Physical Properties (after firing) 

ASTM Classification Class Q Class Q Class Q Class Q Class Q Class R Class R Class R Class R Class S Class S
Max. Service Temperature (°C) 1300 1300 1300 1300 1350 1370 1370 1370 1400 1480 1520

Chemical Analysis (XRF)

 AL2O3 (%) 40 40 40 40 40 38 45 40 42 43 50
SiO2 (%) 43 42 40 40 42 43 39 42 38 44 40
Fe2O3 (%) 2.5 3.0 2.5 2.5 3.0 2.5 2.5 2.5 1.5 2.0 0.8
Bulk Density (ASTM C134) Dried at (110°C) Maximum (Kg/m³) 1300 1520 1300 1300 1520 1550 1550 1300 1400 1550 1600
Fired to (815°C) 1250 1400 1200 1200 1400 1500 1500 1200 1350 1450 1500
(1250°C)     1200 1200       1200      
(1300°C) 1250 1450     1450            
(1370°C)           1500 1500   1400    
(1480°C)                   1500 1500

Cold Crushing Strength (ASTM C133) 

 Dried at (110°C) Minimum (Kg/cm2) 60 120 50 70 120 140 180 40 70 150 175
Fired to (815°C) 40 70 35 50 70 75 140 30 50 75 75
(1250°C)     40 80       40      
(1300°C) 70 90     90            
(1370°C)           120 180   80    
(1480°C)                   175 175

Permanent Linear Change (ASTM C113)

Fired to (815°C) Maximum (%) -0.20 -0.20 -0.20 -0.30 -0.20 -0.20 -0.20 -0.40 -0.20 -0.40 -0.40
(1250°C)     -1.50 -1.50       -1.50      
(1300°C) -1.50 -1.50     -1.50            
(1370°C)           -1.50 -1.50   -1.50    
(1480°C)                   -1.50 -1.50

Thermal Conductivity (BS 1902)

 Mean Temp. (°C) 400 W/mK 0.33 0.40 0.26 0.30 0.40 0.45 0.45 0.26 0.40 0.45 0.45
600 0.35 0.42 0.29 0.32 0.42 0.47 0.47 0.29 0.42 0.47 0.47
800 0.39 0.44 0.32 0.34 0.44 0.49 0.49 0.32 0.44 0.49 0.49