Binder Jet 3D Printing of 316L Stainless Steel: Orthogonal Printing and Sintering Process Optimization

Binder jet 3D printing (BJ3DP) is an additive manufacturing technique that uses a liquid binder to selectively deposit powder layer by layer to fabricate 3D parts followed by sintering. Herein, the printing parameters, sintering temperature, and holding time of 316L stainless steel (SS) materials produced by BJ3DP technique are systematically investigated. Based on the L9 orthogonal experimental design, the green parts can achieve the highest relative density of approximate to 55.9%, when the layer thickness, binder saturation, and roller traverse speed are 150 mu m, 35%, and 100 mm s(-1), respectively. Five green parts printed using the optimal parameters are subsequently sintered under different temperatures and holding time. All the as-sintered samples consist of a primary gamma-Fe phase and a small amount of delta-ferrite phase. After sintering at 1435 degrees C for 7.5 h, the as-sintered samples obtain the highest relative density of approximate to 92.1% along with the most excellent mechanical properties, displaying ultimate tensile strength of approximate to 558 MPa and an elongation of approximate to 41%. The mechanical properties of these samples sintered at 1435 degrees C for 7.5 h are also superior to those of the annealed 316L SS in ASTM A276/A276M-17.