Transcript Dias nummer 1 - HASLE Refractories

Properties of Refractory Castables
Tina Stendal Svendsen
Product 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 rupture
Provides information on
material structure (QC)
Hot modulus of rupture
Characterize 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°C
Abrasion media: SiC grains
Testing angle: 45° and 90°
Results:
≤ 5cm3 loss: excellent
5cm3 to 10cm3: very good
10cm3 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
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