A preparation method of a high wear-resistant and long-life cemented carbide

Abstract

The present invention belongs to the technical field of cemented carbides, and particularly relates to a preparation method of a high-wear-resistant and long-life cemented carbide. The method includes Step 1: preparing alumina coating, Step 2: weighing raw materials, Step 3: ball milling, and Step 4: sintering. In the present invention, WC with multiple particle sizes is compounded, and the cemented carbide is comprehensively modified by alumina and rare earths, and the optimal component formula is adjusted, which synergistically improves the hardness, toughness and wear resistance of the cemented carbide and increases the service life of the cemented carbide.

Description

Technical Field

[0001] The present invention belongs to the technical field of cemented carbides, and particularly relates to a preparation method of a highly wear-resistant and long-life cemented carbide. Background Art

[0002] As a high-performance structural material, cemented carbide is widely used in industrial production for manufacturing cutting tools, drilling equipment, molds, etc. due to its excellent hardness, wear resistance and thermal stability. Traditional cemented carbide is mainly composed of refractory metal carbides (such as tungsten carbide WC) and metal binders (such as cobalt Co). Although this material performs excellently in many aspects, there are still some limitations. Moreover, with the continuous deepening of industrial applications, the requirements for the performance of cemented carbide are getting higher and higher, and traditional cemented carbide materials often fail to meet the performance requirements.

[0003] In order to improve the performance of cemented carbide, researchers have tried various modification methods. Common ones such as adding alumina, carbon materials such as graphene, etc. can improve the hardness, strength, etc. of cemented carbide. However, due to the dispersion problem between components, it is difficult to achieve a comprehensive improvement in the comprehensive performance of the alloy material, especially in terms of hardness, toughness and wear resistance. In view of the above problems, it is necessary to further modify cemented carbide. Summary of the Invention

[0004] To solve the above technical problems, the present invention provides a preparation method of a highly wear-resistant and long-life cemented carbide, and the steps of the method are as follows:

[0005] Step 1: Prepare alumina-coated material

[0006] Modify alumina with vinyl silane coupling agent to obtain modified alumina;

[0007] Add the modified alumina into water, add peroxide initiator, styrene, divinylbenzene, stir and disperse evenly, quickly heat up to 75 - 95 °C, end the reaction after reacting for 1 - 3 h, then wash with ethanol and dry for standby to obtain alumina-coated material;

[0008] Among them, the dosage of vinyl silane coupling agent is 2 - 4 wt% of the mass of alumina;

[0009] The mass ratio of alumina, styrene and divinylbenzene is 1:0.8 - 1.5:0.03 - 0.05;

[0010] Step 2: Weigh raw materials

[0011] Weigh raw materials according to the following formula: 55 - 85 parts of WC-1, 15 - 45 parts of WC-2, 6 - 10 parts of Co powder, 0.1 - 0.5 parts of Y2O3, 0.3 - 0.7 parts of alumina-coated material;

[0012] Step 3: Ball milling

[0013] Mix WC-1, WC-2, Co powder, and Y2O3 in ethylene glycol. After uniform dispersion, transfer them to a planetary ball mill for ball milling at a rotational speed of 500 - 700 rpm for 1 - 3 h;

[0014] Stop ball milling, add coated alumina, heat up to 900 - 1100 °C, carbonize for 8 - 12 min, then start ball milling at a rotational speed of 250 - 350 rpm. After milling for 12 - 18 min, a cemented carbide composite powder is obtained;

[0015] Among them, an inert gas is used for protection during the ball milling process;

[0016] Step 4: Sintering

[0017] Adopt a spark plasma sintering process for sintering at a sintering temperature of 1450 - 1500 °C, a sintering pressure of 50 - 70 MPa, hold for 30 - 50 min, and then slowly cool down to room temperature.

[0018] In Step 1, the vinyl silane coupling agent includes one or two of vinyltrimethoxysilane and vinyl-tris(2-methoxyethoxy)silane.

[0019] The water includes one or two of deionized water and distilled water.

[0020] The peroxide initiator includes one or more of benzoyl peroxide, diisopropylbenzene peroxide, and di-tert-butyl peroxyisopropylbenzene.

