increased. Meanwhile, the addition of chromium can obviously delay ferrite pearlite transformation, and ferrite transformation cannot occur in the air cooling process after rolling of the steel plate, so that the steel plate avoids a pearlite ferrite transformation zone in the air cooling process, and austenite is directly transformed into martensite. Therefore, the addition range of chromium in the present invention is 0.30 to 0.70%.
Nickel Ni: nickel can increase the hardenability of steel in steel, and the strength of steel is continuously increased along with the increase of nickel content in steel, but the toughness is not obviously reduced. In medium-high carbon steel, since nickel can reduce the pearlite transformation temperature, the pearlite is refined, 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 intermetallic compounds of nickel and aluminum can further enhance 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 addition range of nickel is 2 to 6%.
Titanium Ti: titanium is a strong carbide forming element, and TiN can be formed in steel, and acts as particles for austenite nucleation, thereby serving to refine austenite grains. The addition of trace Ti in the invention mainly plays 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 Ti addition range selected in the present invention is 0.01 to 0.05%.
Vanadium V: vanadium is a strong carbide forming element and has the functions of precipitation strengthening and fine grain strengthening in the material. As the Mn content in the steel is too high, the coarsening of crystal grains is easy to occur, and the addition of trace vanadium elements is beneficial to refining the structure and improving the alloy strength. Meanwhile, the carbide precipitation of V has the function of dispersion strengthening, and the strength of the steel can be further improved. Therefore, the range of vanadium selected in the invention is 0.02-0.10%.
Molybdenum Mo: molybdenum can improve the hardenability and the heat strength performance of the steel plate in the steel, so that the thick steel plate with a larger section is quenched deeply and completely quenched. In high carbon steel, molybdenum reduces the tendency of carbides to form a continuous network at grain boundaries, reduces retained austenite in the steel, and relatively increases the hardness and wear resistance of the steel sheet matrix. Similarly, molybdenum is a noble metal because of its high cost, and therefore, in the present invention, molybdenum is added in the range of 0.40 to 0.90%.
Meanwhile, in the invention, the elements are also required to be more than or equal to 8.4 percent and less than or equal to (Ni+8Cr+10Mo) and less than or equal to 16.4 percent.
Furthermore, the matrix structure of the 1500 MPa-level high-strength self-strength and high-toughness protective steel plate provided by the invention is air-cooled martensite, retained austenite and carbide which is diffused and precipitated.
The air-cooled martensite refers to martensite formed in the air-cooling process of the rolled steel plate, and mainly is supersaturated lath martensite; the residual austenite refers to austenite which is formed by enrichment of elements in the air cooling process and has high stability and does not generate martensitic transformation at room temperature; the carbide precipitated by diffusion means carbide precipitated from martensite during the formation of martensite.
Further, the 1500 MPa-grade high-strength self-toughening 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 break of 10-16%, and the Charpy impact energy at-40 ℃ of 80-120J.
Further, the thickness of the 1500 MPa-grade high-strength self-toughening protective steel plate provided by the invention is 4-25 mm.
Further, unavoidable impurities in the 1500 MPa-level high-strength self-toughening protective steel plate provided by the invention comprise: p: < 0.02%, S: less than 0.02%.
The invention also provides a manufacturing method of the 1500 MPa-level high-strength self-toughening protective steel plate, which comprises the following steps: smelting, casting, heating, rolling and air cooling the steel plate.
Wherein, each step is specifically:
s1: smelting, namely smelting the components of the 1500 MPa-level high-strength self-toughening protective steel plate.
S2: casting, and casting into steel ingot or continuous casting billet.
S3: heating, and heating a steel ingot or a casting blank.
S4: rolling, namely rolling the steel ingot after cogging; the continuous casting billet is directly rolled.
S5: and (5) air cooling the steel plate.
By adopting the scheme, the rolled steel plate is directly air-cooled to room temperature without on-line or off-line heat treatment for the steel plate rolled to the thickness of a finished product, so that heat treatment resources are saved, the production efficiency of the steel plate is improved, and the production cost of the ultra-high strength steel plate is reduced. The thickness of the steel plate manufactured by the 1500 MPa-grade high-strength self-toughening protective steel plate and the manufacturing method thereof is 4-25 mm, the yield strength of the steel plate at room temperature is 900-1100 MPa, the tensile strength is 1400-1600 MPa, the elongation after breaking exceeds 10-16%, and the Charpy impact energy at-40 ℃ is 80-120J.
