Cemented carbide composite structure and preparation method therefor

Abstract

A cemented carbide composite structure (10) and a preparation method therefor. The cemented carbide composite structure (10) comprises a support body (12) and a cemented carbide body (14), wherein the support body (12) is of a mesh-shaped or cage-shaped skeletal structure, the support body (12) is arranged in the cemented carbide body (14), and the support body (12) is metallurgically bonded to the cemented carbide body (14).

Description

Cemented carbide composite structure and method for manufacturing the same

[0001] Priority information

[0002] The present application claims priority to the Chinese patent application No. 202410478570.5, filed on April 19, 2024, entitled "Cemented carbide composite structure and method for manufacturing the same", the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0003] The present application relates to the field of cemented carbide powder metallurgy, in particular to a cemented carbide composite structure and a method for manufacturing the same. BACKGROUND

[0004] Cemented carbide is generally a composite material formed by taking metal (such as steel) as a binder phase and taking refractory metal carbide (mainly including titanium carbide, tungsten carbide) as a hard phase, and powder metallurgy is a commonly used method for preparing cemented carbide. For example, steel-bonded cemented carbide takes steel as a binder phase. Due to the addition of steel, the main performance of steel-bonded cemented carbide is between that of steel and ceramic, and the steel-bonded cemented carbide can be machined, heat treated and welded while having high hardness and high wear resistance. It has broad application prospects in the fields of tool and die materials, wear-resistant parts, high-temperature and corrosion-resistant components, impact and crushing tools, cutting tools, measuring instruments and other measurement instruments, national defense and military industry, navigation, aerospace, etc.

[0005] The high hardness and wear resistance of cemented carbide mainly come from refractory metal carbide particles (hard particles), but the binder phase also needs to have a certain hardness and wear resistance to prevent the binder phase from being worn out, so that the hard particles lose the adhesion and support of the binder phase and fall off. Therefore, the binder phase and the hard particles have high hardness, which is also the fundamental reason for the poor toughness of cemented carbide. In working conditions with high impact force, cemented carbide is prone to cracking and chipping. If the proportion of the binder phase is increased (equivalent to reducing the proportion of the hard particles) or the hardness of the binder phase is reduced, the toughness of the cemented carbide is significantly improved, but the wear resistance is also significantly reduced. It is one of the key problems to broaden the development and application of cemented carbide to maintain high hardness and wear resistance while having high toughness.

[0006] Therefore, it is necessary to provide a composite structure and a method for manufacturing the same, which can improve the toughness of cemented carbide while maintaining the hardness and wear resistance of cemented carbide. SUMMARY

[0007] The technical problem solved by the present application is to provide a cemented carbide composite structure and a method for manufacturing the same, which can effectively improve the toughness of cemented carbide while maintaining the hardness and wear resistance of cemented carbide.

[0008] To solve the above technical problems, one technical solution of the present application is: a hard alloy composite structure, characterized in that it comprises a support body and a hard alloy body, the support body is a reticular or cage-like framework structure, the support body is embedded in the hard alloy body, and the support body and the hard alloy body are metallurgically combined. Since the hard alloy has poor deformation ability, when the support body is not added, the position subjected to impact force cannot absorb energy through plastic deformation, but absorbs external force through local fracture. After adding the support body, when subjected to external force at a certain position, the force will cause the entire support body to deform slightly, thereby absorbing the capacity and reducing the risk of local fracture. The design concept is to replace local large deformation (fracture) with overall slight deformation.

[0009] The present application also provides a preparation method of the hard alloy composite structure, comprising the following steps:

[0010] providing a green compact pressing die;

[0011] placing the hard alloy powder and the support body into the green compact pressing die, and compacting the hard alloy powder to form a green compact together with the support body; and

[0012] sintering the compacted green compact to form the hard alloy composite structure;

[0013] The support body is a reticular or cage-like framework structure, and the sintered hard alloy powder and the support body are metallurgically combined.

[0014] The present application has the beneficial effects that: the present application embeds the support body with a reticular or cage-like framework structure in the hard alloy body, the support body and the hard alloy body are metallurgically combined, which can effectively improve the toughness of the hard alloy body, while maintaining the hardness and wear resistance of the hard alloy body. BRIEF DESCRIPTION OF DRAWINGS

[0015] Fig. 1 is a schematic view of a hard alloy composite structure according to an embodiment of the present application.

