INJECTION MOLDING OF 316L STAINLESS STEEL POWDER USING PALM OIL BINDER SYSTEM

Abstract

This paper focuses on the investigation to produce sintered specimens of stainless-steel parts produced by vertical injection molding technique. The stainless-steel powder was mixed using z-blade mixer with the thermoplastic binder system comprising polyethylene, paraffin wax, stearic acid, palm stearin, and palmitic acid at different volume percent (%). The feedstock was then studied in terms of viscosity and shear rate using a capillary rheometer. The feedstock was molded using vertical injection molding machine. After molding, the green molded specimen was immersed in the solvent to extract part of the binder system. The specimens were then sintered under vacuum atmosphere at a temperature of 1360 °C. The physical and mechanical properties of the sintered specimen, such as density, hardness, porosity, shrinkage, weight loss, ultimate tensile strength and elongation, achieved the minimum requirement for the Standard Metal Powder Industries Federation (MPIF) 35. The microstructure of the sintered specimens also showed the twin structure of stainless steel and also ferrite and pearlite phases.