Large-thickness high-heat-stability high-temperature-wear-resistant steel and preparation method thereof

Abstract

The invention belongs to the technical field of steel and iron materials, and discloses large-thickness high-heat-stability high-temperature-wear-resistant steel and a preparation method thereof. The steel comprises the following components in percentage by weight: 0.35 to 0.40 percent of C, 1.2 to 1.7 percent of Si, 1.0 to 1.5 percent of Mn, 2.1 to 3.0 percent of Cr, 0.7 to 1.0 percent of Mo, 0.4 to 0.6 percent of Ti, 0.8 to 1.3 percent of W, less than or equal to 0.005 percent of S, less than or equal to 0.003 percent of P and the balance of Fe and impurities. The mass ratio of Ti to C is 1.2-1.6, the ratio of Cr to Mo is 3: 1-5: 1, and Si and W form a synergistic anti-softening mechanism. The steel is subjected to air cooling after rolling, quenching and tempering treatment to form a martensite-TiC composite structure, and the structure in the thickness direction is uniform. At room temperature, the tensile strength is not less than 1600MPa, the hardness is not less than 550HV, the impact energy is not less than 20J, and the ductility is not less than 9%; and the wear resistance at 550 DEG C is improved by more than two times compared with the traditional NM450.

Description

Technical Field

[0001] The present invention relates to the technical field of steel materials, and in particular to a high-thickness, high-thermal-stability, high-temperature wear-resistant steel and a preparation method thereof. Background Art

[0002] High-temperature wear is widely present in industrial working conditions such as metallurgical equipment, mining machinery, heat treatment furnaces, and wear-resistant liners. The service temperature usually exceeds 400°C, and in some areas it even reaches over 550°C. In such a high-temperature service environment, the material must not only withstand complex loads and high-frequency abrasive impact, but also must have excellent thermal stability and softening resistance. Since steel materials have both good processing performance and cost advantages, they are still the mainstream choice for high-temperature wear components. Therefore, the development of a high-thermal stability wear-resistant steel that has high-temperature hardness retention, oxidation resistance and wear resistance has become an important research direction in this field.

[0003] Most of the existing high-temperature wear-resistant steels are based on medium-carbon low-alloy systems, and alloying elements such as Cr, Mo, and W are added to improve the tendency to soften in the heat. However, there are still obvious deficiencies in the construction of strengthening mechanisms and the control of thermal stability of the organization. For example, CN115595512A adopts a low-alloy system design, and cooperates with tempering treatment to improve the toughness and thermal stability of the material. This invention mainly relies on the dispersion and precipitation of carbides during the tempering process for strengthening, but does not systematically construct a particle strengthening mechanism with high-temperature stability. Its organizational retention ability is limited, and it is difficult to adapt to more stringent high-temperature service environments. CN107881415A proposes to use a composite precipitation phase of nano-scale (Ti, Mo) C and VC to achieve high-temperature hardness retention. Its organization is a single martensite, and the source of the strengthening phase is complex. Unlike the present invention, this technical solution does not precisely control the source and composition of the strengthening phase, and does not systematically construct a particle-matrix synergistic mechanism. The present invention achieves in-situ precipitation of TiC particles by controlling the Ti / C ratio, and suppresses dislocation recovery behavior and carbide coarsening through Cr and Mo, significantly improving the thermal stability and mechanical properties of the material at high temperatures. CN103205650A adopts a multi-element design of medium-low carbon and Cr-Mo-VW-RE, and forms a V-series precipitation phase through high-temperature tempering to enhance high-temperature performance. Although its alloy system is relatively complex, the type of strengthening phase is unclear, making it difficult to achieve precise control of high-temperature service performance. This is essentially different from the present invention's strategy of strengthening the dominant role of TiC and regulating particles with high interface bonding.

[0004] In general, the existing technologies still have common problems in the following aspects: the strengthening phase is mainly coarse M-type carbides, the particles have poor thermal stability, and are prone to coarsening or falling off at high temperatures; there is a lack of control over the interface bonding between particles and the matrix, and they cannot effectively bear high-temperature loads; the alloying elements have not formed a systematic synergistic mechanism, and it is difficult to balance organizational stability and strengthening efficiency; the process adaptability or component cost is poor, which affects its large-scale engineering application.

