Multi-layer gradient impact-resistant material based on high-strength and high-toughness steel and manufacturing method of multi-layer gradient impact-resistant material

Abstract

The invention relates to the technical field of protective armor materials, and particularly discloses a multi-layer gradient impact-resistant material based on high-strength and high-toughness steel and a manufacturing method. The multi-layer gradient impact-resistant material comprises a high-toughness steel plate and a bonding layer which are arranged at an interval, the first layer of material and the last layer of material of the multi-layer gradient impact-resistant material are high-toughness steel plates. By adopting the multi-layer gradient impact-resistant material disclosed by the invention, a multi-layer structure of the multi-layer gradient impact-resistant material can prevent cracks at a crater from quickly expanding in the material, and the energy absorption capacity is improved under the condition of the same material thickness. Through reasonable material performance gradient design, the bullet crushing function of the bullet facing surface high-hardness material can be fully played, and meanwhile, the deformation energy absorption function of the bullet backing surface high-toughness material can be fully played.

Description

Technical Field

[0001] The present invention relates to the technical field of protective armor materials, and in particular to a multi-layer gradient impact-resistant material based on high-strength and toughness steel and a manufacturing method thereof. Background Art

[0002] Currently, protective armor materials used in the industry fall into two main categories: homogeneous protective materials and composite protective materials. Homogeneous protective materials primarily consist of single-layer, high-strength and tough steel plates. Due to their uniform structure, these plates offer stable protective performance and strong resistance to multiple, intensive rounds. However, crater cracks outside the impact point tend to propagate rapidly within the uniform structure, creating adiabatic shear bands and penetrating channels within the structure, reducing the material's energy absorption and elastic resistance. Compared to composite protective materials, homogeneous steel plates are also heavier.

[0003] Currently, composite steel plates are made of two or more layers, and are manufactured through hot rolling or explosive welding followed by overall heat treatment. This approach offers the advantage of achieving composite and fusion at the metal microstructure level. However, overall heat treatment cannot optimize the properties of the different layers, especially when the hardness difference is significant. The tempering temperature of ultra-high-hardness materials is lower than that of medium- and high-hardness materials.

[0004] Composite protective materials primarily consist of a composite structure of ceramics and fibers. Ceramics primarily include oxide ceramics such as alumina and boron carbide, while fibers primarily include ultra-high molecular weight polyethylene (UHMWPE) and Kevlar. Composite protective materials offer advantages such as lightweight and high protection levels. However, due to the shattering of ceramics and breakage of fibers upon impact, their resistance to multiple, intensive rounds is inferior to that of high-strength steel. Furthermore, composite materials are significantly more expensive than high-strength steel.

[0005] Therefore, it is necessary to provide a multi-layer gradient impact-resistant material and manufacturing method based on high-strength and tough steel to solve the problem of rapid crack propagation in homogeneous high-strength and tough steel thick plate materials, and the impact of crack propagation on energy absorption and protective performance, further improve the protective performance of high-strength and tough steel materials, and solve the problem that the performance of each layer of materials in the overall heat treatment scheme after hot rolling or explosive welding cannot be adjusted to the optimal state. Summary of the Invention

[0006] The present invention aims to solve at least one of the technical problems existing in the above-mentioned prior art. To this end, the present invention proposes a multi-layer gradient impact-resistant material based on high-strength and toughness steel and a manufacturing method to solve the problem that cracks in homogeneous high-strength and toughness steel thick plates extend rapidly, and crack expansion affects energy absorption and protective performance, further improve the protective performance of high-strength and toughness steel materials, and solve the problem that the performance of each layer of materials in the overall heat treatment scheme after hot rolling or explosive welding cannot be adjusted to the optimal state.

[0007] A first aspect of the present invention provides a multi-layer gradient impact-resistant material based on high-strength and toughness steel.

[0008] Specifically, the multi-layer gradient impact-resistant material includes high-strength and toughness steel plates and adhesive layers that are spaced apart from each other; The first layer and the last layer of the multi-layer gradient impact-resistant material are high-strength and toughness steel plates.

