Properties of stabilised Ni-Cr cast steel exposed to the effect of carburising atmosphere and thermal fatigue

In this paper results investigation of an effect of niobium and/ or titanium as well as silicon on the resistance of 0,3%C-30%Ni-18%Cr cast steel to the carburising effect and thermal shocks at a temperature of 900 degrees C under the carburising atmosphere of carbon potential equal to 0,9% are shown. Eight test alloys were manufactured in which the content of niobium was changing in a range of 0-1,75%, that of titanium in a range of 0,03-1,00%, and of silicon in a range of 1,34-2,48% (wt. - %). Quantitative relationships were plotted to describe the effect of stabilizing elements on an increase of specimen weight and volume content of carbide phases in the external layers of specimens. Also the susceptibility to crack formation and mechanical properties after carburising process are shown. It has been proved that, with exception of the resistance to carburising effect, the examined elements deteriorate the cast steel properties.