A mining hard alloy tooth and a passivation method thereof

Abstract

The application belongs to the technical field of mining hard alloy, and particularly relates to a mining hard alloy tooth and a passivation method thereof, the passivation method comprising the following steps: S1, obtaining a first mining hard alloy tooth and sodium phosphate; S2, adding the first mining hard alloy tooth, pure water and the sodium phosphate into a passivation machine for passivation to obtain a mining hard alloy tooth; the first mining hard alloy tooth comprises large teeth and small teeth, the diameter of the large teeth is greater than 8 mm, and the diameter of the small teeth is less than or equal to 8 mm. The application increases the contact area and improves the passivation efficiency by matching the large teeth and the small teeth, and the production efficiency is also improved; the sodium phosphate with weak alkalinity is selected as the passivating agent, the oxide layer and impurities of the hard alloy tooth can be removed, a passivation film is formed, and the surface quality is improved; moreover, the passivation machine is surrounded by resin, and the softness of the resin prevents the hard alloy tooth from being poured into the passivation machine to cause edge and corner defects.

Description

Technical Field

[0001] This application relates to the field of cemented carbide technology for mining, specifically, to a cemented carbide tooth for mining and a passivation method thereof. Background Technology

[0002] Mining carbide teeth are essential tools in mining, tunneling, and other engineering projects, and their performance directly affects construction efficiency and service life. However, during the manufacturing process, sintering, grinding, and other processes can create defects such as micro-cracks and burrs on the surface of the carbide teeth. These defects reduce the strength, wear resistance, and impact resistance of the carbide teeth, thus affecting their service life.

[0003] To improve the performance of cemented carbide teeth, passivation treatment is usually required after sintering. This serves two purposes: first, to improve the surface brightness and appearance of the teeth; and second, to expose surface defects, preventing them from being used in downstream applications and affecting their service life.

[0004] Currently, commonly used passivation methods for cemented carbide teeth mainly include: Mechanical passivation: This method uses methods such as sandblasting, rolling, and vibratory grinding to remove burrs and microcracks from the surface of the cemented carbide teeth through the impact and friction of abrasives. This method is simple to operate and uses simple equipment, but it easily damages the surface of the cemented carbide teeth and is difficult to control the passivation effect. Chemical passivation: This method uses chemical reagents such as acids and alkalis to corrode the surface of the cemented carbide teeth and remove surface defects. This method has a good passivation effect, but it easily causes environmental pollution and requires high safety protection for operators. Electrolytic passivation: This method uses the cemented carbide teeth as the anode and electrolyzes them in an electrolyte to remove surface defects through electrochemical action. This method has a good passivation effect and is easy to control, but the equipment cost is high, and it requires high precision in the selection of the electrolyte and the control of process parameters.

[0005] Existing mechanical passivation methods for cemented carbide teeth have the following drawbacks: It is difficult to simultaneously achieve the passivation effect and the surface quality of the cemented carbide teeth; it can easily cause environmental pollution or pose safety hazards to operators; and the equipment cost is high, the process is complex, and large-scale production is difficult. Summary of the Invention

[0006] To solve the above-mentioned technical problems, this application provides a passivation method for mining cemented carbide teeth, comprising the following steps: S1, obtaining a first mining cemented carbide tooth and sodium phosphate; S2, adding the first mining cemented carbide tooth, pure water and the sodium phosphate into a passivation machine for passivation to obtain the mining cemented carbide tooth; the first mining cemented carbide tooth includes a large tooth and a small tooth, wherein the diameter of the large tooth is >8mm and the diameter of the small tooth is ≤8mm.

[0007] As a preferred embodiment of the passivation method for a mining cemented carbide tooth described in this application, in step S1, the mass ratio of the large tooth to the small tooth is 1:(1-3).

[0008] As a preferred embodiment of the passivation method for a mining cemented carbide tooth described in this application, in step S2, the liquid-to-solid ratio of the pure water to the first mining cemented carbide tooth is (0.1-0.15):1L / kg, and the ratio of sodium phosphate to the pure water is 8-12g / L.

[0009] As a preferred embodiment of the passivation method for a mining cemented carbide tooth described in this application, in step S2, the edge chipping and corner chipping rate of the mining cemented carbide tooth is ≤0.03%.

