| Item | Index | ||||
| International code name | SK35 | SK36 | SK37 | SK38 | SK40 |
| Al2O3 % | >=48 | >=55 | >=65 | >=75 | >=80 |
| Fe2O3 % | <=2 | <=2 | <=2 | <=2 | <=2 |
| Refractoriness ℃ | >=1750 | >=1770 | >=1790 | >=1790 | >=1790 |
| Apparent porosity % | <=22 | <=22 | <=23 | <=23 | <=21 |
| Cold crushing strength Mpa | >=39 | >=44 | >=49 | >=54 | >=65 |
| Refractoriness under load(0.2MPa) ℃ | >=1420 | >=1470 | >=1500 | >=1520 | >=1530 |
| Reheating Linear Change (1500℃ 2h) % | +0.1~ -0.4 *1450℃ | +0.1~ -0.4 | +0.1~ -0.4 | +0.1~ -0.4 | +0.1~ -0.4 |