A New Sintered Hard Metal Composite
Extensive work has been performed on WC-Co hard metals for mining tools, tool inserts and other components. Cobalt is widely used as the binder metal because it’s good wetting behavior and solubility. However, the cost is high. Fe-Cr-Ni alloys show similar characteristics to Cobalt regard to melting temperature and crystal structure. Additionally, Fe-Cr-Ni alloys are a less expensive and nontoxic alternative. The present work analyze sintering characteristics of the WC / Fe-Cr-Ni alloys composite and development of new sintered hard metal composite for mining tools. The composite WC-316L was processed via Powder Metallurgy and sintering was performed at different temperatures: 1200oC, 1300oC and 1400oC rate and 20oC and isotherm 1hour in vacuum atmosphere. The composite sintered WC-316L was characterized by XRD, SEM and Vickers micro hardness test. The samples processed at temperatures of 1200oC and 1300oC showed considerable porosity, heterogeneity microstructure, low density relative and low Micro hardness, 300 HV and 700 HV, respectively. The samples sintered at temperature 1400oC showed higher homogeneity microstructure compared to the samples sintered at temperatures of 12000C and 13000C, higher density relative, 86%, and micro hardness value compatible with the composite WC-Co, 1890 HV.These analyzes infer that stainless steel can be used instead of cobalt.
Francisco Ambrozio Filho and Aloisio Nelmo Klein
A. A.A. Santos et al., "A New Sintered Hard Metal Composite", Materials Science Forum, Vol. 802, pp. 114-119, 2014