Optimizing Rheological Behavior of Steel Feedstocks in Advanced Process of Alloying Powder Injection Molding

The rheological behavior of feedstocks used in powder injection molding technology influences strongly on the final properties of the products. Powder loading is one of the important factors that have a great distribution on rheological behaviors. By using the gas atomized spherical 316L stainless steel powder and the binder of 55% paraffin wax+ 40% polyethylen+ 5% stearic acid, four kinds of feedstocks were prepared at the powder loading of 60, 64, 68 and 72%. To find the proper feedstock and molding temperature, the applied shear rate on the samples has been increased from 100 to 1000 l/s in three different temperatures. The investigations demonstrate that 68% powder loading is the optimal one. This sample shows the minimum sensitivity to shear rate and temperature and in a wide range of temperature has a nearly steady viscosity, consequently demonstrate the best behavior during injection molding.