Physical Data

1)

expansion coefficient

5.0×10-6K-1

a)working point

>1100°C

b)softening point

760-790°C

c)annealing point

530-550°C

d) Strain Point

515°C

2)

density p at25°C

2.32

Chemical Data

1)

hydrolytic resistance

0.035H1

2)

acid resistance

I1

3)

alkali resistance

A2

Composition

1)

SiO2

75

2)

B2O3

11.2

3)

Al2O3

5.4

4)

Fe2O3

0.02

5)

CaO

0.6

6)

K2O

0.5

7)

Na2O

6.5

8)

BaO

0.3