[0021] Preferably, the dosage of the vinyl silane coupling agent is 2.5 - 3.5 wt% of the mass of alumina.

[0022] Preferably, quickly heat up to 80 - 90 °C and react for 1.5 - 2.5 h.

[0023] In Step 2, preferably, weigh the raw materials according to the following formula: 60 - 80 parts of WC-1, 20 - 40 parts of WC-2, 7 - 9 parts of Co powder, 0.2 - 0.4 parts of Y2O3, and 0.4 - 0.6 parts of coated alumina;

[0024] Among them, the average particle size of WC-1 is 0.2 - 0.8 μm, and the average particle size of WC-2 is 1 - 6 μm;

[0025] Preferably, the average particle size of WC-1 is 0.4 - 0.6 μm, and the average particle size of WC-2 is 3 - 5 μm.

[0026] Among them, the average particle size of Co powder is 0.6 - 1 μm;

[0027] The average particle size of Y2O3 is 0.4 - 0.6 μm;

[0028] The average particle size of alumina is 0.3 - 0.5 μm.

[0029] In step 3, the inert gas is nitrogen or argon.

[0030] Secondly, the present invention provides a highly wear-resistant and long-life cemented carbide, which is prepared by using the above method.

[0031] In addition, the present invention also provides an application of a highly wear-resistant and long-life cemented carbide, and this cemented carbide is used for preparing tunneling teeth, coal mining picks, rotary drilling teeth, turning tools, milling cutters, planing tools, drill bits, etc.

[0032] Preferably, the cemented carbide is used for preparing tunneling teeth, coal mining picks, and rotary drilling teeth.

[0033] The advantages and beneficial effects of the present invention are as follows:

[0034] (1) In the present invention, alumina is added for modification. Since alumina has high hardness and high-temperature stability, it can significantly improve the wear resistance of the cemented carbide. In addition, the addition of alumina can also improve the fracture toughness of the cemented carbide, thereby enhancing the impact resistance of the material.

[0035] The present invention also uses WC with various particle sizes for compounding, comprehensively modifies the cemented carbide with alumina and rare earths, and adjusts to obtain the optimal component formula, synergistically improving the hardness, toughness and wear resistance of the cemented carbide.

[0036] On the basis of the above formula, the present invention also optimizes the parameters of the sintering process, and the obtained cemented carbide is more dense and its performance is further improved.

[0037] (2) Previous studies have shown that the carbon content has a great influence on the performance of the cemented carbide. Too little or too much carbon content will lead to an increase in pores and a decrease in density. In the prior art, carbon materials such as graphene are used to improve the mechanical properties of the cemented carbide, such as strength and toughness. However, the density difference between graphene and the metal matrix material is large, and it is difficult to achieve uniform dispersion by traditional mechanical mixing methods, resulting in problems with the performance of the obtained cemented carbide.

[0038] Therefore, how to evenly disperse carbon materials in cemented carbide and avoid agglomeration has always been a technical problem. After many attempts and failures, the inventor creatively proposed a new modification method. This method cross-links and coats the surface of alumina with polymers and carbonizes them during the ball milling process. Through this innovative process, the polymer is in-situ polymerized to coat alumina, and the carbonized network carbon chains are coated on the surface of alumina and further evenly distributed during the ball milling process, forming a carbon layer wrapped on the surface of alumina. This process solves the problem of uneven mixing of carbon materials and cemented carbide components, and can effectively improve the hardness, strength and toughness of cemented carbide, thereby improving the wear resistance and service life of the material.

[0039] (3) The present invention modifies cemented carbide by coating alumina, rare earth, etc., and combines the compounding of WC with various particle sizes and the improvement of process parameters to obtain cemented carbide with the best performance, and the hardness parameter exceeds 2000HV 30 , and the toughness parameter exceeds 14 MPa·m 1 / 2 , and the wear rate parameter is controlled not higher than 4×10 -7 mm 3 ·N -1 ·m -1 , and the obtained cemented carbide has excellent comprehensive performance.

