Elastic body impact resistant steel plate and preparation method and application thereof

Abstract

The invention provides a projectile impact resistant steel plate and a preparation method and application thereof, and relates to the technical field of high-strength steel for armor protection, the projectile impact resistant steel plate is formed by hot rolling compounding and heat treatment of at least one high-strength steel substrate and at least one high-toughness steel substrate, and the high-strength steel substrates and the high-toughness steel substrates are alternately stacked; the high-strength steel substrate on the outermost side is a projectile body impact surface of the projectile body impact resistant steel plate; the thickness ratio of the high-strength steel substrate to the high-toughness steel substrate adjacent to the high-strength steel substrate to the high-toughness steel substrate is 1: (1-20); the impedance ratio of the high-strength steel substrate to the high-toughness steel substrate adjacent to the high-strength steel substrate to the high-toughness steel substrate is (1.1-1.5): 1. By limiting the thickness ratio and impedance ratio of the high-strength steel substrate and the high-toughness steel substrate in the steel plate resistant to projectile impact and utilizing interface shock wave response, the reflection / transmission ratio is effectively controlled, and engineering management of shock waves is achieved.

Description

Technical Field

[0001] This invention relates to the field of high-strength armor protection steel technology, and in particular to a steel plate resistant to projectile impact, its preparation method and application. Background Technology

[0002] As a pillar industry of the national economy and defense industry, the materials industry plays a crucial supporting role in equipment performance and safety assurance. Despite the rapid development of protective technologies both domestically and internationally in recent years, with the emergence of various protective materials such as ceramics, polymer composites, and lightweight alloys, steel remains the most widely used armor protection material when considering engineering adaptability, manufacturability, and life-cycle cost. Among these, high-strength, high-hardness armor steel plates still possess significant advantages in mechanical properties and ballistic / corrosion resistance.

[0003] Currently available ballistic impact resistant composite materials still have many problems that need to be solved in practical applications: First, under high-energy, high-speed impact, the sheet material is prone to penetration, severe bulging on the back, or delamination due to interlayer shear, resulting in a significant reduction in protective effectiveness. Furthermore, engineering practices often rely on methods like "strengthening / hardening" or "simple thickening" to improve ballistic resistance, but this increases the risk of embrittlement in high-strength layers, adds to the weight and volume burden, and lacks systematic constraints on the propagation, reflection, and transmission of shock waves between different layers. Additionally, the material formulation design is still imperfect and cannot effectively meet the performance requirements under complex impact load conditions. These problems severely restrict the widespread application of ballistic impact-resistant composite sheets in military protection, aerospace, and other fields.

[0004] In view of this, the present invention is proposed, which designs impact-resistant steel plates from the perspective of impedance matching of composite materials based on the stress wave transmission theory in the impact resistance process. Summary of the Invention

[0005] The purpose of this invention is to provide a steel plate resistant to projectile impact, its preparation method, and its application. This invention effectively controls the reflection / transmission ratio by limiting the thickness ratio and impedance ratio of the high-strength steel substrate and the high-toughness steel substrate in the projectile impact resistant steel plate, and by utilizing the "interface shock wave response", thus achieving engineering management of shock waves.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: The present invention provides a steel plate resistant to projectile impact, which is formed by hot rolling and heat treatment of at least one high-strength steel substrate and at least one high-toughness steel substrate, wherein the high-strength steel substrate and the high-toughness steel substrate are alternately stacked; the outermost high-strength steel substrate is the projectile impact surface of the steel plate resistant to projectile impact; The thickness ratio of two adjacent high-strength steel substrates and high-toughness steel substrates is 1:(1-20). The impedance ratio of two adjacent high-strength steel substrates and high-toughness steel substrates is (1.1-1.5):1.

[0007] Furthermore, based on the above technical solution, the impedance of both the high-strength steel substrate and the high-toughness steel substrate is (4.2~6.6)×10. 7 Pa·s / m; And / or, the absolute value of the reflection coefficient of the steel plate resisting projectile impact is 0.05-0.2; And / or, the thickness of the high-strength steel substrate after hot rolling composite is 0.5 to 8 mm, preferably 1 to 3 mm; And / or, the thickness of the high-toughness steel substrate after hot rolling composite is 1 to 20 mm, preferably 3 to 12 mm.

[0008] Furthermore, based on the above technical solution, the high-strength steel substrate comprises the following components: C: 0.32–0.42%, Si: 0.20–0.60%, Mn: 0.80–1.50%, Cr: 0.30–1.20%, Ni: 0.10–0.60%, Mo: 0.20–0.60%, Co: 0–0.80%, Nb+V+Ti: 0.04–0.20%, B: 0.0003–0.0030%, Al: ≤0.05%, RE: ≤0.12%, P ≤0.015%, S ≤0.01%, O ≤0.003%, Se+Sn+Sb ≤0.01%, with the remainder being Fe and other uncontrollable residual elements.

[0009] Furthermore, based on the above technical solution, the high-toughness steel substrate comprises the following components: C: 0.22–0.30%, Si: 0.15–0.45%, Mn: 1.00–1.80%, Cr: 0.10–0.80%, Ni: 0.80–3.00%, Mo: 0.10–0.40%, Co: 0–0.20%, Nb+V+Ti: 0.02–0.20%, B: 0–0.0015%, Al: ≤0.05%, RE: ≤0.12%, P ≤0.015%, S ≤0.01%, O ≤0.003%, Se+Sn+Sb ≤0.01%, with the remainder being Fe and other uncontrollable residual elements.

[0010] Furthermore, based on the above technical solution, the thickness of the steel plate resistant to ballistic impact is 2.5 to 200 mm, which can be achieved by multi-layer stacking.

[0011] Furthermore, based on the above technical solution, the mechanical properties of the high-strength steel substrate include: yield strength of 1400-1700 MPa, tensile strength of 1800-2400 MPa, elongation of 6-10%, impact energy of over 21J at -40℃, and hardness of 480-630 HBW. And / or, the mechanical properties of the high-toughness steel substrate include: yield strength of 1000-1300 MPa, tensile strength of 1400-1800 MPa, elongation of 10-15%, impact energy of -40℃ reaching 34 J or more, and hardness of 350-480 HBW. And / or, the mechanical properties of the steel plate resistant to ballistic impact include: yield strength ≥1450 MPa, tensile strength ≥1750 MPa, elongation ≥8%, impact energy at -40℃ ≥30J, and hardness ≥500HBW.

