A high-performance cemented carbide wear-resistant steel ball and its application

Abstract

This invention belongs to the field of wear-resistant materials technology, and provides a high-performance cemented carbide wear-resistant steel ball and its application. This invention uses an alloy steel matrix containing elements such as C, Cr, Ni, Mo, V, Ti, and B, and constructs Cr7C3 and Cr... at the grain boundaries. 23 A continuous network of interconnected C6 nanofibers, 0.08–0.15 μm thick, with a volume fraction of 6.0–12.0 vol%, is formed by the in-situ precipitation of 30–60 nm TiC and VC nanoceramic particles within the grains, with a volume fraction of 2.0–4.5 vol%. This results in a composite reinforcement structure combining grain boundary strengthening and dispersion strengthening. The material is prepared through powder granulation coating and two-stage hot isostatic pressing sintering, achieving a significant improvement in strength and wear resistance. The alloy steel grain size is 0.5–1.5 μm, the sintering temperature is 1150–1210℃, and the aging temperature is 800–1000℃. This design solves the problem of insufficient performance of existing cemented carbide wear-resistant steel balls and has significant application value in mining grinding.

Description

Technical Field

[0001] This invention belongs to the field of wear-resistant materials technology, specifically relating to a high-performance cemented carbide wear-resistant steel ball and its application. Background Technology

[0002] With the rapid development of modern industry, the performance requirements for wear-resistant steel balls in mineral processing, ball milling, and pulverizing fields are becoming increasingly stringent. This is especially true in high-strength grinding equipment such as large ball mills and autogenous mills, where wear-resistant steel balls, as the core grinding media, endure extremely harsh working environments. During mineral processing, wear-resistant steel balls need to withstand high-frequency impact loads, intense wear, and complex stress states for extended periods, placing extremely high demands on the material's mechanical and wear-resistant properties. Excellent strength is fundamental to ensuring that wear-resistant steel balls do not fracture under high impact loads, while superior wear resistance is crucial for maintaining dimensional stability and grinding efficiency during long-term use. Simultaneously, with the continuous increase in mineral hardness and processing volume, traditional wear-resistant steel balls are prone to excessive wear and short service life during operation, severely impacting production efficiency and economic benefits. Therefore, developing new types of cemented carbide wear-resistant steel balls with high strength and excellent wear resistance is of great significance for improving the working efficiency of grinding equipment, reducing operating costs, and promoting technological progress in related industries.

[0003] The development of cemented carbide wear-resistant steel balls currently faces a major technical bottleneck in coordinating and optimizing strength and wear resistance. Existing technologies have significant limitations in terms of material microstructure design and manufacturing processes. Traditional cemented carbide wear-resistant steel balls typically employ single alloying strengthening or simple carbide dispersion strengthening strategies. This design approach struggles to achieve excellent wear resistance while ensuring sufficient strength, primarily due to the lack of an effective multi-scale synergistic strengthening mechanism within the material. For example, Chinese patent CN106086602A discloses a production process for high-chromium alloy steel balls, but it suffers from uneven distribution of the strengthening phase and insufficient grain boundary bonding strength. Furthermore, the sintering parameters in existing manufacturing processes have limited control precision, making it difficult to accurately regulate the material's microstructure, resulting in the size, distribution, and morphology of the strengthening phase failing to reach optimal levels. Simultaneously, traditional single-stage heat treatment processes cannot effectively combine grain boundary strengthening and precipitation strengthening, making the material prone to failure at weak points under complex stress conditions. The root cause of these technical deficiencies lies in the lack of in-depth understanding of the strengthening mechanism of materials and systematic means of controlling the microstructure. Therefore, it is urgent to develop new material design concepts and preparation technologies to break through existing performance bottlenecks. Summary of the Invention

[0004] (1) Technical problems to be solved

[0005] The purpose of this invention is to provide a high-performance cemented carbide wear-resistant steel ball and its application, solving the problem of insufficient strength and wear resistance of current cemented carbide wear-resistant steel balls.

[0006] (2) Technical solution

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] A high-performance cemented carbide wear-resistant steel ball comprises a dense alloy steel matrix composed of alloy steel grains; the chemical composition of the alloy steel matrix, by mass percentage, is: C 0.6%-1.0%, Cr 2.2%-3.8%, Ni 3%-6%, Mo 0.2%-1.2%, V 0.15%-0.6%, Ti 0.05%-0.3%, B 0.25%-0.8%, Si 0.3%-0.9%, Mn 0.2%-0.8%, N 0.01%-0.08%, with the balance being Fe and unavoidable impurities;

[0009] The grain boundaries of the alloy steel grains contain Cr7C3 and / or Cr 23 A continuous network composed of C6, which is formed by interconnecting rod-shaped nanowhiskers or nanoparticles, has a thickness of 0.08μm-0.15μm and a three-dimensional volume fraction of 6.0vol%-12.0vol%. The network exhibits a honeycomb-like closed cell morphology in a two-dimensional cross-section.

[0010] In-situ self-generated nano-ceramic particles are distributed within the grains of the alloy steel. These nano-ceramic particles are one or more of TiC and VC, with an average particle size of 30nm-60nm and a volume fraction of 2.0vol%-4.5vol%.

[0011] The continuous grain boundary network coexists with the nano-ceramic particles but is not interconnected, forming a composite reinforcement structure that combines grain boundary strengthening and dispersion strengthening.

[0012] Furthermore, the average diameter of the rod-shaped nanocrystals is 15nm-25nm, and the average length is 60nm-120nm;

[0013] The nano-ceramic particles are mainly distributed within the grains rather than at the grain boundaries; the average grain size of the alloy steel grains is 0.5μm-1.5μm.

[0014] Furthermore, there is a thin chromium-rich transitional interface layer with a thickness of 2nm-4.5nm between Cr7C3 and / or Cr23C6 and the alloy steel matrix in the continuous network.

[0015] This invention employs a design combining multi-element alloying and multi-scale composite strengthening, primarily to enhance the strength and wear resistance of cemented carbide wear-resistant steel balls. By precisely controlling the composition ratios of alloying elements such as C, Cr, Ni, Mo, V, Ti, B, Si, Mn, and N, a dense alloy steel matrix is ​​constructed, laying a solid foundation for the subsequent formation of strengthening phases. At the grain boundaries, a layer composed of Cr7C3 and Cr... 23 The continuous network structure composed of C6, formed by the interconnection of rod-shaped nanowhiskers or nanoparticles to create a honeycomb-like closed cell morphology, effectively prevents crack propagation at grain boundaries and significantly improves the material's impact resistance. Simultaneously, in-situ self-generated nanoscale TiC and VC ceramic particles are present within the alloy steel grains. These hard phase particles are uniformly distributed within the grains, achieving dispersion strengthening by hindering dislocation movement. More importantly, the continuous grain boundary network and the nanoceramic particles employ a spatially isolated design, allowing grain boundary strengthening and dispersion strengthening mechanisms to work synergistically at different scales, avoiding the limitations of a single strengthening mechanism. Furthermore, Cr7C3 and Cr... 23 The thin, chromium-rich interfacial layer formed between C6 and the alloy steel matrix further optimizes the interfacial bonding strength between the reinforcing phase and the matrix, ensuring the effectiveness of stress transfer and thus achieving a significant improvement in the overall performance of the material.

