Measurement of the Yield Stress of a Stainless Steel Feedstock

摘要

The accurate knowledge of the flow behavior of feedstocks is of great importance for computer simulation and optimization of the powder injection process. The feedstocks for powder injection molding are highly filled polymer compounds. The particles are in close proximity with one another. A yield point was often observed at low shear rates as an indication of temporary particle network structure within melt. The main objective of this work was to examine the yield stress and flow behavior of stainless steel feedstock and modeling of viscosity as input for the simulation. The rheological measurements were performed at low shear rates and low shear stress conditions using the parallel plate rheometer. The rheological data obtained from rotational rheometer were compared to the measurement made on a slit-die rheometer. The results obtained using the rotational rheometer tests and extrapolation by Cross equation with Herschel-Bulkley extension produced similar results. The extrapolation by Herschel-Bulkley using the slit die rheometer data shows much higher yield stress.