A high-hardness wear-resistant steel alloy based on solid solution strengthening and its preparation method

Abstract

This invention discloses a high-hardness wear-resistant steel bond alloy based on solid solution strengthening and its preparation method, relating to the field of powder metallurgy. The high-hardness wear-resistant steel bond alloy based on solid solution strengthening comprises the following components by weight: 32-38 parts of (Ti,Cr,Mo)C solid solution particles, 55-65 parts of Fe powder, 0.5-2 parts of Ni powder, 0.2-1 parts of Mn powder, and 0.1-0.3 parts of ultrafine carbon black. The high-hardness wear-resistant steel bond alloy based on solid solution strengthening provided by this invention has a reduced oxygen content and significantly reduced oxide inclusions; under the same high-speed wire drawing conditions, its service life can reach more than three times that of traditional GT35; carbon content fluctuations are effectively controlled, and martensitic hardness stability is significantly improved.

Description

Technical Field

[0001] This invention belongs to the field of powder metallurgy technology, and particularly relates to a high-hardness wear-resistant steel bond alloy based on solid solution strengthening and its preparation method. Background Technology

[0002] Steel-bonded alloys are a type of composite material that combines a hard phase (such as TiC, WC, etc.) with a steel matrix. They possess the high hardness and wear resistance of cemented carbide with the good machinability and heat treatability of steel, and are widely used in wire drawing dies, cutting tools, and various wear-resistant parts. Among them, the GT35 type steel-bonded alloy, with TiC as the hard phase and CrMo low-alloy steel as the binder phase, has become one of the more mature steel-bonded alloy varieties due to its relatively balanced comprehensive performance. Its TiC mass fraction is typically about 35%, and the binder phase is about 65%.

[0003] In the current preparation process of GT35 steel alloys, carbon black is usually added to supplement the system with carbon during the later ball milling mixing stage. However, under wet ball milling conditions, carbon black easily reacts with oxygen in the air or the ball milling media to generate carbon monoxide, making it difficult to accurately control the carbon content of the system. This, in turn, can easily cause problems such as fluctuations in the hardness of the martensitic structure and uneven microstructure during subsequent quenching, affecting the stability of the material properties.

[0004] Meanwhile, in existing processes, alloying elements such as Cr and Mo are mostly introduced in the later mixing stage, which limits their solid solution degree in the TiC hard phase. This makes it difficult to stably form a uniform and continuous (Ti,Cr,Mo)C solid solution reinforced layer on the surface of TiC particles, thus limiting the bonding strength and interfacial strengthening effect between the hard phase and the steel matrix. Under harsh service conditions such as high-speed, high-load wire drawing, these problems further restrict the improvement of the material's wear resistance, resulting in a generally short actual service life. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a high-hardness wear-resistant steel alloy based on solid solution strengthening and its preparation method. The specific technical solution is as follows: A high-hardness wear-resistant steel alloy based on solid solution strengthening, comprising the following components by weight: 32-38 parts of (Ti,Cr,Mo)C solid solution particles, 55-65 parts of Fe powder, 0.5-2 parts of Ni powder, 0.2-1 parts of Mn powder, and 0.1-0.3 parts of ultrafine carbon black.

[0006] Preferably, the (Ti,Cr,Mo)C solid solution particles are prepared by the following components by weight: 40-50 parts TiO2 powder, 0.4-1.2 parts core-shell structured carbon-metal oxide composite carbon source, and 0.5-2.0 parts Cr-Mo composite oxide.

[0007] Preferably, the core-shell structured carbon-metal oxide composite carbon source is prepared by the following components in parts by weight: 1-3 parts of ultrafine activated carbon black, 2-5 parts of Cr2O3, and 4-10 parts of MoO3.

[0008] Preferably, the Cr-Mo composite oxide specifically comprises the following components in parts by weight: 0.2~0.8 parts of Cr2O3 and 0.3~1.2 parts of MoO3.

[0009] The present invention also provides a preparation method for preparing a high-hardness wear-resistant steel alloy based on solid solution strengthening as described in any one of the above claims, the preparation method comprising the following steps: S1. Mix (Ti,Cr,Mo)C solid solution particles, Fe powder, Ni powder, Mn powder and ultrafine carbon black evenly according to the weight parts to obtain mixed powder A; S2. The mixed powder A is pressed into a preform to obtain a blank; S3. Vacuum sinter the preform to obtain a sintered body; S4. The sintered body is obtained by quenching and tempering heat treatment.

[0010] Preferably: In step S2, the compression molding pressure is 150~300 MPa; In step S3, the vacuum sintering temperature is 1450~1480℃, the holding time is 1~2 h, and the vacuum degree is 10~50 Pa. In step S4, oil quenching is used for quenching, and the tempering temperature is 200~400℃.

