Fatigue properties of sintered manganese steels

Fatigue properties of sintered manganese steels containing 2 and 3% of Mn as well as 0.3 and 0.7% of C are presented in this contribution. Endurance limit for 107 cycles was determined on the basis of S-N curves, using the method of plane bending. The effects of sintering conditions are analyzed, namely the sintering temperature (1120, 1200 and 1180degreesC) as well as the effect of oxidation purity of sintering atmosphere on the fatigue behaviour of the studied types of sintered Mn steels. The results have shown that the endurance limit increases with content of Mn and C, but decisive for the fatigue strength is the oxidation purity of the sintering atmosphere. The values of the endurance limits fall within the range of 125-175 MPa, where the highest value corresponds to Fe-3Mn-0.7C material after sintering at the temperature of 1180degreesC in the atmosphere with the dew-point of -55degreesC. The presented results form a part of the agenda oriented on the development of new types of economically and ecologically advantageous structural manganese sintered steels, which should replace Fe-Ni-Cu-Mo alloyed systems currently in use.