Abstract
A study has been made on the mechanical properties of sintered Cr-Mo steels (Fe-l o%Cr-0.2o%Mo-0.35%C) containing metallic Mo, Mo carbide, or ferro-Mo powders as an alloying additive. The static tensile and fatigue properties were compared with those of Cr-Mo steel made from prealloyed atomized powders.
The microstructure of prealloyed specimens was observed to be relatively homogeneous, whereas the premixed specimens showed a heterogeneous microstructure caused by Mo segregation.
The effect of microstructural heterogeneity, caused by a different way of Mo addition, on static tensile properties was scarcely distinguished. On the other hand, fatigue strength was affected by these microstructures.
Abrupt change in hardness of segregated area led to a decrease in fatigue strength. However, the fatigue strength was improved by the presence of the microstructural heterogeneity where gradual changes in hardness existed.
