CN-122003512-A - WC-based cemented carbide

Abstract

A WC-based cemented carbide suitable for a substrate of a surface-coated cutting tool or the like, comprising 6.0 to 10.0 mass% of Co, 0.08 to 0.90 mass% of Cr (wherein Cr content (% by mass)/Co content (% by mass) is 10% or less), 0.0 to 3.8 mass% of M (one or more of V, ta, nb, ti and Zr) and 4.5 to 7.5 mass% of C, the remainder being W and unavoidable impurities, the WC-based cemented carbide having a binder phase comprising Co as a main component, a hard phase comprising W carbide as a main component, and a gamma phase comprising M carbide as a main component, wherein among crystal grains constituting the hard phase, a cumulative particle size C99 (μm) of 99% is 3.30 or less, a cumulative particle size C99 (μm) of 99% and a cumulative particle size C50 (μm) of 50% are 4.80 or more and a hard phase of 4.80 or more, and a ratio of the binder phase to the hard phase to the total length of the interface phase is 35% or less.

Inventors

• KONDO Shota

Assignees

• 三菱综合材料株式会社

Dates

Publication Date

20260508

Application Date

20241024

Priority Date

20231025

Claims (2)

1. 1. A WC-based hard alloy is characterized in that, Comprises 6.0 to 10.0 mass% of Co, 0.08 to 0.90 mass% of Cr, 0.0 to 3.8 mass% of M and 4.5 to 7.5 mass% of C, and the balance of W and unavoidable impurities, wherein the content of Cr/Co is less than 10%, the content of Cr and the content of Co are in mass%, the M is one or more of V, ta, nb, ti and Zr, The WC-based cemented carbide has a binding phase, a hard phase and a gamma phase, The binder phase is composed mainly of Co, the hard phase is composed mainly of W carbide, the gamma phase is composed mainly of M carbide, In the crystal grains constituting the hard phase, the cumulative particle number 99% particle diameter C99 is 3.30 or less, the cumulative particle number 99% particle diameter C99 and the cumulative particle number 50% particle diameter C50 have a C99/C50 of 4.80 or more and 6.50 or less, wherein the unit of the cumulative particle number 99% particle diameter C99 and the cumulative particle number 50% particle diameter C50 is μm, The phase interface length of the hard phase in contact with the bonding phase is 35% or more of the total phase interface length of the hard phase.
2. 2. The WC-based cemented carbide according to claim 1, wherein, The Rockwell hardness HRA is 88.8 or more and 90.6 or less.

Description

WC-based cemented carbide Technical Field The application relates to WC-based hard alloy. The present application claims priority based on Japanese patent application No. 2023-183208 filed on 25/10/2023. All the details described in this japanese patent application are incorporated by reference into the present specification. Background WC-based cemented carbide is used, for example, as a substrate for cutting tools and a substrate for surface-coated cutting tools (hereinafter, sometimes referred to as coated tools). Here, the clad tool is a tool having an Al 2O3 layer or a TiCN layer deposited on a base as a clad layer, and is used for cutting processing of carbon steel, cast iron, alloy steel, and the like. In cutting processes where the tip is at a high temperature, such as cutting processes of stainless steel, the tip of the coated tool may be plastically deformed, resulting in premature tool life. On the other hand, if the hardness of the matrix is increased to suppress such plastic deformation, the chipping resistance is lowered. Accordingly, there is a need for a matrix made of WC-based cemented carbide having both plastic deformation resistance and chipping resistance, and for example, the following proposals have been made. Patent document 1 describes a WC-based cemented carbide comprising a hard phase including tungsten carbide particles and a binder phase containing a cobalt-iron group element as a main component, wherein the WC-based cemented carbide is excellent in plastic deformation resistance, satisfying B/a≤0.05, when the particle number of the tungsten carbide particles is a and the particle number of the tungsten carbide particles having a point number of contact points with other tungsten carbide particles of 1 point or less is B. Patent document 2 describes a WC-based cemented carbide comprising 10 to 13 mass% of at least one of Cr, which is 2 to 8 mass% of Cr, 0.2 to 0.5 mass% of TaC, and NbC, the remainder being composed of WC, the WC-based cemented carbide having a hardness of 88.6 to 89.5hra, a ratio D80/D20 of 80% diameter D 80 of WC cumulative particle size to 20% diameter D 20 of 2.0 to 80/D20 to 4.0, the D 80 being 4.0 to 4.86 μm, and a WC bond c of 0.36 to 0.43, the WC-based cemented carbide being excellent in chipping resistance. Patent document 1, patent publication 6256415 Patent document 2 Japanese patent No. 6774645 Disclosure of Invention The present invention has been made in view of the above-described circumstances and the above-described proposals, and an object thereof is to provide a WC-based cemented carbide having excellent plastic deformation resistance and chipping resistance when used as a base body for cutting tools and cladding tools. With respect to WC-based cemented carbide according to an embodiment of the present invention, Comprises 6.0 to 10.0 mass% of Co, 0.08 to 0.90 mass% of Cr (wherein the Cr content (mass%)/Co content (mass%) is 10% or less), 0.0 to 3.8 mass% of M (one or more of V, ta, nb, ti and Zr) and 4.5 to 7.5 mass% of C, the balance being W and unavoidable impurities, The WC-based cemented carbide has a binding phase, a hard phase and a gamma phase, The binder phase is composed mainly of Co, the hard phase is composed mainly of W carbide, the gamma phase is composed mainly of M carbide, In the crystal grains constituting the hard phase, the cumulative particle number 99% particle diameter C99 (μm) is 3.30 or less, the ratio C99/C50 of the cumulative particle number 99% particle diameter C99 (μm) to the cumulative particle number 50% particle diameter C50 (μm) is 4.80 or more and 6.50 or less, The ratio (L) of the interface length in contact with the crystal grains constituting the binder phase to the total interface length of the crystal grains constituting the hard phase is 35% or more. The WC-based cemented carbide may also satisfy the following (1). (1) The Rockwell Hardness (HRA) is 88.8 or more and 90.6 or less. The WC-based cemented carbide according to the foregoing embodiment has excellent plastic deformation resistance and chipping resistance particularly when used as a base body for cutting tools and clad tools. Detailed Description The present inventors have studied hard alloys which impart excellent plastic deformation resistance and fracture resistance when used as a base body of a cladding tool, and first, the WC-based hard alloys described in the foregoing patent documents 1 and 2 have recognized the following items (1) and (2). (1) The WC-based cemented carbide described in patent document 1 reaches the tool life early in providing for the intermittent cutting process. (2) The WC-based cemented carbide described in patent document 2 is insufficient in plastic deformation resistance when provided for high-speed high-feed cutting processing. The present inventors have further conducted intensive studies. As a result, the following findings were obtained, and the present invention was derived. (A) The plastic deformation resista