Relative density of selective laser sintering AISI316L stainless steel products

In order to improve the relative density of metal samples manufactured by selective laser sintering (SLS), trace Si was added into AISI316L stainless steel powders, and then the SLS samples were degreased, cold isostatic pressed (CIP) and liquid sintered at 1250°C and hot isostatic pressed (HIP). According to relative density measurement, SEM and energy spectrum analysis, the effect of isostatic pressing (IP) pressure on relative density of AISI316L samples was studied, and action mechanism of Si element on the relative density was analyzed in SLS/IP process. The results show that, relative density of SLS samples with Si addition increases with increasing of CIP pressure, and the relative density increases by the most at 100 MPa and reaches 80.3% at 500 MPa, the CIP mechanisms are sintering necks crushing, metal particles displacement and plastic deformation; the relative density reaches 93% or so after liquid sintering at 1250°C due to the addition of Si; relative density reaches about 95.3% after HIP at 1250°C/120 MPa, which satisfies the requirement of engineering application. So the relative density of AISI316L samples fabricated by SLS can be improved by the IP and liquid sintering of truce Si.