Wear-resistant alloy material suitable for scraper of belt conveyor sweeper and preparation method of wear-resistant alloy material

Abstract

The invention discloses a wear-resistant alloy material suitable for a scraper of a belt conveyor sweeper and a preparation method of the wear-resistant alloy material, and belongs to the technical field of hard alloy material manufacturing in the powder metallurgy field. The brand of the alloy material is QH10, the alloy material comprises the following components in percentage by mass: 9.5-10% of a binding phase and the balance of WC, the grain size of WC is 0.6-0.8 mu m, and the Fisher particle size of Co is 0.6-1.3 mu m. The preparation method comprises the steps of ingredient wet grinding, compression molding, degreasing sintering, annealing treatment and the like. By optimizing the alloy composition proportion and the preparation process, the alloy material is uniform in microstructure and few in defects such as holes and thickness, and has high hardness, fracture toughness, cutting edge breakage resistance, wear resistance and corrosion resistance. Compared with tool steel blades made of manganese steel, common hard alloy materials and the like, the service life of the sweeper scraping piece made of the material is greatly prolonged, and the use requirements under different working conditions can be met.

Description

Technical Field

[0001] This invention belongs to the field of powder metallurgy technology and relates to a cemented carbide material manufacturing technology, especially a wear-resistant alloy material suitable for belt conveyor cleaner scrapers and its preparation method. Background Technology

[0002] Scraper blades are the core component of belt conveyor cleaners, widely used in large heavy industrial sites such as mines, coal washing plants, power plants, and steel mills to clean various conveyed materials such as coal slurry, cement, stone, metal, and food. As a key component of conveying equipment, scraper blades must possess excellent wear resistance, corrosion resistance, and toughness to reduce replacement frequency, improve production efficiency, and lower manual intervention costs.

[0003] Currently, most scraper blades on the market use high-wear-resistant, high-strength cemented carbide strips as their core material. While this can guarantee scraping performance and service life to a certain extent, many technical bottlenecks remain. From a market perspective, although existing foreign alloy scraper blades use cemented carbide materials, they are not well-suited to the complex and diverse working conditions in China, and suffer from high prices, long production and procurement cycles, making it difficult to meet the actual needs of domestic enterprises. Although some domestic material manufacturers have attempted to develop cemented carbide scraper blades, existing products have not yet achieved the expected results in key performance indicators such as wear resistance and toughness. During use, problems such as edge chipping, rapid wear, and cracks caused by internal stress during processing frequently occur, leading to high scraper replacement frequency. This not only increases production costs but also seriously affects the continuity of material conveying.

[0004] From the perspective of material properties, the core problems of existing cemented carbide scrapers stem from imperfections in composition design and preparation processes. On the one hand, traditional alloy materials suffer from poor grain size control, with coarse grain structures making it difficult to balance hardness and toughness. On the other hand, issues such as insufficient ball milling, unreasonable sintering process parameters, and incomplete stress relief during preparation result in uneven microstructure, including defects such as pores and inclusions, which in turn affect the overall mechanical properties of the material. Therefore, developing a scraper scraper alloy material with stable physical properties, controllable microstructure and defects, excellent machinability, and longer service life, along with its preparation method, has become a pressing technical challenge in this field. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a wear-resistant alloy material suitable for belt conveyor cleaner scrapers and its preparation method.

[0006] The technical problem solved by this invention is achieved through the following technical solution:

[0007] A wear-resistant alloy material suitable for scraper blades of belt conveyor cleaners, characterized in that: the alloy material grade is QH10, and its composition by mass percentage includes: 9.5-10% binder phase, with the balance being tungsten carbide (WC).

[0008] The tungsten carbide (WC) has a grain size of 0.6–0.8 μm, and the binder phase has a Fisher grain size of 0.6–1.3 μm.

