High-temperature-resistant hot-rolled coiled plate

Abstract

The invention relates to the technical field of metal composite materials, and discloses a high-temperature-resistant hot-rolled coiled plate. The cross section structure of the hot-rolled coil plate sequentially comprises a tough core base body, a functional gradient transition layer integrally connected with the tough core base body and an in-situ self-repairing composite surface layer integrally connected with the functional gradient transition layer from inside to outside, and the functional gradient transition layer contains high-temperature-resistant ceramic nanoparticles. The volume fraction of the in-situ self-repairing composite surface layer is continuously increased from the interface of the in-situ self-repairing composite surface layer and the tough core matrix to the outer side, and a plurality of micron-sized microcapsules packaged with a repairing agent are dispersed and distributed in the in-situ self-repairing composite surface layer. The interface thermal stress is effectively relieved through the functional gradient transition layer, and surface layer stripping is prevented; and meanwhile, the in-situ self-repairing composite surface layer can actively trigger microcapsules to release a repairing agent when microcracks are generated, in-situ healing of damage is achieved, the structural stability of the hot-rolled coil plate under the severe working condition is improved, and the service life of the hot-rolled coil plate under the severe working condition is prolonged.

Description

Technical Field

[0001] This invention relates to the field of metal composite materials technology, specifically to a high-temperature resistant hot-rolled coil. Background Technology

[0002] Hot-rolled coils, as a fundamental industrial material, are widely used in key fields such as machinery manufacturing, transportation, energy and chemical engineering, and aerospace. With the continuous development of modern industrial technology, many core equipment and key components need to operate for extended periods under increasingly harsh environments of high temperature, high stress, and alternating thermal cycles. This poses unprecedented challenges to the high-temperature performance of traditional hot-rolled coils, including their oxidation resistance, thermal stability, and structural reliability.

[0003] To improve the high-temperature protection capability of hot-rolled coils, existing technologies typically employ a strategy of preparing a high-temperature resistant protective coating (such as a ceramic coating) on ​​the surface of the steel substrate. However, this simple physical composite structure has inherent defects that are difficult to overcome. Due to the significant differences in physical properties, especially in the coefficient of thermal expansion, between the metal substrate and the ceramic coating, a weak physical interface with abrupt performance changes is formed. During equipment start-up and shutdown or fluctuations in operating conditions, repeated temperature changes can lead to the generation and accumulation of huge thermal mismatch stresses at the interface. When this stress exceeds the interfacial bonding strength, it can easily cause the coating to crack, blister, or even peel off over a large area, causing the protective layer to fail prematurely and failing to provide long-term protection.

[0004] Furthermore, even high-temperature resistant materials that employ integral alloying or surface reinforcement treatments are inevitably susceptible to the development of microcracks on their surfaces during service due to factors such as thermal fatigue, mechanical loads, or environmental corrosion. Traditional materials passively endure this early damage and lack the ability to repair themselves. Once these microcracks form, they will continue to expand and merge under sustained stress, eventually evolving into macroscopic failure, seriously threatening the structural safety and service life of the entire component.

[0005] Therefore, the purpose of this invention is to provide a high-temperature resistant hot-rolled coil to overcome the shortcomings of the prior art. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a high-temperature resistant hot-rolled coil, which solves the problems of premature structural failure and short service life caused by interface spalling due to thermal mismatch stress and the lack of active repair capability of materials against early microcrack damage in traditional high-temperature resistant composite materials.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a high-temperature resistant hot-rolled coil, wherein the cross-sectional structure of the high-temperature resistant hot-rolled coil comprises, from the inside to the outside, the following: A robust core matrix; A functionally graded transition layer is integrally connected with the robust core matrix. The functionally graded transition layer contains high-temperature resistant ceramic nanoparticles, and the volume fraction of the high-temperature resistant ceramic nanoparticles continuously increases outward along the thickness direction of the functionally graded transition layer. An in-situ self-healing composite surface layer is integrally connected with the functional gradient transition layer, wherein multiple micron-sized microcapsules are diffusely distributed in the in-situ self-healing composite surface layer.

[0008] Preferably, the material of the high-temperature resistant ceramic nanoparticles is at least one of titanium carbide, silicon carbide, or aluminum oxide.

[0009] Preferably, in the functionally graded transition layer, the volume fraction of the high-temperature resistant ceramic nanoparticles continuously increases from the interface between the functionally graded transition layer and the tough core matrix, and the final value of the volume fraction of the high-temperature resistant ceramic nanoparticles on the side of the functionally graded transition layer near the in-situ self-healing composite surface layer is in the range of 15%-20%.

[0010] Preferably, the in-situ self-healing composite surface layer also contains the high-temperature resistant ceramic nanoparticles.

