Каталог Dormer Pramet фрезерование 2021 - 2022 - страница 204

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9 HM MATERIALS HM materials A sintered powder metallurgy substrate, consisting of a metallic carbide composite with binder metal. The most central raw material is tungsten carbide (WC). Tungsten carbide contributes to the hardness of the material. Tantalum carbide (TaC), titanium carbide (TiC) and Carbide Materials(or Hard Materials) niobium carbide (NbC) complements WC and adjusts the properties to what is desired. These three materials are called cubic carbides.Cobalt (Co) acts as a binder and keeps the material together. Carbide materials are often characterised by high compression strength, high hardness and therefore high wear resistance, but also by limited flexural strength and toughness. Carbide is used in taps, reamers, milling cutters, drills and thread milling cutters. Properties HSS materials HM materials K10/30F(often used for solid tools) Hardness (HV30) 800 – 950 1300 – 1800 1600 Density (g/cm3) 8.0 – 9.0 7.2 – 15.0 14.45 Compressive strength (N/mm2) 3000 – 4000 3000 – 8000 6250 Flexural strength, (bending) (N/mm2) 2500 – 4000 1000 – 4700 4300 Heat resistance (°C) 550 1000 900 E-module (KN/mm2) 260 – 300 460 – 630 580 Grain size (μm) – 0.2 – 10.0 0.8 The combination of hard particle (WC) and binder metal (Co) give the following changes in characteristics. Characteristic Higher WC content give Higher Co content give Hardness Higher hardness Lower hardness Compressive strength (CS) Higher CS Lower CS Bending strength (BS) Lower BS Higher BS Grain size also influences the material properties. Small grain sizes means higher hardness and coarse grains give more toughness. 203