[0040] (4) The present invention is only a simple modification, with a simple process and low requirements for equipment. There is no need to introduce new equipment, and the modification effect is excellent, having a broad application prospect. Detailed implementation manners

[0041] In order to enable those skilled in the art to better understand the solution of the present invention and make the technical means, creative features, achieved purposes and effects of the present invention easy to understand, the technical solutions in the embodiments of the present invention are clearly and completely described below.

[0042] This embodiment is only a part of the embodiments of the present invention and does not represent all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of the present invention.

[0043] Raw materials

[0044] WC-1, with an average particle size D50 of 0.5 μm;

[0045] WC-2, with an average particle size D50 of 4 μm;

[0046] Co powder, with an average particle size D50 of 0.8 μm;

[0047] Y2O3, with an average particle size D50 of 0.5 μm;

[0048] Aluminum oxide with an average particle size D50 of 0.4 μm.

[0049] Example 1

[0050] A method for preparing a highly wear-resistant and long-life cemented carbide, the steps of the method are as follows:

[0051] Step 1: Prepare coated aluminum oxide

[0052] Modify aluminum oxide with vinyltrimethoxysilane to obtain modified aluminum oxide;

[0053] Add the modified aluminum oxide to water, add benzoyl peroxide, styrene, and divinylbenzene, stir and disperse evenly, quickly heat up to 85 °C, end the reaction after 2 h, then wash with ethanol and dry for standby to obtain coated aluminum oxide;

[0054] Among them, the dosage of the silane coupling agent is 3 wt% of the mass of aluminum oxide;

[0055] The mass ratio of aluminum oxide, styrene, and divinylbenzene is 1:1:0.04;

[0056] Step 2: Weigh raw materials

[0057] Weigh raw materials according to the following formula: 60 parts of WC-1, 40 parts of WC-2, 7 parts of Co powder, 0.2 part of Y2O3, and 0.4 part of coated aluminum oxide;

[0058] Step 3: Ball milling

[0059] Mix WC-1, WC-2, Co powder, and Y2O3 in ethylene glycol, disperse evenly and transfer to a planetary ball mill for ball milling at a speed of 600 rpm for 2 h;

[0060] Stop ball milling, add coated aluminum oxide, heat up to 1000 °C, carbonize for 10 min, then start ball milling at a speed of 300 rpm, and obtain a cemented carbide composite powder after milling for 15 min;

[0061] Use N2 protection during ball milling;

[0062] Step 4: Sintering

[0063] Adopt a spark plasma sintering process for sintering, with a sintering temperature of 1480 °C, a sintering pressure of 60 MPa, heat preservation for 40 min, and then slowly cool down to room temperature.

[0064] Example 2

[0065] A method for preparing a highly wear-resistant and long-life cemented carbide, the steps of the method are as follows:

[0066] Step 1: Prepare alumina-coated material

[0067] Modify alumina with vinyltrimethoxysilane to obtain modified alumina;

[0068] Add the modified alumina into water, add benzoyl peroxide, styrene, and divinylbenzene, stir and disperse evenly, quickly raise the temperature to 85 °C, end the reaction after reacting for 2 h, then wash with ethanol and dry for standby to obtain alumina-coated material;

[0069] Among them, the dosage of the silane coupling agent is 3 wt% of the mass of alumina;

[0070] The mass ratio of alumina, styrene, and divinylbenzene is 1:1:0.04;

[0071] Step 2: Weigh raw materials

[0072] Weigh raw materials according to the following formula: 70 parts of WC-1, 30 parts of WC-2, 8 parts of Co powder, 0.3 part of Y2O3, and 0.5 part of alumina-coated material;

[0073] Step 3: Ball milling

[0074] Mix WC-1, WC-2, Co powder, and Y2O3 in ethylene glycol, transfer it to a planetary ball mill for ball milling after dispersing evenly, the rotation speed is 600 rpm, and mill for 2 h;

[0075] Stop ball milling, add alumina-coated material, raise the temperature to 1000 °C, carbonize for 10 min, then start ball milling, the rotation speed is 300 rpm, and obtain the cemented carbide composite powder after milling for 15 min;

[0076] Use N2 for protection during the ball milling process;

[0077] Step 4: Sintering

[0078] Adopt the spark plasma sintering process for sintering, the sintering temperature is 1480 °C, the sintering pressure is 60 MPa, keep warm for 40 min, and then slowly cool down to room temperature.