[0010] As a preferred embodiment of the passivation method for mining cemented carbide teeth described in this application, in step S2, the lining material of the passivation machine is resin.

[0011] As a preferred embodiment of the passivation method for a mining cemented carbide tooth described in this application, in step S2, the ratio of the mass of the first mining cemented carbide tooth to the rotation speed of the passivation machine is (6-12) kg: 1 r / min, and the passivation time is 1-5 h.

[0012] As a preferred embodiment of the passivation method for mining cemented carbide teeth described in this application, step S2 further includes cleaning and drying the mining cemented carbide teeth.

[0013] In a preferred embodiment of the passivation method for mining cemented carbide teeth described in this application, in step S2, the cleaning medium is pure water, and the drying is carried out in an oven.

[0014] This application also provides a cemented carbide tooth for mining, which is prepared by the passivation method of the above-mentioned cemented carbide tooth for mining.

[0015] As a preferred embodiment of the cemented carbide teeth for mining described in this application, the roughness of the cemented carbide teeth is ≤0.8μm, the surface of the cemented carbide teeth has a dense passivation film, the passivation film is composed of cobalt phosphate and tungsten phosphate, the thickness of the passivation film is ≥15nm, and the wear of the cemented carbide teeth is ≤0.033cm when tested using the method of standard number GB / T34501-2017. 3 After immersing the mining cemented carbide teeth in 31% HCl solution at room temperature for 24 hours, the weight loss rate of the mining cemented carbide teeth is ≤0.35%.

[0016] The beneficial effects of this application are as follows:

[0017] This application proposes a passivation method for cemented carbide teeth used in mining. By employing a combination of large and small teeth, products from the same furnace can be passivated together, resulting in strong traceability. The combination of large and small teeth increases the contact area and improves passivation efficiency, while also increasing production efficiency. By selecting weakly alkaline sodium phosphate as the passivating agent, a weakly alkaline environment is provided to prevent acid corrosion of the product surface and its impact on product performance. Sodium phosphate ionizes in aqueous solution: Na₃PO₄ → 3Na + +PO4 3- In this process, phosphate ions play a central role in the passivation reaction, reacting with cobalt and tungsten ions on the surface of the cemented carbide; 3Co 2+ +2PO4 3- →Co3(PO4)2↓,W 6+ +2PO4 3- →W(PO4)2↓; Phosphate ions react with cobalt ions to form cobalt phosphate precipitate on the surface of cemented carbide, and phosphate ions react with tungsten ions to form tungsten phosphate precipitate on the surface of cemented carbide. The cobalt phosphate and tungsten phosphate precipitates form a dense passivation film that adheres to the surface of cemented carbide, which can isolate the external corrosive environment and protect the cemented carbide; Sodium phosphate can remove the oxide layer and impurities of cemented carbide teeth and form a passivation film to improve its surface quality; Moreover, the inside of the passivation machine is surrounded by resin, and the softness of the resin prevents the cemented carbide teeth from chipping or breaking off edges when poured into the passivation machine. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0019] Figure 1 This is a morphological image of the mining cemented carbide teeth prepared in Example 1 of this application;

[0020] Figure 2 The image shows the morphology of the cemented carbide teeth for mining prepared in Comparative Example 1 of this application.

[0021] Figure 3 The image shows the XRD pattern of the cemented carbide teeth for mining prepared in Comparative Example 1 of this application.

[0022] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0023] The technical solutions in the embodiments will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0024] This application provides a passivation method for mining cemented carbide teeth, comprising the following steps: S1, obtaining a first mining cemented carbide tooth and sodium phosphate;

[0025] S2. The first mining cemented carbide tooth, pure water and sodium phosphate are added to a passivation machine for passivation to obtain the mining cemented carbide tooth; the first mining cemented carbide tooth includes a large tooth and a small tooth, the diameter of the large tooth is >8mm and the diameter of the small tooth is ≤8mm.