[0009] Preferably, the hardness of the high-strength and toughness steel plate is 400-700 HBW.

[0010] Further preferably, the hardness of the high-strength and toughness steel plate is 450-700 HBW.

[0011] More preferably, the hardness of the high-strength and toughness steel plate is 450-650 HBW.

[0012] Preferably, the thickness of the high-strength and toughness steel plate is 0.5-2.5 mm.

[0013] Further preferably, the thickness of the high-strength and toughness steel plate is 0.8-2.5 mm.

[0014] More preferably, the thickness of the high-strength and toughness steel plate is 0.8-2.2 mm.

[0015] Preferably, the thickness of the adhesive layer is 0.2-1.5 mm.

[0016] More preferably, the thickness of the adhesive layer is 0.2-1.2 mm.

[0017] More preferably, the thickness of the adhesive layer is 0.2-1 mm.

[0018] A second aspect of the present invention provides a method for manufacturing a multi-layer gradient impact-resistant material based on high-strength and toughness steel.

[0019] Specifically, the manufacturing method includes the following steps: The high-strength and tough steel plate surface is strengthened by shot blasting, the high-strength and tough steel plate is cleaned, the high-strength and tough steel plate surface is coated with an adhesive, multiple layers of high-strength and tough steel plates are pressed and bonded, and cured at room temperature to obtain the multi-layer gradient impact-resistant material based on high-strength and tough steel.

[0020] Preferably, the step of strengthening shot peening the surface of the high-strength and toughness steel plate includes: When the hardness of high-strength and tough steel plate is ≥500 HBW, steel wire shot is used with a diameter of 0.5~2 mm, a shot peening coverage of ≥100%, and a surface residual compressive stress of 350~450 MPa; When the hardness of high-strength and toughness steel plate is less than 500 HBW, cast iron shot is used. The diameter of the cast iron shot is 0.5-2 mm, the shot peening coverage is ≥100%, and the surface residual compressive stress is 300-400 MPa. Excessive surface residual compressive stress will cause deformation and warping of the high-strength and toughness steel plate.

[0021] Preferably, the surface strengthening shot peening of the high-strength and toughness steel plate can use multi-nozzle shot peening equipment, using but not limited to hanging methods to achieve simultaneous shot peening of both sides of the high-strength and toughness steel plate.

[0022] Preferably, the step of cleaning the high-strength and tough steel plate includes: cleaning the high-strength and tough steel plate with isopropyl alcohol or a special metal cleaning agent. The cleaning process is used to remove surface oil and dust and improve the bonding strength of the adhesive.

[0023] Further preferably, the dedicated metal cleaning agent includes an emulsifying cleaning agent.

[0024] More preferably, the emulsifiable cleaning agent includes at least one of OP-10 and hydrocarbon cleaning agent.

[0025] Preferably, the step of coating the surface of the high-strength and toughness steel plate with an adhesive comprises: Applying epoxy resin adhesive to the bonding surface of the high-strength and tough steel plate; Wherein, the coverage rate of the epoxy resin adhesive on the bonding surface is greater than 90%.

[0026] Preferably, the pressure for pressing and bonding the multiple layers of high-strength and toughness steel plates is 1-5 MPa.

[0027] Preferably, the room temperature curing time is 24 to 72 hours.

[0028] More preferably, the room temperature curing time is 48 to 72 hours.

[0029] More preferably, the room temperature curing time is 48 h.

[0030] Preferably, the epoxy resin adhesive comprises a two-component epoxy steel adhesive.

[0031] Further preferably, the two-component epoxy steel bonding adhesive includes at least one of Henkel LOCTITE EA 9394 AERO, Xianghuan Concrete Z8 or Ruishengte steel bonding adhesive.

[0032] Preferably, the surface coating method of the multi-layer gradient impact-resistant material based on high-strength and toughness steel is a baking coating process or a cold spray painting process.

