CEMENTED CARBIDE AND WORKING TOOL

• Main Authors: CHIHARA KENTARO, MORIGUCHI HIDEKI
• Format: Patent
• Language: English; Japanese
• Published: 13.08.2015
• Subjects: ALLOYS; BORING; CHEMISTRY; FERROUS OR NON-FERROUS ALLOYS; MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR; METALLURGY; MILLING; PERFORMING OPERATIONS; TRANSPORTING; TREATMENT OF ALLOYS OR NON-FERROUS METALS; TURNING

PROBLEM TO BE SOLVED: To provide a cemented carbide that has smaller bias of particle size distribution of hard phase particles as compared with that of the conventional ones and is excellent in abrasion resistance and defect resistance.SOLUTION: The cemented carbide is formed by binding a hard phase mainly composed of WC particles with a binder phase mainly composed of Co. An average particle size of WC particles constituting the hard phase of the cemented carbide is less than 0.4 μm and a degree of dispersion as an index showing uniformity of the WC particle size is 0.55 or less, preferably, 0.50 or less. [the degree of dispersion is a value obtained by dividing the half value width (circle equivalent diameter when the cumulative frequency is 75%-circle equivalent diameter when the cumulative frequency is 25%) by the average particle size (50% particle size) of the WC particles]. An average circularity of the WC particles is 0.68 or more, preferably, 0.75 or more. The cemented carbide has more excellent abrasion resistance and defect resistance than those of the conventional ones and consequently, and thereby can be suitably used for various working tools. 【課題】従来よりも硬質相粒子の粒度分布の偏りが小さい超硬合金を提供する。【解決手段】ＷＣ粒子を主体とする硬質相がＣｏを主体とする結合相により結合されてなる超硬合金である。この超硬合金の硬質相を構成するＷＣ粒子の平均粒径が０．４μｍ未満であり、かつ、ＷＣ粒子径の均一性を表す指標である分散度数が０．５５以下、好ましくは０．５０以下である超硬合金。［分散度数は、ＷＣ粒子の粒度分布の半値幅（累計頻度７５％のときの円相当直径−累計頻度２５％のときの円相当直径）を、ＷＣ粒子の平均粒径（５０％粒径）で除した値］前記ＷＣ粒子の平均円形度が０．６８以上、好ましくは、０．７５以上である超硬合金。【効果】前記超硬合金は、従来よりも優れた耐摩耗性・耐欠損性を有しているので、種々の加工工具に好適に利用できる。【選択図】図１