[0026] Wherein, the mass ratio of the large tooth to the small tooth is 1:(1-3); specifically, the mass ratio of the large tooth to the small tooth is any one of 1:1, 1:2, 1:3 and any range between any two;

[0027] The liquid-to-solid ratio of the pure water to the first mining cemented carbide tooth is (0.1-0.15):1L / kg, and the ratio of sodium phosphate to pure water is 8-12g / L; the lining material of the passivation machine is resin; the ratio of the mass of the first mining cemented carbide tooth to the rotation speed of the passivation machine is (6-12)kg:1r / min, and the passivation time is 1-5h; the mining cemented carbide tooth is cleaned and dried; the cleaning medium is pure water, and the drying is carried out in an oven.

[0028] Specifically, the liquid-to-solid ratio of the pure water to the first mining cemented carbide tooth is any one or any two of the following: 0.1:1L / kg, 0.11:1L / kg, 0.12:1L / kg, 0.13:1L / kg, 0.14:1L / kg, and 0.15:1L / kg; the ratio of the sodium phosphate to the pure water is any one or any two of the following: 8g / L, 9g / L, 10g / L, 11g / L, and 12g / L; the ratio of the mass of the first mining cemented carbide tooth to the rotational speed of the passivation machine is any one or any two of the following: 6kg:1r / min, 7kg:1r / min, 8kg:1r / min, 9kg:1r / min, 10kg:1r / min, 11kg:1r / min, and 12kg:1r / min; and the passivation time is any one or any two of the following: 1h, 2h, 3h, 4h, and 5h.

[0029] The technical solution of this application will be further described below with reference to specific embodiments.

[0030] Example 1

[0031] Obtain the first type of cemented carbide teeth for mining and sodium phosphate. The total weight of the first type of cemented carbide teeth is 300 kg. The first type of cemented carbide teeth for mining includes large teeth and small teeth. The diameter of the large teeth is 9 mm and the diameter of the small teeth is 6 mm. The mass ratio of the large teeth to the small teeth is 1:3.

[0032] Large teeth, small teeth, pure water and sodium phosphate were added to a passivation machine with a resin liner for passivation. The volume of pure water was 30L, the mass of sodium phosphate was 240g, the speed of the passivation machine was 30r / min, and the passivation time was 5h.

[0033] After passivation, the large and small teeth are placed in a sieve and washed with pure water. After washing, they are transferred to an oven for drying to obtain mining cemented carbide teeth.

[0034] The cemented carbide teeth for mining prepared in Example 1 were tested, and the results were as follows: the surface of the cemented carbide teeth for mining was free of pits, the edge chipping rate was 0.02%, the roughness was ≤0.6μm, and the surface of the cemented carbide teeth for mining had a dense passivation film composed of cobalt phosphate and tungsten phosphate, with a thickness of 16nm; the cemented carbide teeth for mining were tested using the method of standard number GB / T34501-2017, and the wear amount of the cemented carbide teeth for mining was 0.0326cm. 3 After immersing and corroding mining cemented carbide teeth in a 31% HCl solution at room temperature for 24 hours, the weight loss rate of the mining cemented carbide teeth was 0.314%. (Please refer to...) Figure 1 , Figure 1 This is a morphological image of the cemented carbide teeth for mining prepared in Example 1 of this application.

[0035] Example 2

[0036] Obtain the first type of cemented carbide teeth for mining and sodium phosphate. The total weight of the first type of cemented carbide teeth is 300 kg. The first type of cemented carbide teeth for mining includes large teeth and small teeth. The diameter of the large teeth is 15 mm and the diameter of the small teeth is 7 mm. The mass ratio of the large teeth to the small teeth is 1:2.

[0037] Large teeth, small teeth, pure water and sodium phosphate were added to a passivation machine with a resin liner for passivation. The volume of pure water was 36L, the mass of sodium phosphate was 360g, the speed of the passivation machine was 25r / min, and the passivation time was 3h.

[0038] After passivation, the large and small teeth are placed in a sieve and washed with pure water. After washing, they are transferred to an oven for drying to obtain mining cemented carbide teeth.

[0039] The cemented carbide teeth for mining prepared in Example 2 were tested, and the results were as follows: the surface of the cemented carbide teeth for mining was free of pits, the edge chipping rate was 0.03%, the roughness was ≤0.8μm, and the surface of the cemented carbide teeth for mining had a dense passivation film composed of cobalt phosphate and tungsten phosphate, with a thickness of 15nm; the cemented carbide teeth for mining were tested using the method of standard number GB / T34501-2017, and the wear amount of the cemented carbide teeth for mining was 0.033cm. 3 After immersing and corroding the mining cemented carbide teeth in 31% HCl solution at room temperature for 24 hours, the weight loss rate of the mining cemented carbide teeth was 0.343%.