[0016] A method for preparing a high-performance cemented carbide wear-resistant steel ball includes the following steps:

[0017] Step S1: Prepare alloy steel powder according to chemical composition, granulate the alloy steel powder to obtain powder clusters, and introduce a coating layer containing chromium precursor and carbon precursor on the surface of the clusters, wherein the amount of chromium precursor introduced is 0.6 wt%–1.0 wt%, and the molar ratio of chromium precursor to carbon precursor is 7:3–10:3.

[0018] Step S2: The coated powder clusters are subjected to hot isostatic pressing sintering at a temperature of 1150℃–1210℃, a pressure of 100 MPa–150 MPa, and a holding time of 2 h–4 h, to densify the powder clusters and form an alloy steel grain structure; and to allow the coating layer elements at the original inter-cluster interface positions to form Cr7C3 and / or Cr at the grain boundaries of the alloy steel grains. 23 A continuous network structure composed of C6, wherein the network is formed by interconnecting rod-shaped nanowhiskers and / or nanoparticles; at the same time, carbide-forming elements such as Ti and V are dissolved into the matrix to form a supersaturated solid solution;

[0019] Step S3: The sintered body is aged to allow Ti and V elements in the supersaturated solid solution to precipitate in situ within the grains, forming nano-ceramic particles.

[0020] Further, in step S1, the powder clusters are prepared by mixing alloy steel powder and binder at a mass ratio of 95:5-98:2 to form a slurry, followed by spray drying and granulation to form clusters. The drying air inlet temperature is 150℃-200℃, the feeding rate is 10mL / min-30mL / min, and the atomization pressure is 0.2 MPa-0.4 MPa. The average particle size of the obtained clusters is 50 μm-200 μm, and the binder is selected from polyvinyl alcohol, polyethylene glycol, or carboxymethyl cellulose.

[0021] Furthermore, in step S1, the chromium-containing precursor is selected from one of nano-chromium powder, chromium organic salt, or chromium oxide sol, and the carbon precursor is selected from one of phenolic resin or dopamine carbon source; the coating treatment adopts a wet coating process, with a coating temperature of 60℃–80℃ and a coating time of 2 h–4 h.

[0022] Furthermore, step S2 employs a two-stage hot isostatic pressing sintering process: the first stage involves holding the temperature at 1150℃–1170℃ for 1 h–2 h to achieve cluster densification and the formation of new grain boundaries; the second stage involves raising the temperature to 1180℃–1210℃ and holding it for a short period of 2 min–8 min to promote the segregation of Cr and C in the coating layer along the grain boundaries and the formation of a continuous network of interconnected rod-shaped nanowhiskers and / or nanoparticles; the entire sintering process is carried out under a protective atmosphere, which is argon or nitrogen.

[0023] Furthermore, in step S2, the heating rate is 10℃ / min–30℃ / min, and the pressure is 120 MPa–140 MPa; the cooling rate after sintering is controlled at 5℃ / min–20℃ / min.

[0024] Furthermore, the aging process in step S3 is characterized by an aging temperature of 800℃–1000℃ and a time of 2h–4h; a cooling rate of 5℃ / min–15℃ / min after aging; and the aging is carried out under an argon protective atmosphere.

[0025] Application of a high-performance cemented carbide wear-resistant steel ball in mining grinding media.

[0026] This invention employs a combination of powder granulation coating and staged heat treatment to enhance the strength and wear resistance of cemented carbide wear-resistant steel balls. By spray-drying and granulating alloy steel powder with binders such as polyvinyl alcohol, polyethylene glycol, or carboxymethyl cellulose, powder clusters of specific sizes are formed, providing an ideal carrier structure for subsequent coating. A coating layer containing chromium and carbon precursors is introduced onto the cluster surface. By precisely controlling the molar ratio of chromium precursors (such as nano-chromium powder, chromium organic salts, or chromium oxide sol) to carbon precursors (such as phenolic resin or dopamine carbon source), a material basis for the formation of grain boundary strengthening phases is established. The innovation of the two-stage hot isostatic pressing (HIP) sintering process lies in the densification of powder clusters and the formation of new grain boundaries in the first stage, and the promotion of Cr and C elements along the grain boundaries in the coating layer through short-time high-temperature treatment in the second stage, forming Cr7C3 and Cr2C3 interconnected by rod-shaped nanocrystals and nanoparticles. 23 The C6 continuous network structure is also present. During sintering, carbide-forming elements such as Ti and V dissolve into the matrix to form a supersaturated solid solution, creating conditions for subsequent aging precipitation. During aging treatment, Ti and V elements precipitate in situ within the grains, forming nano-ceramic particles. These particles, together with the continuous grain boundary network, construct a multi-scale composite strengthening system, enabling grain boundary strengthening and dispersion strengthening mechanisms to work in a coordinated manner, resulting in a significant improvement in the overall material performance.

[0027] (3) Beneficial technical effects

[0028] Significantly improves material strength and impact resistance: By constructing a structure of Cr7C3 and Cr at the grain boundaries of alloy steel. 23 The continuous network reinforcement structure composed of C6, which is formed by interconnected rod-shaped nanocrystals or nanoparticles to create a honeycomb-like closed cell morphology, can effectively prevent the initiation and propagation of cracks at grain boundaries. At the same time, the presence of a thin layer of transitional chromium-rich interface further optimizes the interfacial bonding strength between the reinforcing phase and the matrix, ensuring the effectiveness of stress transfer, thereby significantly improving the overall strength and impact resistance of the cemented carbide wear-resistant steel ball.

[0029] Significantly improves wear resistance and service life: By in-situ generating nano-sized TiC and VC ceramic particles inside the grains of alloy steel, these hard phase particles are uniformly distributed within the grains. By hindering dislocation movement, they achieve a dispersion strengthening effect, effectively improving the hardness and wear resistance of the material. At the same time, the nano-ceramic particles and the continuous network of grain boundaries adopt an unconnected spatial distribution design, avoiding excessive aggregation and embrittlement of the hard phase, and ensuring the stability and reliability of the material during long-term wear.

[0030] Achieving synergistic effects of multi-scale composite strengthening: Through the composite reinforcement structure design that combines grain boundary strengthening and dispersion strengthening, the two different strengthening mechanisms can work synergistically at different scale levels, avoiding the limitations of a single strengthening mechanism and achieving a comprehensive improvement in the mechanical properties of the material. At the same time, the precisely controlled alloy element composition ratio provides an ideal chemical environment for the formation of each strengthening phase, ensuring the maximization of the composite strengthening effect.