[0011] Preferably, the (Ti,Cr,Mo)C solid solution particles are prepared by the following steps: S01. Mix TiO2 powder, core-shell structured carbon-metal oxide composite carbon source, and Cr-Mo composite oxide evenly to obtain mixed powder B; S02. The mixed powder B is placed in a reducing atmosphere and subjected to a high-temperature carbothermic reduction reaction to obtain (Ti,Cr,Mo)C solid solution particles.

[0012] Preferably, in step S02: The reducing atmosphere is a mixture of H2 and Ar, wherein the volume fraction of H2 is 10%~20%; The reaction temperature is 1350~1550℃, and the temperature is maintained for 2~4 hours.

[0013] Preferably, the core-shell structured carbon-metal oxide composite carbon source is prepared through the following steps: S001. Mix ultrafine activated carbon black, Cr2O3, and MoO3 to obtain mixture C; S002. The mixture C is subjected to ball milling; S003. The mixture C after ball milling is dried to obtain a core-shell structured carbon-metal oxide composite carbon source.

[0014] Preferably: In step S002, the ball milling process is performed using a planetary ball mill with a ball-to-material mass ratio of (8~12):1, the ball milling medium is ethanol, the rotation speed is 200~400 rpm, and the ball milling time is 12~36 h. In step S003, the drying process is vacuum drying, with a temperature of 60~100℃ and a drying time of 8~16 h.

[0015] The high-hardness wear-resistant steel alloy based on solid solution strengthening provided by this invention has the following beneficial effects: 1. The oxygen content is reduced, and the oxide inclusions are significantly reduced.

[0016] 2. Under the same high-speed wire drawing conditions, its service life can be more than 3 times that of the traditional GT35.

[0017] 3. Carbon content fluctuations are effectively controlled, and the stability of martensitic hardness is significantly improved. Detailed Implementation

[0018] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be described in detail below. The description in this part is only exemplary and explanatory, and should not be used to limit the scope of protection of the present invention in any way.

[0019] This embodiment provides a high-hardness wear-resistant steel alloy based on solid solution strengthening, which is made of the following components by weight: 32-38 parts of (Ti,Cr,Mo)C solid solution particles, 55-65 parts of Fe powder, 0.5-2 parts of Ni powder, 0.2-1 parts of Mn powder, and 0.1-0.3 parts of ultrafine carbon black.

[0020] Among them, (Ti,Cr,Mo)C solid solution particles, as the hard phase, form a (Ti,Cr,Mo)C rim layer (core-shell structure) on their surface, which significantly improves the wettability and interfacial bonding strength with the steel matrix, reduces the interfacial energy, and improves the resistance to spalling. The ultrafine carbon black added later is used to precisely fine-tune the final carbon content, avoiding carbon fluctuations and oxygen introduction caused by traditional large-scale carbon addition. Ni improves the hardenability and toughness of the steel matrix, and Mn enhances solid solution strengthening and deoxidation. The overall composition design allows the material to obtain a matrix structure of martensite + a small amount of retained austenite after vacuum sintering, and after quenching and tempering, it has both high hardness and certain toughness.

[0021] The particle size of ultrafine carbon black is preferably less than 1.0 μm. This particle size can ensure its highly uniform dispersion in the mixed powder and rapid dissolution in the steel matrix in the early stage of sintering, so as to achieve precise control of carbon content. On the other hand, carbon black with larger particle size is prone to local carbon enrichment and uneven structure.

[0022] The high-hardness wear-resistant steel alloy based on solid solution strengthening provided in this embodiment has the following beneficial effects: 1. The oxygen content is reduced, and the oxide inclusions are significantly reduced.

[0023] 2. Under the same high-speed wire drawing conditions, its service life can be more than 3 times that of the traditional GT35.

[0024] 3. Carbon content fluctuations are effectively controlled, and the stability of martensitic hardness is significantly improved.

[0025] The above-mentioned effects are mainly due to the introduction of an in-situ solid solution strengthening mechanism in the hard phase synthesis stage of this embodiment, and the precise carbon replenishment through trace amounts of ultrafine carbon black, which completely avoids the oxygen introduction and carbon fluctuation problems caused by the traditional large amount of carbon replenishment in the later stage, thereby improving the microstructure and interface state of the material from the source.

[0026] Further, by weight, the (Ti,Cr,Mo)C solid solution particles are made from the following components: 40-50 parts TiO2 powder, 0.4-1.2 parts core-shell structured carbon-metal oxide composite carbon source, and 0.5-2.0 parts Cr-Mo composite oxide.

[0027] Specifically, in this embodiment, a carbothermal reduction method is used in the hard phase synthesis stage. TiO2 is used as the titanium source, and a core-shell structured carbon-metal oxide composite carbon source (FCC component) is used as the main carbon source and the carrier of Cr and Mo. At the same time, an appropriate amount of Cr-Mo composite oxide is added. Under a reducing atmosphere, TiO2 is reduced simultaneously and Cr and Mo are dissolved in situ to form (Ti,Cr,Mo)C solid solution particles with a core-shell structure.

