The process of infiltration in drilling tools of rocks using powders of tungsten and tungsten carbides: characteristics and results of the microstructure and cermet hardness

Abstract

The process of infiltration for manufacturing of rock drilling tools (crown) analyzed three process with the utilization of the three powders (matrix), two containing tungsten carbides and one containing tungsten particles, on the microstructure and hardness of a hard metal for rock drilling tool (crown) were investigated. The crown samples were prepared by the infiltration technique, where the compacted matrix powder in a graphite mold, assembled with a steel shank, was infiltrated by a copper alloy in order to consolidate the hard metal and to join it with the steel shank. The powders and/or the cross-sections of the hard metals were characterized by chemical analysis, X-ray diffraction, particle size analysis, density, optical and scanning electron microscopy, energy dispersive spectroscopy, and differential thermal analysis. Beside the predominant phases, tungsten carbide and/or tungsten, the powders presented a small fraction of metallic particles. The results of microstructural analysis of hard metals were correlated with the chemical, phase, particle size and morphology, and compressibility characteristics of the powders investigated. Also were determinate the micro and macro-hardness of the hard metals and realized the microstructural analysis on the region of the interface between the hard metals and the steel shank and also difference of temperature on process of infiltration on each matrix powder.