ASTM C155-97 Classification

 20/23 23 23 24 25 25 25 25 26 26 26 26 28 28 29 30 30 32
ISO 2245 Classification 125-0.5-L 125-0.5-L 130-0.65-L 130-0.7-L 135-0.8-L 135-0.9 135-1.1 135-0.6-L 140-0.75-L 140-0.8-L 140-1.0 140-0.9-L 150-0.8-L 150-0.9-L - 160-0.9-L 160-1.0-L 170-1.25-L
Classification Temperature    (°C) 1230 1230 1300 1300 1350 1350 1350 1350 1400 1400 1400 1400 1500 1510 1550 1600 1620 1730
Density, Avg lb/ft³ 32 36 40 44 50 56 69 38 47 50 62 54 49 55 54 54 64 78
ASTM C134-95 kg/m³ 520 580 650 700 800 900 1100 615 750 800 1000 870 780 880 860 870 1030 1250
lb/Beq 1.91 2.12 2.38 2.56 2.93 3.30 4.03 2.25 2.75 2.93 3.66 3.19 2.86 3.22 3.15 3.19 3.77 4.58
Kg/str 0.85 0.94 1.06 1.14 1.30 1.47 1.79 1.00 1.22 1.30 1.63 1.42 1.27 1.43 1.40 1.42 1.68 2.04
Cold Crushing Strength lb/in² 175 260 320 360 360 580 870 260 360 320 610 580 435 360 334 119.62 363 510
ASTM C133-97 Mpa 1.2 1.8 2.2 2.5 2.5 4.0 6.0 1.8 2.5 2.2 4.2 4.0 3.0 2.5 2.3 3.1 2.5 3.5
Kg/cm² 12.2 18.4 22.4 25.5 25.5 40.8 61.2 18.4 25.5 22.4 42.8 40.8 30.6 25.5 23.5 31.61 25.5 35.6

Modulus of Rupture

lb/in²

 100 145 175 245 205 320 450 200 230 220 360 360 230 230 305 260 250 305
ASTM C133-97 Mpa 0.7 1.0 1.2 1.7 1.4 2.2 3.1 1.4 1.6 1.5 2.5 2.5 1.6 1.6 2.1 1.8 1.7 2.1
Kg/cm² 7.1 10.2 12.2 17.3 14.3 22.4 31.6 14.3 16.3 15.3 25.5 25.5 16.3 16.3 21.4 18.35 17.3 21.4
Permanent Linear Change, %
ASTM C210-85
2250°F 1230°C * 24hrs 0.0 0.0                                
2370°F 1300°C * 24hrs     -0.5 -0.5                            
2460°F 1350°C * 24hrs         -0.5 -0.5 -0.5 -0.4                    
2550°F 1400°C * 24hrs                 -0.6 -0.4 -0.4 -0.4            
2732°F 1500°C * 8hrs                         0.46          
2750°F 1510°C * 24hrs                           -0.9        
2822°F 1550°C * 8hrs                             -0.38      
2912°F 1600°C * 8hrs                               -0.48    
2950°F 1620°C * 24hrs                                 -1.3  
3150°F 1730°C * 24hrs                                   -0.9
Reversible Linear Thermal

Expansion (%) at 1100°C

 0.45 0.48 0.48 0.48 0.50 0.50 0.50 0.50 0.55 0.55 0.55 0.55 0.60 0.60 0.60 0.65 0.65 0.70
Thermal Conductivity, Btu-in/ft²,hr,°F
ASTM C182-88
Mean Temperature °C (°F), W/m-k
200 (392) 1.04/0.15 1.04/0.15 1.18/0.17 1.25/0.18 1.46/0.21 1.60/0.23 2.02/0.29                      
400 (752) 1.18/0.17 1.25/0.18 1.32/0.19 1.39/0.20 1.67/0.24 1.88/0.27 2.23/0.32 1.25/0.18 1.67/0.24 1.88/0.27 2.44/0.35 2.01/0.30 1.60/0.23 1.81/0.26 1.81/0.26 2.23/0.32 2.72/0.39 3.41/0.49
600 (1112) 1.32/0.19 1.39/0.20 1.53/0.22 1.60/0.23 1.95/0.28 2.09/0.30 2.51/0.36 1.32/0.19 1.81/0.26 2.09/0.30 2.65/0.38 2.30/0.33 1.740.25 2.02/0.29 1.95/0.28 2.37/0.34 2.93/0.42 3.48/0.50
800 (1472) 1.53/0.22 1.60/0.23 1.81/0.26 1.88/0.27 2.23/0.32 2.44/0.35 2.79/0.40 1.46/0.21 1.95/0.28 2.30/0.33 2.85/0.41 2.51/0.36 1.81/0.26 2.16/0.31 2.02/0.29 2.51/0.36 2.30/0.43 3.55/0.51
1000 (1832) 1.67/0.24 1.81/0.26 2.09/0.30 2.16/0.31 2.58/0.37 2.79/0.40 3.13/0.45 1.60/0.23 2.16/0.31 2.51/0.36 3.06/0.44 2.72/0.39 1.95/0.28 2.37/0.34 2.16/0.31 2.58/0.37 3.07/0.44 3.69/0.53
To convert Btu-in/ft²,hr,°F to kcal-m²,hr,°C multiply by 0.124
Chemical Analysis
Alumina Al2O3 (%) 50 50 50 50 50.5 50.5 50.5 50.5 54 56 54 54 67 67 70 73 73 77
Ferric Oxide Fe3O3 (%) 0.9 0.9 0.9 0.9 0.85 0.85 0.85 0.85 0.83 0.80 0.83 0.83 0.6 0.6 0.57 0.55 0.5 0.4
Calcium Oxide CaO (%) 0.27 0.27 0.27 0.27 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.35 0.35 0.38 0.38 0.38 0.38