The effect of varying carbon content and shot peening upon fatigue performance of prealloyed sintered steels

The aim of the work was to find out how the modification of surface treatment and microstructures aspect the fatigue characteristics of the considered sintered materials. Two dfferent systems were prepared: as-sintered and shot peened prealloyed sintered (Astaloy CrL based) steels with addition of 0.5% and 0.7% C. Sintering was carried out in laboratory tube furnace in an atmosphere of pure gases 75%N2+25%H2. The sintering temperature was 1180°C and sintering time was 60 min. Heating and cooling rates were 10°C/min. Fatigue tests were carried out in symmetric plane bending at stress ratio R=-1 with frequency of about 24 Hz. The presented experimental results showed that prealloyed water-atomised steels, with surface modification, exhibit positive effects on the fatigue failure resistance, and for that reason are suitable for high-performance applications.