SIST EN ISO 4490:2018 PDF

Overview

EN ISO 4490:2018 (ISO 4490:2018) specifies a standardized test method for measuring the flow rate of metallic powders using a calibrated funnel, commonly called the Hall flowmeter. The method quantifies how long it takes for a 50 g test portion of a freely flowing metallic powder (including powders for hard metals) to pass through a standardized orifice. It applies only to powders that flow freely through the specified test orifice.

Key Topics and Requirements

• Principle: Measurement of elapsed time for 50 g of powder to flow through a calibrated funnel (reported as seconds per 50 g).
• Apparatus:
  • Calibrated funnel (Hall flowmeter) of standardized dimensions made from non‑magnetic, corrosion‑resistant metal with adequate hardness and wall thickness.
  • Rigid stand with a vibration‑free base.
  • Balance with accuracy of ±0.05 g.
  • Timing device with accuracy of ±0.1 s.
  • Reference grit (reference powder) for funnel calibration.
• Calibration:
  • Manufacturer supplies a calibrated funnel. Reference grit is dried at 110 °C for 60 min, cooled in a desiccator, and five determinations are made on 50 g until five values fall within 0.4 s. The average (nominally 40.0 s ± 0.5 s/50 g) is stamped on the funnel.
  • Users should periodically verify calibration. If reference flow deviates, a correction factor (40.0 ÷ measured value) may be applied; investigate cause (wear or coating). Discontinue use if reference flow