Tensile Properties of Fe-Cr and Fe-(Cr, Mn) Sintered Steels Applied by Low-Pressure Carburisation

The use of Cr or Mn as alloying elements plays a prominent role in sintered iron-based materials, as they possess the ability to enhance the strength of materials through the addition of small quantities, due to their high quenching multiples. However, Cr and Mn, which are also a readily oxidisable element, is preferentially oxidised by the presence of H2O and CO2 in the atmosphere in the conventional carburising process using hydrocarbon-modified gas. The oxidation of Cr and Mn during carburising represents a significant challenge to address, as it can lead to significant variations in the mechanical strength of sintered and carburised materials. We focused on low-pressure carburisation, which has the potential to suppress Cr and Mn oxidation. This paper will demonstrate such an effect on the tensile properties of Fe-Cr and Fe-(Cr, Mn) sintered steels applied by the low-pressure carburisation.