The microstructure and properties forming sintered M35 HSS base cermets
Jarosław Indra, Jan Leżański AGH University of Science and Technology, Department of Physical and Powder Metallurgy, Mickiewicza 30, 30-059 Cracow, Poland
Quarterly No. 1, 2005 pages 79-84
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abstract In this paper the manufacturing process and properties of sintered M35 high speed steel with addition of tungsten carbide WC cermets have been studied. The chemical composition of M35 steel is presented in Table 1. Morphology of powder particles M35 steel and tungsten carbide WC are shown in Figure 1. The raw powders were mixed together in a ceramic mortar for 60 minutes. The following composition was investigated: M35+10 wt.% WC. Cold compacting in a rigid, rectangular die at 800 MPa was followed by sintering in vacuum furnace at six different temperatures in the range 1150÷1220°C under vacuum pressure below 10−2 Pa. The sintering process assembled with three stages: annealing at 950oC for 30 minutes, isothermal sintering for 60 minutes and cooling with furnace. The as-sintered specimens were subjected to density and microhardness measurements. Density was measured on the base of Archimedes’ law. Figure 2 shows the results of density of sintered M35+10 wt.% WC cermets. For the microhardness measurement Hanemann harness testing machine was used. For microstructure examination light and SEM microscopy techniques were employed. Diffractometer TUR M62 with HZG4 goniometer was employed for X-ray diffraction analysis. On the base of results and microstructure observation it may be concluded that the processing parameters and tungsten carbide content simultaneously affect the as-sintered properties of the investigated cermets. Key words: cermet, high speed steel, tungsten carbide, pressing, sintering