[0012] Furthermore, based on the above technical solution, the surface bonding rate of the two adjacent high-strength steel substrates and high-toughness steel substrates after hot rolling composite in the ballistic impact resistant steel plate is 100%.

[0013] The present invention also provides a method for preparing the ballistic impact resistant steel plate as described above, comprising the following steps: S1: At least one high-strength steel substrate and at least one high-toughness steel substrate are alternately stacked and then hot-rolled to obtain a hot-rolled composite steel plate; S2: The hot-rolled composite steel plate is subjected to a combination of quenching and tempering to obtain a steel plate resistant to projectile impact.

[0014] Furthermore, based on the above technical solution, the quenching and tempering combination treatment includes: low-temperature quenching and low-temperature tempering treatment, or high-temperature quenching, low-temperature quenching and low-temperature tempering treatment. The low-temperature quenching includes: a temperature of 900-850℃ and a holding time of 1.5-3 min / mm; The low-temperature tempering temperature is 150-320℃, and the holding time is 1.5-3 min / mm; The high-temperature quenching temperature is 1020-980℃, and the holding time is 1.5-3 min / mm; After either low-temperature quenching or high-temperature quenching, water quenching is used for cooling. And / or, the hot rolling conditions include an initial rolling temperature of 850-1200°C, a final rolling temperature of 740-850°C, and a deformation rate of 60-90%.

[0015] The present invention also provides an application of the ballistic impact resistant steel plate as described above or the ballistic impact resistant steel plate prepared by the ballistic impact resistant steel plate preparation method as described above, wherein the steel plate is used in the preparation of unmanned vehicle armor, armored vehicle armor, civilian vehicle protective armor or key building protective components.

[0016] The present invention provides a steel plate resistant to projectile impact, its preparation method, and its application, the beneficial effects of which include at least the following: 1. This invention effectively controls the reflection coefficient of the steel plate resisting projectile impact by limiting the thickness ratio and impedance ratio of the high-strength steel substrate and the high-toughness steel substrate in the projectile impact-resistant steel plate and utilizing the "interface shock wave response". This reduces the peak stress of the projectile, avoids the problems of steel plate cracking and back bulging, improves the penetration resistance, and realizes the engineering management of shock waves.

[0017] 2. This invention improves equipment protection performance and reduces weight by approximately 20% through the composite of high-strength and high-toughness materials (the composite material's resistance to projectile impact is enhanced, allowing for thinner composite plates for the same projectile impact strength). This increases the power-to-weight ratio, improving vehicle mobility and battlefield response speed. Its excellent corrosion resistance and low-temperature toughness ensure high reliability in cold regions, mountainous terrain, and complex combat environments. Furthermore, it is applicable to track covers, boom connection structures, and load-bearing components of lightweight equipment. The material's high toughness and good weldability ensure structural safety and reliability under complex operating conditions, high vibration, and impact loads, improving overall battlefield support capabilities. Attached Figure Description

[0018] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of a projectile impact test provided in Application Example 1 of the present invention; Figure 2 This is a schematic diagram of a projectile impact test provided in Application Example 2 of the present invention; Figure 3 This is a schematic diagram of the ballistic impact test provided in Application Example 3 of the present invention; Figure 4 This is a schematic diagram of the ballistic impact test provided in Application Example 4 of the present invention. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. Those skilled in the art should understand that the embodiments described are merely illustrative of the invention and should not be considered as specific limitations thereof. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention. Process parameters not specifically specified in the following embodiments are generally performed under conventional conditions.

[0021] The endpoints and any values ​​of the ranges disclosed in this invention are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this invention.

[0022] According to a first aspect of the present invention, a steel plate resistant to projectile impact is provided, which is formed by hot rolling and heat treatment of at least one high-strength steel substrate and at least one high-toughness steel substrate, wherein the high-strength steel substrate and the high-toughness steel substrate are alternately stacked; the outermost high-strength steel substrate is the projectile impact surface of the steel plate resistant to projectile impact. The thickness ratio of two adjacent high-strength steel substrates and high-toughness steel substrates is 1:(1-20), such as 1:3, 1:5, 1:7, 1:9, 1:10, 1:13, 1:15, 1:17, 1:19, etc. The impedance ratio of two adjacent high-strength steel substrates and high-toughness steel substrates is (1.1-1.5):1, such as 1.1:1, 1.2:1, 1.3:1, 1.4:1, 1.5:1, etc.; Specifically, the impedance difference between steel billets of different impedances affects the reflection and transmission of the projectile's shock wave at the interface between the two billets. This invention limits the impedance ratio of two adjacent high-strength steel substrates and high-toughness steel substrates to (1.1-1.5):1. By combining steel billets with different impedances, when impacted by a projectile, the impedance difference affects the propagation and energy distribution of the shock wave. The part with relatively high impedance (i.e., the high-strength steel substrate) can more effectively block the projectile, while the part with relatively low impedance (i.e., the high-toughness steel substrate) can better absorb and disperse energy. When the impedance difference between the two substrates is too small (e.g., an impedance ratio of 1.02:1), the interface reflection and controllable unloading effect are very weak, and the system tends to be close to a "single material" response, making it difficult to leverage the synergistic advantages of "high Z-side plate bullet consumption and low Z-side backplate buffering". Therefore, the design should be within a moderate contrast window to achieve effective interface unloading / energy diversion while ensuring that the interface strength is higher than the interface shear and normal tensile stress, avoiding the degradation of "overall impact resistance" into "single-layer failure".