[0005] Therefore, how to construct a strengthening mechanism with particle stability, interface coordination and alloy synergistic effect to improve the mechanical properties and organizational stability of steel under medium and high temperature conditions is still one of the key technical problems that need to be solved urgently in the field of high-temperature wear-resistant steel, and it is also an important direction for future research on high-performance high-temperature wear-resistant steel. Summary of the Invention

[0006] The present invention aims to address the reliability issues of existing low-alloy wear-resistant steels during high-temperature service, resulting from particle failure, structural softening, and mechanical property degradation. This overcomes key bottlenecks such as poor thermal stability, TiC particle coarsening, and interface instability under high-temperature, high-wear conditions. By optimizing the design of alloying elements such as Ti, Cr, Mo, Si, and W, and synergistically controlling the in-situ precipitation behavior of TiC particles and the thermal stability regulation mechanism, combined with staged cooling and a rational heat treatment process path, the present invention constructs a multi-scale reinforced structure and high-temperature stable microstructure with TiC at its core, achieving excellent mechanical properties and wear resistance stability for thick and large-sized steels in medium- and high-temperature service environments.

[0007] The technical solution of the present invention is as follows: a thick, high-thermal-stability, high-temperature wear-resistant steel, the chemical composition of which comprises, by mass percentage, C: 0.35% to 0.40%, Si: 1.2% to 1.7%, Mn: 1.0% to 1.5%, Cr: 2.1% to 3.0%, Mo: 0.7% to 1.0%, Ti: 0.4% to 0.6%, W: 0.8% to 1.3%, S≤0.005%, P≤0.003%, and the remainder is Fe and unavoidable impurities; the mass ratio of Ti to C is 1.2 to 1.6, and TiC particles are in-situ precipitated through a continuous casting solidification process to form a dispersion-strengthened structure with a particle size of 0.1 μm to 3.0 μm and a bimodal distribution characteristic, wherein the TiC particles are the main strengthening phase.

[0008] Cr and Mo are set in a mass ratio of 3:1 to 5:1 to synergistically regulate the interface bonding strength and thermal stability of TiC particles.

[0009] Si and W form a thermal stability control platform, with a total synergistic addition percentage of 2.0% to 3.0%. Si reduces the diffusion rate of carbon atoms through grain boundary segregation, while W enhances the red hardness and failure resistance of TiC by forming (Ti, W)C composite carbides. The two elements synergistically create a thermal stability control platform at the microstructural level, ensuring that TiC particles maintain their effective strengthening effect at 550°C, maintaining a hardness retention rate of at least 85% at high temperatures.

[0010] During the solidification process, TiC particles form a bimodal distribution structure through staged cooling rate control. The cooling rate in the initial solidification stage is 1.5℃ / s~3.0℃ / s, generating large TiC particles with a particle size of 1.0μm~3.0μm, accounting for 35%~50% of the total; the cooling rate in the final solidification stage is 0.3℃ / s~0.8℃ / s, forming small TiC particles with a particle size of 0.1μm~0.5μm, accounting for 30%~40% of the total. Large TiC particles provide high-temperature load support, while small TiC particles inhibit grain growth and microstructure coarsening.

[0011] Cr and Mo form enriched areas in the matrix, which regulate the alloy environment around TiC particles, reduce the interfacial chemical potential and enhance the interfacial bonding strength, inhibit the dissolution-reprecipitation, dislocation recovery and carbide coarsening behavior of TiC particles, and enhance its high-temperature dimensional stability.

[0012] Si reduces the carbon diffusion rate through solid solution strengthening and grain boundary segregation, while W forms composite carbides with Ti to improve the red hardness and thermal stability of TiC. The two work together to build a thermal stability control platform to prevent TiC from coarsening and failure in high temperature environments.

[0013] The thick, high-thermal-stability, high-temperature-wear-resistant steel is suitable for thickness specifications of 80 mm to 120 mm, and obtains a martensite-TiC composite structure with uniform structure in the thickness direction and uniform distribution of strengthening particles.