Further, the rolled steel sheet is air-cooled to room temperature.
Specifically, after the steel plate is air cooled to room temperature, carbon, manganese, nickel, chromium and molybdenum added into the steel have the effects of deferring pearlite transformation and improving austenite stability, and the martensite transformation temperature Ms is between 200 and 300 ℃. Meanwhile, according to the calculation result of the continuous cooling transformation curve of the steel plate, it can be determined that pearlite transformation does not occur in the steel during air cooling of the rolled steel plate, and austenite in the steel is directly transformed into lath martensite structure during cooling. Since the cooling system of the steel sheet is air cooling, the cooling rate is low, and after the formation of martensite, carbon in the steel is precipitated from supersaturated martensite and diffused into surrounding non-transformed austenite, so that the stability of the surrounding non-transformed austenite is promoted to be improved, the martensitic transformation temperature is lowered, and the volume fraction of martensite in the steel is gradually increased with a gradual decrease in temperature. Part of austenite is reduced to a temperature lower than room temperature due to enrichment of carbon element, so that part of residual austenite which does not undergo martensitic transformation is present in the steel sheet cooled to room temperature by air cooling. In addition, after martensitic transformation, because supersaturated carbon cannot diffuse for a long distance at a low temperature (below the martensitic transformation temperature, the martensitic transformation temperature is 200-300 ℃), part of the carbon can be precipitated in the form of carbide on martensite laths, and because the temperature of carbide precipitation is low and the driving force for carbide growth is insufficient, carbide which is dispersed and distributed in steel is formed, 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 1150-1250 ℃.
Further, in the rolling step, the initial rolling temperature of the slab is 1050 to 1200 ℃.
Further, in the rolling step, the rolling process includes a first stage rolling and a second stage rolling; in the first stage rolling, the initial rolling temperature is 1050-1200 ℃, and when the rolling is carried out to a first thickness, the rolling is carried out on a roller way until the temperature is 850-900 ℃; in the second stage rolling, the initial rolling temperature is 850-900 ℃, the final rolling temperature is 720-780 ℃, and the steel plate is rolled to a finished steel plate with a second thickness.
Further, in the two stages of the above rolling step, the first thickness is 3 to 5 times the thickness of the finished steel sheet; the second thickness is 4-25 mm.
In a preferred embodiment, the slab is heated to 1150-1250 ℃, after exiting the soaking furnace, the slab is rolled at 1050-1200 ℃, when the thickness of the rolled steel plate is 3-5 times of that of the finished steel plate, the slab is rolled on a roller way until the temperature reaches 850-900 ℃, the finishing temperature is controlled at 720-780 ℃, the thickness of the finished steel plate is 4-25 mm, and the rolled steel plate is directly cooled to room temperature in an air mode.
Specifically, the two-stage rolling is mainly because rolling is started at 1050-1200 ℃, the temperature is above the recrystallization temperature of the material, and sufficient deformation is applied to the material in the temperature range, so that dynamic recrystallization of the steel plate is facilitated in the rolling deformation process, and the effect of grain refinement can be achieved. As the rolling passes proceed, the temperature of the steel sheet is also decreasing and the degree of dynamic recrystallization is gradually decreasing. When the thickness of the finished steel plate is 3-5 times of the thickness of the plate, the plate blank is heated to 850-900 ℃, and part of deformed grains which are not fully subjected to dynamic recrystallization can be subjected to austenite grain recovery and recrystallization in the process of being heated, so that the austenite grains before finish rolling are fully refined. The second stage rolling is started at 850-900 c because at this temperature the steel sheet will not substantially undergo recrystallization of the deformed austenite grains, i.e. the deformation of the steel sheet at this stage will be able to retain the deformed austenite grains until the rolling is completed. 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 advanced than that of the first stage rollingThe method is improved in one step. In general, the second stage rolling increases defects in austenite by increasing deformation and inhibiting recovery, provides sufficient nucleation positions for subsequent austenite to martensite transformation, plays a role in refining martensite laths, and improves the strength of the steel plate. The finishing temperature is controlled to be 720 ℃ or higher because the temperature is higher than Ac of the steel plate 3 The temperature, the steel plate is always the rolling deformation completed in the austenite region, and the components in the steel plate can be always kept uniform because no transformation occurs.