[0023] Furthermore, billets of different thicknesses have different "durations" and "degrees" of blocking and absorbing energy from shock waves. By rationally allocating the thickness of billets with different properties, the thickness ratio of two adjacent high-strength steel substrates and high-toughness steel substrates can be within the range of 1:(1-20). This ensures that the billet (high-strength steel substrate) that is first impacted effectively blocks the projectile, while the subsequent billet (high-toughness steel substrate) fully absorbs the remaining impact energy. If the high-strength steel substrate is relatively too thin (for example, the thickness ratio of two adjacent high-strength steel substrates and high-toughness steel substrates is 1:25), its initial impact resistance will be insufficient when impacted by the projectile, and it may be quickly penetrated by the projectile, failing to effectively resist the projectile. If the high-toughness steel substrate is relatively too thin (for example, the thickness ratio of two adjacent high-strength steel substrates and high-toughness steel substrates is 2:1), after the high-strength part resists the projectile, the subsequent energy absorption capacity will be poor, which may lead to interlayer damage of the plate and failure to effectively absorb the impact energy of the projectile.

[0024] In summary, the impedance ratio of two adjacent high-strength steel substrates and high-toughness steel substrates determines the reflection ratio of the shock wave at the steel / steel composite interface, while the thickness ratio of the two types of steel plates determines the energy absorption capacity of each substrate layer. The synergistic effect of the two can achieve efficient energy distribution and absorption. By reasonably limiting the impedance ratio and thickness ratio of two adjacent high-strength steel substrates and high-toughness steel substrates, this invention enables the steel plate to effectively block the projectile and absorb the remaining energy to the maximum extent when subjected to projectile impact, thereby significantly improving its impact resistance performance.

[0025] In an optional embodiment of the present invention, the impedance of both the high-strength steel substrate and the high-toughness steel substrate is (4.2~6.6)×10. 7 Pa·s / m, for example 4.4×10 7Pa·s / m, 4.8×10 7 Pa·s / m, 5×10 7 Pa·s / m, 5.2×10 7 Pa·s / m, 5.4×10 7 Pa·s / m, 5.6×10 7 Pa·s / m, 5.8×10 7 Pa·s / m, 6×10 7 Pa·s / m, 6.2×10 7 Pa·s / m, 6.4×10 7 Pa·s / m, etc.; The thickness of the high-strength steel substrate after hot rolling composite is 0.5 to 8 mm (e.g., 1 mm, 2 mm, 3 mm, 5 mm, 7 mm, etc.), preferably 1 to 3 mm; The thickness of the high-toughness steel substrate after hot rolling composite is 1 to 20 mm (e.g., 2 mm, 3 mm, 5 mm, 7 mm, 10 mm, 12 mm, 15 mm, 17 mm, etc.), preferably 3 to 12 mm.

[0026] The absolute value of the reflection coefficient of the steel plate resistant to projectile impact is 0.05-0.2, such as 0.05, 0.1, 0.15, 0.2, etc.

[0027] Specifically, this invention utilizes "interfacial shock wave response" as a design criterion: the transmission of shock waves in the composite plate is determined by the interlayer characteristic impedance Z = ρc ≈ √Eρ, where Z represents acoustic impedance; ρ is the density of the material; c is the propagation speed of sound waves in the material; and E is the elastic modulus of the material. A high-impedance, high-strength steel substrate is placed on the impact surface for initial energy dissipation and to flatten or disintegrate the warhead; subsequently, a low-impedance, high-toughness steel substrate is used as the back plate for subsequent kinetic energy absorption. Due to the interfacial impedance difference, the incident compression wave undergoes tensile reflection at the high-to-low impedance interface, resulting in controlled unloading of the impact surface and reducing local peak stress; simultaneously, the transmitted wave enters the high-toughness back plate, where its yield-plastic energy dissipation and extended deformation absorb residual kinetic energy and suppress back bulging (BFS).

[0028] Furthermore, this invention utilizes high impedance as the face plate (i.e., high-strength steel substrate) and low impedance as the back plate (i.e., high-toughness steel substrate). The reflected wave formed by the impedance difference acts as an unloading force. The ratio of the reflected wave to the incident wave (reflection coefficient) is calculated using the formula: Reflection coefficient = (Z-back - Z-face) / (Z-face + Z-back). By limiting the impedance difference formed by the high-strength steel substrate and the high-toughness steel substrate, this invention ensures that the reflection coefficient of the prepared ballistic impact-resistant steel plate is between 0.05 and 0.2, exhibiting excellent impact resistance. If the reflection coefficient of the ballistic impact-resistant steel plate is below 0.05, the impedance difference is approximately negligible, and the effect is similar to that of a single-layer plate. If it is above 0.5, although the unloading capacity is strong, the interface requirements are too high, increasing the risk of interface delamination.

[0029] As an optional embodiment of the present invention, the high-strength steel substrate comprises, by weight percentage, the following components: C: 0.32–0.42% (e.g., 0.35%, 0.37%, 0.40%, etc.), Si: 0.20–0.60% (e.g., 0.30%, 0.40%, 0.50%, etc.), Mn: 0.80–1.50% (e.g., 1.0%, 1.20%, 1.40%, etc.), Cr: 0.30–1.20% (e.g., 0.50%, 0.80%, 1.00%, etc.), Ni: 0.10–0.60% (e.g., 0.20%, 0.40%, 0.50%, etc.), Mo: 0.20–0.6%. 0% (e.g., 0.30%, 0.40%, 0.50%), Co: 0–0.80% (e.g., 0.20%, 0.50%, 0.70%), Nb+V+Ti: 0.04–0.20% (e.g., 0.08%, 0.10%, 0.15%, 0.17%), B: 0.0003–0.0030% (e.g., 0.0005%, 0.0010%, 0.0020%), Al: ≤0.05%, RE: ≤0.12%, P ≤0.015%, S ≤0.01%, O ≤0.003%, Se+Sn+Sb ≤0.01%, with the remainder being Fe and other uncontrollable residual elements.

[0030] As an optional embodiment of the present invention, the high-toughness steel substrate comprises the following components by weight percentage: C: 0.22–0.30% (e.g., 0.25%, 0.27%, 0.29%, etc.), Si: 0.15–0.45% (e.g., 0.20%, 0.30%, 0.40%, etc.), Mn: 1.00–1.80% (e.g., 1.20%, 1.40%, 1.60%, etc.), Cr: 0.10–0.80% (e.g., 0.20%, 0.40%, 0.60%, etc.), Ni: 0.80–3.00% (e.g., 1.00%, 1.50%, 2.00%, 2.00%). 50%, Mo: 0.10–0.40% (e.g., 0.20%, 0.30%), Co: 0–0.20% (e.g., 0.05%, 0.10%, 0.15%), Nb+V+Ti: 0.02–0.20% (e.g., 0.05%, 0.10%, 0.15%), B: 0–0.0015% (e.g., 0.0010%, 0.0013%), Al: ≤0.05%, RE: ≤0.12%, P ≤0.015%, S ≤0.01%, O ≤0.003%, Se+Sn+Sb ≤0.01%, the remainder being Fe and other uncontrollable residual elements.