[0033] Further preferably, the baking coating process includes: When the hardness of high-strength and tough steel plate is 500~550 HBW, the coating baking temperature should not be higher than 180℃; When the hardness of high-strength and tough steel plate is 580~630 HBW, the coating baking temperature should not be higher than 140℃; When the hardness of high-strength and tough steel plate is 610~650 HBW, the coating baking temperature should not be higher than 90℃; The baking coating temperature must be lower than the quenching and tempering temperature of the first layer of material to avoid tempering and softening of the material caused by high temperature baking, which will reduce the protective performance of the product.

[0034] Compared with the prior art, the present invention has the following beneficial effects: 1. The multi-layer gradient impact-resistant material of the present invention has a multi-layer structure that can block the rapid expansion of cracks at the crater inside the material and improve energy absorption at the same material thickness.

[0035] 2. The present invention can give full play to the bullet-smashing effect of the high-hardness material on the front surface and the deformation energy absorption effect of the high-toughness material on the back surface through reasonable material property (mainly hardness) gradient design.

[0036] 3. The manufacturing process of the present invention can be used to heat treat each layer of material separately, so as to optimize the performance of each layer of material and fully develop the value of the material.

[0037] 4. The cost of manufacturing multi-layer gradient high-strength and toughness steel materials of the present invention is much lower than that of traditional multi-layer composite protective materials.

[0038] 5. Since the present invention adopts a multi-layer structure, the thickness of each layer of material is very thin. Compared with the homogeneous high-strength and tough steel thick plate, the thin plate can reduce the difficulty of heat treatment and improve the stability and consistency of material performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a schematic structural diagram of the multi-layer gradient impact-resistant material based on high-strength and toughness steel prepared in Example 3. DETAILED DESCRIPTION

[0040] In order to make the technical solution of the present invention more clearly understood by those skilled in the art, the following examples are given for illustration. It should be noted that the following examples do not limit the scope of protection claimed by the present invention.

[0041] Unless otherwise specified, the raw materials, reagents, or devices used in the following examples can be obtained from conventional commercial sources or by existing known methods.

[0042] Example 1 A multi-layer gradient impact-resistant material based on high-strength and toughness steel and a manufacturing method.

[0043] When using Protection Level 2, as specified in the GA141-2010 "Police Body Armor" standard, a two-layer high-strength and toughness steel plate structure can be used. The first layer is made of high-strength and toughness steel plate with a hardness of 500-550 HBW and a thickness of 1 mm, and the second layer is made of high-strength and toughness steel plate with a hardness of 450-490 HBW and a thickness of 1.7 mm. Epoxy resin is used to form a bonding layer between the two steel plates.

[0044] The steps of the manufacturing method include: Surface strengthening shot peening of high-strength and tough steel plate: The first layer of high-strength and tough steel plate is made of steel wire shot with a diameter of 0.5~2 mm, a shot peening coverage rate ≥100%, and a surface residual compressive stress of 350~450 MPa; the second layer of high-strength and tough steel plate is made of cast iron shot with a diameter of 0.5~2 mm, a shot peening coverage rate ≥100%, and a surface residual compressive stress of 300~400 MPa.

[0045] Cleaning of high-strength and tough steel plates: Use isopropyl alcohol to clean high-strength and tough steel plates to remove surface oil and dust and improve adhesive bonding strength.

[0046] Adhesive is applied to the surface of the high-strength and tough steel plate: the epoxy resin adhesive is applied to the bonding surface of each high-strength and tough steel plate by a roller, and the coverage rate of the epoxy resin adhesive on the bonding surface is greater than 90%.

[0047] Press bonding of multiple layers of high-strength and tough steel plates: Use a fixed fixture to press the two layers of high-strength and tough steel plates together with a pressure of 1~5 MPa.

[0048] Room temperature curing: After 48 hours of room temperature curing, the fixture is removed to produce a multi-layer gradient impact-resistant material based on high-strength and toughness steel. The coating and baking temperature of this material in later product applications should not exceed 180°C.

[0049] Example 2 A multi-layer gradient impact-resistant material based on high-strength and toughness steel and a manufacturing method.