[0079] Example 3

[0080] A preparation method of a highly wear-resistant and long-life cemented carbide, the steps of the method are as follows:

[0081] Step 1: Prepare alumina-coated material

[0082] Modify alumina with vinyltrimethoxysilane to obtain modified alumina;

[0083] Add the modified alumina into water, then add benzoyl peroxide, styrene, and divinylbenzene. Stir to disperse evenly, quickly heat up to 85 °C, end the reaction after 2 h, then wash with ethanol and dry for standby to obtain alumina-coated material;

[0084] Among them, the dosage of silane coupling agent is 3 wt% of the mass of alumina;

[0085] The mass ratio of alumina, styrene, and divinylbenzene is 1:1:0.04;

[0086] Step 2: Weigh raw materials

[0087] Weigh raw materials according to the following formula: 80 parts of WC-1, 20 parts of WC-2, 9 parts of Co powder, 0.4 part of Y2O3, and 0.6 part of alumina-coated material;

[0088] Step 3: Ball milling

[0089] Mix WC-1, WC-2, Co powder, and Y2O3 in ethylene glycol, transfer to a planetary ball mill for ball milling after uniform dispersion, the rotation speed is 600 rpm, and mill for 2 h;

[0090] Stop ball milling, add alumina-coated material, heat up to 1000 °C, carbonize for 10 min, then start ball milling, the rotation speed is 300 rpm, and obtain the cemented carbide composite powder after milling for 15 min;

[0091] Use N2 protection during ball milling;

[0092] Step 4: Sintering

[0093] Adopt the spark plasma sintering process for sintering, the sintering temperature is 1480 °C, the sintering pressure is 60 MPa, keep warm for 40 min, and then slowly cool down to room temperature.

[0094] Comparative Example 1

[0095] A preparation method of a highly wear-resistant and long-life cemented carbide, the method steps are as follows:

[0096] Step 1: Prepare modified alumina

[0097] Modify alumina with vinyltrimethoxysilane to obtain modified alumina;

[0098] Among them, the dosage of silane coupling agent is 3 wt% of the mass of alumina;

[0099] Step 2: Weigh raw materials

[0100] Weigh raw materials according to the following formula: 70 parts of WC-1, 30 parts of WC-2, 8 parts of Co powder, 0.3 part of Y2O3, and 0.5 part of modified alumina;

[0101] Step 3: Ball milling

[0102] Mix WC-1, WC-2, Co powder, and Y2O3 in ethylene glycol. After dispersing evenly, transfer them to a planetary ball mill for ball milling at a speed of 600 rpm for 2 h;

[0103] Stop ball milling, add modified alumina, heat up to 1000 °C, start ball milling after heating for 10 min at a speed of 300 rpm, and obtain the cemented carbide composite powder after milling for 15 min;

[0104] Use N2 protection during ball milling;

[0105] Step 4: Sintering

[0106] Adopt the spark plasma sintering process for sintering, with a sintering temperature of 1480 °C, a sintering pressure of 60 MPa, keep the temperature for 40 min, and then slowly cool down to room temperature.

[0107] Comparative Example 2

[0108] A preparation method of a high wear-resistant and long-life cemented carbide, the steps of the method are as follows:

[0109] Step 1: Prepare alumina mixture

[0110] Modify alumina with vinyltrimethoxysilane to obtain modified alumina;

[0111] Mix the modified alumina and polystyrene to obtain an alumina mixture;

[0112] Among them, the dosage of the silane coupling agent is 3 wt% of the mass of alumina;

[0113] The mass ratio of alumina to polystyrene is 1:1:0.04;

[0114] Step 2: Weigh raw materials

[0115] Weigh raw materials according to the following formula: 70 parts of WC-1, 30 parts of WC-2, 8 parts of Co powder, 0.3 part of Y2O3, and 0.5 part of alumina mixture;

[0116] Step 3: Ball milling

[0117] Mix WC-1, WC-2, Co powder, and Y2O3 in ethylene glycol. After dispersing evenly, transfer them to a planetary ball mill for ball milling at a speed of 600 rpm for 2 h;

[0118] Stop ball milling, add the alumina mixture, heat up to 1000 °C, carbonize for 10 min, then start ball milling at a rotational speed of 300 rpm. After milling for 15 min, a cemented carbide composite powder is obtained;

[0119] Use N2 protection during the ball milling process;

[0120] Step 4: Sintering

[0121] Adopt the spark plasma sintering process for sintering, with a sintering temperature of 1480 °C, a sintering pressure of 60 MPa, and keep the temperature for 40 min, then slowly cool down to room temperature.

