A casting processing technology of mine machinery wear-resistant parts

Abstract

This invention relates to the field of wear-resistant casting manufacturing technology and discloses a casting process for wear-resistant parts for mining machinery. The process includes: preparing wear-resistant alloy raw materials containing Cr, Mo, Ni, V, Ti, B, and rare earth elements according to a specified ratio; after smelting, slag removal, and composite purification treatment, adding rare earth ferrosilicon, ferrotitanium, ferrovanadium, and ferroboron for composite modification; setting a ceramic-reinforced prefabricated layer made of TiC particles, WC particles, Cr3C2 particles, and an inorganic binder at the position corresponding to the working surface of the wear-resistant part in the mold; then pouring molten steel into the mold, allowing the molten steel to penetrate into the ceramic-reinforced prefabricated layer and form a metallurgical bond; after sand removal, riser cutting, rough machining, and normalizing, quenching, and tempering treatments, the wear-resistant part for mining machinery is obtained. This invention can improve the abrasive wear resistance of the working surface of the wear-resistant part while maintaining core toughness, and is suitable for manufacturing wear-resistant components for mining crushing, conveying, and grinding equipment.

Description

Technical Field

[0001] This invention relates to the field of wear-resistant casting manufacturing technology, specifically a casting process for wear-resistant parts for mining machinery. Background Technology

[0002] Wear-resistant parts for mining machinery are widely used in crushers, ball mills, conveying equipment, mining equipment, and screening equipment. Typical components include hammers, liners, toothed plates, bucket teeth, guard plates, and wear blocks. These components are subjected to long-term impact, compression, sliding friction, and erosion from ore and sand during service, operating in harsh environments. Failure modes mainly manifest as surface wear, localized spalling, crack propagation, and impact fracture. Therefore, wear-resistant parts typically require high surface hardness, good impact toughness, and stable microstructure uniformity. Currently, most wear-resistant parts for mining machinery are made of high-manganese steel, high-chromium cast iron, or low-alloy wear-resistant steel. High-manganese steel has a certain work hardening ability, but under medium-low impact or fine-grained abrasive conditions, the hardened layer is insufficient, resulting in rapid early wear. High-chromium cast iron has high hardness, but the continuous distribution of carbides can easily lead to increased brittleness, making it prone to chipping under impact conditions. Although low-alloy wear-resistant steel has good toughness, its surface wear resistance is limited, making it difficult to meet the requirements for long-term use in highly abrasive ore environments. In addition, the following problems exist in the existing wear-resistant parts casting process: First, the control of inclusions and gases in the melt is insufficient, which easily leads to shrinkage cavities, slag inclusions and microcracks, affecting the service life of wear-resistant parts; Second, the wear-resistant phases mostly rely on the natural precipitation of alloying elements, and the size and distribution of the wear-resistant phases are difficult to control precisely; Third, the wear-resistant parts adopt the same microstructure design as a whole, making it difficult to balance the high hardness of the working surface and the high toughness of the core; Fourth, the subsequent heat treatment process mostly adopts a single quenching and tempering method, and the content of residual austenite and the distribution of carbides are unstable, resulting in large fluctuations in the wear resistance of different batches of products. Therefore, it is necessary to provide a casting process for wear-resistant parts of mining machinery. Through the synergistic control of melt purification, composite modification, working surface gradient reinforcement and graded heat treatment, the hardness, abrasive wear resistance and impact spalling resistance of the working surface of the wear-resistant parts can be improved without significantly reducing the overall toughness, thereby extending the service life of the wear-resistant parts of mining machinery. Summary of the Invention

[0003] In order to overcome the shortcomings of existing technologies that make it difficult to balance surface wear resistance and core toughness in wear-resistant parts, this invention provides a casting and processing technology for wear-resistant parts of mining machinery that can reduce casting defects and improve the wear resistance and impact spalling resistance of the working surface.