[0031] Optimizing the controllability and reproducibility of the preparation process: The preparation process, which combines powder granulation coating with staged heat treatment, achieves precise control over the microstructure of the material. The two-stage hot isostatic pressing sintering process ensures the orderly formation of the continuous grain boundary network and the uniform precipitation of nano-ceramic particles. At the same time, strict control of process parameters ensures the stability of product quality and batch-to-batch consistency, providing a reliable technical guarantee for industrial production. Attached Figure Description

[0032] Figure 1 This invention illustrates the effect of the amount of chromium-containing precursor introduced on hardness and impact toughness.

[0033] Figure 2 This invention relates to the effect of sintering temperature on hardness and wear rate.

[0034] Figure 3 This invention relates to the effect of aging temperature on wear rate and compressive strength.

[0035] Figure 4 This is a microscopic morphology image of the cemented carbide wear-resistant steel ball prepared in Example 2 of the present invention.

[0036] Figure 5 This is an EDX elemental analysis diagram of the continuous network of the cemented carbide wear-resistant steel ball prepared in Example 2 of the present invention.

[0037] Figure 6 The EDX elemental analysis diagram of the TiC nanoceramic particles in the cemented carbide wear-resistant steel ball prepared in Example 2 of this invention.

[0038] Figure 7 The image shows the XRD phase analysis of the cemented carbide wear-resistant steel ball prepared in Example 2 of this invention.

[0039] Figure 8 This is a microscopic morphology diagram of the cemented carbide wear-resistant steel ball of Embodiment 2 of the present invention.

[0040] Figure 9 This is a comparison chart of hardness and impact toughness between embodiments and comparative examples of the present invention.

[0041] Figure 10 This is a comparison chart of wear rate and compressive strength between embodiments and comparative examples of the present invention.

[0042] Figure 11 This is a comparison chart of the linear thermal expansion coefficient and hardness of the embodiments and comparative examples of the present invention.

[0043] Figure 12 This is a comparison diagram of impact toughness and compressive strength between embodiments and comparative examples of the present invention.

[0044] Figure 13 This is a comparison chart of wear rate and linear thermal expansion coefficient between embodiments and comparative examples of the present invention. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0046] Example 1: A high-performance cemented carbide wear-resistant steel ball, comprising a dense alloy steel matrix composed of alloy steel grains; the chemical composition of the alloy steel matrix in this example, by mass percentage, is: C 0.8%, Cr 3.0%, Ni 4.5%, Mo 0.7%, V 0.35%, Ti 0.18%, B 0.5%, Si 0.6%, Mn 0.5%, N 0.04%, with the balance being Fe and unavoidable impurities; at the grain boundaries of the alloy steel grains in this example, there are Cr7C3 and Cr... 23 The continuous network composed of C6, in this embodiment, is formed by interconnected rod-shaped nanowhiskers and nanoparticles, with a thickness of 0.11 μm and a three-dimensional volume fraction of 9.0 vol%. This network exhibits a honeycomb-like closed-cell morphology in a two-dimensional cross-section. In this embodiment, in-situ self-generated nanoceramic particles are distributed within the alloy steel grains. These nanoceramic particles are TiC and VC, with an average particle size of 45 nm and a volume fraction of 3.2 vol%. The grain boundary continuous network in this embodiment coexists with and is not interconnected with the nanoceramic particles, forming a composite reinforcement structure combining grain boundary strengthening and dispersion strengthening. The rod-shaped nanowhiskers in this embodiment have an average diameter of 20 nm and an average length of 90 nm. The nanoceramic particles in this embodiment are mainly distributed within the grains rather than at grain boundaries. The average grain size of the alloy steel grains in this embodiment is 1.0 μm. In this embodiment, Cr7C3 and Cr... 23 There is a thin chromium-rich interfacial layer with a thickness of 3.2 nm between C6 and the alloy steel matrix.

[0047] The preparation method of this embodiment includes the following steps: Step S1: Prepare alloy steel powder according to the chemical composition, granulate the alloy steel powder to obtain powder clusters, and introduce a coating layer containing chromium precursor and carbon precursor on the surface of the clusters, wherein the amount of chromium precursor introduced is 0.8wt%, and the molar ratio of chromium precursor to carbon precursor is 8:3; Step S2: Perform hot isostatic pressing sintering on the coated powder clusters, the sintering temperature is 1180℃, the pressure is 125MPa, and the holding time is 3h, so that the powder clusters are densified to form an alloy steel grain structure; and the coating layer elements at the original cluster interface position form Cr7C3 and Cr at the grain boundaries of the alloy steel grains. 23 The continuous network structure composed of C6, in this embodiment, is formed by interconnected rod-shaped nanocrystals and nanoparticles; simultaneously, carbide-forming elements such as Ti and V are dissolved into the matrix to form a supersaturated solid solution; step S3: the sintered body is subjected to aging treatment, causing Ti and V elements in the supersaturated solid solution to precipitate in situ within the grains to form nano-ceramic particles. In step S1, the powder clusters are prepared by mixing alloy steel powder and binder at a mass ratio of 96:4 to form a slurry, which is then spray-dried and granulated to form clusters. The drying inlet air temperature is 175℃, the feed rate is 20mL / min, and the atomization pressure is 0.3MPa; the average particle size of the resulting clusters is 125μm. In this embodiment, polyvinyl alcohol is used as the binder. In step S1, nano-chromium powder is used as the chromium precursor, and phenolic resin is used as the carbon precursor in this embodiment; the coating treatment adopts a wet coating process, with a coating temperature of 70℃ and a coating time of 3h. Step S2 employs a two-stage hot isostatic pressing sintering process: the first stage involves holding at 1160℃ for 1.5 hours to achieve cluster densification and the formation of new grain boundaries; the second stage involves heating to 1195℃ and holding for a short period of 5 minutes to promote the segregation of Cr and C in the coating layer along the grain boundaries and the formation of a continuous network of interconnected rod-shaped nanocrystals and nanoparticles. The entire sintering process is carried out under a protective atmosphere, which in this embodiment is argon. The heating rate in step S2 is 20℃ / min, and the pressure is 130 MPa; the cooling rate after sintering is controlled at 12℃ / min. Step S3 involves aging at 900℃ for 3 hours; the cooling rate after aging is 10℃ / min; the aging in this embodiment is carried out under an argon protective atmosphere.

[0048] This embodiment uses medium parameter configuration, which has good process stability and composition balance. It is suitable for mining ball milling operations under standard working conditions. While ensuring strength and wear resistance, it has high process reproducibility and is particularly suitable for mass production applications.