[0031] As an optional embodiment of the present invention, the thickness of the steel plate resisting ballistic impact is 2.5 to 200 mm (e.g., 5 mm, 10 mm, 20 mm, 30 mm, 50 mm, 70 mm, 100 mm, 150 mm, 170 mm, etc.).

[0032] As an optional embodiment of the present invention, the mechanical properties of the high-strength steel substrate include: yield strength of 1400-1700 MPa (e.g., 1500 MPa, 1600 MPa, 1650 MPa, etc.), tensile strength of 1800-2400 MPa (e.g., 1900 MPa, 2000 MPa, 2100 MPa, 2200 MPa, etc.), elongation of 6-10% (e.g., 7%, 8%, 9%, etc.), impact energy at -40℃ reaching 21 J or more, and hardness of 480-630 HBW (e.g., 500 HBW, 520 HBW, 550 HBW, 600 HBW, etc.). The mechanical properties of the high-toughness steel substrate include: yield strength of 1000–1300 MPa (e.g., 1100 MPa, 1150 MPa, 1200 MPa, 1250 MPa, etc.), tensile strength of 1400–1800 MPa (e.g., 1500 MPa, 1600 MPa, 1700 MPa, etc.), elongation of 10–15% (e.g., 11%, 12%, 13%, etc.), impact energy of over 34 J at -40℃, and hardness of HBW 350–480 (e.g., 370, 400, 450, etc.). The mechanical properties of the steel plate resistant to ballistic impact include: yield strength ≥1450 MPa, tensile strength ≥1750 MPa, elongation ≥8%, impact energy at -40℃ reaching ≥30J, and hardness ≥HBW500.

[0033] As an optional embodiment of the present invention, the surface bonding rate of the two adjacent high-strength steel substrates and high-toughness steel substrates after hot rolling composite in the ballistic impact resistant steel plate is 100%.

[0034] According to a second aspect of the present invention, a method for preparing a steel plate resistant to projectile impact as described above is provided, comprising the following steps: S1: At least one high-strength steel substrate and at least one high-toughness steel substrate are alternately stacked and then hot-rolled to obtain a hot-rolled composite steel plate; S2: The hot-rolled composite steel plate is subjected to a combination of quenching and tempering to obtain a steel plate resistant to projectile impact.

[0035] As an optional embodiment of the present invention, the quenching and tempering combination treatment includes low-temperature quenching and low-temperature tempering treatment, or high-temperature quenching, low-temperature quenching and low-temperature tempering treatment.

[0036] Specifically, when the steel plate has obtained sufficient martensitic matrix, but there is still a certain amount of residual austenite RA (such as 5-12%), and there are high requirements for dimensional stability, wear resistance and fatigue resistance, then low temperature quenching and low temperature tempering treatment are selected. When steel plates are required to meet the maximum hardness and wear resistance, while significantly reducing residual austenite (RA) and improving dimensional stability, and the raw material has a high degree of alloying, many coarse carbides, and it is difficult to achieve both dissolution and grain refinement in a single austenitization process, high-temperature quenching, low-temperature quenching, and low-temperature tempering are used.

[0037] As an optional embodiment of the present invention, the hot rolling conditions include an initial rolling temperature of 850-1200℃ (e.g., 950℃, 1000℃, 1100℃, etc.), a final rolling temperature of 740-850℃ (e.g., 770℃, 800℃, 830℃, etc.), and a deformation rate of 60-90% (e.g., 62%, 67%, 75%, 80%, 85%, etc.).

[0038] Specifically, during hot rolling, a high rolling deformation rate causes the grains to be elongated and broken, forming finer grains, thereby improving the strength and toughness of the material. This allows the high-strength steel substrate and the high-toughness steel substrate of the ballistic impact-resistant steel plate to exhibit better resistance strength and energy absorption capacity when subjected to impact.

[0039] As an optional embodiment of the present invention, the low-temperature quenching includes: a temperature of 900-850℃ (e.g., 870℃, 880℃, etc.), and a holding time of 1.5-3min / mm (e.g., 2min / mm, 2.5min / mm, etc.). The holding time is calculated based on the thickness of the composite steel plate; the greater the thickness, the longer the holding time. The low-temperature tempering temperature is 150-320℃ (e.g., 200℃, 250℃, 300℃, etc.), and the holding time is 1.5-3min / mm (e.g., 2min / mm, 2.5min / mm, etc.). The high-temperature quenching temperature is 1020-980℃ (e.g., 990℃, 1000℃, 1010℃, etc.), and the holding time is 1.5-3min / mm (e.g., 2min / mm, 2.5min / mm, etc.). After the low-temperature quenching or high-temperature quenching is completed, water quenching is used for cooling.

[0040] According to a third aspect of the invention, an application of a steel plate resistant to projectile impact as described above is provided, the steel plate being used in the manufacture of armor for unmanned vehicles, armor for armored vehicles, protective armor for civilian vehicles, or protective components for key buildings.

[0041] The present invention will now be described in further detail with reference to specific embodiments and comparative examples.

[0042] Example 1 This embodiment provides a steel plate resistant to projectile impact, which is formed by hot rolling and heat treatment of a high-strength steel substrate and a high-toughness steel substrate, wherein the high-strength steel substrate and the high-toughness steel substrate are stacked alternately; the outermost high-strength steel substrate is the projectile impact surface of the steel plate resistant to projectile impact; The thickness ratio of the high-strength steel substrate to the high-toughness steel substrate is 1:4; The impedance of the high-strength steel substrate is 4.9 × 10⁻⁶. 7 Pa·s / m; The impedance of the high-toughness steel substrate is 4.3 × 10⁻⁶. 7 Pa·s / m; The absolute value of the reflection coefficient of the steel plate resistant to projectile impact is 0.07.

