Review of the flowability measuring techniques for powder metallurgy industry

Abstract

The flowability of bulk solids can be treated as one of the fundamental properties that determine their behaviour through industrial processes. Developing a standard meaningful test for measuring flowability has always been a challenge and numerous methods exist, based on the correlation of a number of physical properties such as gravity flowrate, internal strength, bulk density change, etc., which are thought to represent the ability of a powder to flow in some sort of a conceptual situation. Different industries have employed and standardized different techniques for flowability measurement, and the results these obtain may not correlate. The article details an investigation into the ability of various flowability measuring methods to detect small changes in the powder flow properties. Four flowability measuring methods, Hall flow, Hausner ratio, compressibility, and shear cell (manual and automated), were used to measure the flowability of four physically and chemically similar iron blends. Industry standard methods and the shear cell were not able to rank the blends with confidence. Influence of container wall friction is also investigated in the presented work.