Sintered Dual-phase Steels Produced from Pre-alloyed Fe-Cr-Mo Powder

Abstract

The sintered Fe-Cr-Mo-xC steels (where x = 0.05, 0.15, 0.25, 0.35 and 0.45 wt.% C) were produced by vacuum sintering and followed by slow cooling. The sintered steels showed microstructures consisting of mixed a + a¢ phases. The formation of a¢ phase was discussed with respect to the classical model for bainitic transformation. The morphologies of the a¢ phase regions changed from a thick film to a dark island to a bulk form with increasing C content. With the added C contents < 0.25 wt.%, the sintered steels showed low tensile strength and hardness but high ductility. When the C contents ≥ 0.25 wt.%, the sintered Fe-Cr-Mo-xC steels gained strength from the a¢ phase, whose volume fraction was increased with increasing C content.