[0049] Example 2: A high-performance cemented carbide wear-resistant steel ball, comprising a dense alloy steel matrix composed of alloy steel grains; the chemical composition of the alloy steel matrix in this example, by mass percentage, is: C 0.6%, Cr 2.2%, Ni 3.0%, Mo 0.2%, V 0.15%, Ti 0.05%, B 0.25%, Si 0.3%, Mn 0.2%, N 0.01%, with the balance being Fe and unavoidable impurities; In this embodiment, the grain boundaries of the alloy steel grains contain a continuous network composed of Cr7C3. This continuous network is formed by interconnected rod-shaped nanofibers, with a thickness of 0.08 μm and a three-dimensional volume fraction of 6.0 vol%. The network exhibits a honeycomb-like closed-cell morphology in a two-dimensional cross-section. In this embodiment, in-situ self-generated nano-ceramic particles are distributed within the alloy steel grains. These nano-ceramic particles are TiC, with an average particle size of 30 nm and a volume fraction of 2.0 vol%. The continuous grain boundary network and the nano-ceramic particles coexist and are not interconnected, forming a composite reinforcement structure combining grain boundary strengthening and dispersion strengthening. The rod-shaped nanofibers in this embodiment have an average diameter of 15 nm and an average length of 60 nm. The nano-ceramic particles in this embodiment are mainly distributed within the grains rather than at grain boundaries. The average grain size of the alloy steel grains in this embodiment is 0.5 μm. A thin, 2.0 nm thick transition chromium-rich interface layer exists between the Cr7C3 and the alloy steel matrix in the continuous network of this embodiment.

[0050] The preparation method of this embodiment includes the following steps: Step S1: Prepare alloy steel powder according to the chemical composition, granulate the alloy steel powder to obtain powder clusters, and introduce a coating layer containing chromium precursor and carbon precursor on the surface of the clusters, wherein the amount of chromium precursor introduced is 0.6wt%, and the molar ratio of chromium precursor to carbon precursor is 7:3; Step S2: Perform hot isostatic pressing sintering on the coated powder clusters, the sintering temperature is 1150℃, the pressure is 100MPa, and the holding time is [not specified]. The process takes 2 hours to densify the powder clusters, forming an alloy steel grain structure. The coating elements at the original cluster interfaces form a continuous network structure of Cr7C3 at the grain boundaries of the alloy steel grains. In this embodiment, the network is formed by interconnected rod-shaped nanofibers. Simultaneously, carbide-forming elements such as Ti and V dissolve into the matrix to form a supersaturated solid solution. Step S3: The sintered body is aged to allow Ti and V elements in the supersaturated solid solution to precipitate in situ within the grains, forming nano-ceramic particles. In step S1, the powder clusters are prepared by mixing alloy steel powder and a binder at a mass ratio of 98:2 to form a slurry, which is then spray-dried and granulated to form clusters. The drying inlet air temperature is 150°C, the feed rate is 10 mL / min, and the atomization pressure is 0.2 MPa. The average particle size of the resulting clusters is 50 μm. In this embodiment, polyethylene glycol is used as the binder. In step S1, the chromium-containing precursor is a chromium organic salt, and in this embodiment, the carbon precursor is a dopamine carbon source. The coating process uses a wet coating method at a temperature of 60°C for 2 hours. Step S2 employs a two-stage hot isostatic pressing sintering: the first stage involves holding at 1150°C for 1 hour to achieve cluster densification and the formation of new grain boundaries; the second stage involves heating to 1180°C and holding for 2 minutes to promote the segregation of Cr and C along the grain boundaries in the coating layer and the formation of a continuous network of interconnected rod-shaped nanocrystals. The entire sintering process is carried out under a protective atmosphere, which in this embodiment is nitrogen. The heating rate in step S2 is 10°C / min, and the pressure is 120 MPa; the cooling rate after sintering is controlled at 5°C / min. Step S3 involves an aging treatment at 800°C for 2 hours; the cooling rate after aging is 5°C / min; the aging in this embodiment is carried out under an argon protective atmosphere.

[0051] This embodiment employs a low-alloy configuration and a fine grain structure design, exhibiting excellent toughness and impact resistance. It is suitable for coarse crushing operations under high impact loads, and is particularly suitable for processing mineral raw materials with high hardness, maximizing impact resistance while ensuring basic wear resistance.

[0052] Example 3: A high-performance cemented carbide wear-resistant steel ball, comprising a dense alloy steel matrix composed of alloy steel grains; the chemical composition of the alloy steel matrix in this example, by mass percentage, is: C 1.0%, Cr 3.8%, Ni 6.0%, Mo 1.2%, V 0.6%, Ti 0.3%, B 0.8%, Si 0.9%, Mn 0.8%, N 0.08%, with the balance being Fe and unavoidable impurities; at the grain boundaries of the alloy steel grains in this example, there are Cr... 23 The continuous network composed of C6, in this embodiment, is formed by interconnected nanoparticles with a thickness of 0.15 μm and a three-dimensional volume fraction of 12.0 vol%. This network exhibits a honeycomb-like closed-cell morphology in a two-dimensional cross-section. In this embodiment, in-situ self-generated nano-ceramic particles are distributed within the alloy steel grains. These nano-ceramic particles are VC, with an average particle size of 60 nm and a volume fraction of 4.5 vol%. The grain boundary continuous network and nano-ceramic particles coexist and are not interconnected, forming a composite reinforcement structure combining grain boundary strengthening and dispersion strengthening. The rod-shaped nanowhiskers in this embodiment have an average diameter of 25 nm and an average length of 120 nm. The nano-ceramic particles are mainly distributed within the grains rather than at grain boundaries. The average grain size of the alloy steel grains in this embodiment is 1.5 μm. In this embodiment, Cr... 23 There is a thin chromium-rich transitional interface layer with a thickness of 4.5 nm between C6 and the alloy steel matrix.

[0053] The preparation method of this embodiment includes the following steps: Step S1: Prepare alloy steel powder according to the chemical composition, granulate the alloy steel powder to obtain powder clusters, and introduce a coating layer containing chromium precursor and carbon precursor on the surface of the clusters, wherein the amount of chromium precursor introduced is 1.0 wt%, and the molar ratio of chromium precursor to carbon precursor is 10:3; Step S2: Perform hot isostatic pressing sintering on the coated powder clusters, the sintering temperature is 1210℃, the pressure is 150MPa, and the holding time is 4h, so that the powder clusters are densified to form an alloy steel grain structure; and the coating layer elements at the original cluster interface position form a chromium-containing coating layer at the grain boundaries of the alloy steel grains. 23The continuous network structure composed of C6, in this embodiment, is formed by interconnected nanoparticles; simultaneously, carbide-forming elements such as Ti and V are dissolved into the matrix to form a supersaturated solid solution; step S3: the sintered body is subjected to aging treatment, causing Ti and V elements in the supersaturated solid solution to precipitate in situ within the grains to form nano-ceramic particles. In step S1, the powder clusters are prepared by mixing alloy steel powder and binder at a mass ratio of 95:5 to form a slurry, which is then spray-dried and granulated to form clusters. The drying inlet air temperature is 200℃, the feed rate is 30mL / min, and the atomization pressure is 0.4MPa; the average particle size of the resulting clusters is 200μm. In this embodiment, carboxymethyl cellulose is used as the binder. In step S1, the chromium-containing precursor is chromium oxide sol, and in this embodiment, the carbon precursor is phenolic resin; the coating treatment adopts a wet coating process, with a coating temperature of 80℃ and a coating time of 4h. Step S2 employs a two-stage hot isostatic pressing sintering process: the first stage involves holding at 1170℃ for 2 hours to achieve cluster densification and the formation of new grain boundaries; the second stage involves heating to 1210℃ and holding for a short period of 8 minutes to promote the segregation of Cr and C in the coating layer along the grain boundaries and the formation of a continuous network of interconnected nanoparticles; the entire sintering process is carried out under a protective atmosphere, which in this embodiment is argon. The heating rate in step S2 is 30℃ / min, and the pressure is 140MPa; the cooling rate after sintering is controlled at 20℃ / min. Step S3 involves aging at 1000℃ for 4 hours; the cooling rate after aging is 15℃ / min; the aging in this embodiment is carried out under an argon protective atmosphere.