[0014] The thick, high-thermal-stability, high-temperature-wear-resistant steel has a tensile strength of ≥1600 MPa, a hardness of ≥550 HV, an impact energy of ≥20 J, and an elongation after fracture of ≥9% at room temperature, and a hardness retention rate at a high temperature of 550°C of not less than 85% relative to the hardness at room temperature.

[0015] A method for preparing high-thickness, high-thermal stability, high-temperature wear-resistant steel, comprising the following specific steps:

[0016] S1. Smelting and continuous casting: Molten steel is obtained by melting according to the set composition. The molten steel is kept at 1600℃~1650℃ and then continuously cast to obtain a continuously cast slab. By controlling the solidification cooling rate, TiC particles are precipitated and dispersed in situ during the solidification process; by controlling the solidification cooling rate, the cooling rate in the initial solidification stage is 1.5℃ / s~3.0℃ / s, generating large TiC particles with a particle size of 1.0μm~3.0μm, and the cooling rate in the final solidification stage is 0.3℃ / s~0.8℃ / s, forming small TiC particles with a particle size of 0.1μm~0.5μm; the initial solidification stage refers to the stage when the metal begins to transform from liquid to solid, and the temperature is close to the liquidus; the final solidification stage refers to the stage when most of the metal has transformed from liquid to solid, and the remaining liquid metal gradually completes solidification and finally transforms into solid, and the temperature is close to the solidus.

[0017] S2. Homogenization and hot rolling: The obtained continuous casting slab is homogenized at 1150°C to 1250°C and hot rolled by controlled rolling; the final rolling temperature is controlled at 880°C to 920°C, and the slab is air-cooled after rolling with an average cooling rate controlled at 0.5°C / s to 1.0°C / s;

[0018] S3, quenching treatment: heat the hot-rolled plate to 880°C to 920°C, heat it to 600°C at a heating rate of 100°C / h, then heat it to the target temperature at a heating rate of 200°C / h, keep it at that temperature for 3 minutes per millimeter of plate thickness, and then quickly cool it to room temperature with water to obtain a quenched plate;

[0019] S4. Tempering treatment: Heat the quenched plate to 180℃~220℃, keep it warm for 2 minutes per millimeter of plate thickness, and then air cool it to obtain thick, high-temperature wear-resistant steel with high thermal stability.

[0020] The present invention uses TiC particles as the main reinforcement phase, and achieves precise control of their particle size, quantity, and distribution through controlling the composition ratio and regulating the solidification behavior, thereby constructing a dual-peak strengthening mechanism centered on "load sharing and structural pinning." The specific principles are as follows:

[0021] (1) Ti / C ratio regulation of in-situ precipitation behavior: A relatively excessive Ti content (Ti / C of 1.2–1.6) ensures the formation of stable TiC in-situ particles during solidification, thus avoiding delayed precipitation, uneven size, or agglomeration in the later stages.

[0022] (2) Solidification thermodynamics and cooling rate segmented control mechanism: By regulating the solidification cooling rate in stages (fast cooling in the early stage and slow cooling in the final stage), TiC is induced to precipitate in the form of different particle sizes at the grain boundaries / inside the grains, forming two main peaks of 0.1μm~0.5μm and 1.0μm~3.0μm, meeting the multi-scale strengthening requirements.

[0023] (3) Cr-Mo microalloy enrichment synergistic mechanism: Cr and Mo form enrichment areas around TiC particles, regulating the interfacial carbon diffusion and binding energy, improving the interfacial stability and dimensional stability of TiC particles by reducing the carbon potential and strain energy, and inhibiting their dissolution and coarsening at high temperatures.

[0024] (4) Si-W thermal stability co-control mechanism: Si solid solution strengthens the matrix and inhibits carbon migration; W partially enters the TiC lattice to form a stable (Ti, W)C composite carbide, which improves the particle's resistance to softening and high-temperature instability. The two work synergistically at the microstructural level to construct a stable particle-matrix system.

[0025] (5) Integrated design of microstructure control paths: Through controlled rolling-air cooling-quenching-tempering and other paths, the uniformity of TiC particle distribution and consistency of microstructure direction are effectively guaranteed, the problem of microstructure performance degradation in the center of thick steel plates is avoided, and the overall service consistency is improved.