[0011] Preferably, in the in-situ self-healing composite surface layer, the volume fraction of the high-temperature resistant ceramic nanoparticles is 20%-30%.

[0012] Preferably, the micron-sized microcapsule comprises a microcapsule shell and a repair agent core encapsulated by the microcapsule shell.

[0013] Preferably, the material of the microcapsule shell is niobium or molybdenum.

[0014] Preferably, the core material of the repair agent is a low-melting-point metallic glass or a low-eutectic-point alloy that is liquid at a preset working temperature.

[0015] Preferably, the eutectic alloy is a tin-bismuth alloy or a zinc-aluminum alloy.

[0016] Preferably, the material of the strong and tough core matrix is ​​high-strength low-alloy steel or bainitic steel.

[0017] This invention provides a high-temperature resistant hot-rolled coil. It has the following beneficial effects: 1. This invention establishes a functional gradient transition layer between a strong and tough core matrix and an in-situ self-healing composite surface layer, and continuously increases the volume fraction of high-temperature resistant ceramic nanoparticles along the thickness direction within this layer. This creates a bridge for smooth performance transition between layers with different material properties, effectively alleviating the huge interfacial stress generated during thermal cycling due to the mismatch of thermal expansion coefficients. It solves the technical problem of traditional coatings or overlays being prone to cracking and peeling, enhances the bonding strength and thermal cycling stability of the composite structure, and ensures the structural integrity of the coil at high temperatures.

[0018] 2. This invention disperses multiple micron-sized microcapsules in an in-situ self-healing composite surface layer. When microcracks appear on the material surface due to fatigue or impact, the stress field at the crack tip can actively trigger the microcapsules to rupture and release the repair agent core encapsulated inside. The repair agent core automatically fills the crack and completes in-situ repair through capillary action, realizing intelligent response and suppression of early damage, effectively preventing further damage propagation, endowing the material with the ability to self-heal damage, and significantly extending its service life and reliability under harsh working conditions.

[0019] 3. This invention integrates a robust core matrix that provides basic load-bearing capacity, a functional gradient transition layer that solves interface matching problems, and an in-situ self-healing composite surface layer that provides high-temperature protection and damage repair capabilities into an integrated structural design. This allows the coil to retain the high strength and high toughness of the core matrix while achieving smooth loading of surface protection functions through the gradient layer. Combined with the self-healing capability of the surface layer, it overcomes the inherent contradiction between material hardness and toughness, and between high-temperature protection and structural stability, and achieves synergistic optimization of multiple performance characteristics. Attached Figure Description

[0020] Figure 1 This is a perspective view of the present invention; Figure 2 This is a schematic diagram of the functional gradient transition layer of the present invention; Figure 3 This is a schematic diagram of the in-situ self-healing composite surface layer of the present invention.

[0021] Among them, 10 is a strong and tough core matrix; 20 is a functional gradient transition layer; 21 is high-temperature resistant ceramic nanoparticles; 30 is an in-situ self-healing composite surface layer; 31 is a micron-sized microcapsule; 32 is a microcapsule shell; and 33 is a repair agent core. Detailed Implementation