[0054] This embodiment adopts a high alloying and densely distributed reinforcing phase design, which has extremely high hardness and wear resistance. It is suitable for fine grinding operations with ultra-high wear resistance requirements, and is particularly suitable for processing extremely hard minerals and long-term continuous operation conditions, maximizing wear resistance while maintaining sufficient toughness.

[0055] Example 4: A high-performance cemented carbide wear-resistant steel ball, comprising a dense alloy steel matrix composed of alloy steel grains; the chemical composition of the alloy steel matrix in this example, by mass percentage, is: C 0.9%, Cr 2.8%, Ni 5.2%, Mo 0.9%, V 0.45%, Ti 0.22%, B 0.6%, Si 0.7%, Mn 0.6%, N 0.06%, with the balance being Fe and unavoidable impurities; at the grain boundaries of the alloy steel grains in this example, there are Cr7C3 and Cr... 23The continuous network composed of C6, in this embodiment, is formed by interconnected rod-shaped nanowhiskers, with a thickness of 0.12 μm and a three-dimensional volume fraction of 10.5 vol%. This network exhibits a honeycomb-like closed-cell morphology in a two-dimensional cross-section. In this embodiment, in-situ self-generated nano-ceramic particles are distributed within the alloy steel grains. These nano-ceramic particles are TiC and VC (mass ratio 6:4), with an average particle size of 50 nm and a volume fraction of 3.8 vol%. The grain boundary continuous network in this embodiment coexists with and is not interconnected with the nano-ceramic particles, forming a composite reinforcement structure combining grain boundary strengthening and dispersion strengthening. The rod-shaped nanowhiskers in this embodiment have an average diameter of 22 nm and an average length of 105 nm. The nano-ceramic particles in this embodiment are mainly distributed within the grains rather than at grain boundaries. The average grain size of the alloy steel grains in this embodiment is 1.2 μm. In this embodiment, Cr7C3 and Cr... 23 There is a thin chromium-rich transitional interface layer with a thickness of 3.8 nm between C6 and the alloy steel substrate.

[0056] The preparation method of this embodiment includes the following steps: Step S1: Prepare alloy steel powder according to the chemical composition, granulate the alloy steel powder to obtain powder clusters, and introduce a coating layer containing chromium precursor and carbon precursor on the surface of the clusters, wherein the amount of chromium precursor introduced is 0.9wt%, and the molar ratio of chromium precursor to carbon precursor is 9:3; Step S2: Perform hot isostatic pressing sintering on the coated powder clusters, the sintering temperature is 1195℃, the pressure is 135MPa, and the holding time is 3.5h, so that the powder clusters are densified to form an alloy steel grain structure; and the coating layer elements at the original cluster interface position form a Cr7C3 and Cr2O3 structure at the grain boundaries of the alloy steel grains. 23The continuous network structure composed of C6, in this embodiment, is formed by interconnected rod-shaped nanocrystals; simultaneously, carbide-forming elements such as Ti and V are dissolved into the matrix to form a supersaturated solid solution; step S3: the sintered body is subjected to aging treatment, so that the Ti and V elements in the supersaturated solid solution precipitate in situ within the grains to form nano-ceramic particles. In step S1, the powder clusters are prepared by mixing alloy steel powder and binder at a mass ratio of 97:3 to form a slurry, which is then spray-dried and granulated to form clusters. The drying inlet air temperature is 185°C, the feed rate is 25 mL / min, and the atomization pressure is 0.35 MPa; the average particle size of the obtained clusters is 160 μm. In this embodiment, the binder is a mixture of polyvinyl alcohol and polyethylene glycol (mass ratio 7:3). In step S1, the chromium precursor is a mixture of nano-chromium powder and chromium organic salt (mass ratio 6:4). In this embodiment, the carbon precursor is a dopamine carbon source. The coating process is a wet coating process with a coating temperature of 75°C and a coating time of 3.5 h. Step S2 employs a two-stage hot isostatic pressing sintering: the first stage is held at 1165°C for 1.8 h to achieve cluster densification and the formation of new grain boundaries; the second stage is heated to 1200°C and held for a short time of 6 min to promote the segregation of Cr and C in the coating layer along the grain boundaries and the formation of a continuous network of interconnected rod-shaped nanocrystals. The entire sintering process is carried out under a protective atmosphere, which in this embodiment is a mixture of argon and nitrogen (volume ratio 8:2). In step S2, the heating rate is 25°C / min and the pressure is 135 MPa; the cooling rate after sintering is controlled at 15°C / min. The aging treatment temperature in step S3 is 950℃, and the time is 3.5h; the cooling rate after aging is 12℃ / min; the aging in this embodiment is carried out under an argon protective atmosphere.

[0057] This embodiment employs an optimized composite design and a hybrid reinforcement strategy to achieve the best balance of strength, toughness, and wear resistance. It is suitable for comprehensive grinding operations under complex and variable working conditions, and is particularly suitable for high-end application scenarios that require simultaneous consideration of multiple performance requirements. It has good adaptability and comprehensive performance.

[0058] Comparative Example 1: Basically the same as Example 1, except that the C content in the chemical composition of the alloy steel matrix is ​​1.5%.

[0059] Comparative Example 2: It is basically the same as Example 1, except that the amount of chromium-containing precursor introduced in step S1 is 0.4wt%, so that the thickness of the continuous grain boundary network is 0.05μm.

[0060] Comparative Example 3: It is basically the same as Example 1, except that the aging treatment temperature in step S3 is 1100℃, so that the average particle size of the nano-ceramic particles is 80nm.

[0061] Comparative Example 4: Basically the same as Example 1, except that the amount of chromium-containing precursor introduced in step S1 is 0.3 wt%.

[0062] Comparative Example 5: It is basically the same as Example 1, except that the sintering temperature in step S2 is 1100℃.

[0063] Comparative Example 6: It is basically the same as Example 1, except that the sintering pressure in step S2 is 80 MPa.