[0040] Example 3

[0041] Obtain the first type of cemented carbide teeth for mining and sodium phosphate. The total weight of the first type of cemented carbide teeth is 300 kg. The first type of cemented carbide teeth for mining includes large teeth and small teeth. The diameter of the large teeth is 21 mm and the diameter of the small teeth is 8 mm. The mass ratio of the large teeth to the small teeth is 1:1.

[0042] Large teeth, small teeth, pure water and sodium phosphate were added to a passivation machine with a resin liner for passivation. The volume of pure water was 45L, the mass of sodium phosphate was 540g, the speed of the passivation machine was 50r / min, and the passivation time was 1h.

[0043] After passivation, the large and small teeth are placed in a sieve and washed with pure water. After washing, they are transferred to an oven for drying to obtain mining cemented carbide teeth.

[0044] The cemented carbide teeth for mining prepared in Example 3 were tested, and the results were as follows: the surface of the cemented carbide teeth for mining was free of pits, the edge chipping rate was 0.02%, the roughness was ≤0.7μm, and the surface of the cemented carbide teeth for mining had a dense passivation film composed of cobalt phosphate and tungsten phosphate, with a thickness of 18nm; the cemented carbide teeth for mining were tested using the method of standard number GB / T34501-2017, and the wear amount of the cemented carbide teeth for mining was 0.0328cm. 3 After immersing and corroding the mining cemented carbide teeth in 31% HCl solution at room temperature for 24 hours, the weight loss rate of the mining cemented carbide teeth was 0.324%.

[0045] Comparative Example 1

[0046] The difference between this comparative example and Example 1 is that sodium phosphate was not added during passivation; all other steps are the same as in Example 1.

[0047] Please see Figure 2 and Figure 3 , Figure 2The image shows the morphology of the cemented carbide teeth for mining prepared in Comparative Example 1 of this application. Figure 3 The image shows an XRD pattern of the cemented carbide teeth for mining prepared in Comparative Example 1 of this application. The results of testing the cemented carbide teeth for mining prepared in Comparative Example 1 are as follows: Figure 2 This indicates that the surface of the cemented carbide teeth used in mining has small pits and cracks; the chipping rate of the cemented carbide teeth used in mining is 0.08%, and the roughness is ≤1.2μm; Figure 3 This indicates that no passivation film has formed on the surface of the cemented carbide teeth used in mining, and oxidation has occurred. Tests were conducted on the cemented carbide teeth using the method specified in GB / T34501-2017, and the wear amount was found to be 0.0421 cm. 3 After immersing and corroding the mining cemented carbide teeth in 31% HCl solution at room temperature for 24 hours, the weight loss rate of the mining cemented carbide teeth was 0.431%.

[0048] Comparative Example 2

[0049] The difference between this comparative example and Example 1 is that 180g of sodium phosphate was added during passivation; all other steps were the same as in Example 1.

[0050] The cemented carbide teeth for mining prepared in Comparative Example 2 were tested, and the results were as follows: the surface of the cemented carbide teeth for mining was free of pits, the edge chipping rate was 0.05%, the roughness was ≤0.9μm, and the surface of the cemented carbide teeth for mining had a dense passivation film composed of cobalt phosphate and tungsten phosphate, with a thickness of 7nm; the cemented carbide teeth for mining were tested using the method of standard number GB / T34501-2017, and the wear amount of the cemented carbide teeth for mining was 0.0352cm. 3 After immersing and corroding the mining cemented carbide teeth in 31% HCl solution at room temperature for 24 hours, the weight loss rate of the mining cemented carbide teeth was 0.392%.

[0051] Comparative Example 3

[0052] The difference between this comparative example and Example 1 is that sodium carbonate of the same mass is used instead of sodium phosphate during passivation, while the other steps are the same as in Example 1.