[0028] In the FCC component, the carbon core slowly releases active carbon atoms at high temperature for the reduction reaction from TiO2 to TiC; the outer shell Cr2O3+MoO3 is simultaneously reduced, and the released Cr and Mo atoms preferentially diffuse to the surface of the newly formed TiC particles to form a uniform (Ti,Cr,Mo)Cr rim layer (solid solution shell); additional Cr-Mo composite oxides are used to finely adjust the total amount and ratio of Cr / Mo to ensure uniform composition of the solid solution layer and avoid local oversaturation or depletion.

[0029] Beneficially, through this in-situ synthesis method, the hard phase is transformed from traditional pure TiC into a (Ti,Cr,Mo)C solid solution. The rim layer can significantly improve the wettability of the hard phase and the steel matrix, and improve the interfacial bonding strength. At the same time, it avoids the oxygen introduction and carbon fluctuation problems caused by later carbon addition, and reduces porosity and oxygen content from the source, laying the foundation for obtaining a low-defect and highly uniform microstructure.

[0030] Furthermore, by weight, the core-shell structured carbon-metal oxide composite carbon source is prepared from the following components: 1-3 parts of ultrafine activated carbon black, 2-5 parts of Cr2O3, and 4-10 parts of MoO3.

[0031] Specifically, the FCC component employs a core-shell structure design: ultrafine activated carbon black serves as the core, providing a highly active and easily controlled-release carbon source; Cr2O3 and MoO3 composite oxides serve as the outer shell, uniformly coating the surface of the carbon particles through mechanical compounding. During the subsequent carbothermal reduction process, the carbon core is slowly oxidized and released, while the oxide shell is simultaneously reduced. Cr and Mo atoms are released in situ at the atomic scale and diffuse into the TiC particles, achieving uniform solid solution.

[0032] The reason for choosing ultrafine activated carbon black instead of ordinary carbon black or graphite is that the specific surface area of ​​activated carbon black is usually >500m². 2 / g, with a large number of functional groups on the surface, high chemical activity, low carbothermic reduction onset temperature and uniform reaction; particle size <0.5 μm, which is conducive to the formation of a thin and continuous oxide coating layer and ensures that the carbon release rate is controllable.

[0033] The mass ratio of Cr2O3 to MoO3 tends to be 1:(1.5~2.5) (with more MoO3) because Mo plays a more significant role in lowering the liquid phase sintering temperature and improving wettability, while Cr contributes more to solid solution strengthening and anti-oxidation. The combination of the two can achieve the best overall effect.

[0034] Beneficially, this core-shell design allows the carbon source and alloying elements to be "pre-bound" within the same particle, avoiding the problem of uneven solid solution caused by the spatial separation of the carbon source and alloying elements in traditional processes; at the same time, it can significantly reduce the oxygen introduction pathways in the wet grinding carbon replenishment stage, achieving low oxygen content and low porosity.

[0035] Furthermore, the Cr-Mo composite oxide specifically comprises the following components in parts by weight: 0.2~0.8 parts of Cr2O3 and 0.3~1.2 parts of MoO3.

[0036] In this embodiment, Cr2O3 and MoO3 come from two sources: one part is already coated in the FCC component shell (added along with the FCC), and the other part is added as an additional component to fine-tune the total Cr / Mo amount and atomic ratio (target Cr:Mo atomic ratio 1:(1.2~2.5)). This "stepwise introduction" strategy ensures both the in-situ uniform release of Cr / Mo and allows for precise compensation based on different batches of raw materials or target performance.

[0037] The reason for dividing it into two parts is that the Cr / Mo ratio in the FCC shell has been optimized to promote uniform coating and initial solid solution, but the total amount is limited; the additional part can be flexibly adjusted to avoid excessively high or low Cr or Mo in the solid solution layer.

[0038] Beneficially, through this fine regulation, the composition and thickness of the (Ti,Cr,Mo)C rim layer are more uniform, the bonding between the hard phase and the matrix is ​​stronger, and the resistance to crack propagation is improved, which is the microscopic basis for the material's high bending strength and significantly extended wear life.

[0039] This embodiment also provides a preparation method for preparing a high-hardness wear-resistant steel alloy based on solid solution strengthening as described in any one of the above embodiments. The preparation method includes the following steps: S1. Mix (Ti,Cr,Mo)C solid solution particles, Fe powder, Ni powder, Mn powder and ultrafine carbon black evenly according to the weight parts to obtain mixed powder A.

[0040] S2. Press the mixed powder A into a preform to obtain a preform.

[0041] S3. Vacuum sinter the preform to obtain a sintered body.

[0042] S4. The sintered body is obtained by quenching and tempering heat treatment.