[0026] Beneficial effects of the present invention:

[0027] (1) Precise control of particle distribution and significant improvement in service performance: The bimodal distribution structure of TiC particles in the thick, high-temperature wear-resistant steel with high thermal stability is clear, the quantity is controlled, and the strengthening mechanism is clear, so that the thick, high-temperature wear-resistant steel with high thermal stability still has good strength and wear resistance at 550℃, achieving dual optimization of organizational stability and mechanical properties.

[0028] (2) Excellent high-temperature dimensional stability: Under the control of the multi-element alloy system, TiC particles are not easy to coarsen, dissolve or become unstable at the interface during high-temperature service, which significantly delays the thermal softening process of the material and improves service reliability and life.

[0029] (3) Suitable for thick plates with strong uniformity of structure: Through reasonable controlled rolling and heat treatment system, good consistency of structure in thickness direction can be obtained even in thick plates with a thickness of 80mm to 120mm, overcoming the problem of softening or deterioration of structure in the center of traditional wear-resistant steel thick plates.

[0030] (4) Outstanding comprehensive performance and high industrial application value: The material has excellent room temperature strength, hardness and toughness, and its high temperature wear resistance is more than 2 times higher than that of conventional NM450. It is particularly suitable for key components in metallurgical equipment, mining machinery, high temperature transportation and other medium and high temperature wear conditions, and has good prospects for engineering promotion. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 Schematic diagram of Example 1; (a) is a SEM image of the steel plate of Example 1, and (b) is a TEM image of the steel plate of Example 1;

[0032] Figure 2Schematic diagram of Comparative Example 1; (a) is a SEM image of the steel plate of Comparative Example 1, and (b) is a TEM image of the steel plate of Comparative Example 1;

[0033] Figure 3 This is the SEM image of Example 1 of the present invention after being kept at 550°C;

[0034] Figure 4 This is the SEM image of comparative example 1 of the present invention after being kept warm at 550°C. DETAILED DESCRIPTION

[0035] Example 1 (120 mm thick steel plate);

[0036] This embodiment provides a thick, high-temperature wear-resistant steel with high thermal stability and a preparation method thereof. The steel plate has a thickness of 120 mm. The steel's chemical composition (by mass percentage) is: C: 0.40%, Si: 1.7%, Mn: 1.5%, Cr: 3.0%, Mo: 1.0%, Ti: 0.6%, W: 1.3%, S ≤ 0.005%, P ≤ 0.003%, with the remainder being Fe and unavoidable impurities. The Ti / C mass ratio is 1.5, meeting the requirement for controlling the proportion of in-situ TiC particles.

[0037] The preparation process is as follows:

[0038] (1) Smelting and continuous casting:

[0039] Molten steel is obtained by melting according to the set composition. The molten steel is kept at 1620°C and then continuously cast into continuous casting slabs. By controlling the cooling rate at the initial solidification stage to 1.5°C / s to 3.0°C / s and the cooling rate at the final solidification stage to 0.3°C / s to 0.8°C / s, TiC particles are precipitated in situ during the solidification process, forming a bimodal distribution structure of 0.1μm to 3.0μm.

[0040] (2) Homogenization and hot rolling:

[0041] The continuous casting slab is heated to 1200°C and kept at this temperature for 3 hours before being subjected to controlled rolling to obtain a hot rolled plate. The final rolling temperature is 920°C, and the plate is air-cooled after rolling. The average cooling rate is controlled at 0.5°C / s to 1.0°C / s.

[0042] (3) Quenching treatment:

[0043] The hot-rolled plate was heated to 920°C in a two-stage heating method, firstly to 600°C at a heating rate of 100°C / h, and then to the target temperature at a heating rate of 200°C / h. After being kept at a constant temperature for 360 minutes, it was water-cooled to room temperature to obtain a quenched plate.

[0044] (4) Tempering treatment:

[0045] The quenched plate was heated to 200°C, kept at this temperature for 240 minutes and then air-cooled to form a composite strengthening structure with martensite as the matrix and TiC particles dispersed.