[0004] To achieve the above objectives, the present invention provides the following technical solution: a casting and processing technology for wear-resistant parts of mining machinery, comprising the following steps: S1. Prepare wear-resistant alloy raw materials according to the following mass percentages: C 0.45-0.85%, Si 0.40-1.20%, Mn 0.80-1.80%, Cr 2.50-6.50%, Mo 0.20-0.80%, Ni 0.20-1.00%, V 0.08-0.35%, Ti 0.05-0.25%, B 0.001-0.006%, RE 0.01-0.06%, P≤0.030%, S≤0.020%, with the balance being Fe and unavoidable impurities. S2. Melt the wear-resistant alloy raw material to 1580-1640℃, remove the slag, add the composite purifying agent and keep it at the temperature for 8-15 minutes to obtain purified molten steel. S3. Add a composite modifier to the purified molten steel. The composite modifier includes rare earth ferrosilicon, ferrotitanium, ferrovanadium and ferroboron. After adding, stir for 1 to 3 minutes and adjust the temperature of the molten steel to 1540 to 1600°C. S4. A ceramic reinforcing prefabricated layer is set in the mold at the position corresponding to the working surface of the wear-resistant part. The ceramic reinforcing prefabricated layer is prepared by mixing TiC particles, WC particles, Cr3C2 particles and inorganic binder and then drying. S5. Pour the molten steel obtained in step S3 into the mold, allowing the molten steel to penetrate into the ceramic-reinforced prefabricated layer and metallurgically bond with it. The pouring temperature is 1510-1570℃. After pouring, keep it warm and cool to obtain a casting with a gradient-reinforced working surface. S6. After cleaning the sand, cutting the riser and rough machining the casting, normalizing, quenching and tempering are performed in sequence to obtain wear-resistant parts for mining machinery.

[0005] Further, in step S2, the composite purifying agent is composed of Ca-Si alloy, Al particles and calcium fluoride, with a mass ratio of 1:(0.2~0.6):(0.1~0.4), and the amount of composite purifying agent added is 0.08~0.25% of the mass of molten steel.

[0006] Further, in step S3, the total amount of composite modifier added is 0.20 to 0.60% of the mass of molten steel, wherein the mass ratio of rare earth ferrosilicon, ferrotitanium, ferrovanadium and ferroboron is 1:(0.8 to 1.5):(0.6 to 1.2):(0.05 to 0.20).

[0007] Further, in step S4, the ceramic-reinforced precast layer comprises, by mass percentage: 30-50% TiC particles, 15-35% WC particles, 10-25% Cr3C2 particles, 5-15% high-alumina cement, and 1-5% graphite powder.

[0008] Furthermore, in step S4, the ceramic-reinforced preform is first dried at 80–120°C for 1–3 hours, and then preheated at 250–400°C for 0.5–2 hours before being placed into the mold.

[0009] Furthermore, in step S5, a metal chill is provided on one side of the working surface of the mold, and the distance between the metal chill and the ceramic-reinforced preform is 10-20 mm.

[0010] Further, in step S6, the normalizing treatment is: heating the casting to 880-930℃, holding it at that temperature for 1.5-3 hours, and then air cooling; the quenching treatment is: heating the casting to 900-960℃, holding it at that temperature for 1-2.5 hours, and then air cooling; the tempering treatment is: holding the casting at 280-320℃ for 2-4 hours, and then air cooling.

[0011] Furthermore, in step S6, a cryogenic treatment is included between the quenching treatment and the tempering treatment. The cryogenic treatment involves cooling the casting to -80 to -120°C and holding it at that temperature for 1 to 3 hours.