[0122] Comparative Example 3

[0123] A preparation method of a high wear-resistant and long-life cemented carbide, the method steps are as follows:

[0124] Step 1: Prepare the alumina mixture

[0125] Modify alumina with vinyltrimethoxysilane to obtain modified alumina;

[0126] Add graphene and mix it evenly with the modified alumina to obtain the alumina mixture;

[0127] Among them, the dosage of the silane coupling agent is 3 wt% of the mass of alumina;

[0128] The ratio of alumina to graphene is 1:1;

[0129] Step 2: Weigh the raw materials

[0130] Weigh the raw materials according to the following formula: 70 parts of WC-1, 30 parts of WC-2, 8 parts of Co powder, 0.3 parts of Y2O3, 0.5 parts of the alumina mixture;

[0131] Step 3: Ball milling

[0132] Mix WC-1, WC-2, Co powder, and Y2O3 in ethylene glycol, disperse evenly, and then transfer to a planetary ball mill for ball milling at a rotational speed of 600 rpm for 2 h;

[0133] Stop ball milling, add the alumina mixture, heat up to 1000 °C, heat for 10 min, then start ball milling at a rotational speed of 300 rpm. After milling for 15 min, a cemented carbide composite powder is obtained;

[0134] Use N2 protection during the ball milling process;

[0135] Step 4: Sintering

[0136] Sintering is carried out by the spark plasma sintering process, with a sintering temperature of 1480 °C, a sintering pressure of 60 MPa, holding for 40 min, and then slowly cooling to room temperature.

[0137] Comparative Example 4

[0138] A method for preparing a highly wear-resistant and long-life cemented carbide, the method comprising the following steps:

[0139] Step 1: Prepare alumina-coated

[0140] Alumina is modified with vinyltrimethoxysilane to obtain modified alumina;

[0141] The modified alumina is added to water, benzoyl peroxide, styrene, and divinylbenzene are added, stirred and dispersed evenly, quickly heated to 85 °C, the reaction is terminated after 2 h, and then washed with ethanol and dried for standby to obtain alumina-coated;

[0142] Among them, the dosage of the silane coupling agent is 3 wt% of the mass of alumina;

[0143] The mass ratio of alumina, styrene, and divinylbenzene is 1:2.5:0.04;

[0144] Step 2: Weigh the raw materials

[0145] Weigh the raw materials according to the following formula: 70 parts of WC-1, 30 parts of WC-2, 8 parts of Co powder, 0.3 parts of Y2O3, and 0.5 parts of alumina-coated;

[0146] Step 3: Ball milling

[0147] WC-1, WC-2, Co powder, and Y2O3 are mixed in ethylene glycol, dispersed evenly and then transferred to a planetary ball mill for ball milling at a speed of 600 rpm for 2 h;

[0148] Stop ball milling, add alumina-coated, heat to 1000 °C, carbonize for 10 min, then start ball milling at a speed of 300 rpm, and obtain a cemented carbide composite powder after milling for 15 min;

[0149] N2 protection is used during ball milling;

[0150] Step 4: Sintering

[0151] Sintering is carried out by the spark plasma sintering process, with a sintering temperature of 1480 °C, a sintering pressure of 60 MPa, holding for 40 min, and then slowly cooling to room temperature.

[0152] Test

[0153] Next, performance tests were conducted on the obtained modified cemented carbide. Among them, the Vickers hardness was measured using a Vickers hardness tester; the strength and fracture toughness of the alloy were tested using a three-point bending fracture test; a ball-on-disk friction and wear test was carried out with a loading force of 100 N, a rotation speed of 500 r / min, and a time of 30 min. Generally, three groups of tests were conducted to take the average data, and the test results are shown in Table 1 below.