[0046] The microstructure is tempered martensite and TiC particles. The TiC particle size shows a bimodal distribution, with 0.1μm~0.5μm particles accounting for about 35% and 1.0μm~3.0μm particles accounting for about 48%, which are evenly distributed in the grain boundaries and subgrain boundaries.

[0047] Room temperature properties: tensile strength 1865MPa, elongation 9.4%, hardness 562HV, impact energy 21J;

[0048] High temperature performance (550℃): tensile strength 767MPa, elongation 38%, hardness 493HV, impact energy 37J, hardness retention rate 87.7%.

[0049] Example 2 (100 mm thick steel plate);

[0050] This example uses a 100 mm thick sample with the following chemical composition: C: 0.37%, Si: 1.5%, Mn: 1.3%, Cr: 2.5%, Mo: 0.8%, Ti: 0.5%, W: 1.0%, S≤0.005%, P≤0.003%, with the remainder being Fe and unavoidable impurities; the Ti / C mass ratio is 1.35.

[0051] The preparation process is the same as that in Example 1, with only the parameters adjusted appropriately:

[0052] The finishing temperature is 900°C; the target temperature of the quenching treatment is 900°C, and the holding time is 300 minutes; the heating temperature of the tempering treatment is 200°C, and the holding time is 200 minutes.

[0053] After testing, the microstructure is tempered martensite and TiC particles. The TiC particles have a bimodal distribution, with 0.1μm~0.5μm particles accounting for about 37% and 1.0μm~3.0μm particles accounting for about 46%, which are evenly distributed in the grain boundaries and subgrain boundaries.

[0054] Room temperature properties: tensile strength 1816MPa, elongation 9.9%, hardness 571HV, impact energy 25J;

[0055] High temperature performance (550℃): tensile strength 793MPa, elongation 39%, hardness 494HV, impact energy 35J, hardness retention rate about 86.5%.

[0056] Example 3 (80 mm thick steel plate);

[0057] The sample thickness of this example was 80 mm, used to verify the structural uniformity and performance consistency of the present invention at medium thickness. The steel chemical composition was as follows: C: 0.35%, Si: 1.2%, Mn: 1.0%, Cr: 2.1%, Mo: 0.7%, Ti: 0.4%, W: 0.8%, S ≤ 0.005%, P ≤ 0.003%, with the balance being Fe; the Ti / C mass ratio was 1.43.

[0058] The preparation process is the same as that in Example 1, with only the parameters adjusted appropriately:

[0059] The final rolling temperature is 880°C; the target temperature of the quenching treatment is 880°C, and the holding time is 240 minutes; the heating temperature of the tempering treatment is 180°C, and the holding time is 160 minutes.

[0060] After testing, the microstructure is tempered martensite and TiC particles. The TiC particles have a bimodal distribution, with 0.1μm~0.5μm particles accounting for about 38% and 1.0μm~3.0μm particles accounting for about 42%, which are evenly distributed in the grain boundaries and subgrain boundaries.

[0061] Room temperature properties: tensile strength 1886MPa, elongation 10.4%, hardness 568HV, impact energy 24J;

[0062] High temperature performance (550℃): tensile strength 783MPa, elongation 37%, hardness 497HV, impact energy 38J, hardness retention rate 87.5%.

[0063] Comparative Example 1 (Ti element is removed and TiC strengthening phase is not generated);

[0064] This comparative example is consistent with the composition and process of Example 2, except that the Ti element is not added, and the TiC in-situ strengthening phase cannot be formed. The final structure is a single martensite. Due to the lack of the TiC strengthening phase, the final structure is mainly martensite, and the strengthening ability is limited.

[0065] Performance tests showed that at room temperature, the tensile strength was 1315 MPa, the elongation after fracture was 12.5%, the surface hardness was 446 HV, and the impact energy was 42 J. At 550°C, the tensile strength was 567 MPa, the elongation after fracture was 41%, the surface hardness was 308 HV, and the impact energy was 65 J. Due to the failure of the reinforcement phase and the softening of the structure, the plasticity is enhanced, and the impact toughness increases at high temperatures.