[0012] Compared with the prior art, the present invention has the following beneficial technical effects: This invention achieves a composite microstructure in mining machinery wear-resistant parts through the synergistic combination of wear-resistant alloy composition design, composite purification of molten steel, rare earth composite modification, ceramic particle working surface reinforcement, and subsequent heat treatment processes. Specifically, the combined use of elements such as Cr, Mo, V, Ti, B, and RE improves the hardenability of the matrix, refines grains, and improves carbide morphology, preventing brittle cracking caused by coarse, continuous carbide distribution. The composite purifying agent, composed of Ca-Si alloy, Al particles, and calcium fluoride, reduces oxide inclusions, sulfide inclusions, and fine inclusions in the molten steel, lowering casting porosity, shrinkage, and microcrack defects. The composite modification treatment of rare earth ferrosilicon, ferrotitanium, ferrovanadium, and ferroboron further improves the as-cast microstructure, resulting in a finer and more dispersed distribution of the wear-resistant phases. This enhances the crack resistance, microstructure stability, and reliability of the wear-resistant parts under repeated impact and abrasive wear conditions. This invention incorporates a ceramic-reinforced precast layer composed of TiC, WC, and Cr3C2 particles on the working surface of wear-resistant parts. During casting, molten steel penetrates the gaps between the ceramic particles and forms a firmly bonded gradient reinforcement layer with the metal matrix. This allows the working surface to withstand the cutting and erosion wear from ores and sand, reducing direct wear on the metal matrix. Unlike ordinary surface weld overlays or coatings, this gradient reinforcement layer forms synchronously with the casting matrix during the casting process, resulting in a stable interface bond and reducing the likelihood of peeling, chipping, and cracking. Simultaneously, by using metal chills to increase the solidification rate of the working surface area, combined with normalizing, quenching, tempering, and optional cryogenic treatment, the microstructure can be further refined, residual stress reduced, and retained austenite decreased. This improves hardness retention and impact resistance, thereby extending the service life of wear-resistant parts in mining machinery such as crusher hammers, liners, tooth plates, bucket teeth, and guard plates, and reducing equipment downtime for replacement and maintenance costs. Attached Figure Description

[0013] Figure 1 The image shows a scanning electron microscope (SEM) image of the reinforcing layer on the working surface of the wear-resistant part of the mining machinery prepared in Example 1. Detailed Implementation

[0014] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0015] The raw materials and equipment used in this application embodiment can all be commercially available products, specifically as follows: Ca-Si alloy can be Ca28Si60 type silicon-calcium alloy produced by Anyang Hengxing Metallurgical Materials Co., Ltd.; Al particles can be industrial aluminum particles produced by Gongyi Huayu Aluminum Co., Ltd., with a purity ≥99.0%; calcium fluoride can be metallurgical grade CaF2 powder produced by Lingshou Jinyuan Mineral Products Processing Plant, with a CaF2 content ≥90%; rare earth ferrosilicon can be FeSiRE23 type rare earth ferrosilicon alloy produced by Baotou Huashang Rare Earth Alloy Co., Ltd.; ferrotitanium can be FeTi30 ferrotitanium produced by Jinzhou Special Metallurgical New Materials Co., Ltd.; ferrovanadium can be FeV50 ferrovanadium produced by Panzhihua Iron and Steel Group Co., Ltd.; and ferroboron can be FeB20C0.5 ferroboron produced by Liaoning Hongtuo New Materials Co., Ltd. The above raw materials can also be replaced by similar commercially available products that meet the same composition range and metallurgical quality requirements.

[0016] The TiC particles used in the ceramic-reinforced precast layer can be TiC ceramic powder produced by Shanghai Yaotian New Material Technology Co., Ltd., with a particle size of 40-80 mesh; the WC particles can be WC particles produced by Zhuzhou Hard Alloy Group Co., Ltd., with a particle size of 60-100 mesh; the Cr3C2 particles can be chromium carbide particles produced by Nangong Naiyat Alloy Welding Materials Co., Ltd., with a particle size of 60-100 mesh; the high-alumina cement can be CA-70 type high-alumina cement produced by Zhengzhou Dengfeng Melting Material Co., Ltd.; and the graphite powder can be flake graphite powder produced by Qingdao Huatai Lubrication and Sealing Technology Co., Ltd., with a particle size of 100-200 mesh. All the above particles are sieved and dried before use to ensure the molding stability of the ceramic-reinforced precast layer and the uniformity of molten steel penetration.

[0017] RE represents rare earth elements, specifically Ce.

