Mass fraction, %:

SiO₂, not less

Fe₂O₃, no more

93,0

2,0

Fire resistance, ºС, not less

1690

Open porosity, no more, %

for nozzle products

for all other products

22

24

Density, g/cm³, no more

2,37

Compressive strength, not less, N/mm²

for nozzle products

for all other products

30

27,5

Residual changes in dimensions at a temperature of 1450 ºС, %, no more

+0,4

Starting temperature of softening, ºС, not less

1620

Mass fraction SiO₂, %, not less

91

Apparent density, g/cm³, no more

1,2

Ultimate compressive strength, N/mm², not less

4,5

Residual changes in dimensions at a temperature of 1550ºС, %, no more

1,0

Thermal conductivity, W/(m.K), at an average temperature ºС, no more than:

350±25

650±25

0,6

0,7