Strengthening Process. Increase Toughness, Control Fractures.

We make use of different strengthening processes in order to adapt glass, as a versatile, high-tech material, to its respective intended use. Touchening produces systematic mechanical stress in the material which has a positive effect on the proporties of the glass. We process the glass by different strengthening methods depending on the field of application.

Tempered safety glass

Tempered safety glass consists of a single, specially thermally treated panel. The glass is heated to ca. 600 °C and then cooled suddenly. The center of the glass pulls back from the glass surface, which is being compressed. This process gives TSG an increased resistance to shocks and impacts. It is not sensitive to large changes in temperature and breaks into small, blunt pieces when exposed to extreme pressure. This reduces the risk of injury.

Production of safety glass by thermal tempering

Semi-tempered glass (STG)

STG is exposed to a thermal tempering process just like TSG. However, the cooling process is slower, which results in less of a tension difference in the glass between the center and the surface. The resistance to bending lies somewhere between that of standard float glass and tempered safety glass. If broken, the resulting pieces resemble those of normal, non-hardened float glass.

Chemical Strengthening

If glass is exposed to a defined salt bath treatment, the resulting exchange of ions within a thin surface layer creates strong compressive stress that significantly improves the resistance properties of the glass. The chemical strengthening process is used primarily to strengthen thin glass up to 3 mm in thickness. The chemical strengthening process is ideal because the surface retains its flatness while also becoming more resistant to scratching.

Properties of tempered glasses at a glance

Properties	Stone impact resistance
FLOAT Glass Untreated	No change
TSG Tempered Safety Glass	No change
STG Semi Tempered Glass	No change
CSG Chemically Strengthened Glass	~ +40 %
Properties	Flexural strength
FLOAT Glass Untreated	~ 45 N/mm²
TSG Tempered Safety Glass	~ 120 N/mm²
STG Semi Tempered Glass	~ 70 N/mm²
CSG Chemically Strengthened Glass	> 150 N/mm²
Properties	Temperature shock resistance
FLOAT Glass Untreated	~ 40 K
TSG Tempered Safety Glass	~ 150 K
STG Semi Tempered Glass	~ 100 K
CSG Chemically Strengthened Glass	> 200 K
Properties	Cutting capability
FLOAT Glass Untreated	Yes
TSG Tempered Safety Glass	No
STG Semi Tempered Glass	No
CSG Chemically Strengthened Glass	Conditional
Properties	Appearance of fracture
FLOAT Glass Untreated	Splitting
TSG Tempered Safety Glass	Friable structure
STG Semi Tempered Glass	Splitting
CSG Chemically Strengthened Glass	Splitting
Properties
FLOAT Glass Untreated
TSG Tempered Safety Glass
STG Semi Tempered Glass
CSG Chemically Strengthened Glass

Properties	FLOAT Glass Untreated	TSG Tempered Safety Glass	STG Semi Tempered Glass	CSG Chemically Strengthened Glass
Stone impact resistance	No change	No change	No change	~ +40 %
Flexural strength	~ 45 N/mm²	~ 120 N/mm²	~ 70 N/mm²	> 150 N/mm²
Temperature shock resistance	~ 40 K	~ 150 K	~ 100 K	> 200 K
Cutting capability	Yes	No	No	Conditional
Appearance of fracture	Splitting	Friable structure	Splitting	Splitting