[0018] Example 1 This embodiment provides a casting and processing technology for wear-resistant parts of mining machinery, specifically for crusher liners, which includes the following steps: S1. Prepare wear-resistant alloy raw materials according to the following mass percentages: C 0.45%, Si 0.40%, Mn 0.80%, Cr 2.50%, Mo 0.20%, Ni 0.20%, V 0.08%, Ti 0.05%, B 0.001%, RE 0.01%, P≤0.030%, S≤0.020%, with the balance being Fe and unavoidable impurities. S2. Add the above wear-resistant alloy raw materials to a medium-frequency induction furnace for smelting. The smelting temperature is controlled at 1580℃. After the raw materials are completely melted, remove the surface slag. Then add 0.08% of the composite purifying agent by mass of the molten steel. The composite purifying agent is composed of Ca-Si alloy, Al particles and calcium fluoride, with a mass ratio of 1:0.2:0.1. After adding, keep the temperature for 8 minutes to obtain purified molten steel. S3. Add 0.20% of the composite modifier by mass of the molten steel to the purified molten steel. The composite modifier is composed of rare earth ferrosilicon, ferrotitanium, ferrovanadium and ferroboron in a mass ratio of 1:0.8:0.6:0.05. Stir for 1 minute after adding and adjust the temperature of the molten steel to 1540℃. S4. A ceramic-reinforced precast layer is placed in the mold at the position corresponding to the working surface of the liner. The ceramic-reinforced precast layer is composed of 39% TiC particles, 35% WC particles, 20% Cr3C2 particles, 5% high-alumina cement, and 1% graphite powder by mass percentage. After the above components are mixed evenly, water is added to make a plastic material, which is then pressed into a precast layer that matches the shape of the working surface of the liner. The precast layer is first dried at 80℃ for 1 hour, then preheated at 250℃ for 0.5 hours before being placed into the mold. S5. Pour the molten steel obtained in step S3 into the mold, allowing the molten steel to penetrate into the gaps between the particles of the ceramic-reinforced precast layer and form a metallurgical bond with it. The pouring temperature is 1510℃. A metal chill is placed on one side of the working surface of the mold, with a distance of 10mm between the metal chill and the ceramic-reinforced precast layer. After pouring, the mold is kept warm and cooled to obtain a casting with a gradient-reinforced working surface. S6. After cleaning the sand, cutting the risers and rough machining the casting, heat treatment is carried out: first, the casting is heated to 880℃, held for 1.5h and then air-cooled for normalizing treatment; then heated to 900℃, held for 1h and then air-cooled for quenching treatment; then deep cryogenic treatment at -100℃ for 2h; finally, tempering treatment at 280℃ for 2h and then air-cooled to obtain wear-resistant parts for mining machinery.

[0019] Depend on Figure 1 It is evident that the ceramic hard particles such as TiC, WC, and Cr3C2 are distributed in irregular blocks within the metal matrix. The particles are tightly bonded to the matrix interface, with no obvious through cracks or large-area pores observed. The metal matrix has a fine and dense structure, and the hard phase is evenly distributed, indicating that the molten steel can penetrate the ceramic-reinforced preform layer well and form a stable bond, thereby improving the working surface's resistance to abrasive wear and impact spalling.

