A high-strength and high-toughness cemented carbide and its preparation method and application

Abstract

The present invention discloses a high-strength and high-toughness cemented carbide and its preparation method and application, which relates to the technical field of cemented carbide. WC powder and Co powder are used as raw materials, an inhibitor is added, and the process is followed by batching, ball milling, spray drying, extrusion molding and pressure sintering. The specific surface area of ​​the WC powder is 1.6-2.1m 2 / g, with a particle size of 1.0≤(D90-D10) / D50≤1.2; and an Fsss particle size of <0.8μm. The present invention improves the uniformity of the cemented carbide structure by controlling the particle size and specific surface area of ​​the raw WC powder, thereby enhancing the strength and toughness of the cemented carbide. Furthermore, the use of paraffin as a preforming agent in the ball milling process, instead of the traditional PEG-type preforming agent, effectively reduces moisture absorption by the compact. The ball mill uses a cemented carbide material with a similar particle size to the powder, reducing the inclusion of coarse particles in the mixture caused by milling wear and tear, thereby effectively improving the hardness and wear resistance of the cemented carbide.

Description

Technical Field

[0001] The present invention relates to the technical field of cemented carbide, and in particular to a high-strength and high-toughness cemented carbide and a preparation method and application thereof. Background Art

[0002] Titanium alloys have poor thermal conductivity, only 1 / 6 that of 45# steel. The high heat generated during machining cannot be effectively dissipated, and a large amount of heat accumulates on the cutting edge, causing a sharp rise in temperature, resulting in a decrease in blade hardness, softening of the blade, and accelerated tool wear. Titanium alloys also have a high affinity for the workpiece, leading to severe tool sticking during machining. This increases friction between the tool body and the workpiece, resulting in significant heat release and reduced tool life. Roughing and semi-finishing titanium alloys require high-impact applications, which necessitates tool materials with both high strength and high toughness.

[0003] Cutting tools have a wide range of sub-applications in the 3C industry, among which titanium alloy material processing is a relatively typical sub-field. Titanium alloy processing has high requirements on tool performance, large tool wear, short tool life, and more frequent replacement. With the growth of the 3C equipment parts processing supply chain in China and the increasingly prominent application trend of titanium alloy materials on mobile phones, the application of titanium alloy processing will increase, and the demand for cutting tools will also increase accordingly.

[0004] Titanium alloy machining places high demands on tool performance, resulting in high tool wear, short tool life, and more frequent tool replacement. To improve the machinability of titanium alloys, domestic and international scholars and engineers have conducted extensive research. These studies include optimizing machining parameters, efficient cooling methods, improving tool geometry, tool coating processes, and selecting tool substrates. Currently, ultrafine cemented carbide remains the preferred tool material for machining titanium alloys. Research has primarily focused on the chemical wear between cemented carbide tool substrates and titanium alloys, with limited coverage of the relationship between the physical and mechanical properties of cemented carbide tool substrates and tool life. Summary of the Invention

[0005] The purpose of the present invention is to solve at least one of the technical problems existing in the prior art and to provide a high-strength and high-toughness cemented carbide and its preparation method and application.

[0006] The technical solutions of the present invention are as follows:

[0007] A method for preparing high-strength and high-toughness cemented carbide, which uses WC powder and Co powder as raw materials, adds an inhibitor, and sequentially undergoes batching, ball milling, spray drying, extrusion molding, and pressure sintering to obtain the product;

[0008] Among them, the specific surface area of ​​WC powder is 1.6-2.1m 2 / g, particle size: 1.0≤(D90-D10) / D50≤1.2; Fsss particle size <0.8μm.

[0009] As a preferred embodiment of the present invention, the inhibitors include Cr3C2 and VC, accounting for 0.5-1.0% of the mass of the WC powder.

[0010] As a preferred solution of the present invention, the Co powder accounts for 10-12% of the mass of the WC powder.

[0011] As a preferred embodiment of the present invention, the ball milling time is 50-70 hours, paraffin molding agent is added during ball milling, and the ball mill is made of a hard alloy material with a particle size close to that of the powder.

[0012] As a preferred embodiment of the present invention, the pressure sintering temperature is 1400-1420° C., and the sintering pressure is 6-9 MPa.

[0013] The present invention also discloses a high-strength and high-toughness cemented carbide, which is prepared by any of the above preparation methods.

