BS EN ISO 4490:2018 pdf download – Metallic powders – Determination of flow rate by means of a calibrated funnel (Hall flowmeter) (ISO 4490:2018) This document specifies a method for determining the flow rate of metallic powders, including powders for hard metals, by means of a calibrated funnel (Hall flowmeter). The method is applicable only to powders which flow freely through the specified test orifice. 2 Normative references There are no normative references in this document. 3 Terms and definitions No terms and definitions are listed in this document. ISO and IEC maintain terminological databases for use in standardization at the following addresses: — ISO Online browsing platform: available at https://www.iso.org/obp — IEC Electropedia: available at http://www.electropedia.org/ 4 Principle Measurement of the time required for 50 g of a metallic powder to flow through the orifice of a calibratedfunnel of standardized dimensions. 5 Apparatus 5.1 Calibrated funnel, the dimensions of which are shown in Figure 1. The funnel shall be made of a non-magnetic, corrosion-resistant metallic material with sufficient wall thickness and hardness towithstand distortion and excessive wear. 5.2 Stand and horizontal vibration-free base, which shall support the funnel rigidly. An example isshown in Figure 2. 5.3 Balance of sufficient capacity, capable of weighing the test portion to an accuracy of ±0,05 g. 5.4 Timing device, capable of measuring the elapsed time to an accuracy of ±0,1 s. 5.5 Reference grit, a reference powder 1) used for calibration of the funnel, shall be used. 6 Calibration of the funnel 6.1 Calibration by the manufacturer of the funnel The manufacturer shall supply the flowmeter calibrated as follows. a) Dry the reference grit (5.5) in an open and clean glass jar at 110 °C for 60 min in air. b) Cool the reference grit to room temperature in a desiccator. c) Weigh out 50 g ± 0,1 g of the reference grit. d) Follow the procedure outlined in Clause 8. e) Repeat the procedure with the same 50 g mass of reference grit, until there are five determinations within 0,4 s. f) The average of these five determinations is stamped on the bottom of the funnel and the durationof flow shall be within 40,0 s ± 0,5 s. 6.2 Calibration by the user of the funnel It is recommended that the users periodically verify whether a correction is needed or not. The flow rate of the reference sample shall be determined by...
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