[0043] Furthermore: In step S2, the compression molding pressure is 150~300 MPa.

[0044] In step S3, the vacuum sintering temperature is 1450~1480℃, the holding time is 1~2 h, and the vacuum degree is 10~50 Pa.

[0045] In step S4, oil quenching is used for quenching, and the tempering temperature is 200~400℃.

[0046] Specifically, the pre-synthesized (Ti,Cr,Mo)C solid solution particles are used in the later mixing stage to avoid the problems of uneven dispersion and poor wettability caused by traditional direct mixing of TiC powder; pressing provides the initial density of the billet; vacuum liquid phase sintering (1450~1480℃) makes the steel matrix form a liquid phase, fills the pores and promotes the rearrangement of hard phases; oil quenching + tempering obtains a matrix structure dominated by martensite, achieving a balance between high hardness and toughness.

[0047] Preferred pressing pressure: 150~300 MPa; below 150 MPa, the billet strength is insufficient and prone to cracking; above 300 MPa, delamination or elastic aftereffects are likely to occur. Preferred vacuum degree: 10~50 Pa; effectively inhibits oxidation and promotes gas expulsion. Preferred tempering temperature: 200~400℃; low-temperature tempering maintains high hardness, while medium-temperature tempering improves toughness.

[0048] Beneficially, this process, combined with the aforementioned in-situ solution treatment, enables the final material to simultaneously possess high density, low oxygen content, uniform structure, and excellent quenching response, resulting in a service life significantly superior to that of traditional GT35.

[0049] Furthermore, (Ti,Cr,Mo)C solid solution particles were prepared via the following steps: S01. Mix TiO2 powder, core-shell structured carbon-metal oxide composite carbon source, and Cr-Mo composite oxide evenly to obtain mixed powder B.

[0050] S02. Place the mixed powder B in a reducing atmosphere and carry out a high-temperature carbothermic reduction reaction to obtain (Ti,Cr,Mo)C solid solution particles.

[0051] Furthermore, in step S02: The reducing atmosphere is a mixture of H2 and Ar, with H2 volume fraction of 10%~20%.

[0052] The reaction temperature is 1350~1550℃, and the temperature is maintained for 2~4 hours.

[0053] Specifically, carbothermal reduction is carried out in a mixed atmosphere of H2 / Ar, where H2 promotes oxide reduction and reduces oxygen partial pressure; the temperature is 1350~1550℃ and the holding time is 2~4 h, so that TiO2 is completely converted into carbides, while Cr and Mo are fully dissolved into TiC lattice.

[0054] The optimal range for H2 volume fraction is 10% to 20%: too low a fraction will result in insufficient reduction, while too high a fraction may lead to over-reduction or safety hazards.

[0055] Furthermore, the core-shell structured carbon-metal oxide composite carbon source was prepared through the following steps: S001. Mix ultrafine activated carbon black, Cr2O3, and MoO3 to obtain mixture C.

[0056] S002. Ball milling is performed on mixture C.

[0057] S003. The mixture C after ball milling is dried to obtain a core-shell structured carbon-metal oxide composite carbon source.

[0058] Furthermore: In step S002, the ball milling process uses planetary ball milling with a ball-to-material mass ratio of (8~12):1, the ball milling medium is ethanol, the rotation speed is 200~400 rpm, and the ball milling time is 12~36 h.

[0059] In step S003, the drying process is vacuum drying at a temperature of 60~100℃ for 8~16 hours.

[0060] Specifically, through the high-energy mechanical action (collision, shearing, cold welding) of planetary ball milling, fine Cr2O3 and MoO3 particles are embedded and coated onto the surface of ultrafine activated carbon black, forming a stable core-shell structure. Vacuum drying fixes the coating layer, preventing re-oxidation or moisture absorption during transportation or storage. The uniformity of the core-shell structure directly determines the synchronicity and uniformity of Cr / Mo release during subsequent carbothermic reduction, providing a reliable guarantee for overall low-defect microstructure and high performance.

[0061] Specific embodiments are provided below. These embodiments are intended to enable those skilled in the art to more fully understand the present invention, but do not limit the present invention in any way.

[0062] Step 1: FCC component preparation Take 0.40 g of ultrafine activated carbon black, 0.60 g of Cr2O3 (purity 99.9%), and 1.20 g of MoO3 (purity 99.95%). Add the above three powders to a 250 mL zirconium oxide ball mill jar and add 80 mL of anhydrous ethanol as the medium. The ball milling parameters are: rotation speed 300 rpm, alternating forward and reverse rotation, switching every 30 min, and a total ball milling time of 24 h.

[0063] After ball milling, the slurry was transferred to a glass dish and placed in a vacuum drying oven at 80°C for 12 h (vacuum degree <10 Pa). After drying, a light gray-green composite powder was obtained, weighing 1.92 g.