[0014] The present invention discloses an application of the high-strength and high-toughness cemented carbide as described above in processing titanium alloy, stainless steel and high-temperature alloy materials.

[0015] The beneficial effects of the present invention are as follows: the present invention improves the uniformity of the cemented carbide structure by controlling the particle size and specific surface area of ​​the raw material WC powder, thereby improving the strength and toughness of the cemented carbide; in addition, the paraffin molding agent is used in place of the traditional PEG-type molding agent in the ball milling process, which can effectively reduce the moisture absorption of the pressed green; the ball mill is made of a cemented carbide material with a particle size similar to that of the powder, which reduces the inclusion of coarse particles caused by the ball mill wear and penetration into the mixture, thereby effectively improving the hardness and wear resistance of the cemented carbide. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a microscopic image of Example 1;

[0017] Figure 2 It is the microscopic picture of comparative example 2;

[0018] Figure 3 This is the microscopic image of Comparative Example 3;

[0019] Figure 4 This is the microscopic image of Comparative Example 4;

[0020] Figure 5 is the particle size distribution diagram of Example 1;

[0021] Figure 6 It is the particle size distribution diagram of comparative example 2;

[0022] Figure 7This is the particle size distribution diagram of Comparative Example 4. DETAILED DESCRIPTION

[0023] The following embodiments of the present invention are described in detail. The embodiments described below are exemplary and are only used to explain the present invention, and are not to be construed as limiting the present invention. Where specific techniques or conditions are not specified in the embodiments, the techniques or conditions described in the literature in this field or the product specifications are used. Where the manufacturer of the reagents or instruments is not specified, all are conventional products that can be obtained commercially.

[0024] Example 1

[0025] A method for preparing high-strength and high-toughness cemented carbide, which uses WC powder and Co powder as raw materials, adds an inhibitor, and sequentially undergoes batching, ball milling, spray drying, extrusion molding, and pressure sintering to obtain the product;

[0026] Among them, the specific surface area of ​​WC powder is 2m 2 / g, particle size: (D90-D10) / D50 is 1.1; Fsss particle size is less than 0.8μm. The inhibitor comprises Cr3C2 and VC in a mass ratio of 1:1, accounting for 1.0% of the mass of the WC powder.

[0027] The Co powder accounts for 12% of the mass of the WC powder.

[0028] The ball milling time is 50 hours, paraffin molding agent is added during ball milling, and the ball mill is made of hard alloy with a particle size close to that of the powder.

[0029] The pressure sintering temperature is 1420° C., and the sintering pressure is 6 MPa.

[0030] Comparative Example 2

[0031] A method for preparing high-strength and high-toughness cemented carbide, which uses WC powder and Co powder as raw materials, adds an inhibitor, and sequentially undergoes batching, ball milling, spray drying, extrusion molding, and pressure sintering to obtain the product;

[0032] Among them, the specific surface area of ​​WC powder is 2m 2 / g, particle size: (D90-D10) / D50 is 1.6; Fsss particle size is less than 0.8μm. The inhibitor comprises Cr3C2 and VC in a mass ratio of 1:1, accounting for 1.0% of the mass of the WC powder.

[0033] The Co powder accounts for 12% of the mass of the WC powder.

[0034] The ball milling time is 50 hours, paraffin molding agent is added during the ball milling, and the ball mill is made of a hard alloy material with a particle size close to that of the powder.

[0035] The pressure sintering temperature is 1420° C., and the sintering pressure is 6 MPa.

[0036] Comparative Example 3

[0037] A method for preparing high-strength and high-toughness cemented carbide, which uses WC powder and Co powder as raw materials, adds an inhibitor, and sequentially undergoes batching, ball milling, spray drying, extrusion molding, and pressure sintering to obtain the product;

[0038] Among them, the specific surface area of ​​WC powder is 2m 2 / g, particle size: (D90-D10) / D50 is 1.34; Fsss particle size is less than 0.8μm. The inhibitor comprises Cr3C2 and VC in a mass ratio of 1:1, accounting for 1.0% of the mass of the WC powder.

[0039] The Co powder accounts for 12% of the mass of the WC powder.

[0040] The ball milling time is 50 hours, paraffin molding agent is added during ball milling, and the ball mill is made of hard alloy with a particle size close to that of the powder.

[0041] The pressure sintering temperature is 1420° C., and the sintering pressure is 6 MPa.