[0020] Example 2 This embodiment provides a casting and processing technology for wear-resistant parts of mining machinery, specifically for crusher hammers, which includes the following steps: S1. Prepare wear-resistant alloy raw materials according to the following mass percentages: C 0.65%, Si 0.80%, Mn 1.30%, Cr 4.50%, Mo 0.50%, Ni 0.60%, V 0.22%, Ti 0.15%, B 0.003%, RE 0.035%, P≤0.030%, S≤0.020%, with the balance being Fe and unavoidable impurities. S2. Melt the wear-resistant alloy raw material to 1610℃, remove the slag, and add 0.16% of the composite purifying agent by mass of the molten steel. The composite purifying agent is composed of Ca-Si alloy, Al particles and calcium fluoride, with a mass ratio of 1:0.4:0.25. After adding, keep it at the temperature for 12 minutes to obtain purified molten steel. S3. Add 0.40% of the composite modifier by mass of the molten steel to the purified molten steel. The composite modifier is composed of rare earth ferrosilicon, ferrotitanium, ferrovanadium and ferroboron in a mass ratio of 1:1.2:0.9:0.12. Stir for 2 minutes after adding and adjust the temperature of the molten steel to 1570℃. S4. A ceramic-reinforced precast layer is placed in the mold at the position corresponding to the hammer's striking surface. The ceramic-reinforced precast layer consists of 44% TiC particles, 25% WC particles, 18% Cr3C2 particles, 10% high-alumina cement, and 3% graphite powder by mass percentage. After the above components are mixed evenly, they are pressed into shape, dried at 100℃ for 2 hours, and then preheated at 320℃ for 1 hour before being placed into the mold. S5. Pour the molten steel obtained in step S3 into the mold, allowing the molten steel to fully penetrate into the ceramic-reinforced precast layer. The pouring temperature is 1540℃. Set a metal chill on one side of the working surface of the mold. The distance between the metal chill and the ceramic-reinforced precast layer is 15mm. After pouring, keep it warm and cool to obtain a hammer casting with a gradient-reinforced working surface. S6. After cleaning the sand, cutting the riser and rough machining the casting, first heat it to 905℃, hold it for 2 hours and then air cool it for normalizing treatment; then heat it to 930℃, hold it for 1.8 hours and then air cool it for quenching treatment; then cryogenic treatment at -100℃ for 2 hours; finally, hold it at 300℃ for 3 hours and then air cool it for tempering treatment to obtain wear-resistant parts for mining machinery.

[0021] Example 3 This embodiment provides a casting and processing technology for wear-resistant parts of mining machinery, the object of which is a mining gear plate, and includes the following steps: S1. Prepare wear-resistant alloy raw materials according to the following mass percentages: C 0.85%, Si 1.20%, Mn 1.80%, Cr 6.50%, Mo 0.80%, Ni 1.00%, V 0.35%, Ti 0.25%, B 0.006%, RE 0.06%, P≤0.030%, S≤0.020%, with the balance being Fe and unavoidable impurities. S2. Melt the wear-resistant alloy raw material to 1640℃, remove the slag, and add 0.25% of the composite purifying agent by mass of the molten steel. The composite purifying agent is composed of Ca-Si alloy, Al particles and calcium fluoride, with a mass ratio of 1:0.6:0.4. After adding, keep it at the temperature for 15 minutes to obtain purified molten steel. S3. Add 0.60% of the composite modifier by mass of the molten steel to the purified molten steel. The composite modifier is composed of rare earth ferrosilicon, ferrotitanium, ferrovanadium and ferroboron in a mass ratio of 1:1.5:1.2:0.20. Stir for 3 minutes after adding and adjust the temperature of the molten steel to 1600℃. S4. A ceramic-reinforced precast layer is placed in the mold at the position corresponding to the tooth surface of the tooth plate. The ceramic-reinforced precast layer is composed of 45% TiC particles, 20% WC particles, 15% Cr3C2 particles, 15% high-alumina cement, and 5% graphite powder by mass percentage. After mixing the components, the precast layer is dried at 120℃ for 3 hours, then preheated at 400℃ for 2 hours before being placed into the mold. S5. Pour the molten steel obtained in step S3 into the mold, allowing the molten steel to penetrate the ceramic-reinforced prefabricated layer and bond with the metal matrix. The pouring temperature is 1570℃. A metal chill is placed on one side of the working surface of the mold, with a distance of 20mm between the metal chill and the ceramic-reinforced prefabricated layer. After pouring, the mold is kept warm and cooled to obtain a casting with a gradient-reinforced working surface. S6. After cleaning the sand, cutting the riser and rough machining the casting, first heat it to 930℃, hold it for 3 hours and then air cool it for normalizing treatment; then heat it to 960℃, hold it for 2.5 hours and then air cool it for quenching treatment; then cryogenic treatment at -120℃ for 3 hours; finally, hold it at 320℃ for 4 hours and then air cool it for tempering treatment to obtain wear-resistant parts for mining machinery.

