4th International DAAAM Conference “INDUSTRIAL ENGINEERING – INNOVATION AS COMPETITIVE EDGE FOR SME” 29 - 30th April 2004, Tallinn, Estonia ADHESIVE WEAR BEHAVIOUR OF CARBIDE COMPOSITES AND TOOL STEELS H. Annuka, H. Klaasen, J. Kübarsepp, V. Suvi Tallinn University of Technology, Ehitajate tee 5, 19086 Tallinn, Estonia Abstract: The performance of hard alloys – carbide composites and tool steels (of different composition and structure) in the conditions of prevailing adhesive surface failure (complemented by SEM studies) was investigated. TiC-FeNi Cr C -NiMo 3 2 WC-Co TiC-NiMo 200 85 1.0 89 88 87 86 90 HRA HV ,GPa 30 1.3 1.2 1.1 Adhesive wear resistance , m/mm L 1 200 400 600 800 1000 2000 3000 4000 5000 It was shown that hardness does not enable us to estimate wear resistance of alloys exactly. In respect to adhesive wear resistance, TiC-base cermets with a steel binder and high alloyed tool steels can compete with WC-base hardmetals. Key words: cemented carbides, tool steels, adhesive wear 1. INTRODUCTION Cemented carbides are the most widely used materials for different wear applications owing to their excellent combination of high wear resistance and good strength- toughness (Brooks, 1996). “Tungsten-free” cemented carbides – TiC and Cr 3 C 2 base cermets may be successful in some applications because of their lower friction coefficient, higher specific strength and resistance to oxidation, and more favourable physical properties (Kübarsepp et. al., 1994; Reshetnyak et. al., 1995) Carbide composites are mainly used in service conditions where either high performance in abrasive wear conditions or at elevated temperatures (high speed cutting operations) are required. In complicated service conditions – in non cutting operations, high alloyed tool steels have been more successful (Reshetnyak et. al., 1989). This paper is focused on the tribological behaviour of some prospective TiC- and Cr 3 C 2 -base cermets – on their response as inserts in adhesive wear experiments. The performance of these cermets was compared with WC-base hardmetals and tool steels used in metalforming operations. 2. EXPERIMENTAL PROCEDURE TiC-base cermets with 50, 60 wt% TiC cemented with Ni- steels (8,14 wt% Ni in binder) grades T60/8, T60/14, T70/8, T70/14 and conventional “tungsten-free” cermets on TiC and Cr 3 C 2 -basis, cemented with Ni-25%Mo alloy TN30, 40, 50 and C10, 20, 30 were studied. In addition, we analyzed WC- hardmetals with 10-20 wt% Co-binder (grades H10...H20 and fine grained H10F, H15F) and tool steels (differing in alloying degree 1 wt%...30 %wt), including high-speed steels (HSS). Adhesive wear conditions were realized by cutting mild steel (HV≤180) at low (<20 m⋅min -1 ) speed Reshetnyak et. al., 1989). The adhesive wear resistance was determined as the length of cutting path L 1 , when the wear land h at the lathe tool (specimen) nose achieved the critical value 1 mm. 3. RESULTS AND DISCUSSION 3.1 Carbide composites The relationships shown in Fig. 1 confirm the fact revealed previously that concerns the lack of satisfactory correlation Fig. 1. Adhesive wear resistance of carbide composites vs. hardness. between the abrasive wear resistance and hardness of hardmetals and cermets (Reshetnyak & Kübarsepp, 1994). At equal hardness level the adhesive wear resistance of different carbide composites investigated differed up to 15 times (hardmetal H15F with L 1 = 5300 m/mm and Cr 3 C 2 -cermet C10 with L 1 = 300 m/mm). The results obtained refer to the obvious superiority (up to 12 times at equal hardness) of WC-base hardmetals over conventional “tungsten-free” composites – TiC and Cr 3 C 2 -base cermets with Ni-alloy binder. The Cr 3 C 2 -cermets demonstrate an extraordinary behaviour – a decrease in wear resistance with an increase in the carbide content and hardness. Contrary to the conventional cermets, TiC-base cermets with a steel binder show excellent performance (not lower than that of WC-hardmetals). 167