Martensite Fraction Effect on Fatigue Resistance for Double-Phase Steel Shafts

In this research, the effect of the volumetric fraction of martensitic on the resistance of fatigue of the double-phase steel shafts was studied. A carbon steel 0.108 %C test and other specimen of carbon steel was heated at different temperatures 750,775, 800 and 825°C for a holding time 15 min and then was quenching in water to produce double-phase steel. The different volumetric fractions martensitic that obtanded (8.1, 11.3, 14.6 and 19.4) % Ms (Martensite). Experimental results showed that the fatigue resistance of the double-phase steel shaft was greater than that of the carbon steel metal received. In addition, the best correlation between resistance fatigue and number of failure cycles was in the martensite ratio equal to 11.3% when fatigue resistance was equal to 208 N/mm2 with the number cycles of 400420. The amount of fatigue increased when the volume fraction of martensitis increased and the concomitant decreased in the number of failure cycles. The largest amount of resistance fatigue for double-phase steel 265 N/mm2 was recording at the number cycles of 150320.