[0064] Step 2: Preparation of (Ti,Cr,Mo)C solid solution particles Take 90.0 g of TiO2 powder (rutile type, 99.9% purity), 1.60 g of FCC component, 0.80 g of Cr2O3, and 1.20 g of MoO3. Dry mix the powders in a V-type mixer for 2 h (30 rpm). Load the mixture into an alumina boat, push it into the middle of a tube furnace, and introduce a H2 / Ar mixed gas (15% H2 volume fraction, 200 mL / min total flow rate). After venting for 30 min, raise the temperature. Increase the temperature to 1450℃ at 5℃ / min and hold for 3 h. After holding, allow it to cool naturally to room temperature, maintaining the same gas flow rate throughout. A dark gray powder weighing 72.4 g is obtained after removing it from the furnace.

[0065] Step 3: Preparation of steel-bonded alloy Take 70.0 g of (Ti,Cr,Mo)C solid solution particles, 120.0 g of Fe powder (99.5% purity), 1.2 g of Ni powder, 0.6 g of Mn powder, and 0.4 g of ultrafine carbon black. Add the above powders to a V-type mixer and dry mix for 4 h (25 rpm). Weigh out a single portion of about 25 g of powder and place it into a φ30 mm cemented carbide mold; press unidirectionally at a pressure of 220 MPa for 30 s to obtain a blank with a thickness of about 12 mm. Place the blank into a graphite boat and push it into a vacuum sintering furnace; evacuate to a residual pressure <30 Pa, heat to 1470℃ at 8℃ / min, and hold for 1.5 h; after holding, quickly remove from the furnace and oil quench; immediately after quenching, place in a tempering furnace and hold at 300℃ for 2 h, then cool with the furnace; finally, a disc-shaped sample with a total mass of about 192.6 g is obtained.

[0066] Step 4: Performance Testing 1. Oxygen content: Inert gas melting-infrared absorption method 2. Vickers hardness: Vickers hardness tester (HV10, load 10 kgf, holding time 15 s, average test at 8 points) 3. Bending strength: Three-point bending method (span 30 mm, loading rate 0.5 mm / min, universal testing machine, average of 5 spline samples) 4. Wire drawing die life test: The wire drawing die (die core φ12 mm, working cone angle 8°) is installed on a high-speed wire drawing machine (wire: φ5.5 mm high carbon steel wire drawn to φ4.0 mm, speed 18 m / s, lubricating oil circulation), and the cumulative wire drawing time is recorded until the die hole diameter increases by 0.015 mm or Ra>0.40 μm.

[0067] The test data is shown in Table 1 below: The material prepared in Example 1 has a low oxygen content, and its hardness and bending strength both meet the expected range. It also has a long service life in actual high-speed wire drawing tests.

[0068] Example 2 Step 1: FCC component preparation Take 0.22 g of ultrafine activated carbon black, 0.25 g of Cr2O3 (purity 99.9%), and 0.45 g of MoO3 (purity 99.95%). Add the above three powders to a 100 mL zirconium oxide ball mill jar and add 45 mL of anhydrous ethanol as the medium. The ball milling parameters are: rotation speed 280 rpm, alternating forward and reverse rotation, switching every 30 min, and a total ball milling time of 20 h.

[0069] After ball milling, the slurry was transferred to a glass dish and placed in a vacuum drying oven at 75°C for 14 h (vacuum degree <15 Pa). After drying, a light gray-green composite powder was obtained, weighing 0.87 g.

[0070] Step 2: Preparation of (Ti,Cr,Mo)C solid solution particles Take 90.0 g of TiO2 powder (rutile type, purity 99.9%), 0.90 g of FCC component, 0.40 g of Cr2O3, and 0.60 g of MoO3. Dry mix the powders in a V-type mixer for 2.5 h (28 rpm). Load the mixture into an alumina boat, push it into the middle of a tube furnace, and introduce a H2 / Ar mixed gas (H2 volume fraction 12%, total flow rate 180 mL / min). After venting for 35 min, raise the temperature. Increase the temperature to 1420℃ at 4.5℃ / min and hold for 3.5 h. After holding, allow it to cool naturally to room temperature, maintaining the same gas flow rate throughout. A dark gray powder weighing 71.8 g is obtained after removing it from the furnace.

[0071] Step 3: Preparation of steel-bonded alloy 70.0 g of (Ti,Cr,Mo)C solid solution particles, 120.0 g of Fe powder (99.5% purity), 1.2 g of Ni powder, 0.6 g of Mn powder, and 0.40 g of ultrafine carbon black were added to a V-type mixer and dry-mixed for 4.5 h (24 rpm). A single 25 g sample of powder was weighed and placed into a φ30 mm cemented carbide mold; unidirectional pressing was performed at a pressure of 210 MPa for 35 s, yielding a blank with a thickness of approximately 12 mm. The blank was placed in a graphite boat and pushed into a vacuum sintering furnace; vacuum was applied until the residual pressure was <35 Pa, and the temperature was increased to 1465℃ at 7.5℃ / min and held for 1.8 h; after holding, the blank was quickly removed from the furnace and oil quenched; immediately after quenching, it was placed in a tempering furnace and held at 280℃ for 2.5 h, then cooled with the furnace; finally, a disc-shaped sample with a total mass of approximately 191.9 g was obtained.