[0009] Furthermore, the binder phase is Co or a composite system of Co and Ni, and the total content of Co and Ni is 9.5% to 10% by mass percentage, wherein Ni accounts for 0% to 1 / 3 of the total binder phase by mass, and the balance is tungsten carbide (WC), wherein the tungsten carbide (WC) may contain trace impurities of less than 0.1%.

[0010] Furthermore, the alloy material contains a grain growth inhibitor, namely Cr3C2.

[0011] A method for preparing a wear-resistant alloy suitable for belt conveyor scraper blades, characterized by comprising the following steps:

[0012] Step 1, Batching and Wet Milling: Batch the alloy materials according to the composition ratio, and add grain growth inhibitors and forming agents. First, pre-mill the grain growth inhibitors, forming agents and 1 / 4 to 1 / 3 of the wet milling media for 2 to 5 hours. Then add tungsten carbide (WC), binder phase and the remaining wet milling media and continue ball milling. After ball milling, spray dry to obtain the mixture.

[0013] Step 2, pressing and molding: The mixture is pressed and molded using precision pressing or pre-pressing, cold isostatic pressing and cutting processes to obtain a compact with good density and uniform size.

[0014] Step 3, debinding and sintering: The pressed blank is placed in a pressure furnace for debinding and sintering. The debinding temperature and time are set according to the size of the pressed blank and the type of molding agent. The sintering temperature is 1380-1480℃, the argon gas pressure is 4-10MPa, and the holding time is 0.5-1.5 hours.

[0015] Step 4, Cooling and Annealing: When the pressed billet is cooled to 1000-1200℃, it is rapidly cooled with argon gas. After cooling to below 80℃, it is heated to 500-800℃ for annealing. The annealing temperature is maintained for 3-10 hours to eliminate internal stress and obtain wear-resistant alloy material.

[0016] Furthermore, in step 1, the molding agent is polyethylene glycol, and the amount of the molding agent added is 1 to 4% of the total mass of the raw materials.

[0017] Furthermore, in step 1, the wet grinding medium is anhydrous alcohol, the ball mill speed is 30-40 rpm, and the subsequent ball milling time is 30-60 hours.

[0018] Furthermore, in step 1, granulation is carried out using either spray drying or vacuum drying. Spray drying yields a mixture with excellent flowability, while vacuum drying yields a mixture with excellent pressing performance.

[0019] Moreover, in step 2, the precision pressing molding is achieved by using a dry powder automatic press with a volumetric method and a spray material with excellent flowability, so as to achieve uniform density and excellent appearance quality of the pressed blank.

[0020] Furthermore, in step 3, the degreasing temperature is set according to the type of molding agent: the degreasing temperature for polyethylene glycol and paraffin molding agents is 450-500℃, and the degreasing temperature for other types of molding agents is 280-400℃; the heating time from degreasing to the final sintering temperature is 3.5-6h, and the total sintering time is 25-85h.

[0021] The advantages and positive effects of this invention are:

[0022] 1. The alloy material obtained by this invention has a Rockwell hardness of 90.5–91.5 HRA and a fracture toughness of 11.5–14.0 MPa·m. 1 / 2 With a bending strength of ≥3700MPa, it achieves synergistic improvement in hardness, toughness, and wear resistance compared to existing manganese steel and ordinary hard alloy materials, effectively overcoming the technical defects of existing scrapers that are prone to chipping, rapid wear, and cracking.

[0023] 2. By selecting fine-particle raw materials, adding grain growth inhibitors, and controlling the precise sintering process, the present invention achieves a uniform microstructure in the alloy material, with WC grains all less than 1μm, uniform distribution of the binder phase, and very few defects such as pores and inclusions, thus providing structural assurance for the material's excellent comprehensive performance.

[0024] 3. The material of this invention has both excellent wear resistance and corrosion resistance, and can adapt to the complex working conditions of different places such as mines, power plants, and steel plants. It can clean a variety of materials such as coal slurry, cement, and metal. Comparative experiments show that the scraper blades made of this material have a significantly longer service life than traditional manganese steel and ordinary carbide blades, reducing the frequency of scraper replacement and lowering production costs and manual intervention costs.