[0050] When using Protection Level 5 of the GA141-2010 "Police Body Armor" standard, a three-layer high-strength and toughness steel plate structure can be used. The first layer is made of high-strength and toughness steel plate with a hardness of 580-630 HBW and a thickness of 1.2 mm. The second layer is made of high-strength and toughness steel plate with a hardness of 500-550 HBW and a thickness of 1.2 mm. The third layer is made of high-strength and toughness steel plate with a hardness of 450-490 HBW and a thickness of 1.4 mm. Epoxy resin is used to bond the three layers together to form a bonding layer.

[0051] The steps of the manufacturing method include: Surface strengthening shot peening of high-strength and tough steel plates: The first and second layers of high-strength and tough steel plates are made of steel wire shot with a diameter of 0.5-2 mm, a shot peening coverage of ≥100%, and a surface residual compressive stress of 350-450 MPa. The third layer of high-strength and tough steel plates is made of cast iron shot with a diameter of 0.5-2 mm, a shot peening coverage of ≥100%, and a surface residual compressive stress of 300-400 MPa.

[0052] Cleaning of high-strength and tough steel plates: Use isopropyl alcohol to clean high-strength and tough steel plates to remove surface oil and dust and improve adhesive bonding strength.

[0053] Adhesive is applied to the surface of the high-strength and tough steel plate: the epoxy resin adhesive is applied to the bonding surface of each high-strength and tough steel plate by a roller, and the coverage rate of the epoxy resin adhesive on the bonding surface is greater than 90%.

[0054] Press bonding of multiple layers of high-strength and tough steel plates: Use a fixed fixture to press the three layers of high-strength and tough steel plates together with a pressure of 1~5 MPa.

[0055] Room temperature curing: After 48 hours of room temperature curing, the fixture is removed to produce a multi-layer gradient impact-resistant material based on high-strength and toughness steel. The coating and baking temperature of this material in later product applications should not exceed 140°C.

[0056] Example 3 A multi-layer gradient impact-resistant material based on high-strength and toughness steel and a manufacturing method.

[0057] When using Protection Level 6 in the GA141-2010 "Police Body Armor" standard, a four-layer high-strength and toughness steel plate structure can be used. The first layer uses a high-strength and toughness steel plate with a hardness of 610-650 HBW and a thickness of 1.4 mm. The second layer uses a high-strength and toughness steel plate with a hardness of 580-630 HBW and a thickness of 1.4 mm. The third layer uses a high-strength and toughness steel plate with a hardness of 500-550 HBW and a thickness of 1 mm. The fourth layer uses a high-strength and toughness steel plate with a hardness of 450-500 HBW and a thickness of 1 mm. Epoxy resin is used to bond the four layers together to form a bonding layer.

[0058] The steps of the manufacturing method include: Surface strengthening shot peening of high-strength and tough steel plates: The first to third layers of high-strength and tough steel plates are made of steel wire shot with a diameter of 0.5-2 mm, a shot peening coverage of ≥100%, and a surface residual compressive stress of 350-450 MPa. The fourth layer of high-strength and tough steel plates is made of cast iron shot with a diameter of 0.5-2 mm, a shot peening coverage of ≥100%, and a surface residual compressive stress of 300-400 MPa.

[0059] Cleaning of high-strength and tough steel plates: Use isopropyl alcohol to clean high-strength and tough steel plates to remove surface oil and dust and improve adhesive bonding strength.

[0060] Adhesive is applied to the surface of the high-strength and tough steel plate: the epoxy resin adhesive is applied to the bonding surface of each high-strength and tough steel plate by a roller, and the coverage rate of the epoxy resin adhesive on the bonding surface is greater than 90%.

[0061] Press bonding of multiple layers of high-strength and tough steel plates: Use a fixed fixture to press the two layers of high-strength and tough steel plates together with a pressure of 1~5 MPa.

[0062] Room temperature curing: After 48 hours of room temperature curing, the fixture is removed to produce a multi-layer gradient impact-resistant material based on high-strength and toughness steel. The coating and baking temperature of this material in later product applications should not exceed 90°C.

[0063] This invention tailors the hardness and thickness of the first layer of high-strength steel to the bullet's initial velocity and projectile profile at different protection levels. This allows for the shattering of lead or steel-core bullets upon impact. The projectile disintegration process absorbs some of the kinetic energy, minimizing damage to the protective material. The hardness and thickness of the second and third layers are designed to be lower than that of the first layer, leveraging their greater plasticity and toughness to absorb the remaining kinetic energy of the impact.