[0016] Fig. 2 is a schematic view of a support body of a hard alloy composite structure according to an embodiment of the present application.

[0017] Fig. 3 is a schematic view of a support body of a hard alloy composite structure according to another embodiment of the present application.

[0018] Fig. 4 is a schematic view of a support body of a hard alloy composite structure according to another embodiment of the present application.

[0019] Fig. 5 is a schematic view of a green compact pressing process in a preparation method of a hard alloy composite structure according to an embodiment of the present application.

[0020] Fig. 6 is a schematic view of a green compact pressing process in a preparation method of a hard alloy composite structure according to another embodiment of the present application.

[0021] Figure 7 is a schematic view of a green compact pressing process in a method for manufacturing a cemented carbide composite structure according to another embodiment of the present application. DETAILED DESCRIPTION

[0022] The advantages and features of the present application will be more readily understood from the detailed description that follows, with reference to the accompanying drawings, in which the preferred embodiments of the present application are shown and described. It is to be understood that the foregoing description and specific embodiments are merely illustrative of the present application and that changes in the details of the present application can be made without departing from the scope of the present application.

[0023] Referring to Figure 1, a cemented carbide composite structure 10 according to an embodiment of the present application comprises a support body 12 and a cemented carbide body 14. The support body 12 is a net or cage structure. The support body 12 is embedded in the cemented carbide body 14, and the support body 12 is metallurgically bonded to the cemented carbide body 14. The cemented carbide body 14 covers the support body 12, and the cemented carbide body 14 also fills the gaps of the net or cage structure of the support body 12, thus forming an integrated structure with the support body as the skeleton and the cemented carbide body as the muscle, and the cemented carbide body and the support body supporting each other.

[0024] The cemented carbide body 14 is sintered from a cemented carbide powder. The cemented carbide powder comprises a hard phase and a binder phase. The hard phase is carbide hard particles, and the binder phase is a ferrous alloy.

[0025] In a first embodiment of the cemented carbide powder according to the present application, the binder phase is high manganese steel, and the high manganese steel has the following composition ratio: C: 0.90% to 2.0%, Mn: 10.0% to 15.0%, Si: 0.30% to 1.0%, Mo: 0.5% to 4.0%, Cr: 0.5% to 4.0%, and the balance being Fe. The above ratios are mass percentages. The hard phase is titanium carbide (TiC) particles, and the purity of the titanium carbide particles is greater than 95%. The volume percentage of the high manganese steel in the cemented carbide powder is 50% to 70%, and the volume percentage of the titanium carbide in the cemented carbide powder is 30% to 50%.

[0026] In a second embodiment of the cemented carbide powder according to the present application, the binder phase is high manganese steel, and the high manganese steel has the same composition and form as in the first embodiment. The hard phase is tungsten carbide (WC) particles, and the purity of the tungsten carbide particles is greater than 95%.

[0027] In a third embodiment of the cemented carbide powder according to the present application, the binder phase is high chromium cast iron, and the high chromium cast iron has the following composition ratio: C: 2.0% to 6.5%, Mn: 0.5% to 3%, Si: 0.30% to 1.5%, Mo: 0.5% to 3.0%, Cr: 10% to 20%, and the balance being Fe. The above ratios are mass percentages.

[0028] The hard phase is titanium carbide particles, and the purity of the titanium carbide particles is more than 95%. The volume percentage of the high-chromium cast iron in the hard alloy powder is 50%-70%, and the volume percentage of the titanium carbide in the hard alloy powder is 30%-50%.

[0029] In the fourth embodiment of the hard alloy powder, the binder phase is a high-chromium cast iron component, and the composition and proportion of the high-chromium cast iron are as follows: C: 2.0%-6.5%, Mn: 0.5%-3%, Si: 0.30%-1.5%, Mo: 0.5%-3.0%, Cr: 10%-20%, and the balance is Fe. The above proportion is a mass percentage. The hard phase is tungsten carbide particles, the volume percentage of the high-chromium cast iron in the hard alloy powder is 50%-70%, and the volume percentage of the tungsten carbide in the hard alloy powder is 30%-50%.

[0030] In addition, in the embodiments of the present application, the hard phase can also include other carbide hard particles, such as silicon carbide, chromium carbide, and vanadium carbide, and the hard phase can also include a mixture of a plurality of carbide hard particles.