[0025] 4. The processes used in this invention, such as batching, ball milling, pressing, and sintering, are all mature processes in the field of powder metallurgy. The equipment is highly compatible, the process parameters are highly controllable, and it is suitable for large-scale industrial production. Moreover, the production cycle is short, which can meet the bulk purchasing needs of domestic enterprises. Compared with imported products, it has a greater cost advantage and supply stability. Attached Figure Description

[0026] Figure 1 The image shows the microstructure of the alloy material of this invention (SEM image, EHT=15.00kV, WD=9.1mm, Mag=5.00KX, Signal A=AsB).

[0027] Figure 2 Metallographic photograph of the microstructure of the alloy material of this invention (magnification 1500x). Detailed Implementation

[0028] The embodiments of the present invention will be further described in detail below with reference to the accompanying drawings:

[0029] A wear-resistant alloy material suitable for scraper blades of belt conveyor cleaners, the alloy material grade is QH10, and its innovation lies in the fact that its composition, by mass percentage, includes: 9.5-10% binder phase, the balance being tungsten carbide (WC), and may contain trace impurities of less than 0.1%.

[0030] Preferably, the tungsten carbide (WC) has a grain size of 0.6–0.8 μm; and the binder phase has a Fisher grain size of 0.6–1.3 μm.

[0031] More preferably, the binder phase is Co, or a composite system of Co and Ni can also be used, i.e., the total mass percentage of (Co+Ni) is 9.5-10%, wherein Ni accounts for 0-1 / 3 of the total binder phase by mass, and the balance is WC (which may contain trace impurities of less than 0.1%). The addition of Ni can further optimize the corrosion resistance and toughness of the material.

[0032] A method for preparing a wear-resistant alloy suitable for belt conveyor cleaner scraper blades, the innovation of which lies in the following steps:

[0033] Ingredient preparation and wet milling: Ingredients are prepared according to the above-mentioned design ratio, and 1-4% of the total mass of raw materials are added as a molding agent (preferably polyethylene glycol) and a grain growth inhibitor (preferably Cr3C2). The grain growth inhibitor, molding agent and 1 / 4 to 1 / 3 of the wet milling media (preferably anhydrous alcohol) are pre-milled for 2-5 hours. Then WC, binder phase (Co or Co+Ni) and the remaining wet milling media are added, and the mixture is ball-milled in a ball mill at a speed of 30-40 rpm for 30-60 hours. After ball milling, the mixture is granulated by spray drying (to obtain a mixture with excellent flowability) or vacuum drying (to obtain a mixture with excellent pressing performance) to obtain a qualified mixture.

[0034] Compression molding: Precision pressing or pre-pressing + cold isostatic pressing + cutting process is used for compression molding; among which, precision compression molding uses a dry powder automatic press with volumetric method and a spray material with excellent flowability to obtain a compact with good density, uniform size and excellent appearance quality.

[0035] Debinding and sintering: The compact is placed in a pressure rapid cooling furnace for debinding and sintering. The debinding temperature and time are set according to the compact size and the type of molding agent. The debinding temperature for polyethylene glycol and paraffin molding agents is 450-500℃, and the debinding temperature for other types of molding agents is 280-400℃. The heating time from debinding to the final sintering temperature is 3.5-6 hours, the sintering temperature is controlled at 1380-1480℃, the argon gas pressure is 4-10 MPa, and the holding time is 0.5-1.5 hours. The total sintering time is 25-85 hours to ensure that the binder phase completely wets the hard phase WC, the WC grains grow and develop completely, and the binder phase layer is evenly distributed without local coarse binder phase agglomeration.

[0036] Cooling and annealing: After sintering, when the alloy blank is cooled to 1000-1200℃, argon gas is injected for rapid cooling. After cooling to below 80℃, the temperature is raised to 500-700℃ for annealing treatment, and the temperature is held for 3-10 hours to completely eliminate the internal stress generated by rapid cooling in the material.