[0064] Comparative Example 7: Basically the same as Example 1, except that the amount of chromium-containing precursor introduced in step S1 is 1.3 wt%, so that the three-dimensional volume fraction of the grain boundary continuous network is 15.0 vol.

[0065] Comparative Example 8: It is basically the same as Example 1, except that the Ti content in the chemical composition of the alloy steel matrix is ​​0.02% and the V content is 0.08%, so that the volume fraction of the nano-ceramic particles is 1.0 vol.

[0066] Comparative Example 9: Basically the same as Example 1, except that the molar ratio of chromium-containing precursor to carbon precursor in step S1 is 5:3.

[0067] Comparative Example 10: Basically the same as Example 1, except that the aging treatment temperature in step S3 is 700°C.

[0068] Comparative Example 11: Basically the same as Example 1, except that the second stage heat preservation time in step S2 is 15 min.

[0069] Comparative Example 12: It is basically the same as Example 1, except that the sintering temperature in step S2 is 1250℃ and the holding time is 6h, so that the average grain size of the alloy steel grains is 2.5μm.

[0070] Comparative Example 13: Basically the same as Example 1, except that the coating temperature in step S1 is 40°C.

[0071] Comparative Example 14: It is basically the same as Example 1, except that a single-stage hot isostatic pressing sintering process is used in step S2, and the temperature is held at 1180℃ for 3 hours.

[0072] Comparative Example 15: It is basically the same as Example 1, except that in step S1, no surface coating treatment is performed, and the alloy steel powder clusters are directly sintered.

[0073] Performance testing:

[0074] Hardness Testing Experiment: The test object is a high-performance cemented carbide wear-resistant steel ball. Test Objective: To evaluate the surface hardness and hardness distribution uniformity of the material, and to determine the material's resistance to plastic deformation. Test Principle: The indentation hardness test principle is adopted. A standard indenter is pressed into the material surface under a specified load, and the hardness value is calculated by measuring the indentation size. Experimental Method: The steel ball sample is embedded and polished to a mirror finish. A Vickers hardness tester is used to test at different positions on the sample surface. The indenter is a diamond pyramidal indenter, the load is 30 kg, and the holding time is 15 seconds. The hardness value is calculated by measuring the diagonal length of the indentation. Standard Basis: Performed according to GB / T4340.1-2009 "Metallic Materials - Vickers Hardness Test - Part 1: Test Method". Key Parameters: Room temperature 23±2℃, relative humidity 45%-65%, load holding time 15±1 seconds, at least 10 points tested per sample. Data Processing: Calculate the average hardness, standard deviation, and hardness distribution range; evaluate hardness uniformity; hardness value is expressed as HV30.

[0075] Impact Toughness Test Experiment: The test object is a standard impact specimen prepared from high-performance cemented carbide wear-resistant steel ball material. Test Objective: To evaluate the toughness and impact fracture resistance of the material under dynamic impact loads. Test Principle: The pendulum impact test principle is adopted to measure the energy absorbed by the specimen during fracture under impact load. Experimental Method: The steel ball material is processed into a standard V-notch specimen of 10mm×10mm×55mm, with a notch depth of 2mm and a notch root radius of 0.25mm. The test is conducted using a pendulum impact testing machine with a pendulum energy of 150J and an impact velocity of 5.2m / s. Standard Basis: The test is performed according to GB / T 229-2020 "Charpy Pendulum Impact Test Method for Metallic Materials". Key Parameters: Test temperature 23±2℃, specimen support span 40mm, impact point located at the center of the specimen opposite the notch, and at least 3 specimens per group. Data Processing: The impact absorbed energy is recorded, and the average value and standard deviation are calculated. Impact toughness is expressed as αkV (J / cm²). 2 This indicates that the ductile-brittle transition characteristics of the material are being evaluated.

[0076] Wear Resistance Test Experiment: The test object is a high-performance cemented carbide wear-resistant steel ball. Test Objective: To evaluate the wear resistance and wear mechanism of the steel ball under simulated working conditions. Test Principle: The ball-disc wear test principle is adopted. Under controlled load and rotation speed, sliding friction is generated with the ball and the mating material, and the wear mass loss and wear rate are measured. Experimental Method: A 30mm diameter steel ball sample is installed on a ball-disc wear testing machine. The mating material is a hardened steel disc (HRC58-62). A load of 294N is applied, the rotation speed is 200r / min, and the wear time is 60min. The test is conducted under dry friction conditions. Standard Basis: ASTM G99-17 is referenced and revised according to the characteristics of the ball milling media. Key Parameters: Room temperature 25±3℃, relative humidity ≤60%, load accuracy ±2%, rotation speed accuracy ±1%, weighing accuracy before and after the test 0.1mg. Data Processing: The wear mass loss, wear rate, and friction coefficient are calculated; the wear surface morphology is analyzed; and the wear resistance level is evaluated.

[0077] Compressive Strength Test Experiment: The test object is a cylindrical compression specimen prepared from high-performance cemented carbide wear-resistant steel ball material. Test Objective: To evaluate the ultimate strength and deformation characteristics of the material under uniaxial compressive load. Test Principle: The uniaxial compression test principle is adopted, measuring the stress-strain relationship of the material under compressive load until failure. Experimental Method: The steel ball material is processed into a cylindrical specimen with a diameter of 10 mm and a height of 15 mm. The end face parallelism deviation is ≤0.02 mm. A universal testing machine is used for compression testing, with a loading speed of 0.5 mm / min, continuously loading until the specimen fails. Standard Basis: Refer to GB / T 7314-2017 "Metallic Materials - Compression Test at Room Temperature". Key Parameters: Test temperature 23±2℃, loading speed 0.5±0.1 mm / min, strain measurement accuracy 0.1%, force measurement accuracy ±0.5%, no less than 5 specimens per group. Data Processing: Plot stress-strain curves, calculate compressive strength, elastic modulus, and yield strength, and analyze the material's compressive deformation behavior and failure mode.

[0078] Thermal Expansion Coefficient Test Experiment: Test Object: Rod-shaped specimens prepared from high-performance cemented carbide wear-resistant steel balls. Test Objective: To determine the linear thermal expansion coefficient of the material at different temperatures and evaluate its thermal stability. Test Principle: A push-rod thermal dilatometer is used to measure the length change of the material during the heating process, and the linear thermal expansion coefficient is calculated. Experimental Method: The steel ball material is processed into round rod specimens with a length of 25 mm and a diameter of 6 mm, and a surface roughness Ra ≤ 0.8 μm. The temperature is raised from room temperature to 800 °C using a thermal dilatometer under an argon protective atmosphere at a heating rate of 5 °C / min, and the temperature and length changes are recorded in real time. Standard Basis: Performed according to GB / T 4339-2008 "Determination of Characteristic Parameters of Thermal Expansion of Metallic Materials". Key Parameters: Heating rate 5 ± 0.5 °C / min, temperature measurement accuracy ± 1 °C, length change measurement accuracy ± 0.1 μm, argon flow rate 50-100 mL / min. Data Processing: The average linear thermal expansion coefficient is calculated for different temperature ranges, thermal expansion curves are plotted, and the thermal expansion behavior and phase transformation characteristics of the material are analyzed.