The beneficial effects of the invention are as follows:
1. through reasonable design of chemical components, more stable austenite is added in the steel, the element of pearlite ferrite transformation is delayed, the rolled steel plate does not generate pearlite ferrite transformation in the process of air cooling to room temperature, martensitic transformation is generated when the steel plate is cooled to below the martensitic transformation temperature, the self tempering effect is achieved on the steel plate by utilizing the slow cooling process of the air cooling process, carbide is separated out to produce a strengthening effect on the steel plate, meanwhile, 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 cooled to room temperature after being rolled, and the finished steel plate does not need to be subjected to traditional heat treatments 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 the 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 mass production in medium and thick plate production lines.
4. The 1500 MPa-level high-strength self-toughening protective steel plate has a matrix structure of air-cooled martensite, retained austenite and dispersed carbide at room temperature, has a yield strength of 900-1100 MPa, a tensile strength of 1400-1600 MPa, an elongation after fracture of more than 10-16%, and a Charpy impact energy of 80-120J at-40 ℃, and can be manufactured to produce a steel plate with a thickness of 4-25 mm.
Detailed Description
Further advantages and effects of the present invention will become apparent to those skilled in the art from the disclosure of the present specification, by describing the embodiments of the present invention with specific examples. While the description of the invention will be described in connection with the preferred embodiments, it is not intended to limit the inventive features to the implementation. Rather, the purpose of the invention described in connection with the embodiments is to cover other alternatives or modifications, which may be extended by the claims based on the invention. The following description contains many specific details for the purpose of providing a thorough understanding of the present invention. The invention may be practiced without these specific details. Furthermore, some specific details are omitted from the description in order to avoid obscuring the invention. It should be noted that, without conflict, the embodiments of the present invention and features of the embodiments may be combined with each other.
The present invention will be further described with reference to specific examples in order to make the objects, technical solutions and advantages of the present invention more apparent. However, the present invention is not limited to the following embodiments, and various technical solutions thereof should be included in the scope of the present invention.
The components of the steel of the invention are shown in Table 1, and Table 2 shows the performance parameters of the steel of the invention.
Examples
Example 1
1) Smelting the alloy by adopting an electric furnace or a converter, and casting into steel ingots or continuous casting billets; the weight percentages of the components are shown in table 1;
2) The steel ingot or the plate blank is heated to 1250 ℃, the initial rolling temperature of the first stage rolling of the steel plate is 1200 ℃, the thickness of the finished steel plate is 3 times,
3) And cooling to 860 ℃ to start rolling in the second stage, wherein the final rolling temperature is 730 ℃, rolling to 15mm thick finished steel plates, and cooling the rolled steel plates to room temperature by air.
Example 2
1) Smelting the alloy by adopting an electric furnace or a converter, and casting into steel ingots or continuous casting billets; 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 rolling to 5 times of the thickness of the finished steel plate;
3) And cooling to 900 ℃ to start rolling in the second stage, wherein the final rolling temperature is 760 ℃, rolling to a finished steel plate with the thickness of 10mm, and cooling the rolled steel plate to room temperature by air.
Example 3
1) The alloy is smelted by adopting an electric furnace or a converter, and is poured into steel ingots or continuous casting billets; the weight percentages of the components are shown in table 1;
2) The steel ingot or the plate blank is heated to 1200 ℃, the initial rolling temperature of the first stage rolling of the steel plate is 1150 ℃, and the thickness of the finished steel plate is 4 times;
3) And cooling to 860 ℃ to start rolling in the second stage, wherein the final rolling temperature is 750 ℃, rolling to a 20mm thick finished steel plate, and cooling the rolled steel plate to room temperature by air.
Example 4
1) The alloy is smelted by adopting an electric furnace or a converter, and is poured into steel ingots or continuous casting billets; the weight percentages of the components are shown in table 1;
2) Heating the steel ingot or the 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) And cooling to 870 ℃ to start rolling in the second stage, wherein the final rolling temperature is 740 ℃, rolling to a finished steel plate with the thickness of 12mm, and cooling the rolled steel plate to room temperature by air.
Example 5
1) The alloy is smelted by adopting an electric furnace or a converter, and is poured into steel ingots or continuous casting billets; the weight percentages of the components are shown in table 1;
2) Heating the steel ingot or the plate blank to 1210 ℃, wherein the initial rolling temperature of the first stage rolling of the steel plate is 1150 ℃, and rolling to 5 times of the thickness of the finished steel plate;
3) And cooling to 880 ℃ to start rolling in the second stage, wherein the final rolling temperature is 720 ℃, rolling to a finished steel plate with the thickness of 18mm, and air cooling the rolled steel plate to room temperature.