[0022] Comparative Example 1 The difference between this comparative example and Example 3 is that the composite purifying agent composed of Ca-Si alloy, Al particles and calcium fluoride was not added in step S2, and only conventional slag removal was performed after smelting. The other raw material ratios, ceramic reinforcement preforms, casting conditions and heat treatment conditions are the same as in Example 3.

[0023] Comparative Example 2 The difference between this comparative example and Example 3 is that the composite modifier composed of rare earth ferrosilicon, ferrotitanium, ferrovanadium and ferroboron was not added in step S3. The molten steel was simply adjusted to the same casting temperature and then directly cast. The remaining steps were the same as in Example 3.

[0024] Comparative Example 3 The difference between this comparative example and Example 3 is that: in step S4, no ceramic-reinforced precast layer composed of TiC particles, WC particles and Cr3C2 particles is set; the working surface and core of the casting are both made of the same low-alloy wear-resistant steel matrix; and the remaining alloy composition, steel purification, composite modification, casting and heat treatment conditions are the same as in Example 3.

[0025] Comparative Example 4 The difference between this comparative example and Example 3 is that only conventional quenching and tempering are performed in step S6, without normalizing and cryogenic treatment; the quenching temperature is 960℃, held for 2.5 hours and then air-cooled; the tempering temperature is 320℃, held for 4 hours and then air-cooled; the remaining steps are the same as in Example 3.

[0026] To verify the performance of the wear-resistant parts for mining machinery obtained in Examples 1-3 and Comparative Examples 1-4 of this invention, chemical composition, microstructure, working surface hardness, core impact performance, abrasive wear performance, interfacial bonding strength of the reinforcing layer, and casting defect area ratio were tested on each group of wear-resistant parts. At least three samples were used in each group, and the average value of the test results was taken. 1. Chemical composition testing Samples were taken from the vicinity of the gating system and risers and from the non-working area of ​​the casting body in each group. After grinding and cleaning, the elemental content was determined using a spark discharge atomic emission spectrometer. The test was conducted in accordance with GB / T 4336-2016 "Determination of Multi-Element Content in Carbon Steel and Medium-Low Alloy Steel - Spark Discharge Atomic Emission Spectrometry (Conventional Method)" to confirm that the contents of major elements such as C, Si, Mn, Cr, Mo, Ni, V, and Ti in each example and comparative example met the set range. 2. Rockwell hardness test of working surface The working surface hardness was tested according to GB / T 230.1-2018 "Metallic materials, Rockwell hardness test - Part 1: Test method". Before testing, the working surface of the wear-resistant part was ground flat and cleaned. The test was conducted using an HRC scale. For each sample, 10 points were tested on the reinforcing layer of the working surface, avoiding edges, obvious holes and cracks. The maximum and minimum values ​​were removed, and the average value was taken as the working surface hardness of the sample group. 3. Cardiac impact performance test Impact performance was conducted according to GB / T 229-2020 "Charpy Impact Test Method for Metallic Materials". Standard Charpy V-notch specimens were cut from the core or unreinforced area of ​​the wear-resistant part, with specimen dimensions of 10mm × 10mm × 55mm and a notch depth of 2mm. The test temperature was room temperature, and the impact absorbed energy KV2 was determined using a pendulum impact testing machine. Three parallel specimens were tested in each group, and the average value was taken. This index is used to evaluate the fracture resistance and core toughness of the wear-resistant part under impact conditions. 4. Abrasive wear performance test Abrasive wear performance was tested according to the ASTM G65 dry abrasive rubber wheel wear test method. Wear specimens with working surfaces of each group of wear-resistant parts were machined to approximately 25mm × 75mm × 10mm, with the reinforcing layer of the working surface serving as the wear contact surface. Dry quartz sand was used as the abrasive, the rubber wheel speed was 200 r / min, the load was 130 N, and the wear time was 30 min. The mass of the specimens was weighed before and after the test using an electronic balance with an accuracy of 0.1 mg, and the wear volume loss was calculated using the following formula: Wear volume loss V = (m0 - m1) / ρ In the formula, V represents the wear volume loss in mm³; m0 is the mass before wear, m1 is the mass after wear, and ρ is the sample density. A smaller wear volume loss indicates better resistance to abrasive wear. For ease of comparison, the wear volume loss of Comparative Example 3 is used as the benchmark to calculate the relative wear resistance index: Relative wear resistance index = Wear volume loss of Comparative Example 3 / Wear volume loss of this group. 5. Reinforcement layer interface bonding strength test Shear specimens with the interface were cut from the transition region between the reinforcing layer and the metal matrix. Following the loading principles of GB / T 7314-2017 "Metallic Materials - Compression Test at Room Temperature", a dedicated shear fixture was used on a universal testing machine at a loading speed of 1 mm / min. The maximum load Fmax at which shear failure occurred along the interface of the reinforcing layer was recorded, and the interfacial shear strength was calculated using τ = Fmax / A, where A is the effective shear area. Comparative Example 3 did not have a ceramic reinforcing prefabricated layer, therefore the interfacial bonding strength was not tested.