[0079] The performance of the examples and comparative examples is summarized in Table 1. A comprehensive analysis of the factors affecting the performance of the comparative examples shows that the deterioration of material performance mainly stems from microstructure imbalance and failure of the strengthening mechanism caused by several key parameters deviating from their optimal range. Specifically, excessively high C content leads to excessive carbide precipitation, reducing matrix toughness and increasing wear rate; insufficient chromium precursor results in excessively thin grain boundary network thickness or reduced volume fraction, weakening the grain boundary strengthening effect; excessively high aging temperature causes excessive growth of nano-ceramic particles, reducing the dispersion strengthening effect; excessively low sintering temperature results in insufficient densification and incomplete grain boundary network formation; insufficient sintering pressure leads to reduced material density and the generation of micropore defects; and while excessive grain boundary strengthening phase can slightly increase hardness, it significantly reduces toughness and disrupts the overall performance balance. The low Ti and V content leads to insufficient precipitation of nano-ceramic particles, weakening the dispersion strengthening effect. The low Cr / C molar ratio affects the formation of an ideal grain boundary network. The low aging temperature results in insufficient precipitation of nano-ceramic particles. The excessively long holding time in the second stage causes the grain boundary network to become overdeveloped, reducing toughness. The excessively high sintering temperature and excessively long holding time cause grain coarsening and loss of fine grain strengthening effect. The excessively low coating temperature results in insufficient coating of the precursor, affecting the formation of grain boundary strengthening phase. The single-stage sintering process cannot accurately control the grain boundary network formation process, while the lack of coating treatment completely lacks the grain boundary strengthening mechanism and relies solely on matrix alloying, resulting in the worst performance. The combined effect of these factors proves the critical importance of precise control of each parameter in the patented technology solution for achieving the optimal microstructure and performance balance.

[0080] Table 1 Summary of the performance of the steel balls in the examples and comparative examples

[0081]

[0082] Figure 1To investigate the effect of the amount of chromium-containing precursor introduced on hardness and impact toughness in this invention, the basic parameters were a sintering temperature of 1180℃ and an aging temperature of 900℃, and the variable parameter was the amount of chromium-containing precursor introduced from 0.3% to 1.3 wt%. The results showed that both hardness and impact toughness reached high levels within the range of 0.6% to 1.0 wt%, with the optimal value of 0.8 wt% achieving a hardness of 782 HV30 and an impact toughness of 35.8 J / cm². 2 The performance decreased significantly when the content was too low or too high, which proves the technical rationality of the parameter window. Figure 2 To investigate the effect of sintering temperature on hardness and wear rate in this invention, the basic parameters were 0.8 wt% chromium-containing precursor and aging temperature of 900℃, and the variable parameter was sintering temperature of 1090-1270℃. The results showed that the hardness was highest and the wear rate was lowest in the range of 1150-1210℃. The optimal temperature was 1180℃, with a hardness of 782 HV30 and a wear rate of only 2.15 mg / km. Too low a temperature resulted in insufficient densification, while too high a temperature led to grain coarsening, thus verifying the process advantages of this temperature range. Figure 3 To investigate the effect of aging temperature on wear rate and compressive strength, the basic parameters were 0.8 wt% chromium-containing precursor and sintering temperature of 1180℃, and the variable parameter was aging temperature of 700-1100℃. The results showed that the wear rate was lowest and the compressive strength was highest in the range of 800-1000℃. The optimal temperature was 900℃, with a wear rate of 2.15 mg / km and a compressive strength of 2850 MPa. Too low a temperature resulted in insufficient precipitation, while too high a temperature led to particle coarsening. This fully demonstrates the scientific nature of the process parameter selection and the effectiveness of the technical solution.

[0083] Figures 4 to 7 The microstructure analysis results fully demonstrate the rationality, reliability, and effectiveness of the technical solution of this invention, wherein... Figure 4 The microstructure images clearly show that a uniform and dense microstructure was formed in the alloy steel matrix, with fine and uniformly distributed grains. A continuous reinforcing phase network structure can be observed at the grain boundaries, proving that the hot isostatic pressing sintering process successfully achieved complete densification of powder clusters and ideal microstructure construction. Figure 5 EDX elemental analysis results show that the continuous network at the grain boundaries is mainly composed of Cr and C elements, with continuous and uniform element distribution. This verifies that the chromium-containing precursor and carbon precursor in the coating layer successfully segregated along the grain boundaries during sintering and formed the expected chromium carbide-reinforced phase network, proving the effectiveness of the coating process and sintering parameter design. Figure 6 The grains were found to contain uniformly dispersed nano-sized ceramic particles. EDX analysis confirmed that the main components were Ti and C, proving that the aging treatment successfully induced the in-situ precipitation of Ti elements in the supersaturated solid solution to form TiC nanoparticles, achieving the expected dispersion strengthening effect and verifying the accuracy of the aging process parameters. Figure 7The XRD phase analysis clearly detected characteristic diffraction peaks of the matrix α-Fe phase, grain boundary strengthening phase Cr7C3, and nano-ceramic phases TiC and VC. The phase composition was in complete agreement with the theoretical design, and the peaks were sharp and free of impurities, proving the scientific nature of the entire preparation process and the rationality of the matching of various process parameters. Figure 8 The image shows the microstructure of the cemented carbide wear-resistant steel ball of Example 2 of this invention. It is evident that the low amount of chromium precursor introduced results in the absence of nanocrystals in the microstructure, and the network thickness is relatively thin. This clearly demonstrates that the precursor content is crucial for network morphology formation. The above analysis comprehensively verifies that the technical solution of this invention can stably and reliably prepare cemented carbide wear-resistant steel balls with ideal microstructure and excellent comprehensive performance.