[0072] Step 4: Performance Testing 1. Oxygen content: Inert gas melting-infrared absorption method 2. Vickers hardness: Vickers hardness tester (HV10, load 10 kgf, holding time 15 s, average test at 8 points) 3. Bending strength: Three-point bending method (span 30 mm, loading rate 0.5 mm / min, universal testing machine, average of 5 spline samples) 4. Wire drawing die life test: The wire drawing die (die core φ12 mm, working cone angle 8°) is installed on a high-speed wire drawing machine (wire: φ5.5 mm high carbon steel wire drawn to φ4.0 mm, speed 18 m / s, lubricating oil circulation), and the cumulative wire drawing time is recorded until the die hole diameter increases by 0.015 mm or Ra>0.40 μm.

[0073] The test data is shown in Table 2 below: The material prepared in Example 2 still has a low oxygen content, and its hardness and flexural strength are both excellent. Its performance is slightly lower than that of Example 1, but it is still significantly better than the prior art.

[0074] Example 3 Step 1: FCC component preparation Take 0.55 g of ultrafine activated carbon black, 0.80 g of Cr2O3 (purity 99.9%), and 1.60 g of MoO3 (purity 99.95%). Add the above three powders to a 250 mL zirconium oxide ball mill jar and add 90 mL of anhydrous ethanol as the medium. The ball milling parameters are: rotation speed 320 rpm, alternating forward and reverse rotation, switching every 30 min, and a total ball milling time of 28 h.

[0075] After ball milling, the slurry was transferred to a glass dish and placed in a vacuum drying oven at 85°C for 10 h (vacuum degree <8 Pa). After drying, a light gray-green composite powder was obtained, weighing 2.68 g.

[0076] Step 2: Preparation of (Ti,Cr,Mo)C solid solution particles Take 90.0 g of TiO2 powder (rutile type, 99.9% purity), 2.20 g of FCC component, 1.00 g of Cr2O3, and 1.60 g of MoO3. Dry mix the powders in a V-type mixer for 1.8 h (32 rpm). Load the mixture into an alumina boat, push it into the middle of a tube furnace, and introduce a H2 / Ar mixed gas (18% H2 volume fraction, total flow rate 220 mL / min). After venting for 25 min, raise the temperature. Increase the temperature to 1480℃ at 5.5℃ / min and hold for 2.5 h. After holding, allow it to cool naturally to room temperature, maintaining the same gas flow rate throughout. A dark gray powder weighing 73.1 g is obtained after removing it from the furnace.

[0077] Step 3: Preparation of steel-bonded alloy 70.0 g of (Ti,Cr,Mo)C solid solution particles, 120.0 g of Fe powder (99.5% purity), 1.2 g of Ni powder, 0.6 g of Mn powder, and 0.10 g of ultrafine carbon black were added to a V-type mixer and dry-mixed for 3.8 h (26 rpm). A single 25 g sample of powder was weighed and placed into a φ30 mm cemented carbide mold; unidirectional pressing was performed at a pressure of 230 MPa for 25 s, yielding a blank with a thickness of approximately 12 mm. The blank was placed in a graphite boat and pushed into a vacuum sintering furnace; vacuum was applied until the residual pressure was <25 Pa, and the temperature was increased to 1475℃ at 8.5℃ / min and held for 1.6 h; after holding, the blank was quickly removed from the furnace and oil quenched; immediately after quenching, it was placed in a tempering furnace and held at 320℃ for 2.2 h, then cooled in the furnace; finally, a disc-shaped sample with a total mass of approximately 193.2 g was obtained.

[0078] Step 4: Performance Testing 1. Oxygen content: Inert gas melting-infrared absorption method 2. Vickers hardness: Vickers hardness tester (HV10, load 10 kgf, holding time 15 s, average test at 8 points) 3. Bending strength: Three-point bending method (span 30 mm, loading rate 0.5 mm / min, universal testing machine, average of 5 spline samples) 4. Wire drawing die life test: The wire drawing die (die core φ12 mm, working cone angle 8°) is installed on a high-speed wire drawing machine (wire: φ5.5 mm high carbon steel wire drawn to φ4.0 mm, speed 18 m / s, lubricating oil circulation), and the cumulative wire drawing time is recorded until the die hole diameter increases by 0.015 mm or Ra>0.40 μm.