[0027] Table 1: Performance Tests

[0028] As shown in Table 1, the overall performance of Examples 1-3 is relatively stable, with a working surface hardness of 60.7-62.7 HRC, a core impact absorption energy of 31.6-33.1 J, a wear volume loss of 43.9-46.2 mm³, and an interfacial shear strength of 164-171 MPa. The differences between the examples are small, indicating that the process of this invention has good repeatability and applicability. Compared with the comparative examples, the examples, while maintaining high core toughness, significantly improved the working surface hardness, wear resistance, and reinforcing layer bonding strength. This demonstrates a synergistic effect between composite purification, composite modification, ceramic reinforcing prefabrication, and the heat treatments of normalizing, quenching, deep cryogenics, and tempering, which can form a gradient reinforcement structure with high wear resistance on the working surface and high toughness in the core.

[0029] Comparative examples show that in Comparative Example 1, without the addition of the composite purifying agent, the core impact absorption energy decreased from 33.1 J in Example 3 to 26.4 J, the wear volume loss increased from 43.9 mm³ to 59.8 mm³, and the interfacial shear strength decreased from 171 MPa to 132 MPa. This indicates that insufficient purification of the molten steel increases inclusions, micropores, and interfacial defects, thereby weakening toughness and the bonding quality of the reinforcing layer. In Comparative Example 2, without the addition of the composite modifier, the hardness decreased to 58.9 HRC, and the wear volume loss increased to 66.5 mm³. This indicates that without rare earth, titanium, vanadium, and boron composite modification, grain refinement and carbide dispersion strengthening are insufficient, and the wear-resistant phase distribution is not uniform, leading to a decrease in resistance to abrasive wear.

[0030] Comparative Example 3, without the ceramic reinforcement prefabricated layer, exhibited the lowest working surface hardness (53.6 HRC) and the highest wear volume loss (111.7 mm³), with a relative wear resistance index of 1.00. This indicates that a single low-alloy wear-resistant steel matrix is ​​insufficient to meet the requirements of abrasive wear conditions in mining. Although the core impact absorption energy of Comparative Example 3 was 34.0 J, slightly higher than that of Example 3, its wear resistance was significantly insufficient. This demonstrates that the present invention, by incorporating a ceramic reinforcement layer only on the working surface, can significantly improve the wear resistance of the working surface while maintaining the core toughness. Comparative Example 4, without normalizing and cryogenic treatment, showed a decrease in hardness, impact toughness, wear resistance, and interfacial bonding strength. This indicates that graded heat treatment has a significant effect on refining the microstructure, reducing residual stress, decreasing retained austenite, and improving hardness stability.

[0031] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0032] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

[0033] Those skilled in the art should understand that the above descriptions are merely several specific embodiments of the present invention, and not all embodiments.