[0084] Figures 9 to 13 The performance comparison analysis results comprehensively demonstrate the rationality, reliability, and effectiveness of the technical solution of this invention, wherein... Figure 9 The hardness-impact toughness comparison chart shows that the embodiments of the present invention achieve excellent impact toughness while maintaining high hardness, successfully breaking through the technical bottleneck of the mutual restriction between hardness and toughness in traditional cemented carbide. The data points of the embodiments are clearly located in the performance advantage region, while the comparative examples are scattered in the low performance range, which proves the technical advantage of the synergistic effect of grain boundary network strengthening and nano-ceramic dispersion strengthening. Figure 10 The wear rate-compressive strength comparison chart shows that the embodiments of the present invention have both extremely low wear rate and ultra-high compressive strength, exhibiting excellent wear resistance and load-bearing capacity. In contrast, the comparative examples are significantly inferior to the embodiments in both key performance indicators, verifying the effectiveness of the unique microstructure design and preparation process of the present invention. Figure 11 The linear thermal expansion coefficient-hardness comparison chart shows that the embodiment maintains high hardness while having a moderate thermal expansion coefficient, exhibiting good dimensional stability and thermal stress resistance. The comparative example, on the other hand, shows problems of excessively high thermal expansion coefficient or insufficient hardness, demonstrating the technical advantages of the present invention in terms of thermal stability. Figure 12 The impact toughness-compressive strength comparison chart further verifies the outstanding performance of the embodiment in both toughness and strength, achieving a balance of strength and toughness that is difficult to achieve with traditional materials. In contrast, the comparative embodiment deviates significantly from the optimal performance range, demonstrating the uniqueness and advancement of the technical route of this invention. Figure 13 The wear rate-linear thermal expansion coefficient comparison chart shows that the embodiment is optimal in both wear resistance and thermal stability, two key application performances, while the comparative example has obvious deficiencies in one or more indicators. This comprehensively proves that the present invention, through precise composition design, innovative coating process and optimized heat treatment parameters, has successfully constructed a composite reinforcement system with high hardness, high toughness, low wear rate, high strength and good thermal stability, providing a reliable and effective solution for the technological development of cemented carbide wear-resistant steel balls.

[0085] 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 it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that any equivalent structural transformations made under the concept of the present invention and using the contents of the specification and drawings of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A high-performance cemented carbide wear-resistant steel ball, characterized in that, It comprises a dense alloy steel matrix composed of alloy steel grains; the chemical composition of the alloy steel matrix, by mass percentage, is: C 0.6%-1.0%, Cr 2.2%-3.8%, Ni 3%-6%, Mo 0.2%-1.2%, V 0.15%-0.6%, Ti 0.05%-0.3%, B 0.25%-0.8%, Si 0.3%-0.9%, Mn 0.2%-0.8%, N 0.01%-0.08%, with the balance being Fe and unavoidable impurities; The grain boundaries of the alloy steel grains contain Cr7C3 and / or Cr 23 A continuous network composed of C6, which is formed by interconnecting rod-shaped nanowhiskers or nanoparticles, has a thickness of 0.08μm-0.15μm and a three-dimensional volume fraction of 6.0vol%-12.0vol%. The network exhibits a honeycomb-like closed cell morphology in a two-dimensional cross-section. In-situ self-generated nano-ceramic particles are distributed within the grains of the alloy steel. These nano-ceramic particles are one or more of TiC and VC, with an average particle size of 30nm-60nm and a volume fraction of 2.0vol%-4.5vol%. The continuous grain boundary network coexists with the nano-ceramic particles but is not interconnected, forming a composite reinforcement structure that combines grain boundary strengthening and dispersion strengthening.

2. The high-performance cemented carbide wear-resistant steel ball as described in claim 1, characterized in that, The rod-shaped nanocrystals have an average diameter of 15nm-25nm and an average length of 60nm-120nm. The nano-ceramic particles are mainly distributed within the grains rather than at the grain boundaries; the average grain size of the alloy steel grains is 0.5μm-1.5μm.

3. The high-performance cemented carbide wear-resistant steel ball as described in claim 1, characterized in that, In the continuous network, Cr7C3 and / or Cr 23 There is a thin chromium-rich interfacial layer between C6 and the alloy steel matrix, with a thickness of 2nm-4.5nm.

4. A method for preparing a high-performance cemented carbide wear-resistant steel ball as described in any one of claims 1 to 3, characterized in that, Includes the following steps: Step S1: Prepare alloy steel powder according to chemical composition, granulate the alloy steel powder to obtain powder clusters, and introduce a coating layer containing chromium precursor and carbon precursor on the surface of the clusters, wherein the amount of chromium precursor introduced is 0.6 wt%–1.0 wt%, and the molar ratio of chromium precursor to carbon precursor is 7:3–10:

3. Step S2: The coated powder clusters are subjected to hot isostatic pressing sintering at a temperature of 1150℃–1210℃, a pressure of 100 MPa–150 MPa, and a holding time of 2 h–4 h, to densify the powder clusters and form an alloy steel grain structure; and to allow the coating layer elements at the original inter-cluster interface positions to form Cr7C3 and / or Cr at the grain boundaries of the alloy steel grains. 23 A continuous network structure composed of C6, wherein the network is formed by interconnecting rod-shaped nanowhiskers and / or nanoparticles; at the same time, Ti and V carbide forming elements are dissolved into the matrix to form a supersaturated solid solution; Step S3: The sintered body is aged to allow Ti and V elements in the supersaturated solid solution to precipitate in situ within the grains, forming nano-ceramic particles.

5. The method for preparing a high-performance cemented carbide wear-resistant steel ball as described in claim 4, characterized in that, In step S1, the powder clusters are prepared by mixing alloy steel powder and binder at a mass ratio of 95:5-98:2 to form a slurry, followed by spray drying and granulation to form clusters. The drying inlet air temperature is 150℃-200℃, the feeding rate is 10 mL / min-30 mL / min, and the atomization pressure is 0.2 MPa-0.4 MPa. The average particle size of the obtained clusters is 50 μm-200 μm. The binder is selected from polyvinyl alcohol, polyethylene glycol, or carboxymethyl cellulose.

6. The method for preparing a high-performance cemented carbide wear-resistant steel ball as described in claim 4, characterized in that, In step S1, the chromium-containing precursor is selected from one of nano-chromium powder, chromium organic salt, or chromium oxide sol, and the carbon precursor is selected from one of phenolic resin or dopamine carbon source; the coating treatment adopts a wet coating process, with a coating temperature of 60℃–80℃ and a coating time of 2 h–4 h.

7. The method for preparing a high-performance cemented carbide wear-resistant steel ball as described in claim 4, characterized in that, Step S2 employs a two-stage hot isostatic pressing sintering process: the first stage involves holding the temperature at 1150℃–1170℃ for 1 h–2 h to achieve cluster densification and the formation of new grain boundaries; the second stage involves raising the temperature to 1180℃–1210℃ and holding it for a short period of 2 min–8 min to promote the segregation of Cr and C in the coating layer along the grain boundaries and the formation of a continuous network of interconnected rod-shaped nanowhiskers and / or nanoparticles; the entire sintering process is carried out under a protective atmosphere, which is argon or nitrogen.

8. The method for preparing a high-performance cemented carbide wear-resistant steel ball as described in claim 4, characterized in that, In step S2, the heating rate is 10℃ / min–30℃ / min, and the pressure is 120 MPa–140 MPa; the cooling rate after sintering is controlled at 5℃ / min–20℃ / min.

9. A method for preparing a high-performance cemented carbide wear-resistant steel ball as described in claim 4, characterized in that, The aging treatment temperature in step S3 is 800℃–1000℃, and the time is 2h–4h; the cooling rate after aging is 5℃ / min–15℃ / min; the aging is carried out under an argon protective atmosphere.

10. The application of a high-performance cemented carbide wear-resistant steel ball as described in any one of claims 1 to 3 in mining grinding media.

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