[0037] The properties of cemented carbide are jointly determined by the hard phase and the binder phase. This invention addresses the operational requirements of sweeper blades, focusing on four key indicators: hardness, fracture toughness, wear resistance, and corrosion resistance. Fine-grained WC (0.6–0.8 μm) is used as the hard phase. Compared to traditional coarse-grained WC, the fine-grained structure significantly improves the material's hardness and wear resistance. Furthermore, the preparation technology for WC powder in this particle size range is mature and easy for industrial production.

[0038] The binder phase is selected as Co (or Co+Ni composite system). Co and WC have excellent wettability, which can effectively ensure the bonding strength of the alloy. Adding Ni can further improve corrosion resistance and toughness. The total content of the binder phase is controlled at 9.5-10%, which can ensure the toughness of the material without reducing the hardness and wear resistance due to excessive binder phase.

[0039] This invention ensures uniform mixing of all components and sufficient grain refinement through pre-grinding and long-term ball milling processes. At the same time, the grain growth inhibitor Cr3C2 is added to effectively inhibit the abnormal growth of WC grains during sintering.

[0040] Precision pressing or pre-pressing and cold isostatic pressing processes are used to ensure the density and dimensional accuracy of the compact;

[0041] During the debinding and sintering process, the staged sintering and precise temperature and pressure control design ensure that the binder phase and the hard phase are fully combined, avoiding defects such as pores and inclusions.

[0042] The combination of rapid cooling and annealing after sintering not only ensures the stability of the material's microstructure but also completely eliminates internal stress, preventing cracks from forming during use due to stress release.

[0043] The alloy material of this invention has excellent comprehensive properties, including high hardness, high fracture toughness, excellent resistance to edge chipping, wear resistance, and corrosion resistance. It has a uniform microstructure with few defects such as pores and inclusions, making it suitable for manufacturing scraper blades. It can meet the needs of scraper blades under different working conditions. Experiments have shown that this wear-resistant alloy has a significantly longer service life than tool steel blades made of manganese steel, ordinary cemented carbide, and other similar materials.

[0044] Example 1

[0045] A wear-resistant alloy material suitable for scraper blades of belt conveyor cleaners, with the following composition by mass percentage: Co 9.5%, WC 90.4%, and trace impurities 0.1%; wherein the WC grain size is 0.6μm and the Co Fisher grain size is 0.6μm.

[0046] The preparation method is as follows:

[0047] Ingredients: Weigh out Co powder and WC powder according to the above proportions, add 1% polyethylene glycol as a molding agent and 0.2% Cr3C2 as a grain growth inhibitor.

[0048] Wet milling: Pre-mill Cr3C2, polyethylene glycol and 1 / 4 of anhydrous alcohol for 2 hours, then add Co powder, WC powder and the remaining anhydrous alcohol, and ball mill in a ball mill at 30 rpm for 30 hours. After ball milling, spray dry and granulate.

[0049] Pressing: The compact is obtained by volumetric pressing using a precision pressing process and an automatic dry powder press.

[0050] Degreasing and sintering: The compact is placed in a pressure rapid cooling furnace, degreased at 450℃, the time for degreasing to the sintering temperature is 3.5h, the sintering temperature is 1380℃, the argon gas pressure is 4MPa, the holding time is 0.5h, and the total sintering time is 25h.

[0051] Cooling and annealing: The material was rapidly cooled with argon gas to 1200℃, then cooled to below 80℃, and then heated to 500℃ for annealing. The annealing was carried out for 3 hours to obtain the alloy material.

[0052] The alloy material prepared in this embodiment has a Rockwell hardness of 90.5 HRA and a fracture toughness of 11.5 MPa·m. 1 / 2 With a bending strength of 3700MPa, the scraper blades made from it have a service life 1.5 times longer than ordinary hard alloy scraper blades under coal slime cleaning conditions in mines.

