Refractories Definition & Classification Tina Stendal Svendsen Product Manager
Properties of Refractory Castables Tina Stendal Svendsen Product Manager
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Transcript of Properties of Refractory Castables Tina Stendal Svendsen Product Manager
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Properties of Refractory Castables
Tina Stendal SvendsenProduct Manager
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Refractory materials are subjected to following stress factors:• Thermal - by high temperatures and thermal shock• Mechanical - by pressure, impact, friction and airborne particles • Chemical - by gases, liquids, build-up, slag and melts
The properties of castables and their ability to withstand stresses are determined by:• Raw materials • Particle size distribution• Chemical reaction between raw materials at various temperatures
The properties of refractory castables can be analysed by a range of international test procedures
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Bending strength; Modulus of rupture (EN 1402-6)
Cold modulus of ruptureProvides information on material structure (QC)
Hot modulus of ruptureCharacterize the thermodynamic behaviour of the castable
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Cold Crushing Strength (EN 1402-6)
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Thermal Shock Resistance (EN 993-11)
Air quenching of 950°C hot specimens
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Abrasion resistance (ASTM C 704)
Temperature: 1000°CAbrasion media: SiC grainsTesting angle: 45° and 90°
Results:≤ 5cm3 loss: excellent5cm3 to 10cm3: very good10cm3 to 20cm3: good
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Alkali resistance (CEN/TS 15418)
Test media K2CO3 or K2SO4
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Hot-melt slag and build-up
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Slag resistance: Static test (CEN/TS 15418)
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Hot melt slag resistance (dynamic test)
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Open porosity (EN 933-1)Test pieces are saturated in water under vacuum
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The influence of porosity on castable properties
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Other tests
• Particle size distribution
• Thermal expansion / creep
• Chemical and structural analyses; SEM and XRD
• Thermal conductivity
• Refractoriness / refractoriness under load
• CO-resistance
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Assessment of material data
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Temperature
Thermal property
Application
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Summary• Castables are subjected to thermal, mechanical and chemical
stresses• Wide range of international test standards to measure properties• Some tests are targeted for quality control • Other tests simulate operation conditions (temperature, chemicals)• Test of corrosive slags can both static and dynamic• Test slags at relevant temperatures• There is a close relationship between porosity and the physical and
chemical properties of castables• When comparing datasheets: Be aware of test-temperature and of to
which temperature has the test specimens been prefired prior to test