Different conditions in sintered steels obtained from a mixture of Astaloy CrM(R) and Mn powder grade, have been investigated in order to study their influence. Manganese effect has been studied by mixing 1 and 2 (wt) % with the prealloyed powders and two carbon levels, 0.35 and 0.5 (wt)%. All mixtures have been uniaxially pressed in a floating die up to 700 MPa. Sintering process has been carried out under industrial conditions in dissociated ammonia up to 1120 degreesC for 40 min reaching bainitic microstructures in as sintered condition. With the object of prevent decarburisation and oxidation reactions, quenching have been done under 90N(2)-10H(2)-0.1CH(4) atmosphere and vacuum Austenitized temperature has been chosen on the basis of dilatometric experiments. All mixtures have been oil hardenable effectively. Tempering temperature has been optimised between 150 degreesC to 700 degreesC, with the intention of reach the best compromise between strength and toughness. To comprehend the influence of tempering temperature microstructure and pores features, and some mechanical properties was investigated as well.