Cermetals for cutting edges
Lucyna Jaworska, Barbara Smuk, Dagmara Królicka, Janusz Wszołek Instytut Obróbki Skrawaniem, ul. Wrocławska 37a, 30-011 Kraków
Quarterly No. 3, 2005 pages 21-25
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abstract Cermetals have very good plasticity and high hardness. Properties of these materials are placed between carbides and cutting ceramics. Due to their low chemical affinity to steel and the resistance for high temperatures oxidation of cermetals have better cutting properties than carbides. Application of cermet inserts guarantees the high quality of machining surface (low roughness). Cermets could be used in „dry cutting” process. Materials were sintered at N2, Ar2 and vacuum atmosphe-res at various temperatures. For these researches were used: TiC, TiCN, Mo2C (Tables 1, 2). These materials have low porosity of about 0.05% (Fig. 2). Material with 55 wt.% of TiC and 45 wt.% of (Ni+Mo) has hardness of HV1 18.2 GPa (Tab. 3). Material is characterized by high wear resistance similar to Al2O3 compacts, which was measured on the special IOS apparatus. Cutting inserts were prepared using these cermetals. Wear land width VBB, cutting time, tools live are tested. The 45 steel was machining. Wear land of this inserts VBB = 30 was reached after 12 min (Tab. 4). TiC grains have significant influence on the cutting process. In the future works the finer grains of TiC powders are needed. In this moment material has properties predisposition for cutting tool applications. The functionally graded materials (FGM) were prepared by the layers pressing method (Fig. 1) and the sedimentation method. Functionally graded cermetals have more amount of hard phase in the surface layer and lower participation of this phase in the body frame. FGM secure obtaining of tools (inserts) with hard wear resistance surface layer and the ductile body frame. The gradient of hardness measurement is presented in Figure 4. The functionally graded materials have high porosity. It is a result of various content and conditions of sintering for its layers. Key words: TiC, cermetals, materials for cutting edges, functionally graded materials