[0066] Comparative Example 2 (Ti / C ratio is lower than 1.2, and the in-situ precipitation strengthening effect is insufficient);

[0067] In this comparative example, the C content is 0.35%, the Ti content is reduced to 0.2%, the Ti / C ratio is reduced to 0.57, and other conditions are the same as those in Example 2. Due to the insufficient Ti / C ratio, the amount of TiC precipitation is small and the strengthening effect is not obvious.

[0068] According to performance tests, at room temperature, the tensile strength is 1436MPa, the elongation after fracture is 10.3%, the surface hardness is 488HV, and the impact energy is 26J; at 550℃, the tensile strength is 601MPa, the elongation after fracture is 37%, the surface hardness is 329HV, and the impact energy is 66J.

[0069] Comparative Example 3 (Ti / C ratio is higher than 1.6, and TiC size grows abnormally);

[0070] In this comparative example, the C content is 0.4%, the Ti content is 0.8%, the Ti / C ratio is increased to 2.0, and other conditions are the same as those in Example 2. Due to the increase in the Ti / C ratio, the TiC carbides are larger in size and no bimodal structure is produced, which has excellent hardness, but significantly reduces strength and toughness.

[0071] According to performance tests, at room temperature, the tensile strength is 1329MPa, the elongation after fracture is 8.4%, the surface hardness is 516HV, and the impact energy is 14J; at 550℃, the tensile strength is 524MPa, the elongation after fracture is 31%, the surface hardness is 447HV, and the impact energy is 46J.

[0072] Comparative Example 4 (Insufficient Cr and Mo content, poor high-temperature structural stability);

[0073] In this comparative example, the Cr content is reduced to 0.8% and the Mo content is reduced to 0.15%, and other conditions are consistent with those of Example 2. Due to insufficient alloying elements, the temper softening resistance is poor and the strengthening phase stability is reduced.

[0074] According to performance tests, at room temperature, the tensile strength is 1348MPa, the elongation after fracture is 9.6%, the surface hardness is 471HV, and the impact energy is 19J; at 550℃, the tensile strength is 476MPa, the elongation after fracture is 49%, the surface hardness is 287HV, and the impact energy is 69J.

[0075] Comparative Example 5 (W element removed, high temperature performance decreased);

[0076] In this comparative example, W element was not added, and other components and heat treatment were consistent with those in Example 2. Due to the lack of W's inhibitory effect on the matrix softening behavior, the high-temperature performance was reduced.

[0077] According to performance tests, at room temperature, the tensile strength is 1407MPa, the elongation after fracture is 13.9%, the surface hardness is 478HV, and the impact energy is 26J; at 550℃, the tensile strength is 446MPa, the elongation after fracture is 53%, the surface hardness is 256HV, and the impact energy is 57J.

[0078] A high-temperature reciprocating sliding wear test was carried out on an Rtec MFT-5000 friction and wear testing machine. Examples 1 to 3, comparative examples 1 to 5 and conventional NM450 wear-resistant steel were processed into wear test specimens with a size of 40×10×4 mm. Silicon nitride ceramic balls with high thermal stability were selected for the grinding balls, and the size of the grinding balls was 9.525 mm. Three typical temperatures of 25°C, 300°C and 550°C were selected for the experimental temperature. The sample was heated to the target temperature and kept warm for 20 minutes to make the sample temperature uniform. The load applied in the reciprocating sliding test was 100 N, the frequency was 1 Hz, the scratch length was 10 mm, and the time was 60 minutes. The average value of the three experimental results was taken as the experimental value, and the experimental results are shown in Table 1.

[0079] Table 1 High temperature wear test results

[0080]

[0081] The above description is only a preferred embodiment of the present invention, which is intended to illustrate the principles of the present invention rather than to limit the present invention. Any equivalent transformation, alternative or optimization improvement made within the spirit and technical concept of the present invention shall be deemed to be included in the protection scope of the present invention. The present invention is not limited to the process parameters or component ratios shown in the specific embodiments. Any reasonable adjustment based on the technical ideas of the present invention, if it can achieve the same or similar technical effects as the present invention, shall be protected by the claims of the present invention.