[0022] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] Please see the appendix Figure 1 -Appendix Figure 3 This invention provides a high-temperature resistant hot-rolled coil, the cross-sectional structure of which, from the inside out, comprises: A robust core matrix 10; a functionally graded transition layer 20 integrally connected to the robust core matrix 10, the functionally graded transition layer 20 containing high-temperature resistant ceramic nanoparticles 21, the volume fraction of the high-temperature resistant ceramic nanoparticles 21 continuously increasing outward along the thickness direction of the functionally graded transition layer 20; an in-situ self-healing composite surface layer 30 integrally connected to the functionally graded transition layer 20, the in-situ self-healing composite surface layer 30 containing multiple micron-sized microcapsules 31 dispersedly distributed in the in-situ self-healing composite surface layer 30; the material of the high-temperature resistant ceramic nanoparticles 21 is titanium carbide, silicon carbide, or alumina. One less; In the functionally graded transition layer 20, the volume fraction of high-temperature resistant ceramic nanoparticles 21 continuously increases from the interface between the functionally graded transition layer 20 and the tough core matrix 10, and on the side of the functionally graded transition layer 20 near the in-situ self-healing composite surface layer 30, the final value of the volume fraction of high-temperature resistant ceramic nanoparticles 21 is in the range of 15%-20%; The in-situ self-healing composite surface layer 30 also contains high-temperature resistant ceramic nanoparticles 21; In the in-situ self-healing composite surface layer 30, the volume fraction of high-temperature resistant ceramic nanoparticles 21 is 20%-30%. The micron-sized microcapsule 31 includes a microcapsule shell 32 and a repair agent core 33 encapsulated by the microcapsule shell 32; The material of the microcapsule shell 32 is niobium or molybdenum; The material of the repair agent core 33 is a low-melting-point metallic glass or a low-eutectic-point alloy that is liquid at a preset working temperature; The low-eutectic-point alloy is a tin-bismuth alloy or a zinc-aluminum alloy. The material of the tough core matrix 10 is high-strength low-alloy steel or bainitic steel; Specifically, the high-temperature resistant hot-rolled coil adopts a three-layer integrated composite structure design, forming a cross-sectional system with complementary functions and optimized performance gradients from the inside out. The structure and core characteristics of each layer are as follows: The innermost layer is a strong and tough core matrix 10, which serves as the foundation for the mechanical performance of the coil. Its material is selected from high-strength low-alloy steel or bainitic steel. These two types of steel have both excellent tensile strength and impact toughness, which can provide stable load-bearing capacity for the entire coil, effectively resist mechanical stress and deformation under high-temperature conditions, and at the same time ensure the structural integrity of the coil during processing, transportation and installation, avoiding overall failure due to insufficient core strength; Closely connected to the strong and tough core matrix 10 through an integrated process is the middle functional gradient transition layer 20. The core design highlight of this transition layer is the uniformly dispersed high-temperature resistant ceramic nanoparticles 21 inside. The particle material is preferably at least one of titanium carbide, silicon carbide or aluminum oxide. Among them, titanium carbide has high hardness and excellent high temperature stability, silicon carbide has strong oxidation resistance and low coefficient of thermal expansion, and aluminum oxide has excellent high temperature corrosion resistance. It can be flexibly combined and selected according to the high temperature environment requirements of the specific application scenario of the coil. The volume fraction of these ceramic nanoparticles is continuously increasing along the thickness direction of the functional gradient transition layer 20. Starting from the interface with the tough core matrix 10, the particle volume fraction is 0% to ensure material compatibility and tight connection with the core matrix and avoid interface stress caused by abrupt changes in composition. As it extends outward, the fraction gradually increases until it approaches the side of the outer in-situ self-healing composite surface layer 30, and the final value is stable in the range of 15%-20%. This gradient distribution design can achieve a smooth transition from the toughness of the core matrix to the high temperature resistance of the surface layer, effectively alleviate the difference in the coefficient of thermal expansion between different functional layers, and reduce the risk of interface cracking under high temperature cycling.The outermost layer is an in-situ self-healing composite surface layer 30 integrated with the functional gradient transition layer 20. This surface layer not only continues the high-temperature resistant design but also adds high-temperature resistant ceramic nanoparticles 21, with the volume fraction further increased to 20%-30%. The higher content of ceramic particles can form a denser high-temperature resistant protective barrier on the surface, significantly improving the surface's resistance to high-temperature oxidation, high-temperature wear, and high-temperature corrosion. At the same time, a large number of micron-sized microcapsules 31 are dispersed within the surface layer. These microcapsules adopt a double-layer structure of shell and core. The shell material is niobium or molybdenum, both of which have extremely high melting points. Niobium has a melting point of approximately 2468℃, and molybdenum has a melting point of approximately 2623℃. They can maintain structural stability under the pre-set high-temperature working environment of the coil, preventing premature rupture of the microcapsules. The repair agent core 31 is encapsulated by the shell. 3. Low-melting-point metallic glass or eutectic-point alloys that can be liquid at a preset operating temperature are selected. Specifically, eutectic-point alloys can be tin-bismuth alloys, such as a tin-bismuth alloy with 58% bismuth content (melting point approximately 138℃), or zinc-aluminum alloys, such as a zinc-aluminum alloy with 5% aluminum content (melting point approximately 382℃). When microcracks develop on the surface of the coil under high-temperature conditions due to stress concentration, wear, or corrosion, the crack propagation process will compress and destroy the micron-sized microcapsules 31 along the path. At this time, the microcapsule shell 32 ruptures, and the liquid repair agent core 33 will automatically flow out under capillary action and high-temperature drive, quickly filling the crack gaps. Subsequently, through cooling and solidification or reaction with surrounding materials, a dense repair layer is formed, achieving in-situ autonomous repair of surface damage, significantly extending the service life of the coil, and reducing the maintenance cost of high-temperature equipment.