[0053] Example 2

[0054] A wear-resistant alloy material suitable for scraper blades of belt conveyor cleaners, with the following composition by mass percentage: Co 9.8%, WC 90.2%, and no trace impurities; wherein the WC grain size is 0.7μm and the Co Fisher grain size is 1.0μm.

[0055] The preparation method is as follows:

[0056] Ingredients: Weigh out Co powder and WC powder according to the above proportions, add 2% polyethylene glycol as a molding agent and 0.3% Cr3C2 as a grain growth inhibitor.

[0057] Wet milling: Pre-mill Cr3C2, polyethylene glycol and 1 / 3 of anhydrous alcohol for 3 hours, then add Co powder, WC powder and the remaining anhydrous alcohol, and ball mill in a ball mill at 35 rpm for 45 hours. After ball milling, vacuum dry and granulate.

[0058] Pressing: The pressed blank is obtained by pre-pressing, cold isostatic pressing, and cutting process;

[0059] Degreasing and sintering: The compact is placed in a pressure rapid cooling furnace, degreased at 480℃, the time for degreasing to the sintering temperature is 4.5h, the sintering temperature is 1430℃, the argon gas pressure is 7MPa, the holding time is 1.0h, and the total sintering time is 50h.

[0060] Cooling and annealing: The material was rapidly cooled with argon gas to 1100℃, then cooled to below 80℃, and then heated to 600℃ for annealing. The annealing time was 5 hours to obtain the alloy material.

[0061] The alloy material prepared in this embodiment has a Rockwell hardness of 91.0 HRA and a fracture toughness of 12.8 MPa·m. 1 / 2 With a bending strength of 3850MPa, the scraper blades made from it have a service life 2.0 times longer than ordinary hard alloy scraper blades under the conditions of cleaning fly ash in power plants.

[0062] Example 3

[0063] A wear-resistant alloy material suitable for scraper blades of belt conveyor cleaners, with the following composition by mass percentage: Co 6.5%, Ni 3.0%, WC 90.5%, free of trace impurities; wherein the WC grain size is 0.8μm, the Co grain size is 1.3μm, and the Ni grain size is 1.2μm.

[0064] The preparation method is as follows:

[0065] Ingredients: Weigh out Co powder, Ni powder, and WC powder according to the above proportions, add 4% polyethylene glycol as a molding agent and 0.4% Cr3C2 as a grain growth inhibitor.

[0066] Wet milling: Pre-mill Cr3C2, polyethylene glycol and 1 / 3 of anhydrous alcohol for 5 hours, then add Co powder, Ni powder, WC powder and the remaining anhydrous alcohol, and ball mill in a ball mill at a speed of 40 rpm for 60 hours. After ball milling, spray dry and granulate.

[0067] Pressing: A pressed blank is obtained using a precision pressing process;

[0068] Degreasing and sintering: The compact is placed in a pressure rapid cooling furnace, degreased at 500℃, and the time from degreasing to the sintering temperature is 6 hours. The sintering temperature is 1480℃, the argon gas pressure is 10MPa, and the temperature is held for 1.5 hours. The total sintering time is 85 hours.

[0069] Cooling and annealing: The material was rapidly cooled with argon gas to 1000℃, then cooled to below 80℃, and then heated to 700℃ for annealing. The annealing was carried out for 10 hours to obtain the alloy material.

[0070] The alloy material prepared in this embodiment has a Rockwell hardness of 91.5 HRA and a fracture toughness of 14.0 MPa·m. 1 / 2 With a bending strength of 3900MPa, the scraper blades made from it have a service life 2.2 times longer than ordinary hard alloy scraper blades under the conditions of slag cleaning in steel plants, and their corrosion resistance is significantly better than that of single Co binder phase alloy materials.

[0071] Although embodiments and drawings of the present invention have been disclosed for illustrative purposes, those skilled in the art will understand that various substitutions, variations and modifications are possible without departing from the spirit and scope of the present invention and the appended claims. Therefore, the scope of the present invention is not limited to the contents disclosed in the embodiments and drawings.