Claims

1. A casting and processing technology for wear-resistant parts of mining machinery, characterized in that, Includes the following steps: S1. Prepare wear-resistant alloy raw materials according to the following mass percentages: C 0.45-0.85%, Si 0.40-1.20%, Mn 0.80-1.80%, Cr 2.50-6.50%, Mo 0.20-0.80%, Ni 0.20-1.00%, V 0.08-0.35%, Ti 0.05-0.25%, B 0.001-0.006%, RE 0.01-0.06%, P≤0.030%, S≤0.020%, with the balance being Fe and unavoidable impurities. S2. Melt the wear-resistant alloy raw material to 1580-1640℃, remove the slag, add the composite purifying agent and keep it at the temperature for 8-15 minutes to obtain purified molten steel. S3. Add a composite modifier to the purified molten steel. The composite modifier includes rare earth ferrosilicon, ferrotitanium, ferrovanadium and ferroboron. After adding, stir for 1 to 3 minutes and adjust the temperature of the molten steel to 1540 to 1600°C. S4. A ceramic reinforcing prefabricated layer is set in the mold at the position corresponding to the working surface of the wear-resistant part. The ceramic reinforcing prefabricated layer is prepared by mixing TiC particles, WC particles, Cr3C2 particles and inorganic binder and then drying. S5. Pour the molten steel obtained in step S3 into the mold, allowing the molten steel to penetrate into the ceramic-reinforced prefabricated layer and metallurgically bond with it. The pouring temperature is 1510-1570℃. After pouring, keep it warm and cool to obtain a casting with a gradient-reinforced working surface. S6. After cleaning the sand, cutting the riser and rough machining the casting, normalizing, quenching and tempering are performed in sequence to obtain wear-resistant parts for mining machinery.

2. The casting and processing technology for wear-resistant parts of mining machinery according to claim 1, characterized in that, In step S2, the composite purifying agent is composed of Ca-Si alloy, Al particles and calcium fluoride, with a mass ratio of 1:(0.2-0.6):(0.1-0.4), and the amount of composite purifying agent added is 0.08-0.25% of the mass of molten steel.

3. The casting and processing technology for wear-resistant parts of mining machinery according to claim 1, characterized in that, In step S3, the total amount of composite modifier added is 0.20 to 0.60% of the mass of molten steel, wherein the mass ratio of rare earth ferrosilicon, ferrotitanium, ferrovanadium and ferroboron is 1:(0.8 to 1.5):(0.6 to 1.2):(0.05 to 0.20).

4. The casting and processing technology for wear-resistant parts of mining machinery according to claim 1, characterized in that, In step S4, the ceramic-reinforced precast layer comprises, by mass percentage: 30-50% TiC particles, 15-35% WC particles, 10-25% Cr3C2 particles, 5-15% high-alumina cement, and 1-5% graphite powder.

5. The casting and processing technology for wear-resistant parts of mining machinery according to claim 1, characterized in that, In step S4, the ceramic-reinforced preform is first dried at 80–120°C for 1–3 hours, then preheated at 250–400°C for 0.5–2 hours before being placed into the mold.

6. The casting and processing technology for wear-resistant parts of mining machinery according to claim 1, characterized in that, In step S5, a metal chill is provided on one side of the working surface of the mold, and the distance between the metal chill and the ceramic-reinforced preform is 10-20 mm.

7. The casting and processing technology for wear-resistant parts of mining machinery according to claim 1, characterized in that, In step S6, the normalizing treatment is as follows: the casting is heated to 880-930℃, held for 1.5-3 hours and then air-cooled; the quenching treatment is as follows: the casting is heated to 900-960℃, held for 1-2.5 hours and then air-cooled; the tempering treatment is as follows: the casting is held at 280-320℃ for 2-4 hours and then air-cooled.

8. The casting and processing technology for wear-resistant parts of mining machinery according to claim 1, characterized in that, In step S6, a cryogenic treatment is included between the quenching treatment and the tempering treatment. The cryogenic treatment involves cooling the casting to -80 to -120°C and holding it at that temperature for 1 to 3 hours.

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