[0024] Working principle: First, a strong and tough core matrix 10, composed of high-strength low-alloy steel or bainitic steel, is set up to provide basic structural support and load-bearing capacity for the entire coil, ensuring sufficient strength and toughness when subjected to macroscopic stress and preventing overall brittle fracture. Based on this, a functionally graded transition layer 20 is designed and integrated between the strong and tough core matrix 10 and the outer protective layer. The volume fraction of high-temperature resistant ceramic nanoparticles 21 contained in this transition layer increases continuously and smoothly outwards along the thickness direction from the interface with the strong and tough core matrix 10 until it reaches a certain level near the outermost layer. The layer reaches a preset high concentration, such as 15%-20%. This gradient structural design eliminates the physical weak interfaces formed by abrupt changes in material properties in traditional coatings or overlay materials, allowing key physical properties such as the coefficient of thermal expansion and elastic modulus to transition smoothly. This alleviates the huge interfacial stress caused by the mismatch in thermal expansion and contraction of different materials during repeated heating and cooling cycles, solving common failure problems such as coating cracking and peeling in traditional composite panels. It ensures a strong bond between the core and the surface layer. In the outermost in-situ self-healing composite surface layer 30, on the one hand, a higher volume is diffusely distributed inside the surface layer. The presence of high-temperature resistant ceramic nanoparticles 21, comprising 20%-30% of the material, endows the coil surface with extremely high hardness, wear resistance, and high-temperature oxidation resistance, forming the first robust barrier against harsh external environments. This surface layer also contains a uniform distribution of multiple micron-sized microcapsules 31. When the coil develops microcracks due to thermal fatigue or external impact during service, the stress field at the crack tip preferentially tears apart the microcapsule shells 32 along their propagation path. This allows the encapsulated repair agent core 33, which is liquid at operating temperature (such as low-melting-point metallic glass or eutectic alloy), to be released. Through capillary action, the liquid repair agent rapidly… It automatically penetrates and fills the entire microcrack, then reacts with the fresh metal matrix inside the crack and solidifies, thereby achieving in-situ healing of the damage and effectively preventing the further propagation of the microcrack. In summary, this invention achieves perfect unity of high-temperature protection performance and room-temperature mechanical properties by organically combining and synergistically working the toughening of the core matrix 10, the interface stabilization of the functional gradient transition layer 20, and the surface toughening and intelligent damage repair of the in-situ self-healing composite surface layer 30. This endows traditional hot-rolled coils with unprecedented environmental adaptability, damage tolerance and reliability, and significantly extends their service life.

Claims

1. A high-temperature resistant hot-rolled coil, characterized in that, The cross-sectional structure of the high-temperature resistant hot-rolled coil, from the inside out, includes: Strong and tough core matrix (10); A functional gradient transition layer (20) is integrally connected with the strong and tough core matrix (10). The functional gradient transition layer (20) contains high-temperature resistant ceramic nanoparticles (21), and the volume fraction of the high-temperature resistant ceramic nanoparticles (21) increases continuously outward along the thickness direction of the functional gradient transition layer (20). An in-situ self-healing composite surface layer (30) is integrally connected with the functional gradient transition layer (20), wherein multiple micron-sized microcapsules (31) are diffusely distributed in the in-situ self-healing composite surface layer (30).

2. The high-temperature resistant hot-rolled coil according to claim 1, characterized in that, The material of the high-temperature resistant ceramic nanoparticles (21) is at least one of titanium carbide, silicon carbide or aluminum oxide.

3. The high-temperature resistant hot-rolled coil according to claim 1, characterized in that, In the functional gradient transition layer (20), the volume fraction of the high-temperature resistant ceramic nanoparticles (21) increases continuously from the interface between the functional gradient transition layer (20) and the tough core matrix (10), and the final value of the volume fraction of the high-temperature resistant ceramic nanoparticles (21) on the side of the functional gradient transition layer (20) close to the in-situ self-healing composite surface layer (30) is in the range of 15%-20%.

4. The high-temperature resistant hot-rolled coil according to claim 1, characterized in that, The in-situ self-healing composite surface layer (30) also contains the high-temperature resistant ceramic nanoparticles (21).

5. A high-temperature resistant hot-rolled coil according to claim 4, characterized in that, In the in-situ self-healing composite surface layer (30), the volume fraction of the high-temperature resistant ceramic nanoparticles (21) is 20%-30%.

6. The high-temperature resistant hot-rolled coil according to claim 1, characterized in that, The micron-sized microcapsule (31) includes a microcapsule shell (32) and a repair agent core (33) encapsulated by the microcapsule shell (32).

7. A high-temperature resistant hot-rolled coil according to claim 6, characterized in that, The material of the microcapsule shell (32) is niobium or molybdenum.

8. A high-temperature resistant hot-rolled coil according to claim 6, characterized in that, The core material of the repair agent (33) is a low-melting-point metallic glass or a low-eutectic-point alloy that is liquid at a preset working temperature.

9. A high-temperature resistant hot-rolled coil according to claim 8, characterized in that, The eutectic alloy is a tin-bismuth alloy or a zinc-aluminum alloy.

10. A high-temperature resistant hot-rolled coil according to claim 1, characterized in that, The tough core matrix (10) is made of high-strength low-alloy steel or bainitic steel.

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