high borosilicate glass tube for lighting 1. made of high borosilicate glass 2.explosion proof 3.great transparance

high borosilicate glass tube for lighting

1. made of high borosilicate glass

2.explosion proof

Chemical Compositions and Physical and Chemical Properties of Borosilicate Glass Type 3.3
composition	SiO2	B2O3	R2O	Al2O3	Fe2O3
weight%	80.3	13.0	4.2	2.4	0.035
Physics performance			Numerical Value		Unit
Medium coefficient if linear expansion			3.3±0.1		10-6K-1
Softening point			820±10		°C
Viscosity temperature			510±10		°C
Uper annealing temperature			560±10		°C
Thermal conductivity(20-100°C)			1.2		Wm-1K-1
Temperature for the specific electrical resistance			240		°C
20°C Demsity ρ			2.23±0.02		g/cm3
Endure water under 98 °C			ISO0719-HGB1		/
Endure water under 121 °C			ISO0720-HGA1		/
Acid-proof test			Na2O≤100		µg
Alkali-proof test			ISO0695		/

3.great transparance