PERMEABILITY OF SHORT FIBER REINFORCED POWDER METALLURGY MATERIAL AND ITS APPLICATION IN POROUS MOLD

Abstract

Permeability is one of the key properties for understanding the fluid flow and pressure drop in porous metal. In this study, a novel 304 stainless steel fiber reinforced powder metallurgy (P/M) material is produced. Stainless steel powders and short fibers are alternately laid in layers according to mass fraction and then sintered to produce the porous material. Air and water permeability tests are conducted to characterize the permeability of the material. The powder mesh, porosity, and pore size are varied to investigate the effect of permeability. Porous molds made of the material are designed to perform paperboard molding and plastic-injection experiments. The results demonstrate that the relationship between pressure drop per unit length and flow velocity is a parabola, where air or water flows through the P/M material. The permeability coefficient decreases with increasing powder mesh. Compared to water going through the material, the permeability coefficient is higher and the inertial loss is more significant in case of air. The pore size has greater effect on the permeability, than porosity. The perfect appearance of the paperboard presents a good permeability of the P/M material, showing the promising application in molding.