[0053] The cemented carbide teeth for mining prepared in Comparative Example 3 were tested, and the results were as follows: the surface of the cemented carbide teeth for mining had slight pits, the edge chipping rate was 0.09%, the roughness was ≤1.1μm, and the surface of the cemented carbide teeth for mining had a loose and porous passivation film composed of cobalt oxide and WO3; the cemented carbide teeth for mining were tested using the method of standard number GB / T34501-2017, and the wear amount of the cemented carbide teeth for mining was 0.0384cm. 3After immersing and corroding the mining cemented carbide teeth in 31% HCl solution at room temperature for 24 hours, the weight loss rate of the mining cemented carbide teeth was 0.451%.

[0054] Comparative Example 4

[0055] The difference between this comparative example and Example 1 is that grinding balls are added during passivation, and the ratio of mining cemented carbide teeth to grinding balls is 1:3. All other steps are the same as in Example 1.

[0056] The cemented carbide teeth for mining prepared in Comparative Example 4 were tested, and the results were as follows: the surface of the cemented carbide teeth for mining was free of pits, the chipping rate was 0.03%, the roughness was ≤0.7μm, and the surface of the cemented carbide teeth for mining had a dense passivation film composed of cobalt phosphate and tungsten phosphate, with a thickness of 15nm; the cemented carbide teeth for mining were tested using the method of standard number GB / T34501-2017, and the wear amount of the cemented carbide teeth for mining was 0.0336cm. 3 After immersing and corroding the mining cemented carbide teeth in 31% HCl solution at room temperature for 24 hours, the weight loss rate of the mining cemented carbide teeth was 0.324%.

[0057] Comparative Example 5

[0058] The difference between this comparative example and Example 1 is that the lining material of the passivation machine is not resin, while the other steps are the same as in Example 1.

[0059] The cemented carbide teeth for mining prepared in Comparative Example 5 were tested, and the results were as follows: the surface of the cemented carbide teeth for mining had obvious pits, the edge chipping and corner chipping rate was 0.12%, the roughness was ≤1.2μm, and the surface of the cemented carbide teeth for mining had a dense passivation film composed of cobalt phosphate and tungsten phosphate, with a thickness of 15nm; the cemented carbide teeth for mining were tested using the method of standard number GB / T34501-2017, and the wear amount of the cemented carbide teeth for mining was 0.0363cm. 3 After immersing and corroding the mining cemented carbide teeth in 31% HCl solution at room temperature for 24 hours, the weight loss rate of the mining cemented carbide teeth was 0.361%.

[0060] Comparative Example 6

[0061] The difference between this comparative example and Example 1 is that sodium phosphate was not added during passivation, but a chromium-containing passivation solution was added instead. All other steps are the same as in Example 1.

[0062] The cemented carbide teeth for mining prepared in Comparative Example 6 were tested, and the results were as follows: the surface of the cemented carbide teeth for mining had obvious pits, the edge chipping and corner chipping rate was 0.08%, the roughness was ≤1.1μm, and the surface of the cemented carbide teeth for mining had a relatively dense passivation film, which was composed of chromate and tungsten oxide; the cemented carbide teeth for mining were tested using the method of standard number GB / T34501-2017, and the wear amount of the cemented carbide teeth for mining was 0.0451cm. 3 After immersing and corroding the mining cemented carbide teeth in 31% HCl solution at room temperature for 24 hours, the weight loss rate of the mining cemented carbide teeth was 0.353%.

[0063] Comparative Example 7

[0064] The difference between this comparative example and Example 1 is that the mass ratio of the large tooth to the small tooth is 1:5, while all other steps are the same as in Example 1.

[0065] The cemented carbide teeth for mining prepared in Comparative Example 7 were tested, and the results were as follows: the surface of the cemented carbide teeth for mining had obvious pits, the edge chipping rate was 0.09%, the roughness was ≤1.2μm, and the surface of the cemented carbide teeth for mining had a dense passivation film composed of cobalt phosphate and tungsten phosphate, with a thickness of 15nm; the cemented carbide teeth for mining were tested using the method of standard number GB / T34501-2017, and the wear amount of the cemented carbide teeth for mining was 0.0401cm. 3 After immersing and corroding the mining cemented carbide teeth in 31% HCl solution at room temperature for 24 hours, the weight loss rate of the mining cemented carbide teeth was 0.363%.

