Overview
ISO 1927-6:2012 - "Monolithic (unshaped) refractory products - Part 6: Measurement of physical properties" - specifies standard laboratory methods for measuring key physical properties of unshaped refractory materials (monolithic refractory products). The procedures apply to dense and insulating castables and ramming materials (including plastics), using test pieces prepared and stored according to ISO 1927-5. Tests are defined for conditions both before and after firing.
Key topics and requirements
The standard covers a suite of physical property determinations commonly required for quality control, specification and materials development:
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Geometric bulk density
- Mass and dimensional measurements to calculate ρg = m/V.
- Typical test-piece shapes A–D (examples: Shape A 230 × 114 × 64 mm; cylindrical alternative 50 mm × 50 mm for ramming materials).
- Mass accuracy: nearest 1 g (shapes A–C), ±0.1 g for 50 mm cylinders; dimensional accuracy ±0.1 mm.
- Results reported as mean and individual values.
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Density and porosity
- Bulk, apparent and true density (water absorption methods for dense materials; geometric method for insulating products).
- True density by ISO 5018 methods; porosity expressed in % to 0.1 %.
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Cold modulus of rupture (MoR)
- Three-point bending on dried or fired pieces (support spans 180 mm or 100 mm for small shape D).
- Drying at 110 °C ± 5 °C; stress rates: dense 0.15 MPa/s, insulating 0.05 MPa/s.
- MoR reported in MPa to 0.1 MPa.
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Cold crushing strength (CCS)
- Tests on prismatic halves, cubes (64 mm), or 50 mm cylinders for ramming materials.
- Loading rate typically 1.0 MPa/s ± 0.1 MPa/s; maximum load recorded and reported.
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Permanent linear change, elevated-temperature MoR, refractoriness under load and creep in compression
- Procedures and calculation/reporting requirements for dimensional change on firing, high-temperature strength tests, and deformation under load at temperature.
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Test reporting
- Must include specimen condition, individual and mean values, test method references and tolerances.
Applications and users
ISO 1927-6 is used by:
- Refractory manufacturers for product development and QC of unshaped castables, ramming mixes and plastics.
- Materials and process engineers in steel, cement, glass and foundry industries requiring reliable property data for lining design.
- Independent testing laboratories and R&D units verifying performance before and after firing.
Practical benefits: consistent test methods, comparable data for supplier qualification, acceptance testing and process optimization.
Related standards
Keywords: ISO 1927-6, monolithic refractory products, unshaped refractory, measurement of physical properties, cold crushing strength, modulus of rupture, density, porosity, refractoriness under load.
Open preview (PDF)Monolithic (unshaped) refractory products — Part 6: Measurement of physical properties
