ASTM D7891-24
Standard Test Method for Shear Testing of Powders Using the Freeman Technology FT4 Powder Rheometer Shear Cell
| Označení normy: | ASTM D7891-24 |
| Vydáno: | 15.03.2024 |
| Status: | Active |
| Počet stran: | 12 |
| Sekce: | 04.09 |
| Označení: | effective angle of friction; effective yield locus; flowability; flow function; Freeman Technology; FT4 Powder Rheometer; internal friction angle; powder; rotational shear cell; unconfined yield strength; wall friction; wall friction angle; |
| ASTM označení: | ASTM D7891 |
| Nahrazuje: | D7891-15 |
1.1 This method covers the apparatus and procedures for quantifying the incipient failure properties of a powder as a function of the normal stress for a given level of consolidation. The method also allows the further determination of the unconfined yield strength, internal friction angles, cohesion, flow function, major principal stress and wall friction angle (with the appropriate wall coupon fitted to the correct accessory).
1.2 These parameters are most commonly used to assist with the design of storage hoppers and bins using industry standard calculations and procedures. They can also provide relative classification or comparison of the flow behavior of different powders or different batches of the same powder if similar stress and shear regimes are encountered within the processing equipment.
1.3 The apparatus is appropriate for measuring the properties of powders with a maximum particle size of 1 mm. It is practicable to test powders that have a small proportion of particles of 1 mm or greater, but it is recommended they represent no more than 5 % of the total mass in samples with a normal (Gaussian) size distribution.
1.4 All observed and calculated values shall conform to the guidelines for significant digits and rounding established in Practice D6026.
1.4.1 The procedures used to specify how data are collected/recorded or calculated, in this standard are regarded as the industry standard. In addition, they are representative of the significant digits that generally should be retained. The procedures used do not consider material variation, purpose for obtaining the data, special purpose studies, or any considerations for the user’s objectives; and it is common practice to increase or reduce significant digits of reported data to be commensurate with these considerations. It is beyond the scope of this standard to consider significant digits used in analysis methods for engineering design.
1.5 Units—The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. Reporting of test results in units other than SI shall not be regarded as nonconformance with this standard.
1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.7 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.