5.1 The rate and uniformity of die cavity filling are related to flow properties, which thus influence production rates and uniformity of compacted parts.

5.2 The ability of a powder to flow is a function of interparticle friction. As interparticle friction increases, flow is slowed. Fine powders may not flow. Some powders, often fine powders and lubricated powder mixtures, may not flow through the Hall Flowmeter funnel. Nevertheless, if a larger orifice is provided, such as in the Carney Flowmeter funnel of Test Method B964, a meaningful flow rate may be determined, providing specific information for certain applications.

5.3 Test Method B213, using the Hall Flowmeter funnel, is the preferred method for determining the flowability of metal powders and powder mixtures. The Carney Flowmeter funnel of Method B964 should only be used when powder will not flow through the Hall Flowmeter funnel.

5.4 Humidity and moisture content influence flow rate. Wet or moist powders may not flow.

5.5 These test methods are based on flow of a specified mass of powder. If flow of a specific volume of powder is preferred, Test Method B855 may be used for powders that flow readily through the Hall Flowmeter funnel.

5.6 This test method may be part of the purchase agreement between powder manufacturers and powder metallurgy (PM) part producers, or it can be an internal quality control test by either the producer or the end user.