The effect of B and C addition on structure and properties of sintered Mn-Cr-Mo steels

The effect of boron and/or carbon additions on the microstructure and properties of sintered manganese steels was investigated. These steels were produced based on following powders: pre-alloyed Astaloy CrL and ferromanganese. Sintering was carried out at 1150oC and 1250oC in hydrogen atmosphere. The density, hardness and microstructure were investigated. The main objective of this work was to find correlation between sintering temperature and chemical composition of steel and theirs properties. It was shown that both alloying elements and sintering temperature influence the microstructure and properties of sintered manganese steels. When boron or graphite was added, density and also hardness of the Fe-Mn-Cr-Mo steels were increased. Significant change in hardness were related to changes in the microstructure. Boron has a beneficial effect on the densification process, due to faster and more efficient sintering kinetics. In general, it can be observed that by sintering at higher temperature the microstructure and properties were improved.