[0043] The high-strength steel substrate comprises the following components by weight percentage: The composition is as follows: C 0.42%, Si 0.45%, Mn 1.20%, Cr 1.0%, Ni 0.6%, Mo 0.6%, V 0.06%, B 0.0010%, Al 0.030%, P 0.008%, S 0.006%, with the remainder being Fe and other uncontrollable residual elements. The yield strength is 1580MPa, the tensile strength is 1950MPa, the elongation is 7%, the impact energy at -40℃ is ≥40J, and the hardness is 550HBW.

[0044] The high-toughness steel substrate comprises the following components by weight percentage: The composition is as follows: C 0.26%, Si 0.30%, Mn 1.40%, Ni 2.00%, Cr 0.40%, Mo 0.25%, V 0.03%, Al 0.025%, P 0.008%, S 0.006%, with the remainder being Fe and other uncontrollable residual elements. The yield strength is 1280 MPa, the tensile strength is 1550 MPa, the elongation is 12%, the impact energy at -40℃ is ≥60 J, and the hardness is 450 HBW.

[0045] The total thickness of the ballistic impact-resistant steel plate provided in this embodiment is 4mm; The surface bonding rate of the two adjacent high-strength steel substrates and high-toughness steel substrates after hot rolling composite in the ballistic impact resistant steel plate is 100%.

[0046] This embodiment also provides a method for preparing the above-mentioned steel plate resistant to projectile impact, comprising the following steps: S1: Stack a high-strength steel substrate and a high-toughness steel substrate together, and then hot roll them to obtain a hot-rolled composite steel plate; The initial rolling temperature of the hot-rolled product is 1050℃, the final rolling temperature is 800℃, and the deformation rate is 65%. S2: The hot-rolled composite plate is subjected to a combination of quenching and tempering to obtain a steel plate resistant to projectile impact. The quenching and tempering combination treatment is low-temperature quenching and low-temperature tempering treatment; the low-temperature quenching temperature is 850℃, and the holding time is 10min; water quenching is selected as the cooling method. The low-temperature tempering temperature is 230℃, and the holding time is 12 minutes.

[0047] Application Example 1 The impact-resistant steel plate prepared in Example 1 was used to conduct an impact resistance test on the projectile. Figure 1 As shown: The impact surface of the high-strength steel plate substrate prepared in Example 1, which is resistant to projectile impact, was fired at a test distance of 100m using a 7.63×25 mm steel core bullet. Test results: The steel plate was shot with a 7.63×25 mm steel core bullet without penetration. The impact surface formed a dent, the back side did not bulge, and there was no cracking at the interface between the two substrates.

[0048] Example 2 This embodiment provides a steel plate resistant to projectile impact, which is formed by hot rolling and heat treatment of two high-strength steel substrates of the same thickness and material and one high-toughness steel substrate. The high-strength steel substrate and the high-toughness steel substrate are stacked alternately; the outermost high-strength steel substrate is the projectile impact surface of the steel plate resistant to projectile impact. The thickness ratio of two adjacent high-strength steel substrates and high-toughness steel substrates is 1:4; The impedance of the high-strength steel substrate is 5.3 × 10⁻⁶. 7 Pa·s / m; The impedance of the high-toughness steel substrate is 4.3 × 10⁻⁶. 7 Pa·s / m; The absolute value of the reflection coefficient of the steel plate resistant to projectile impact is 0.10.

[0049] The high-strength steel substrate comprises the following components by weight percentage: The composition is as follows: C 0.37%, Si 0.45%, Mn 1.20%, Cr 1.0%, Ni 0.5%, Mo 0.5%, V 0.06%, B 0.0010%, Al 0.030%, P 0.008%, S 0.006%, with the remainder being Fe and other uncontrollable residual elements. The yield strength is 1700 MPa, the tensile strength is 2100 MPa, the elongation is 8%, the impact energy at -40℃ is ≥25 J, and the hardness is 600 HBW.

[0050] The high-toughness steel substrate comprises the following components by weight percentage: The composition is as follows: C 0.26%, Si 0.30%, Mn 1.40%, Ni 2.00%, Cr 0.40%, Mo 0.25%, V 0.03%, Al 0.025%, P 0.008%, S 0.006%, with the remainder being Fe and other uncontrollable residual elements. The yield strength is 1280 MPa, the tensile strength is 1550 MPa, the elongation is 12%, the impact energy at -40℃ is ≥60 J, and the hardness is 450 HBW.

[0051] The total thickness of the steel plate for resisting projectile impact provided in this embodiment is 8mm; The surface bonding rate of the two adjacent high-strength steel substrates and high-toughness steel substrates after hot rolling composite in the ballistic impact resistant steel plate is 100%.

[0052] This embodiment also provides a method for preparing the above-mentioned steel plate resistant to projectile impact, comprising the following steps: S1: Two high-strength steel substrates and one high-toughness steel substrate are alternately stacked and then hot-rolled to obtain a hot-rolled composite steel plate; The initial rolling temperature of the hot-rolled product is 1050℃, the final rolling temperature is 800℃, and the deformation rate is 75%. S2: The hot-rolled composite plate is subjected to a combination of quenching and tempering to obtain a steel plate resistant to projectile impact. The quenching and tempering combination treatment is low-temperature quenching and low-temperature tempering treatment; the low-temperature quenching temperature is 860℃, and the holding time is 15min; water quenching is selected as the cooling method. The low-temperature tempering temperature is 230℃, and the holding time is 18 minutes.

[0053] Application Example 2 The impact-resistant steel plate prepared in Example 2 was used to conduct an impact resistance test on the projectile. Figure 2 As shown: The impact surface of the high-strength steel plate substrate prepared in Example 2, which is resistant to projectile impact, was fired at a test distance of 100m using a 7.63×25 mm steel core bullet. Test results: The steel plate was shot with a 7.63×25 mm steel core bullet without penetration. The impact surface formed a dent, the back side did not bulge, and there was no cracking at the interface between the two substrates.