[0064] The steel plate surface enhancement shot peening treatment of the present invention can, on the one hand, remove surface impurities such as oxide scale and rust, while also increasing surface roughness and improving the steel plate's bonding strength. Furthermore, based on research, the surface stress around the steel plate's crater is tensile. The compressive stress generated on the steel plate's surface after enhanced shot peening can offset the tensile stress generated by the steel plate's deformation due to impact, thereby improving the steel plate's protective capabilities.

[0065] The present invention uses adhesives and room temperature curing technology to fully preserve the performance of each layer of high-strength and tough steel plates, avoiding tempering and softening of the material caused by high-temperature lamination, which would reduce the material's protective performance.

[0066] The present invention controls the coating baking temperature in the later product application, which can avoid the tempering and softening of the material caused by high-temperature baking and the reduction of the product protection performance.

[0067] The above describes in detail the preferred embodiments of the present invention. It should be understood that those skilled in the art can make numerous modifications and variations based on the concepts of the present invention without inventive effort. Therefore, any technical solutions derived from modifications, equivalent substitutions, improvements, etc. made by those skilled in the art based on the concepts of the present invention through logical analysis, reasoning, or limited experimentation on the basis of the prior art shall be within the scope of protection defined by the claims.

Claims

1. A multi-layer gradient impact-resistant material based on high-strength and toughness steel, characterized in that: It includes high-strength and tough steel plates and adhesive layers spaced apart from each other; The first layer and the last layer of the multi-layer gradient impact-resistant material are high-strength and toughness steel plates.

2. The multi-layer gradient impact-resistant material according to claim 1, characterized in that: The hardness of the high-strength and toughness steel plate is 400-700 HBW.

3. The multi-layer gradient impact-resistant material according to claim 1, characterized in that: The thickness of the high-strength and toughness steel plate is 0.5-2.5 mm.

4. The multi-layer gradient impact-resistant material according to claim 1, characterized in that: The thickness of the adhesive layer is 0.2-1.5 mm.

5. The method for manufacturing a multi-layer gradient impact-resistant material based on high-strength and toughness steel according to any one of claims 1 to 4, characterized in that: The following steps are involved: The high-strength and tough steel plate surface is strengthened by shot blasting, the high-strength and tough steel plate is cleaned, the high-strength and tough steel plate surface is coated with an adhesive, multiple layers of high-strength and tough steel plates are pressed and bonded, and cured at room temperature to obtain the multi-layer gradient impact-resistant material based on high-strength and tough steel.

6. The manufacturing method according to claim 5, characterized in that The step of strengthening shot peening on the surface of the high-strength and toughness steel plate comprises: When the hardness of high-strength and tough steel plate is ≥500 HBW, steel wire shot is used with a diameter of 0.5~2 mm, a shot peening coverage of ≥100%, and a surface residual compressive stress of 350~450 MPa; When the hardness of high-strength and tough steel plate is less than 500 HBW, cast iron shots are used. The diameter of the cast iron shots is 0.5~2 mm, the shot peening coverage is ≥100%, and the surface residual compressive stress is 300~400 MPa.

7. The manufacturing method according to claim 5, characterized in that The step of cleaning the high-strength and toughness steel plate includes: using isopropyl alcohol or a special metal cleaning agent to clean the high-strength and toughness steel plate.

8. The manufacturing method according to claim 5, characterized in that The step of coating the surface of the high-strength and toughness steel plate with an adhesive comprises: Applying epoxy resin adhesive to the bonding surface of the high-strength and tough steel plate; Wherein, the coverage rate of the epoxy resin adhesive on the bonding surface is greater than 90%.

9. The manufacturing method according to claim 5, characterized in that The pressure for pressing and bonding the multi-layer high-strength and toughness steel plates is 1-5 MPa.

10. The manufacturing method according to claim 5, characterized in that The room temperature curing time is 24 to 72 hours.

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