The three yield conditions of a powder continuum (incipient yield, stationary flow, consolidation) are formulated on basis of particle mechanics by the model "stiff particles with soft contacts". So that the direct influence of contact behaviour on flow behaviour is analytically shown. The powder compression behaviour is characterised by a compressibility index. Additionally the compression rate and the specific compression work are explained. So that the correlation between contact compliance, adhesion force intensification and powder flowability can be physically consistent evaluated. The response functions of extreme stressing and flow conditions at material conversion processes, storage and transport can be sufficiently described by these models. Obviously, suitable conclusions may be also drawn to design marketable products of processing industries.