Analysis of die compaction of tungsten carbide and cobalt powder mixtures

Abstract

This paper investigates die compression of tungsten carbide–cobalt powder mixtures, which is an important step in the processing route of cemented carbides. Simple action compression of miscellaneous mixtures has been investigated with an industrial type press allowing measurement of the force applied on both upper and lower punches. In addition, an original apparatus was used to measure the average radial stress applied upon the die, and the frictional shearing force at the powder/die interface was determined through a powder/wall friction apparatus. A mechanical analysis of the data obtained for various tungsten carbide–cobalt powder mixtures provided the intrinsic stress v. density compressibility relation as well as the radial stress transmission coefficient and the powder/die friction coefficient. In this framework, the effect of several material and process parameters on the densification is discussed.