[0031] Please refer to FIG. 2, FIG. 3 and FIG. 4, the support body 12 can be a cylindrical cage structure 121, or a square column cage structure 122, or a plurality of layers of planar net structures 123 are stacked with intervals.

[0032] The support body 12 is made of metal material, and its toughness is stronger than that of the hard alloy body 14. The cage or net structure is formed by crossing metal wires, and can be formed by weaving, casting, welding and other ways. In order to realize better metallurgical bonding between the support body 12 and the hard alloy body 14, the material composition of the binder phase in the support body 12 and the hard alloy body 14 is the same or similar, which can also be stainless steel, high manganese steel or high chromium cast iron. The cross-sectional shape of the metal wire can be circular, rectangular, rhombic or elliptical. The maximum distance between any two points on the cross section of the metal wire is less than 1.5 mm.

[0033] The preparation method of the hard alloy composite structure in the embodiments of the present application includes the following steps:

[0034] S1, providing a blank pressing mold;

[0035] S2, placing the hard alloy powder and the support body into the blank pressing mold, and compacting the hard alloy powder to form a blank together with the support body;

[0036] S3, sintering the compacted blank to form a hard alloy composite structure.

[0037] Referring to Fig. 5, the process of compacting the green compact according to the embodiment of the present application is shown schematically, which comprises the following steps: first filling of the powder, first compaction of the powder, placing the support, second filling of the powder, second compaction of the powder, and demolding.

[0038] In the step of first filling of the powder, a region for placing the support 12 is reserved in the center of the green compacting die 40, and the hard alloy powder 13 is filled between the region for placing the support 12 and the inner wall of the die 40, i.e. the first filling of the hard alloy powder; the step of first compaction of the powder is to compact the first filled hard alloy powder; the step of placing the support is to place the support 12 in the region reserved in the center of the die; the second filling of the hard alloy powder is to fill the hard alloy powder 13 into the cavity or gap in the support 12; the second compaction of the filled hard alloy powder is to compact the hard alloy powder 13 filled in the support 12; and the demolding is to take out the green compact formed by the hard alloy powder and the support from the die 40. In the first compaction, the profile and size of the hard alloy powder outside the green compact are fixed, and in the second compaction, the support 12 is embedded in the hard alloy powder while the structural integrity of the support 12 is reduced.

[0039] Referring to Fig. 6, in another embodiment of the present application, the support 12 can be placed in the green compacting die 40 first, and then the hard alloy powder 13 is placed in the green compacting die 40 and in the cavity or gap of the support 12, and the support 12 and the hard alloy powder 13 are compacted together to form the green compact.

[0040] In another embodiment of the present application, the support 12 can comprise a plurality of planar net structures. Referring to Fig. 6, in the step S2, part of the hard alloy powder 13 is placed in the green compacting die 40, and then a planar net structure support 12 is placed, and the hard alloy powder and the support are compacted; the steps of placing the hard alloy powder and the planar net structure support and compacting the hard alloy powder and the support are repeated until the green compact meeting the specification requirements is obtained; and the green compact formed by the hard alloy powder and the support is taken out from the die.

[0041] In another embodiment of the present application, the support 12 can comprise a plurality of planar net structures. Referring to Fig. 7, in the step S2, part of the hard alloy powder 13 can be placed in the die 40, and then a planar net structure support 12 is placed; the hard alloy powder and the planar net structure support 12 are placed alternately until the predetermined amount of hard alloy powder and the support 12 are placed in the die 40; the hard alloy powder and the support 12 in the die 40 are compacted; and the green compact formed by the hard alloy powder and the support 12 is taken out from the die 40.

[0042] In the above steps, the cemented carbide powder comprises a hard phase and a binder phase, the hard phase is carbide hard particles, and the binder phase is a ferrous alloy. The composition and ratio of the hard phase and the binder phase in the cemented carbide powder have been described in detail in the foregoing embodiments, and will not be repeated here.

[0043] The support body 12 is made of metal material, which is more flexible than the cemented carbide body 14. The support body 12 can be formed by weaving, casting, welding and other ways, and has a cage-shaped or net-shaped structure. In order to realize better metallurgical bonding between the support body 12 and the binder phase in the cemented carbide body 14, the material composition of the support body 12 and the binder phase in the cemented carbide body 14 is the same or similar, and can also be stainless steel, high manganese steel, high chromium cast iron. The cross-sectional shape of the metal wire can be circular, rectangular, rhombic or elliptical. The maximum distance between any two points on the cross section of the metal wire is less than 1.5 mm.