[0054] Example 3 This embodiment provides a steel plate resistant to projectile impact, which is formed by hot rolling and heat treatment of two high-strength steel substrates of the same thickness and material and two high-toughness steel substrates of the same thickness and material. The high-strength steel substrates and the high-toughness steel substrates are stacked alternately; the outermost high-strength steel substrate is the projectile impact surface of the steel plate resistant to projectile impact. The thickness ratio of two adjacent high-strength steel substrates and high-toughness steel substrates is 1:4; The impedance of the high-strength steel substrate is 5.7 × 10⁻⁶. 7 Pa·s / m; The impedance of the high-toughness steel substrate is 4.3 × 10⁻⁶. 7 Pa·s / m; The absolute value of the reflection coefficient of the steel plate resistant to projectile impact is 0.14.

[0055] The high-strength steel substrate comprises the following components by weight percentage: The composition is as follows: C 0.40%, Si 0.45%, Mn 1.0%, Cr 1.20%, Ni 0.6%, Mo 0.4%, V 0.06%, B 0.0010%, Al 0.030%, P 0.008%, S 0.006%, with the remainder being Fe and other uncontrollable residual elements. The yield strength is 1700 MPa, the tensile strength is 2300 MPa, the elongation is 8%, the impact energy at -40℃ is ≥25 J, and the hardness is 630 HBW.

[0056] The high-toughness steel substrate comprises the following components by weight percentage: The composition is as follows: C 0.26%, Si 0.30%, Mn 1.40%, Ni 2.00%, Cr 0.40%, Mo 0.25%, V 0.03%, Al 0.025%, P 0.008%, S 0.006%, with the remainder being Fe and other uncontrollable residual elements. The yield strength is 1280 MPa, the tensile strength is 1550 MPa, the elongation is 12%, the impact energy at -40℃ is ≥60 J, and the hardness is 450 HBW.

[0057] The total thickness of the ballistic impact-resistant steel plate provided in this embodiment is 10mm; The surface bonding rate of the two adjacent high-strength steel substrates and high-toughness steel substrates after hot rolling composite in the ballistic impact resistant steel plate is 100%.

[0058] This embodiment also provides a method for preparing the above-mentioned steel plate resistant to projectile impact, comprising the following steps: S1: Two high-strength steel substrates and two high-toughness steel substrates are alternately stacked and then hot-rolled to obtain a hot-rolled composite steel plate; The initial rolling temperature of the hot-rolled product is 1050℃, the final rolling temperature is 800℃, and the deformation rate is 70%. S2: The hot-rolled composite plate is subjected to a combination of quenching and tempering to obtain a steel plate resistant to projectile impact. The quenching and tempering combination treatment is low-temperature quenching and low-temperature tempering treatment; the low-temperature quenching temperature is 870℃, and the holding time is 20min; water quenching is selected as the cooling method. The low-temperature tempering temperature is 230℃, and the holding time is 22 minutes.

[0059] Application Example 3 The impact-resistant steel plate prepared in Example 3 was used to conduct an impact resistance test on the projectile. Figure 3 As shown: The impact-resistant steel plate substrate of the steel plate prepared in Example 3 was fired at a test distance of 100m using a 7.62 mm armor-piercing incendiary projectile. Test results: The steel plate was not penetrated by a 7.62 mm armor-piercing incendiary round. The impact surface formed a dent, the back side did not bulge, and the interface between the two substrates did not crack. It can withstand the impact of a 7.62 mm armor-piercing incendiary round.

[0060] Example 4 This embodiment provides a steel plate resistant to projectile impact, which is formed by hot rolling and heat treatment of four high-strength steel substrates of the same thickness and material and four high-toughness steel substrates of the same thickness and material. The high-strength steel substrates and the high-toughness steel substrates are stacked alternately; the outermost high-strength steel substrate is the projectile impact surface of the steel plate resistant to projectile impact. The thickness ratio of two adjacent high-strength steel substrates and high-toughness steel substrates is 1:2; The impedance of the high-strength steel substrate is 6.1 × 10⁻⁶. 7 Pa·s / m; The impedance of the high-toughness steel substrate is 4.3 × 10⁻⁶. 7 Pa·s / m; The absolute value of the reflection coefficient of the steel plate resistant to projectile impact is 0.17.

[0061] The high-strength steel substrate comprises the following components by weight percentage: The composition is as follows: C 0.42%, Si 0.45%, Mn 1.20%, Cr 1.20%, Ni 0.6%, Mo 0.6%, V 0.06%, B 0.0010%, Al 0.030%, P 0.008%, S 0.006%, with the remainder being Fe and other uncontrollable residual elements. The yield strength is 1700 MPa, the tensile strength is 2400 MPa, the elongation is 6%, the impact energy at -40℃ is ≥25 J, and the hardness is 630 HBW.

[0062] The high-toughness steel substrate comprises the following components by weight percentage: The composition is as follows: C 0.26%, Si 0.30%, Mn 1.40%, Ni 2.00%, Cr 0.40%, Mo 0.25%, V 0.03%, Al 0.025%, P 0.008%, S 0.006%, with the remainder being Fe and other uncontrollable residual elements. The yield strength is 1280 MPa, the tensile strength is 1550 MPa, the elongation is 12%, the impact energy at -40℃ is ≥60 J, and the hardness is 450 HBW.

[0063] The total thickness of the steel plate for resisting projectile impact provided in this embodiment is 18mm; The surface bonding rate of the two adjacent high-strength steel substrates and high-toughness steel substrates after hot rolling composite in the ballistic impact resistant steel plate is 100%.

[0064] This embodiment also provides a method for preparing a steel plate resistant to projectile impact, comprising the following steps: S1: Four high-strength steel substrates and four high-toughness steel substrates are stacked alternately and then hot-rolled to obtain a hot-rolled composite steel plate. The initial rolling temperature of the hot-rolled product is 1050℃, the final rolling temperature is 800℃, and the deformation rate is 65%. S2: The hot-rolled composite plate is subjected to a combination of quenching and tempering to obtain a steel plate resistant to projectile impact. The quenching and tempering combination treatment includes high-temperature quenching, low-temperature quenching and low-temperature tempering; the high-temperature quenching temperature is 980℃ and the holding time is 28min; the low-temperature quenching temperature is 870℃ and the holding time is 28min; water quenching is used as the cooling method after both high-temperature quenching and low-temperature quenching. The low-temperature tempering temperature is 230℃, and the holding time is 32 minutes.