Table 1 chemical composition (wt.%) of the steel sheets of examples 1 to 5 of the present invention
Example results
The 1500 MPa-level high strength self-strengthening and toughening protective steel sheets of examples 1 to 5 of the present invention were tested for the performances of yield strength, tensile strength, elongation after break, and charpy impact power at-40 ℃ and the like, wherein the tensile test results are two sample averages, the impact power test results are three sample averages, and the test results are shown in table 2 below.
TABLE 2 Properties of the Steel sheets of examples 1 to 5 according to the invention
As can be seen from tables 1 and 2, the steel sheet for high hardness protection produced by the method for producing a 1500 MPa-grade high strength self-toughening steel sheet according to the present invention has a room temperature yield strength of 900 to 1100MPa, a tensile strength of 1400 to 1600MPa, an elongation after breaking of more than 10 to 16%, and a Charpy impact energy of 80 to 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 level, the low-temperature toughness has obvious advantages, the steel plate is directly air-cooled to room temperature after being rolled, the heat treatment of quenching and tempering is not needed, 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 further detailed description of the invention in connection with specific embodiments, and it is not intended to limit the invention to the specific embodiments described. Various changes in form and detail may be made therein by those skilled in the art, including a few simple inferences or alternatives, without departing from the spirit and scope of the present invention.
Claims (7)
1. The manufacturing method of the 1500 MPa-grade high-strength self-toughening protective steel plate is characterized by comprising the following steps of:
smelting, namely smelting components of a 1500 MPa-level high-strength and self-toughness protective steel plate, wherein the 1500 MPa-level high-strength and self-toughness protective steel plate comprises the following chemical components in percentage by mass: c:0.20 to 0.60 percent of Si:0.15 to 0.95 percent of Mn:0.50 to 0.80 percent of Al:0.10 to 0.40 percent of Ti:0.01 to 0.05 percent, V:0.02 to 0.10 percent of Ni: 2-6%, cr:0.30 to 0.70 percent of Mo:0.40 to 0.90 percent, and 8.4 percent or less (Ni+8Cr+10Mo) or less than 16.4 percent, and the balance being Fe and unavoidable impurities;
casting;
heating;
rolling; the rolling process comprises a first stage rolling and a second stage rolling; wherein the method comprises the steps of
In the first stage rolling, the initial rolling temperature is 1050-1200 ℃, and when the rolling is carried out to a first thickness, the rolling is carried out on a roller way until the temperature is 850-900 ℃;
in the second stage rolling, the initial rolling temperature is 850-900 ℃, the final rolling temperature is 720-780 ℃, and the steel plate is rolled to a finished steel plate with a second thickness;
and (5) air cooling the steel plate.
2. The method for producing 1500 MPa-level high-strength, self-toughening, protective steel sheet according to claim 1, wherein the rolled steel sheet is air-cooled to room temperature.
3. The method for manufacturing a 1500MPa grade high strength, self-toughening and protective steel plate according to claim 1, wherein,
in the heating step, the heating temperature of the slab is 1150-1250 ℃.
4. The method of producing a 1500 MPa-level high strength, self-toughening, protective steel sheet according to claim 1, wherein in the rolling step, the first thickness is 3 to 5 times the thickness of the finished steel sheet, and the second thickness is 4 to 25mm.
5. The method for manufacturing a 1500 MPa-level high-strength self-toughening protective steel sheet according to claim 1, wherein the 1500 MPa-level high-strength self-toughening protective steel sheet has a yield strength of 900 to 1100MPa, a tensile strength of 1400 to 1600MPa, an elongation after break of 10 to 16%, and a charpy impact energy at-40 ℃ of 80 to 120J.
6. The method for manufacturing a 1500 MPa-level high-strength self-toughening protective steel sheet according to claim 1, wherein the matrix structure of the 1500 MPa-level high-strength self-toughening protective steel sheet is air-cooled martensite+retained austenite+dispersed carbide.
7. The method for manufacturing a 1500 MPa-level high-strength, self-toughening, protective steel sheet according to claim 1, wherein the unavoidable impurities include: p: < 0.02%, S: less than 0.02%.
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