[0066] Comparative Example 8

[0067] The difference between this comparative example and Example 1 is that the mass ratio of the large tooth to the small tooth is 3:1, while all other steps are the same as in Example 1.

[0068] The cemented carbide teeth for mining prepared in Comparative Example 8 were tested, and the results were as follows: the surface of the cemented carbide teeth for mining had obvious pits, the edge chipping rate was 0.05%, the roughness was ≤1.4μm, and the surface of the cemented carbide teeth for mining had a dense passivation film composed of cobalt phosphate and tungsten phosphate, with a thickness of 15nm; the cemented carbide teeth for mining were tested using the method of standard number GB / T34501-2017, and the wear amount of the cemented carbide teeth for mining was 0.0454cm. 3 After immersing and corroding the mining cemented carbide teeth in 31% HCl solution at room temperature for 24 hours, the weight loss rate of the mining cemented carbide teeth was 0.412%.

[0069] As can be seen from the above embodiments and comparative examples: Example 1, combined with Comparative Example 1, shows that without the addition of sodium phosphate as a passivating agent, the surface of the passivated cemented carbide teeth for mining has fine pits and cracks, the rate of edge chipping and corner chipping increases, no passivation film forms on the surface of the cemented carbide teeth for mining, oxidation occurs, and it is unable to isolate the corrosive environment during use. The increased roughness results in poor wear resistance and corrosion resistance. Example 1, combined with Comparative Example 2, shows that with less sodium phosphate added for passivation, the passivation film formed on the surface after passivation is thinner, the roughness is larger, and the isolation from the corrosive environment is limited, resulting in poor wear resistance and corrosion resistance of the cemented carbide teeth for mining. Example 1, combined with Comparative Example 3, shows that with the addition of sodium carbonate as a passivating agent, the surface after passivation will... The resulting loose and porous passivation film cannot effectively isolate the corrosive environment, has a large roughness, and a greater surface friction, resulting in poor corrosion resistance and wear resistance of the mining cemented carbide teeth. Example 1, combined with Comparative Example 4, shows that although the passivation effect of adding grinding balls is similar to that in Example 1, the grinding balls occupy a large amount of passivation space during passivation, preventing the extensive passivation of cemented carbide teeth. Therefore, the passivation efficiency of cemented carbide teeth in mass production is reduced, affecting the passivation of cemented carbide teeth in subsequent furnaces and making it impossible to trace the cemented carbide teeth to the sintering furnace number. Example 1, combined with Comparative Example 5, shows that the passivation equipment does not contain an inner lining resin, resulting in a large rate of edge and corner chipping and a large surface roughness in the passivated mining cemented carbide teeth. The following factors affect the wear resistance and corrosion resistance of cemented carbide teeth used in mining: Example 1, combined with Comparative Example 6, shows that adding a chromium-containing solution during passivation forms a relatively dense passivation film composed of chromate and tungsten oxide on the alloy surface, but the surface roughness is relatively high, resulting in insufficient wear resistance of the cemented carbide teeth used in mining; Example 1, combined with Comparative Example 7, shows that increasing the amount of small teeth causes more severe impact between teeth, resulting in obvious pitting on the surface of the cemented carbide teeth and an increased rate of edge and corner chipping. Excessive roughness reduces the wear resistance and corrosion resistance of the cemented carbide teeth used in mining; Example 1, combined with Comparative Example 8, shows that a larger proportion of large teeth significantly reduces the passivation efficiency, making it impossible to achieve the required roughness within the same passivation time, thus reducing the wear resistance of the cemented carbide teeth used in mining. The wear resistance and corrosion resistance are demonstrated in Examples 1-3 and Comparative Examples 1-8. These examples show that adding a suitable type and proportion of passivating agent enables the formation of a chemically bonded passivation film on the surface of the passivated cemented carbide teeth through in-situ adsorption-reaction of phosphate particles, with a significantly improved bonding strength. Selecting appropriate cemented carbide tooth combinations and suitable lining materials for the passivation equipment effectively improves the passivation passivity, efficiency, and surface quality of the cemented carbide teeth, while reducing surface roughness. The dense passivation film formed on the surface of the cemented carbide teeth makes the surface smooth and can fill scratches and pits, while also reducing surface friction resistance and improving wear resistance. The dense passivation film formed after passivation effectively isolates the corrosive environment, enhancing corrosion resistance.