Claims

1. A wear-resistant alloy material suitable for scraper blades of belt conveyor cleaners, characterized in that: The alloy material is designated QH10, and its composition, by mass percentage, includes: 9.5-10% binder phase, with the balance being tungsten carbide; The tungsten carbide has a grain size of 0.6–0.8 μm, and the binder phase has a Fisher grain size of 0.6–1.3 μm.

2. The wear-resistant alloy material suitable for belt conveyor cleaner scraper blades according to claim 1, characterized in that: The binder phase is Co.

3. The wear-resistant alloy material suitable for belt conveyor scraper blades according to claim 1, characterized in that: The binder phase is a composite system of Co and Ni, with a total content of 9.5-10% by mass percentage, of which Ni accounts for 0-1 / 3 of the total binder phase by mass, and the balance is tungsten carbide.

4. The wear-resistant alloy material suitable for belt conveyor scraper blades according to claim 1, characterized in that: The alloy material contains a grain growth inhibitor, which is Cr3C2.

5. A method for preparing a wear-resistant alloy suitable for scraper blades of belt conveyor cleaners, characterized in that: This method is based on the wear-resistant alloy material suitable for belt conveyor cleaner scrapers as described in any one of claims 1-3, and includes the following steps: Step 1, Batching and Wet Milling: Batch the alloy materials according to the composition ratio, and add grain growth inhibitors and forming agents. First, pre-mill the grain growth inhibitors, forming agents and 1 / 4 to 1 / 3 of the wet milling media for 2 to 5 hours. Then add tungsten carbide, binder phase and the remaining wet milling media and continue ball milling. After ball milling, spray dry to obtain the mixture. Step 2, pressing and molding: The mixture is pressed and molded using precision pressing or pre-pressing, cold isostatic pressing and cutting processes to obtain a compact with good density and uniform size. Step 3, debinding and sintering: The pressed blank is placed in a pressure furnace for debinding and sintering. The debinding temperature and time are set according to the size of the pressed blank and the type of molding agent. The sintering temperature is 1380-1480℃, the argon gas pressure is 4-10MPa, and the holding time is 0.5-1.5 hours. Step 4, Cooling and Annealing: When the pressed billet is cooled to 1000-1200℃, it is rapidly cooled with argon gas. After cooling to below 80℃, it is heated to 500-800℃ for annealing. The annealing temperature is maintained for 3-10 hours to eliminate internal stress and obtain wear-resistant alloy material.

6. The method for preparing a wear-resistant alloy suitable for belt conveyor cleaner scrapers according to claim 5, characterized in that: In step 1, the molding agent is polyethylene glycol, and the amount of molding agent added is 1 to 4% of the total mass of the raw materials.

7. The method for preparing a wear-resistant alloy suitable for belt conveyor cleaner scrapers according to claim 4, characterized in that: In step 1, the wet grinding medium is anhydrous alcohol, the ball mill speed is 30-40 rpm, and the subsequent ball milling time is 30-60 hours.

8. The method for preparing a wear-resistant alloy suitable for belt conveyor cleaner scraper blades according to claim 4, characterized in that: In step 1, granulation is carried out using either spray drying or vacuum drying. Spray drying yields a mixture with excellent flowability, while vacuum drying yields a mixture with excellent compressibility.

9. A method for preparing a wear-resistant alloy suitable for belt conveyor scraper blades according to claim 4, characterized in that: In step 2, the precision pressing molding is achieved by using a dry powder automatic press with a volumetric method and a spray material with excellent flowability, so as to achieve uniform compact density and excellent appearance quality.

10. A method for preparing a wear-resistant alloy suitable for belt conveyor scraper blades according to claim 4, characterized in that: In step 3, the degreasing temperature is set according to the type of molding agent: the degreasing temperature for polyethylene glycol and paraffin molding agents is 450-500℃, and the degreasing temperature for other types of molding agents is 280-400℃; the heating time from degreasing to the final sintering temperature is 3.5-6 hours, and the total sintering time is 25-85 hours.

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