ISO 14427:2024

Overview

ISO 14427:2024 specifies a standardized method for preparing unbaked test specimens from cold and tepid carbonaceous ramming pastes used in aluminium production and for determining the apparent density after compaction. The method produces green (unbaked) specimens that can be used to measure bulk density after compaction, to determine dimensional change during baking, and as starting samples for subsequent tests on baked specimens. This second edition (2024) updates the earlier 2004 version with corrected falling weight mass and ramming rate values.

Key topics and technical requirements

• Scope: Preparation of unbaked ramming-paste specimens and measurement of apparent density after compaction.
• Test apparatus:
  • Steel rammer cylinder with inner diameter 50 mm.
  • Steel piston and base; falling weight mass 6.7 kg ± 0.1 kg dropping a distance of 50 ± 0.1 mm.
  • Height-measuring device accurate to 0.1 mm, balance accurate to 0.1 g.
  • Heating/cooling cabinet maintaining 5 °C to 100 °C ±0.5 °C.
  • Insulation or thermostatically controlled surround for the cylinder.
• Sample size: Experience indicates about 150–200 g of paste per specimen; sample in accordance with ISO 14422.
• Compaction procedure:
  • Compact with 100 impacts at a rate of about 50 ± 5 impacts/min.
  • Target specimen height after compaction: 50 ± 5 mm; if outside this range, repeat with adjusted mass.
• Density calculation: Apparent density ρ (g/cm3) = m / (π r^2 h), where m = mass of paste (g), r = inner radius of cylinder (cm), h = specimen height (cm). Round to nearest 0.001 g/cm3.
• Precision: Repeatability r = 0.023 g/cm3; Reproducibility R = 0.042 g/cm3 (determined per ISO 5725-2).
• Reporting: Test report must identify sample, document version (ISO 14427:2024), method, date, results, any deviations or unusual observations.

Applications and users

Practical uses and stakeholders include:

• Quality control laboratories in aluminium smelters monitoring ramming paste performance.
• Ramming paste manufacturers and raw-material suppliers for product development and batch control.
• Research and development groups assessing dimensional change on baking and resulting baked properties.
• Third-party testing and certification bodies applying standard test methods for comparison and compliance.

Keywords: ISO 14427:2024, carbonaceous materials, aluminium production, ramming pastes, unbaked test specimens, apparent density, compaction testing, cold ramming, tepid ramming.

Related standards

• ISO 14422 - Sampling of cold-ramming pastes (referenced for sample collection).
• ISO 5725-2 - Accuracy (trueness and precision) of measurement methods and results (used to determine precision).