The combined effects of tungsten carbide additions and manufacturing parameters on microstructure and properties of sintered high speed steel - base materials
Jarosłąw Indra, Jan Leżański Akademia Górniczo-Hutnicza, Wydział Metalurgii i Inżynierii Materiałowej, al. Mickiewicza 30, 30-059 Kraków
Annals 3 No. 7, 2003 pages 187-191
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abstract In this paper the manufacturing process and properties of sintered high speed steel-tungsten carbide composites have been studied. The raw powders were mixed with in ceramic mortar for 30 minutes. The following compositions were investigated: M, M+10wt-%WC, M+20wt-%WC, M+30wt-%WC, M+40wt-%WC, where M is the HSS M35 grade. The mixtures were cold compacted in a rigid, cylindrical die at 400, 600, 800 MPa. The green compacts were sintered at 1160oC for 60 minutes in vacuum. Additionally the compositions M, M+10wt-%WC were sintered at 1175, 1200 and 1220oC for 60 minutes in vacuum. The powder properties are shown in Table 1. Figure 2 shows the variation in green density for each powder mix. The as-sintered densities, densification during sintering and Brinell hardness numbers are presented in Figs 3 and 4, Figs 5 and 6, and Figs 7 and 8, respectively. Microstructures of the high speed steel - base materials are shown in Figure 9. From the analysis of the obtained results and microstructural observation it may be concluded that the as-sintered properties of the investigated materials are affected by both the processing parameters and tungsten carbide content. Key words: high speed steel - base materials, pressing, sintering