Powder injection molded gas and water atomised 316L stainless steel powder mixtures

Gas and water atomised 316L stainless steel powders with different sizes and shapes were blended with different ratios. To improve feedstock flow behaviour, spherical gas atomised powders of 316L were mixed in varying fractions to irregular water atomised ones. These blends were mixed with multicomponent binder formula to prepare the designed feedstocks for mol di ng. Molded feedstocks were then subjected to binder removal by solvent extraction and thermal debinding and sintered at three different temperatures (1320, 1350 and 1380 degrees C for 2 hours) under hydrogen to obtain maximum possible sintered densities with minimum shape distortion. These were followed by mechanical testing to establish PIM microstructure/property relationships of the powder alloy system (GA and WA 316L SS powders) studied in the present work. Sintered specimens showed high % of theoretical densities and therefore subsequent mechanical property evaluations showed good strengths and hardness values. In the light of experimental data of the present work, it was decided that it is beneficial to use blends of water and gas atomised 316L stainless steel powders during PIM processing in terms of price and also material properties.