Claims

1. A thick, high-thermal-stability, high-temperature-wear-resistant steel, characterized in that: The chemical composition of the thick, high-thermal-stability, high-temperature-wear-resistant steel includes, by mass percentage, C: 0.35% to 0.40%, Si: 1.2% to 1.7%, Mn: 1.0% to 1.5%, Cr: 2.1% to 3.0%, Mo: 0.7% to 1.0%, Ti: 0.4% to 0.6%, W: 0.8% to 1.3%, S≤0.005%, P≤0.003%, with the remainder being Fe and unavoidable impurities; the mass ratio of Ti to C is 1.2 to 1.6, and in-situ precipitation of TiC particles is achieved through a continuous casting solidification process, forming a dispersion-strengthened structure with a particle size of 0.1 μm to 3.0 μm and a bimodal distribution characteristic, with TiC particles as the main strengthening phase.

2. The thick, high-thermal-stability, high-temperature-wear-resistant steel according to claim 1, characterized in that: Cr and Mo are set in a mass ratio of 3:1 to 5:1 to synergistically regulate the interface bonding strength and thermal stability of TiC particles.

3. The thick, high-thermal-stability, high-temperature-wear-resistant steel according to claim 1, characterized in that: Si and W construct a thermal stability control platform, and the total mass percentage of synergistic addition is 2.0%~3.0%.

4. The thick, high-thermal-stability, high-temperature-wear-resistant steel according to claim 1, characterized in that: During the solidification process, TiC particles are controlled by staged cooling rates to form a bimodal distribution structure. The cooling rate in the initial solidification stage is 1.5℃ / s~3.0℃ / s, generating large TiC particles with a particle size of 1.0μm~3.0μm, accounting for 35%~50% of the total; the cooling rate in the final solidification stage is 0.3℃ / s~0.8℃ / s, forming small TiC particles with a particle size of 0.1μm~0.5μm, accounting for 30%~40% of the total.

5. The thick, high-thermal-stability, high-temperature-wear-resistant steel according to claim 1, characterized in that: The thick, high-thermal-stability, high-temperature-wear-resistant steel is suitable for thickness specifications of 80 mm to 120 mm, and obtains a martensite-TiC composite structure with uniform structure in the thickness direction and uniform distribution of strengthening particles.

6. The thick, high-thermal-stability, high-temperature-wear-resistant steel according to claim 1, characterized in that: The thick, high-thermal-stability, high-temperature-wear-resistant steel has a tensile strength of ≥1600 MPa, a hardness of ≥550 HV, an impact energy of ≥20 J, and an elongation after fracture of ≥9% at room temperature, and a hardness retention rate at a high temperature of 550°C of not less than 85% relative to the hardness at room temperature.

7. A method for preparing thick, high-thermal-stability, high-temperature-wear-resistant steel according to any one of claims 1 to 6, characterized in that: The specific steps are as follows: S1. Smelting and continuous casting: Molten steel is obtained by melting according to the set composition. The molten steel is kept at 1600℃~1650℃ and then continuously cast to obtain a continuously cast slab. By controlling the solidification cooling rate, TiC particles are precipitated and dispersed in situ during the solidification process; S2. Homogenization and hot rolling: The obtained continuous casting slab is homogenized at 1150°C to 1250°C and hot rolled by controlled rolling; the final rolling temperature is controlled at 880°C to 920°C, and the slab is air-cooled after rolling with an average cooling rate controlled at 0.5°C / s to 1.0°C / s; S3, quenching treatment: heat the hot-rolled plate to 880°C to 920°C, heat it to 600°C at a heating rate of 100°C / h, then heat it to the target temperature at a heating rate of 200°C / h, keep it at that temperature for 3 minutes per millimeter of plate thickness, and then quickly cool it to room temperature with water to obtain a quenched plate; S4. Tempering treatment: Heat the quenched plate to 180℃~220℃, keep it warm for 2 minutes per millimeter of plate thickness, and then air cool it to obtain thick, high-temperature wear-resistant steel with high thermal stability.

8. The method for preparing thick, high-thermal-stability, high-temperature-wear-resistant steel according to claim 7, characterized in that: The controlling of the solidification cooling rate is specifically as follows: the cooling rate in the initial solidification stage is 1.5°C / s to 3.0°C / s, and the cooling rate in the final solidification stage is 0.3°C / s to 0.8°C / s.

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