Physical and mechanical properties of injection moulded 316L stainless steel using waste rubber binder

Abstract

Metal Injection Moulding (MIM) is a cost-effective method in producing a variety of small and high performance parts. This paper investigates the influence of waste rubber binder combined with polyethylene binder on the properties of injection moulded 316L stainless steel. Feedstock formulation was prepared using 32 µm 316L SS powder and mixed with binder system containing 55 wt.% paraffin wax, 35 wt.% PE/WR and 10 wt.% stearic acid. The feedstock was then successfully injection moulded at powder loading of 0.65. The specimens were immersed in n-heptane for five hours at 60 °C in order to remove the paraffin wax and stearic acid. Debinding process produced the defect-free green parts. The parts were then sintered in vacuum atmosphere at temperature ranges of 1320 °C to 1360 °C. The results showed that the highest density achieved was 7.612 g/cm3 at temperature of 1360 °C with tensile strength of 497 MPa while the highest hardness was achieved at 274.8 HV.