Selective laser sintering of high carbon steel powders studied as a function of carbon content

Optimum conditions for laser irradiation to achieve fully dense high carbon steel SLS (selective laser sintering) specimens have been investigated as a function of carbon content in steel powders with the use of steel powders with different carbon contents in the range of 0.33–1.05 mass%C (corresponding to S33C, S50C, S75C and S105C in the JIS standard). Full densification is found to be easily achieved by SLS processing for all high carbon steel powders. The energy density during the SLS process required for full densification decreases as the carbon content increases from 400 J/mm3 for 0.33 and 0.50 mass%C to 267 J/mm3 for 0.75 and 1.05 mass%C. This is considered to be due to the increased wettability of molten Fe–C alloys for the higher carbon contents. The values of microhardness and yield stress of fully dense SLS specimens tend to increase as the carbon content in steel powders increases. At a given carbon content, the values of microhardness and yield stress of fully dense SLS specimens tend to be higher for those produced with a lower energy input (with higher laser scan speeds and larger scan spacings).