Effect of Fe prealloyed powder and the sintering process on the matrix properties of impregnated diamond bits

Abstract

Prealloyed Cr–Fe and prealloyed Fe powders were used as a replacement for widely used tungsten carbide powder to fabricate impregnated diamond bits. The effects of the prealloyed Fe content and sintering process on the matrix properties of the impregnated diamond bits wereinvestigated. The relative density, bending strength, and hardness were tested, and the fracture was analyzed by scanning electron microscopy. The results showedthat as the mass fraction of prealloyed Fe powder increased, the density and bending strength of the matrix decreased, and the hardness increased. The mechanical properties of the matrix increased with increasing sintering temperature; when the temperature was higher than 940 °C, the mechanical propertiestended to stabilize or decrease slightly. When the holding time was 5 min, the relative density, bending strength, and hardness of the matrix material were high. The experimental data showedthat a proper amount of prealloyed Fe can yieldgood mechanical properties, and that prealloyed Cr–Fe and prealloyed Fe can completely replace WC (tungsten carbide) as the framework material of thematrix. In conclusion, it is feasible and reasonable to replace WC powder with prealloyed Fe powder to prepare impregnated diamond bits. This process has significant economic benefits and market prospects.

Keywords

• Prealloyed Cr–Fe
• Prealloyed Fe
• Sintering temperature
• Holding time
• Mechanical properties
• Fracture appearance