[0065] Application Example 4 The impact-resistant steel plate prepared in Example 4 was used to conduct an impact resistance test on the projectile. Figure 4 As shown: The impact-resistant steel plate substrate of the steel plate prepared in Example 4 was fired at a test distance of 100m using a 12.7mm armor-piercing incendiary projectile. Test results: The steel plate was not penetrated by a 12.7mm armor-piercing incendiary round. The impact surface formed a dent, but the back side did not bulge. There was no crack at the interface between the two substrates. It can withstand the impact of a 12.7mm armor-piercing incendiary round.

[0066] Comparative Example 1 The difference between this comparative example and Example 1 is that the thickness ratio of the high-strength steel substrate to the high-toughness steel substrate is 1:25, while the remaining steps and performance parameters are the same as in Example 1.

[0067] The impedance of the high-strength steel substrate is 4.9 × 10⁻⁶. 7 Pa·s / m; The impedance of the high-toughness steel substrate is 4.3 × 10⁻⁶. 7 Pa·s / m; The absolute value of the reflection coefficient of the steel plate resistant to projectile impact is 0.07.

[0068] The steel plate provided in this comparative example has a total thickness of 4 mm (the same as in Example 1), only the thickness ratio is changed; the hot rolling and quenching and tempering processes are performed according to steps S1 and S2 in Example 1.

[0069] Application Example 5 The impact-resistant steel plate prepared in Comparative Example 1 was used to conduct projectile impact tests: The impact surface of a high-strength steel plate substrate prepared in Comparative Example 1 was fired at a test distance of 100m using a 7.63×25 mm steel core bullet. Test results: When the steel plate was shot with a 7.63×25 mm steel core bullet, the impact surface cracked, the back side bulged, and the interface between the two substrates cracked.

[0070] Compared with Example 1, Comparative Example 1 has a thickness ratio of 1:25 between the high-strength steel substrate and the high-toughness steel substrate. The high-strength steel substrate is relatively too thin, and when it is impacted by the projectile, its initial impact resistance is insufficient, the entire plate is damaged, and it cannot effectively resist the projectile.

[0071] Comparative Example 2 The difference between this comparative example and Example 1 is that the thickness ratio of the high-strength steel substrate to the high-toughness steel substrate is 2:1, while the remaining steps and performance parameters are the same as in Example 1.

[0072] The difference between this comparative example and Example 1 is that the thickness ratio of the high-strength steel substrate to the high-toughness steel substrate is 2:1; the remaining steps and performance parameters are the same as in Example 1.

[0073] The impedance of the high-strength steel substrate is 4.9 × 10⁻⁶. 7 Pa·s / m; The impedance of the high-toughness steel substrate is 4.3 × 10⁻⁶. 7 Pa·s / m; The absolute value of the reflection coefficient of the steel plate resistant to projectile impact is 0.07.

[0074] The steel plate provided in this comparative example has a total thickness of 4 mm, with only the thickness ratio changed; the hot rolling and quenching and tempering processes are performed according to steps S1 and S2 in Example 1.

[0075] Application Example 6 The impact-resistant steel plate prepared in Comparative Example 2 was used for projectile impact resistance tests: The impact surface of the high-strength steel plate substrate prepared in Comparative Example 2 was fired at a test distance of 100m using a 7.63×25 mm steel core bullet. Test results: When the steel plate was shot with a 7.63×25 mm steel core bullet, the interface between the two substrates cracked, a pit was formed on the impacted surface, and a bulge appeared on the back.

[0076] Compared with Example 1, Comparative Example 2 has a thickness ratio of 2:1 between the high-strength steel substrate and the high-toughness steel substrate. The high-toughness steel substrate is relatively too thin, and its subsequent energy absorption capacity will be poor when it is impacted by the projectile, resulting in interlayer damage and cracking of the plate and failing to effectively resist the projectile.

[0077] Comparative Example 3 The main difference between this comparative example and Example 1 is that the impedance ratio of the high-strength steel substrate and the high-toughness steel substrate is 0.98:1, specifically including: The high-strength steel substrate comprises the following components by weight percentage: The composition is as follows: C 0.42%, Si 0.45%, Mn 1.20%, Cr 0.3%, Ni 0.1%, Mo 0.2%, V 0.06%, B 0.0010%, Al 0.030%, P 0.008%, S 0.006%, with the remainder being Fe and other uncontrollable residual elements. The yield strength is 1400MPa, the tensile strength is 1950MPa, the elongation is 8%, the impact energy at -40℃ is ≥30J, and the hardness is 500HBW.

[0078] The high-toughness steel substrate comprises the following components by weight percentage: The composition is as follows: C 0.26%, Si 0.30%, Mn 1.40%, Ni 2.00%, Cr 0.40%, Mo 0.25%, V 0.03%, Al 0.025%, P 0.008%, S 0.006%, with the remainder being Fe and other uncontrollable residual elements. The yield strength is 1280 MPa, the tensile strength is 1550 MPa, the elongation is 12%, the impact energy at -40℃ is ≥60 J, and the hardness is 450 HBW.

[0079] The impedance of the high-strength steel substrate is 4.2 × 10⁻⁶. 7 Pa·s / m; The impedance of the high-toughness steel substrate is 4.3 × 10⁻⁶. 7 Pa·s / m; The absolute value of the reflection coefficient of the steel plate resistant to projectile impact is 0.01; The remaining steps and performance parameters are the same as in Example 1.

[0080] Application Example 7 The impact-resistant steel plate prepared in Comparative Example 3 was used for projectile impact resistance tests: The impact surface of the high-strength steel plate substrate prepared in Comparative Example 3 was fired at a test distance of 100m using a 7.63×25 mm steel core bullet. Test results: When the steel plate was shot with a 7.63×25 mm steel core bullet, the impact surface cracked, the back side bulged, and the interface between the two substrates cracked.

[0081] Compared with Example 1, Comparative Example 3 has a lower impedance ratio of less than 1 between the high-strength steel substrate and the high-toughness steel substrate, which prevents controlled unloading and instead exacerbates the incident stress, thus failing to effectively resist the projectile.

