Sintered Steels Alloyed with Manganese: Effect of Alloying Mode

Paper i proceeding, 2010

Manganese has a substantial potential for the production of precision structural parts with high static and dynamic properties. However due to its peculiar properties (oxygen affinity, vapour pressure, ferrite strengthening etc.) issue of appropriate alloying mode remains open. Meticulous attention in this work was focused on the influence of alloying mode – admixing using high-purity electrolytic manganese and medium carbon ferromanganese as well as fully prealloying of water atomized powder. Various phenomena, connected with manganese evaporation and reduction/oxidation behaviour of studied materials were studied by sampling of specimens at different stages of the sintering cycle for extensive study by HR SEM+EDX, XPS, TG etc. The admixed with electrolytic manganese material shows lowest mechanical properties due to more intensive manganese sublimation and oxidation at low temperatures and further inter-granular decohesion failure. Pre-alloyed material is superior to admixed systems due to lower oxidation sensitivity, homogeneous microstructure and absence of large pores after Mn-carriers.