[0070] This application proposes a passivation method for cemented carbide teeth used in mining. By employing a combination of large and small teeth, products from the same furnace can be passivated together, resulting in strong traceability. The combination of large and small teeth increases the contact area and improves passivation efficiency, while also increasing production efficiency. By selecting weakly alkaline sodium phosphate as the passivating agent, a weakly alkaline environment is provided to prevent acid corrosion of the product surface and its impact on product performance. Sodium phosphate ionizes in aqueous solution: Na₃PO₄ → 3Na + +PO4 3- In this process, phosphate ions play a central role in the passivation reaction, reacting with cobalt and tungsten ions on the surface of the cemented carbide; 3Co 2+ +2PO4 3- →Co3(PO4)2↓,W 6+ +2PO4 3- →W(PO4)2↓; Phosphate ions react with cobalt ions to form cobalt phosphate precipitate on the surface of cemented carbide, and phosphate ions react with tungsten ions to form tungsten phosphate precipitate on the surface of cemented carbide. The cobalt phosphate and tungsten phosphate precipitates form a dense passivation film that adheres to the surface of cemented carbide, which can isolate the external corrosive environment and protect the cemented carbide; Sodium phosphate can remove the oxide layer and impurities of cemented carbide teeth and form a passivation film to improve its surface quality; Moreover, the inside of the passivation machine is surrounded by resin, and the softness of the resin prevents the cemented carbide teeth from chipping or breaking off edges when poured into the passivation machine.

[0071] The above description is only a preferred embodiment of this application and does not limit the patent scope of this application. All equivalent structural transformations made using the content of this application's specification under the inventive concept of this application, or direct / indirect applications in other related technical fields, are included within the patent protection scope of this application.

Claims

1. A passivation method for cemented carbide teeth used in mining, characterized in that, Includes the following steps: S1. Obtain the first mining cemented carbide teeth and sodium phosphate; S2. The first mining cemented carbide tooth, pure water and sodium phosphate are added to a passivation machine for passivation to obtain the mining cemented carbide tooth; the first mining cemented carbide tooth includes a large tooth and a small tooth, the diameter of the large tooth is >8mm and the diameter of the small tooth is ≤8mm. In step S2, the mass ratio of the large tooth to the small tooth is 1:(1-3). In step S2, the liquid-to-solid ratio of the pure water to the first mining cemented carbide tooth is (0.1-0.15):1L / kg, and the ratio of sodium phosphate to pure water is 8-12g / L. In step S2, the lining of the passivation machine is made of resin.

2. The passivation method for mining cemented carbide teeth according to claim 1, characterized in that, In step S2, the chipping rate of the mining cemented carbide teeth is ≤0.03%.

3. The passivation method for mining cemented carbide teeth according to claim 1, characterized in that, In step S2, the ratio of the mass of the first mining cemented carbide tooth to the rotation speed of the passivation machine is (6-12) kg: 1 r / min, and the passivation time is 1-5 h.

4. The passivation method for mining cemented carbide teeth according to claim 1, characterized in that, Step S2 further includes cleaning and drying the mining cemented carbide teeth.

5. The passivation method for mining cemented carbide teeth according to claim 4, characterized in that, In step S2, the cleaning medium is pure water, and the drying is carried out in an oven.

6. A type of cemented carbide tooth for mining, characterized in that, The teeth were prepared using the passivation method described in any one of claims 1-5 for mining cemented carbide.

7. A cemented carbide tooth for mining according to claim 6, characterized in that, The surface roughness of the mining cemented carbide teeth is ≤0.8μm. The surface of the mining cemented carbide teeth has a dense passivation film composed of cobalt phosphate and tungsten phosphate, with a thickness ≥15nm. The mining cemented carbide teeth are tested using the method specified in GB / T34501-2017, and the wear amount is ≤0.033cm. 3 After immersing the mining cemented carbide teeth in 31% HCl solution at room temperature for 24 hours, the weight loss rate of the mining cemented carbide teeth is ≤0.35%.

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