[0044] In step S3, the green compact is sintered at high temperature. During the sintering process, the support body 12 will soften, and under the action of the preforming pressure, the metal wire structure of the support body 12 will deform and become tortuous. At the same time, with the melting of the binder phase, the metal wire surface forms good wetting and metallurgical bonding. In this way, the support body 12 becomes a macroscopic skeleton that penetrates through the cemented carbide composite structure. When subjected to external force impact, it absorbs energy, improves the overall impact resistance of the cemented carbide, and reduces the probability of breaking.

[0045] The above is only an embodiment of the present application, and does not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation based on the content of the specification and drawings, or direct or indirect application in other related technical fields, is also included in the patent protection scope of the present application.

Claims

1. A cemented carbide composite structure, c h a r a c t e r i s e d in that The support body is a net or cage skeleton structure, and the support body is embedded in the cemented carbide body and metallurgically combined with the cemented carbide body.

2. The cemented carbide composite structure according to claim 1, characterized in that: The cemented carbide body covers the support body, and the cemented carbide body also fills the gaps of the net or cage skeleton structure of the support body, forming an integrated structure in which the support body is the muscle, the cemented carbide body is the skeleton, and the cemented carbide body and the support body support each other.

3. Cemented carbide composite structure according to claim 1, characterized in that: The support body is made of metal, and its toughness is higher than that of the cemented carbide body.

4. Cemented carbide composite structure according to claim 1, characterized in that: The cemented carbide body is sintered from cemented carbide powder and contains a hard phase and a binder phase.

5. Cemented carbide composite structure according to claim 4, characterized in that: The hard phase is a carbide hard particle, and the binder phase is a ferrous alloy.

6. Cemented carbide composite structure according to claim 5, characterized in that: The carbide hard particle includes at least one of tungsten carbide, titanium carbide, silicon carbide, chromium carbide, and vanadium carbide.

7. Cemented carbide composite structure according to claim 5, characterized in that: The material of the support body is the same as or similar to the material of the binder phase.

8. Cemented carbide composite structure according to claim 5, characterized in that: The binder phase includes high manganese steel, and the composition of the high manganese steel is as follows: C: 0.90%-2.0%, Mn: 10.0%-15.0%, Si: 0.30%-1.0%, Mo: 0.5%-4.0%, Cr: 0.5%-4.0%, and the balance is Fe.

9. Cemented carbide composite structure according to claim 5, characterized in that: The binder phase includes high chromium cast iron, and the composition of the high chromium cast iron is as follows: C: 2.0%-6.5%, Mn: 0.5%-3%, Si: 0.30%-1.5%, Mo: 0.5%-3.0%, Cr: 10%-20%, and the balance is Fe.

10. Cemented carbide composite structure according to claim 1, characterized in that: The support body is a cylindrical cage structure, a square column cage structure, or a multi-layer planar net structure.

11. Cemented carbide composite structure according to claim 1, characterized in that: The support body is formed by intersecting metal wires to form a cage or net structure, and the maximum distance between any two points on the cross section of the metal wire is less than 1.5 mm.

12. A method of producing a cemented carbide composite structure, c h a r a c t e r i s e d in that The method comprises the following steps: Providing a blank pressing mold; Placing the cemented carbide powder and the support body in the blank pressing mold, compacting the cemented carbide powder, and forming a blank together with the support body; and Sintering the compacted blank to form a cemented carbide composite structure; The support body is a net or cage skeleton structure, and the sintered cemented carbide powder is metallurgically combined with the support body.

13. A method of producing a cemented carbide composite structure according to claim 12, characterized in that: The step of placing the cemented carbide powder and the support body in the blank pressing mold and compacting the cemented carbide powder comprises the following steps: reserving a region for placing the support body at the center of the blank pressing mold, filling the cemented carbide powder between the region for placing the support body and the inner wall of the blank pressing mold, compacting the filled cemented carbide powder, placing the support body in the reserved region at the center of the blank pressing mold, filling the cemented carbide powder into the cavities or gaps of the support body, compacting the filled cemented carbide powder again, and demolding, i.e., taking out the blank formed by integrally pressing the cemented carbide powder and the support body from the blank pressing mold.

