Mass fraction, %:

Al₂O₃, no less

Fe₂O₃, no more

39,0

1,5

41,0

1,5

Fire resistance, ºС, not lower

1750

1750

Starting temperature of softening, ºС, not less*

1440

1500

Compressive strength, not less, N/mm²

50

70

Open porosity, no more, %

16

12

Residual changes in dimensions when heated to 1450 ºС, %, no more

0,3

0,2

Broken corners and edges with a total broken length of no more than 15 mm per edge, depth, mm, no more

5

5

Individual smelts with a diameter of more than 3 mm

not allowed

Cracks longer than 15 mm

not allowed

Mass fraction, %: Аl₂О₃, no more

72

42

37

Fe₂О₃, no more

1,2

1,7

-

Огнеупорность, °С, not less

-

1750

1730

Open porosity, %, for products:

nozzled

Не более 21

В пределах 14-20

Не более 23

wall, dome, for air duct fittings of tuyere zones

Не более 24

В пределах 14-20

Не более 25

Compressive strength, N/mm², not less for packed products

50

40

20

wall, dome, for air duct fittings, tuyere areas

30

30

20

Residual changes in dimensions, %, no more, at temperature, °C:

1350

-

-

-0,2

1450

-

-0,4

-

1600

-0,8

-

-

Starting temperature of softening, °C, not lower

1550

1500

1330

Mass fraction, %:

Al₂O₃, no less

Fe₂O₃, no more

Over 62

1,5

No less 75

2,2

Open porosity, no more, %

24

23

Compressive strength, N/mm², not less

25

40

Starting temperature of softening, ºС, not less

-

1420

Deformation temperature under load, ºС, not lower

1450

-

Residual changes in dimensions during heating, %, no more, at temperature, ºС

1500

1600

+0,4

-

-

+2,5

Thermal resistance, heat change, not less

-

3

Mass fraction, %:

Al2O3, not less

Fe2O3, no more

40,0

4,0

50

3,0

60

3,0

Compressive strength, N/mm2, not less

40

40

40

Open porosity, %, no more

22

23

26

Fire resistance, 0С, not lower

1700

1740

1750

Thermal resistance, heat change, not less

6

6

6