A nitrocarburising treatment was carried out on a low alloyed Cr-Mo sintered steel (1?5%Cr, 0?2%Mo) to evaluate its influence on the bending fatigue resistance of the material. Fatigue performance was compared with that obtained by a conventional through hardening and a plasma carburising. Two different green densitise (7?1 and 7?4 g cm 23 ) and two different sintering temperatures (1120 and 1250uC) were adopted during preparing the as sintered steels. Fatigue strength after nitrocarburising on 1120uC sintered steels considerably increases. It is comparable with that obtained by through hardening and slightly better than that obtained by plasma carburising. On samples sintered at 1250uC the fatigue resistance of the nitrocarburissed is worse than expected, because the microstructure is softer and less homogeneous.

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