Influence of Waste Rubber on the Properties and Microstructure of Injection Moulded M2 High Speed Steel

New feedstock formulation for metal injection moulding (MIM) of Molybdenum High Speed Steel (M2 HSS) has been developed. The binder is a multicomponent system consisting of major binder paraffin wax (PW), stearic acid (SA) and minor binder polyethelene waste rubber (PEWR). Injection moulding was conducted successfully using a powder loading of 0.65. Scanning electron micrograph of the green injection moulded part revealed homogenous distribution of the M2 HSS particles in the wax matrix. Paraffin wax and stearic acid were driven off by immersing the injection moulded part into n-heptane for five hours. Vacuum sintering of the brown parts at a temperature range of 1240°C-1280°C resulted in high quality M2 HSS parts. The properties of the sintered part such as physical, mechanical and microstructure were studied and discussed to evaluate the influence of waste rubber in MIM of M2 HSS.