[0079] The test data is shown in Table 3 below: The material prepared in Example 3 has a further reduced oxygen content, and its hardness and flexural strength are at a high level. Under the conditions of the upper limit of FCC component dosage and high Mo content, its wettability and wear resistance are better performed, and the wire drawing die life is longer.

[0080] Comparative Example 1 Step 1: Raw Material Preparation Take 70.0 g of TiC powder (99.5% purity), 118.0 g of Fe powder (99.5% purity), 6.0 g of Cr powder (99.9% purity), 6.0 g of Mo powder (99.9% purity), 2.0 g of Ni powder, 1.0 g of Mn powder, and 1.4 g of carbon black. Place all powders in a V-type mixer and dry mix for 3 hours (30 rpm).

[0081] Step 2: Mixing The above mixed powder was transferred to a 250 mL zirconia ball mill jar, and 80 mL of anhydrous ethanol was added as the medium. The ball milling parameters were: 280 rpm rotation speed, alternating between forward and reverse rotation, switching every 30 min, and a total ball milling time of 18 h.

[0082] After ball milling, the slurry was transferred to a glass dish and placed in a vacuum drying oven at 80°C for 12 h (vacuum degree <10 Pa). After drying, a gray-black mixed powder was obtained, weighing 203.8 g.

[0083] Step 3: Shaping and Sintering A single sample of approximately 25 g of powder was weighed and placed into a φ30 mm cemented carbide mold. Unidirectional pressing was applied at a pressure of 220 MPa for 30 s, resulting in a blank with a thickness of approximately 12 mm. The blank was then placed into a graphite boat and pushed into a vacuum sintering furnace. The furnace was evacuated until the residual pressure was <30 Pa, and the temperature was increased to 1460℃ at a rate of 8℃ / min, held for 1.5 h. After holding, the blank was quickly removed from the furnace and oil quenched. Immediately after quenching, the blank was placed in a tempering furnace and held at 320℃ for 2 h, then cooled in the furnace. Finally, a disc-shaped sample was obtained with a total mass of approximately 198.7 g.

[0084] Step 4: Performance Testing 1. Oxygen content: Inert gas melting-infrared absorption method 2. Vickers hardness: Vickers hardness tester (HV10, load 10 kgf, holding time 15 s, average test at 8 points) 3. Bending strength: Three-point bending method (span 30 mm, loading rate 0.5 mm / min, universal testing machine, average of 5 spline samples) 4. Wire drawing die life test: The wire drawing die (die core φ12 mm, working cone angle 8°) is installed on a high-speed wire drawing machine (wire: φ5.5 mm high carbon steel wire drawn to φ4.0 mm, speed 18 m / s, lubricating oil circulation), and the cumulative wire drawing time is recorded until the die hole diameter increases by 0.015 mm or Ra>0.40 μm.

[0085] The test data is shown in Table 4 below: Comparative Example 1 was prepared using the traditional GT35 process, which resulted in a high oxygen content, low hardness and bending strength, and a short lifespan in actual high-speed wire drawing tests, thus verifying the necessity of improving the technical solution of this invention.

[0086] Comparative Example 2 Step 1: Raw Material Preparation Take 70.0 g of TiC powder (99.5% purity), 120.0 g of Fe powder (99.5% purity), 6.0 g of Cr powder (99.9% purity), 6.0 g of Mo powder (99.9% purity), 1.2 g of Ni powder, 0.6 g of Mn powder, and 1.2 g of ultrafine carbon black. Place all powders in a V-type mixer and dry mix for 3.2 h (28 rpm).

[0087] Step 2: Mixing The above mixed powder was transferred to a 250 mL zirconia ball mill jar, and 75 mL of anhydrous ethanol was added as the medium. The ball milling parameters were: 290 rpm rotation speed, alternating between forward and reverse rotation, switching every 30 min, and a total ball milling time of 20 h.

[0088] After ball milling, the slurry was transferred to a glass dish and placed in a vacuum drying oven at 82°C for 11 h (vacuum degree <12 Pa). After drying, a gray-black mixed powder was obtained, weighing 204.1 g.

[0089] Step 3: Shaping and Sintering A single sample of approximately 25 g of powder was weighed and placed into a φ30 mm cemented carbide mold. Unidirectional pressing was applied at a pressure of 215 MPa for 32 s, resulting in a blank with a thickness of approximately 12 mm. The blank was then placed into a graphite boat and pushed into a vacuum sintering furnace. The furnace was evacuated until the residual pressure was <32 Pa, and the temperature was increased to 1468℃ at a rate of 7.8℃ / min, held for 1.7 h. After holding, the blank was quickly removed from the furnace and oil quenched. Immediately after quenching, the blank was placed in a tempering furnace and held at 310℃ for 2.3 h, then cooled in the furnace. Finally, a disc-shaped sample was obtained with a total mass of approximately 199.3 g.