[0154] Table 1: Properties of Cemented Carbide

[0155]

[0156] As can be seen from the above, in Examples 1-3, the carbon material was uniformly cross-linked and coated on the surface of alumina, which could effectively improve the comprehensive properties of the cemented carbide such as hardness, strength, toughness, and wear resistance. In Comparative Example 1, only alumina was added. Although the cemented carbide had a high hardness, the improvement of the comprehensive properties was limited. In Comparative Example 3, graphene was added, but the dispersion effect was not good. Although the strength of the alloy material was good, the toughness and wear resistance were average. In Comparative Example 4, the content of the added carbon material was relatively high, resulting in a significant decrease in hardness, strength, etc., and also shortening the service life.

[0157] The above shows and describes the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification only illustrates the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a high wear-resistant and long-life cemented carbide, the technical feature of which is that the method comprises the following steps: Step 1: Preparation of coated alumina Modifying aluminum oxide using a vinyl silane coupling agent to obtain modified aluminum oxide; Add the modified alumina to water, add peroxide initiator, styrene and divinylbenzene, stir and disperse evenly, quickly heat to 75-95°C, react for 1-3 hours and then end the reaction, then wash with ethanol and dry for use to obtain coated alumina; in, The amount of vinyl silane coupling agent is 2-4wt% of the mass of alumina; The mass ratio of aluminum oxide, styrene and divinylbenzene is 1:0.8-1.5:0.03-0.05; Step 2: Weigh the raw materials Weigh the raw materials according to the following formula: WC-1 55-85 parts, WC-2 15-45 parts, Co powder 6-10 parts, Y2O3 0.1-0.5 parts, coated alumina 0.3-0.7 parts; Among them, the average particle size of WC-1 is 0.2-0.8μm, and the average particle size of WC-2 is 1-6μm; Step 3: Ball Milling Mix WC-1, WC-2, Co powder and Y2O3 in ethylene glycol, disperse them evenly and transfer them to a planetary ball mill for ball milling at a speed of 500-700 rpm for 1-3 h; Stop ball milling, add coated alumina, raise the temperature to 900-1100°C, carbonize for 8-12 minutes, then start ball milling at a speed of 250-350 rpm, grind for 12-18 minutes to obtain cemented carbide composite powder; Among them, inert gas protection is used during ball milling; Step 4: Sintering The spark plasma sintering process is adopted for sintering, the sintering temperature is 1450-1500°C, the sintering pressure is 50-70MPa, the temperature is kept for 30-50min, and then the temperature is slowly lowered to room temperature.

2. The preparation method according to claim 1, wherein in step 1, the vinyl silane coupling agent comprises one or both of vinyl trimethoxy silane and vinyl tris (2-methoxyethoxy) silane.

3. The preparation method according to claim 1, wherein in step 1, the water comprises one or both of deionized water and distilled water.

4. The preparation method according to claim 1, wherein in step 1, the peroxidation initiator comprises one or more of benzoyl peroxide, dicumyl peroxide, and di-tert-butyl peroxycumene.

5. The preparation method according to claim 1, wherein in step 1, the amount of the vinyl silane coupling agent is 2.5-3.5 wt% of the mass of the alumina.

6. The preparation method according to claim 1, wherein in step 1, the temperature is rapidly raised to 80-90°C and the reaction is carried out for 1.5-2.5 hours.

7. The preparation method according to claim 1, wherein in step 2, the raw materials are weighed according to the following formula: 60-80 parts of WC-1, 20-40 parts of WC-2, 7-9 parts of Co powder, 0.2-0.4 parts of Y2O3, and 0.4-0.6 parts of coated alumina.

8. The preparation method according to claim 1, wherein in step 2, the average particle size of WC-1 is 0.4-0.6 μm, the average particle size of WC-2 is 3-5 μm; the average particle size of Co powder is 0.6-1 μm; the average particle size of Y2O3 is 0.4-0.6 μm; and the average particle size of alumina is 0.3-0.5 μm.

9. The preparation method according to claim 1, wherein in step 3, the inert gas is argon.

10. A high wear-resistant and long-life cemented carbide, the technical feature of which is that it is prepared using the method described in any one of claims 1 to 9.

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