[0082] Performance testing This invention uses GB / T 3621-2022 "Titanium and Steel Plates", GB / T 229-2020 "Charpy Pendulum Impact Test Method for Metallic Materials", and GB / T 22315-2008 "Test Method for Elastic Modulus and Poisson's Ratio of Metallic Materials" to test the mechanical properties of steel plates resisting projectile impact.

[0083] Results data The mechanical properties of the ballistic impact-resistant steel plates prepared in the examples and comparative examples are shown in Table 1: Table 1 In summary, by reasonably limiting the impedance ratio and thickness ratio of two adjacent high-strength steel substrates and high-toughness steel substrates, this invention not only ensures that the steel plate resisting projectile impact has excellent mechanical properties, but also improves the material's resistance to projectile impact, avoids cracking between the two types of steel substrates and avoids bulging on the back of the steel plate. When the steel plate is impacted by a projectile, it can effectively block the projectile and absorb the remaining energy to the maximum extent, thereby significantly improving its impact resistance.

[0084] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A steel plate resistant to projectile impact, characterized in that, It is formed by hot rolling and heat treatment of at least one high-strength steel substrate and at least one high-toughness steel substrate, wherein the high-strength steel substrate and the high-toughness steel substrate are stacked alternately; the outermost high-strength steel substrate is the impact surface of the projectile-resistant steel plate. The thickness ratio of two adjacent high-strength steel substrates and high-toughness steel substrates is 1:(1-20). The impedance ratio of two adjacent high-strength steel substrates and high-toughness steel substrates is (1.1-1.5):

1.

2. The steel plate resistant to projectile impact according to claim 1, characterized in that, The impedance of both the high-strength steel substrate and the high-toughness steel substrate is (4.2~6.6)×10. 7 Pa·s / m; And / or, the absolute value of the reflection coefficient of the steel plate resisting projectile impact is 0.05-0.2; And / or, the thickness of the high-strength steel substrate after hot rolling composite is 0.5 to 8 mm, preferably 1 to 3 mm; And / or, the thickness of the high-toughness steel substrate after hot rolling composite is 1 to 20 mm, preferably 3 to 12 mm.

3. The steel plate resistant to projectile impact according to claim 1, characterized in that, The high-strength steel substrate comprises the following components by weight percentage: C: 0.32–0.42%, Si: 0.20–0.60%, Mn: 0.80–1.50%, Cr: 0.30–1.20%, Ni: 0.10–0.60%, Mo: 0.20–0.60%, Co: 0–0.80%, Nb+V+Ti: 0.04–0.20%, B: 0.0003–0.0030%, Al: ≤0.05%, RE: ≤0.12%, P≤0.015%, S≤0.01%, O≤0.003%, Se+Sn+Sb≤0.01%, with the remainder being Fe and other uncontrollable residual elements.

4. The steel plate resistant to projectile impact according to claim 1, characterized in that, The high-toughness steel substrate comprises, by weight percentage, the following components: C: 0.22–0.30%, Si: 0.15–0.45%, Mn: 1.00–1.80%, Cr: 0.10–0.80%, Ni: 0.80–3.00%, Mo: 0.10–0.40%, Co: 0–0.20%, Nb+V+Ti: 0.02–0.20%, B: 0–0.0015%, Al: ≤0.05%, RE: ≤0.12%, P ≤0.015%, S ≤0.01%, O ≤0.003%, Se+Sn+Sb ≤0.01%, with the remainder being Fe and other uncontrollable residual elements.

5. The steel plate resistant to projectile impact according to claim 1, characterized in that, The thickness of the steel plate used to resist ballistic impact is 2.5 to 200 mm.

6. The steel plate resistant to projectile impact according to claim 1, characterized in that, The mechanical properties of the high-strength steel substrate include: yield strength of 1400-1700 MPa, tensile strength of 1800-2400 MPa, elongation of 6-10%, impact energy of over 21 J at -40℃, and hardness of 480-630 HBW. And / or, the mechanical properties of the high-toughness steel substrate include: yield strength of 1000-1300 MPa, tensile strength of 1400-1800 MPa, elongation of 10-15%, impact energy of -40℃ reaching 34 J or more, and hardness of 350-480 HBW. And / or, the mechanical properties of the steel plate resistant to ballistic impact include: yield strength ≥1450 MPa, tensile strength ≥1750 MPa, elongation ≥8%, impact energy at -40℃ ≥30J, and hardness ≥500HBW.

7. The steel plate resistant to projectile impact according to claim 1, characterized in that, The surface bonding rate of the two adjacent high-strength steel substrates and high-toughness steel substrates after hot rolling composite in the ballistic impact resistant steel plate is 100%.

8. A method for preparing a steel plate resistant to projectile impact as described in any one of claims 1-7, characterized in that, Includes the following steps: S1: At least one high-strength steel substrate and at least one high-toughness steel substrate are alternately stacked and then hot-rolled to obtain a hot-rolled composite steel plate; S2: The hot-rolled composite steel plate is subjected to a combination of quenching and tempering treatment to obtain a steel plate resistant to projectile impact.

9. The method for preparing a steel plate resistant to projectile impact according to claim 8, characterized in that, The quenching and tempering combination treatment includes: low-temperature quenching and low-temperature tempering treatment, or high-temperature quenching, low-temperature quenching and low-temperature tempering treatment. The low-temperature quenching includes: a temperature of 900-850℃ and a holding time of 1.5-3 min / mm; The low-temperature tempering temperature is 150-320℃, and the holding time is 1.5-3 min / mm; The high-temperature quenching temperature is 1020-980℃, and the holding time is 1.5-3 min / mm; After either low-temperature quenching or high-temperature quenching, water quenching is used for cooling. And / or, the hot rolling conditions include an initial rolling temperature of 850-1200°C, a final rolling temperature of 740-850°C, and a deformation rate of 60-90%.

10. The application of a steel plate resistant to projectile impact as described in any one of claims 1-7, or a steel plate resistant to projectile impact as described in any one of claims 8-9, wherein the steel plate is characterized in that, The steel plate is used in the manufacture of armor for unmanned vehicles, armor for armored vehicles, protective armor for civilian vehicles, or protective components for key buildings.

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