| item | rn－42 | hrn－42 | hrn－48 |
| al2o3 % | ≥42 | ≥42 | ≥48 |
| fe2o3 % | ≤1.7 | ≤1.7 | ≤1.7 |
| refractoriness, ℃ | ≥1750 | ≥1750 | ≥1750 |
| bd, g/cm3 | ≥2.15 | ≥2.15 | ≥2.35 |
| ap, % | ≤24/23 | ≤24/21 | ≤24/21 |
| css, mpa | ≥30 | ≥40 | ≥40 |
| rul,0.2mpa，℃ | ≥1400 | ≥1520 | ≥1550 |
| plc（%） | 0～-0.3 | 0～-0.3 | 0～-0.3 |
| thearal shock resistance， (1100℃,water cooling)cycle |
≥20 | ≥30 | ≥40 |
| note：the value in brackets is for checker of regenerative chamber. | |||