[0042] Comparative Example 4

[0043] A method for preparing high-strength and high-toughness cemented carbide, which uses WC powder and Co powder as raw materials, adds an inhibitor, and sequentially undergoes batching, ball milling, spray drying, extrusion molding, and pressure sintering to obtain the product;

[0044] Among them, the specific surface area of ​​WC powder is 1.8m 2 / g, particle size: (D90-D10) / D50 is 1.3; Fsss particle size is less than 0.8μm. The inhibitor comprises Cr3C2 and VC in a mass ratio of 1:1, accounting for 0.5% of the mass of the WC powder.

[0045] The Co powder accounts for 12% of the mass of the WC powder.

[0046] The ball milling time is 50 hours, paraffin molding agent is added during ball milling, and the ball mill is made of hard alloy with a particle size close to that of the powder.

[0047] The pressure sintering temperature is 1420° C., and the sintering pressure is 6 MPa.

[0048] The performance test results of Example 1 and Comparative Examples 2-4 are shown in Table 1.

[0049] Table 1 Performance test results of the embodiments and comparative examples

[0050] The alloy microstructure was observed under an Inspect F50 scanning electron microscope, and the average intercept was measured using the straight line intercept method according to GB / T6394-2017. At the same time, professional software was used to measure the grain size of the alloy microstructure photos. The results are shown in Tables 1 and Figure 1-7 , it was found that the discreteness of the grain size of the embodiment was small, and the relative standard deviation (RSD), also known as the standard deviation coefficient RSD≤30%. At the same time, Example 1 produced a grain size of 0.63μm, and the strength and toughness of the sample were better than those of the comparative example, and its discreteness was the smallest. The main reason was that the specific surface area and particle size distribution were controlled, so that its grain structure was uniform, the discreteness was small, and the strength and toughness were improved. In addition, the paraffin molding agent was used in the ball milling process of the embodiment, which can effectively reduce the moisture absorption of the pressed blank. The ball mill was made of cemented carbide material with a particle size similar to that of the powder, which reduced the coarseness caused by the ball mill wear and penetration into the mixture, thereby effectively improving the hardness and wear resistance of the cemented carbide; finally, the embodiment used high-temperature carburized tungsten carbide powder, which has good temperature sensitivity and can reduce the abnormal growth of alloy grains.

[0051] Therefore, the cemented carbide of the present invention can be well applied to high-performance tool materials specially designed for titanium alloy, stainless steel (especially suitable for 316L stainless steel), and high-temperature alloy rough and fine integration. Properly increasing the grain size in the cemented carbide substrate helps to improve the anti-chipping ability of the cemented carbide tool.

[0052] The above-described embodiments merely represent preferred implementations of the present invention. While the descriptions thereof are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make various other corresponding changes and modifications based on the technical solutions and concepts described above, and all such changes and modifications should fall within the scope of protection of the claims of the present invention.

Claims

1. A method for preparing high-strength and high-toughness cemented carbide, characterized in that: It is made of WC powder and Co powder as raw materials, adding inhibitors, and undergoing batching, ball milling, spray drying, extrusion molding and pressure sintering in sequence; Among them, the specific surface area of ​​WC powder is 1.6-2.1m 2 / g, particle size: 1.0≤(D90-D10) / D50≤1.2; Fsss particle size <0.8μm.

2. The method for preparing a high-strength and high-toughness cemented carbide according to claim 1, characterized in that: The inhibitors include Cr3C2 and VC, accounting for 0.5-1.0% of the mass of the WC powder.

3. The method for preparing a high-strength and high-toughness cemented carbide according to claim 1, characterized in that: The Co powder accounts for 10-12% of the mass of the WC powder.

4. The method for preparing a high-strength and high-toughness cemented carbide according to claim 1, characterized in that: The ball milling time is 50-70 hours, and paraffin molding agent is added during ball milling.

5. The method for preparing high-strength and high-toughness cemented carbide according to claim 1, characterized in that: The pressure sintering temperature is 1400-1420° C., and the sintering pressure is 6-9 MPa.

6. The method for preparing high-strength and high-toughness cemented carbide according to claim 1, characterized in that: The WC powder is high-temperature carbonized WC powder.

7. A high-strength and high-toughness cemented carbide, characterized in that: The method is prepared by any one of claims 1 to 6.

8. Use of the high-strength and high-toughness cemented carbide according to claim 7 in processing titanium alloy, stainless steel and high-temperature alloy materials.

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