Hard material

Abstract

To provide a hard material capable of reducing a burden of a user by achieving weight saving of an edge tool while maintaining sharpness as the edge tool peculiar to cemented carbide.SOLUTION: A hard material of the present invention includes: a first hard phase containing a compound of any one of a carbide, a nitride, and a carbonitride of W or Ti; a second hard phase containing a compound of any one of a carbide, a nitride, and a carbonitride of one element selected from the group consisting of Cr, Mo, V, Nb, Ta, Zr; and a binder phase containing Ni. A percentage of the binder phase is in a range of 20.0-50.0% in terms of wt.%.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a hard material mainly formed from a hard phase including carbides of W, Ti, etc. [Background technology]

[0002] Conventionally, the stainless steel used for cutting tools (cutting implements) such as knives and kitchen knives has mainly been martensitic stainless steel, typified by SUS440C (see Patent Document 1). In addition to martensitic stainless steel, cutting tools made from ceramics and cemented carbide are also gradually increasing. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2023-53601 Summary of the Invention [Problem to be solved by the invention]

[0004] However, while martensitic stainless steel knives are resistant to chipping, they do not retain their sharpness for long, which results in the need to sharpen the cutting edge more frequently.In addition, ceramic knives require a certain level of skill to sharpen, which limits their use in the general household.

[0005] Additionally, although the blades retain their sharpness for a long time, they are vulnerable to chipping, and if the chipping is particularly severe, it cannot be repaired, which can lead to the end of the blade's lifespan. Furthermore, although carbide blades are both chip-resistant and sharp, they are heavier than blades made from other materials, which places a physical burden on the user.

[0006] Therefore, the objective of the present invention is to provide a hard material that can reduce the weight (lightweight) of a blade while maintaining the sharpness that is characteristic of cemented carbide, thereby reducing the burden on the cook (user). [Means for solving the problem]

[0007] In order to solve the above-mentioned problems, the present invention provides a hard material having a first hard phase containing any compound of carbide, nitride, or carbonitride of W or Ti, a second hard phase containing any compound of carbide, nitride, or carbonitride of an element selected from the group consisting of Cr, Mo, V, Nb, Ta, and Zr, and a binder phase containing Ni, wherein the proportion of the binder phase is in the range of 20.0% to 50.0% by weight.

[0008] The proportion of the second hard phase in the hard material may be in the range of 0.3% to 5.0% by weight. Furthermore, the grain size of the carbides contained in the first hard phase and the second hard phase may be in the range of 0.3 μm to 3.0 μm. [Effects of the Invention]

[0009] The hard material of the present invention has a hard phase containing compounds such as WC and TiC, and a significantly increased content of Ni, the main component of the binder phase, thereby achieving a reduction in weight (lightweighting) while maintaining the sharpness of a blade that is characteristic of cemented carbide, thereby reducing the burden on the cook (user). Furthermore, by limiting the first hard phase to Ti carbides, nitrides, or carbonitrides, it is possible to achieve a further weight reduction compared to when the first hard phase is W carbides, nitrides, or carbonitrides, or a composite carbide, nitride, or carbonitride of W and Ti. DETAILED DESCRIPTION OF THE INVENTION

[0010] The first hard phase, the second hard phase, and the binder phase that form the hard material according to one embodiment of the present invention will be described in detail below.

[0011] (1st hard phase) The first hard phase is a phase containing a compound of any of carbide, nitride, and carbonitride of W (tungsten) or Ti (titanium), and contributes to the high toughness and high hardness properties of the hard material.

[0012] (Second hard phase) The second hard phase is a phase containing any compound of carbide, nitride, or carbonitride of an element selected from the group consisting of Cr, Mo, V, Nb, Ta, and Zr, and has the role of suppressing the grain growth of compounds such as carbides, nitrides, and carbonitrides of W and Ti in the first hard phase described above, thereby bringing out the properties of the first hard phase (high toughness and high hardness).

[0013] (bonded phase) The binder phase is a phase containing Ni, and accounts for the largest proportion in the hard material, with the proportion of the binder phase in the hard material ranging from 20.0% to 50.0% by weight. The binder phase serves to bind hard nitrides, carbides, and carbonitrides together through sintering.

[0014] Although Co is generally used as the binder phase in some cases, the binder phase forming the hard material of the present invention is limited to Ni because by using only Ni as the binder phase, rust resistance required for cutting tools can be obtained.

[0015] The proportion of the second hard phase in the hard material is preferably in the range of 0.3% to 5.0% by weight, and the grain size of the carbides contained in the first hard phase and the second hard phase is preferably in the range of 0.3 μm to 3.0 μm.

[0016] Next, a method for manufacturing a hard material according to one embodiment of the present invention will be described. First, any one of WC powder, TiC powder, TiN powder, and TiCN powder can be used as the powder for forming the first hard phase. Furthermore, any one of carbide-based powders such as Cr3C2 powder, Mo powder or Mo2C powder, VC powder, NbC powder, TaNbC powder, and ZrC powder, or nitride-based powders such as Cr2N powder, VN powder, NbN powder, TaN powder, and ZrN powder is used as the powder for forming the second hard phase. Ni powder is added as the powder for forming the binder phase, and the resulting mixture is mixed and pulverized using an attritor or ball mill. After that, a molding aid such as wax is added to produce a mixed powder.

[0017] When Mo powder is used as the powder for forming the second hard phase, C powder may also be added to obtain the carbide. Furthermore, the carbide, nitride, and carbonitride powders are not limited to the aforementioned powders, and powders containing elements for forming the first and second hard phases may be selected and used. Furthermore, the mixed powder may be dried, granulated, and classified using a spray dryer or the like.

[0018] Following the above-described steps, the mixed powder is molded to produce a green compact, which is then subjected to a sintering process to finally obtain the hard material of the present invention as a sintered body. Regarding the molding method, in addition to press molding using a mold, CIP (Cold Isostatic Pressing) molding or the like may also be used. Furthermore, regarding the sintering process, it is preferable that the sintering temperature is in the range of 1340 to 1500°C, and the sintering time is in the range of 30 to 360 minutes.

Claims

1. A hard material having a first hard phase containing a compound of any one of carbide, nitride and carbonitride of W or Ti, a second hard phase containing a compound of any one of carbide, nitride and carbonitride of an element selected from the group consisting of Cr, Mo, V, Nb, Ta and Zr, and a binder phase containing Ni, wherein the proportion of the binder phase in the hard material is in the range of 20.0% to 50.0% by weight.

2. 2. The hard material according to claim 1, wherein the proportion of the second hard phase in the hard material is in the range of 0.3% to 5.0% by weight.

3. 3. The hard material according to claim 2, wherein the grain size of the carbides contained in the first hard phase and the second hard phase is in the range of 0.3 μm to 3.0 μm.