14. A method of producing a cemented carbide composite structure according to claim 12, characterized in that: The step of placing the cemented carbide powder and the support body in the blank pressing mold and compacting the cemented carbide powder comprises the following steps: placing the support body in the blank pressing mold, placing the cemented carbide powder into the blank pressing mold and the cavities or gaps of the support body, and compacting the support body and the cemented carbide powder to form a blank.

15. A method of producing a cemented carbide composite structure according to claim 12, characterized in that: The support body comprises a plurality of planar net structures. The step of placing the cemented carbide powder and the support body in the blank pressing mold and compacting the cemented carbide powder comprises the following steps: placing the hard alloy powder into the green compact pressing die, and then placing a piece of the planar net structure support body, and compacting the hard alloy powder and the support body; repeating the steps of placing the hard alloy powder, placing the planar net structure support body, and compacting the hard alloy powder and the support body until a green compact meeting the specification requirements is obtained; demolding, and taking out the green compact in which the hard alloy powder is integrally formed with the support body from the die.

16. A method of producing a cemented carbide composite structure according to claim 12, characterized in that: The support body comprises a plurality of planar net structures. The step of placing the hard alloy powder and the support body into the green compact pressing die and compacting the hard alloy powder comprises: placing the hard alloy powder into the green compact pressing die, and then placing a piece of the planar net structure support body; alternately placing the hard alloy powder and the planar net structure support body until a predetermined amount of the hard alloy powder and the support body is placed in the green compact pressing die, compacting the hard alloy powder and the support body in the green compact pressing die, and taking out the green compact in which the hard alloy powder is integrally formed with the support body from the green compact pressing die.

17. A method of producing a cemented carbide composite structure according to claim 12, characterized in that: The hard alloy powder comprises a hard phase and a binder phase; the hard phase comprises carbide hard particles, and the binder phase comprises a ferrous alloy.

18. A method of producing a cemented carbide composite structure according to claim 17, characterized in that: The carbide hard particles comprise at least one of tungsten carbide, titanium carbide, silicon carbide, chromium carbide, and vanadium carbide.

19. A method of producing a cemented carbide composite structure according to claim 17, characterized in that: The material of the support body is the same as or similar to the material of the binder phase.

20. A method of producing a cemented carbide composite structure according to claim 17, characterized in that: The binder phase comprises high manganese steel, and the high manganese steel has the following component ratio: C: 0.90% to 2.0%, Mn: 10.0% to 15.0%, Si: 0.30% to 1.0%, Mo: 0.5% to 4.0%, Cr: 0.5% to 4.0%, and the balance of Fe; the hard phase comprises titanium carbide; the volume percentage of the high manganese steel in the hard alloy powder is 50% to 70%, and the volume percentage of the titanium carbide in the hard alloy powder is 30% to 50%.

21. A method of producing a cemented carbide composite structure according to claim 17, characterized in that: The binder phase comprises high chromium cast iron, and the high chromium cast iron has the following component ratio: C: 2.0% to 6.5%, Mn: 0.5% to 3%, Si: 0.30% to 1.5%, Mo: 0.5% to 3.0%, Cr: 10% to 20%, and the balance of Fe.

22. A method of producing a cemented carbide composite structure according to claim 21, characterized in that: The hard phase comprises titanium carbide, and the volume percentage of the high chromium cast iron in the hard alloy powder is 50% to 70%, and the volume percentage of the titanium carbide in the hard alloy powder is 30% to 50%.

23. A method of producing a cemented carbide composite structure according to claim 21, c h a r a c t e r i s e d in that: The hard phase comprises tungsten carbide, and the volume percentage of the high chromium cast iron in the hard alloy powder is 50% to 70%, and the volume percentage of the tungsten carbide in the hard alloy powder is 30% to 50%.

24. A method of producing a cemented carbide composite structure according to claim 12, characterized in that: The support body is in a cylindrical cage structure, a square column cage structure, or a laminated structure in which a plurality of planar net structures are alternately arranged.

25. A method of producing a cemented carbide composite structure according to claim 12, characterized in that: The support body is formed by intersecting metal wires into a cage or net structure, and the maximum distance between any two points on the cross section of the metal wire is less than 1.5 mm.

Images