The Effect of Manganese on Microstructure Development and Diffusion Characteristics in Admixed Fe-Mn-C Sintered Steels

Paper in proceeding, 2010

The aim of this work is to determine the effect of manganese on the microstructure development of admixed Fe-Mn-C sintered steels, as well as to study the diffusion characteristics of Mn in the Fe matrix. Admixed systems were prepared on the base of sponge iron powder, with addition of 0.3 % C and 3% Mn added as ferromanganese. Sintering was carried out in laboratory tube furnace in an atmosphere of pure gases mixture 25 % N2 + 75 % H2 with the dew point of -30°C. The specimens were sintered at 750, 900, 1050, 1150 and 1200°C for 3 minutes. The obtained microstructures were complex and graded due to the local chemical heterogeneities of these materials with different Mn and C concentration. More detailed investigation reveal that diffusion induced grain boundary migration (DIGM) is the dominant alloying mechanism in sintered manganese steels. On the basis of presented results, Mn apparent diffusion coefficient and penetration depth were calculated.