[0090] Step 4: Performance Testing 1. Oxygen content: Inert gas melting-infrared absorption method 2. Vickers hardness: Vickers hardness tester (HV10, load 10 kgf, holding time 15 s, average test at 8 points) 3. Bending strength: Three-point bending method (span 30 mm, loading rate 0.5 mm / min, universal testing machine, average of 5 spline samples) 4. Wire drawing die life test: The wire drawing die (die core φ12 mm, working cone angle 8°) is installed on a high-speed wire drawing machine (wire: φ5.5 mm high carbon steel wire drawn to φ4.0 mm, speed 18 m / s, lubricating oil circulation), and the cumulative wire drawing time is recorded until the die hole diameter increases by 0.015 mm or Ra>0.40 μm.

[0091] The test data is shown in Table 5 below: Although Comparative Example 2 optimized the amount of carbon added and the addition of alloying elements in the later stage, it did not adopt the FCC core-shell composite carbon source and in-situ carbothermal reduction solid solution strengthening process, resulting in a still high oxygen content and limited improvement in interface wettability. In actual high-speed wire drawing tests, the life improvement was not significant and the performance improvement was small.

[0092] This article uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the technical scope disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be within the scope of protection of the present invention.

Claims

1. A high-hardness wear-resistant steel alloy based on solid solution strengthening, characterized in that, The product is made by weight of the following components: 32-38 parts of (Ti,Cr,Mo)C solid solution particles, 55-65 parts of Fe powder, 0.5-2 parts of Ni powder, 0.2-1 parts of Mn powder, and 0.1-0.3 parts of ultrafine carbon black.

2. The high-hardness wear-resistant steel alloy based on solid solution strengthening according to claim 1, characterized in that, The (Ti,Cr,Mo)C solid solution particles are prepared by the following components based on parts by weight: 40-50 parts TiO2 powder, 0.4-1.2 parts core-shell structured carbon-metal oxide composite carbon source, and 0.5-2.0 parts Cr-Mo composite oxide.

3. The high-hardness wear-resistant steel alloy based on solid solution strengthening according to claim 2, characterized in that, By weight, the core-shell structured carbon-metal oxide composite carbon source is made from the following components: 1-3 parts ultrafine activated carbon black, 2-5 parts Cr2O3, and 4-10 parts MoO3.

4. The high-hardness wear-resistant steel alloy based on solid solution strengthening according to claim 2, characterized in that, The Cr-Mo composite oxide specifically comprises the following components in parts by weight: 0.2~0.8 parts of Cr2O3 and 0.3~1.2 parts of MoO3.

5. A preparation method, characterized in that, The preparation method for the high-hardness wear-resistant steel alloy based on solid solution strengthening as described in any one of claims 1 to 4 comprises the following steps: S1. Mix (Ti,Cr,Mo)C solid solution particles, Fe powder, Ni powder, Mn powder and ultrafine carbon black evenly according to the weight parts to obtain mixed powder A; S2. The mixed powder A is pressed into a preform to obtain a blank; S3. Vacuum sinter the preform to obtain a sintered body; S4. The sintered body is obtained by quenching and tempering heat treatment.

6. The preparation method according to claim 5, characterized in that: In step S2, the compression molding pressure is 150~300 MPa; In step S3, the vacuum sintering temperature is 1450~1480℃, the holding time is 1~2 h, and the vacuum degree is 10~50 Pa. In step S4, oil quenching is used for quenching, and the tempering temperature is 200~400℃.

7. The preparation method according to claim 5 or 6, characterized in that, The (Ti,Cr,Mo)C solid solution particles were prepared by the following steps: S01. Mix TiO2 powder, core-shell structured carbon-metal oxide composite carbon source, and Cr-Mo composite oxide evenly to obtain mixed powder B; S02. The mixed powder B is placed in a reducing atmosphere and subjected to a high-temperature carbothermic reduction reaction to obtain (Ti,Cr,Mo)C solid solution particles.

8. The preparation method according to claim 7, characterized in that, In step S02: The reducing atmosphere is a mixture of H2 and Ar, wherein the volume fraction of H2 is 10%~20%; The reaction temperature is 1350~1550℃, and the temperature is maintained for 2~4 hours.

9. The preparation method according to claim 7, characterized in that, The core-shell structured carbon-metal oxide composite carbon source was prepared through the following steps: S001. Mix ultrafine activated carbon black, Cr2O3, and MoO3 to obtain mixture C; S002. The mixture C is subjected to ball milling; S003. The mixture C after ball milling is dried to obtain a core-shell structured carbon-metal oxide composite carbon source.

10. The preparation method according to claim 9, characterized in that: In step S002, the ball milling process is performed using a planetary ball mill with a ball-to-material mass ratio of (8~12):1, the ball milling medium is ethanol, the rotation speed is 200~400 rpm, and the ball milling time is 12~36 h. In step S003, the drying process is vacuum drying, with a temperature of 60~100℃ and a drying time of 8~16 h.

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