TK Chemical Tempering Kilns

Chemical tempering of glass is obtained by immersing the material to be treated in a bath of molten potassium salts at temperatures above 400° C. The potassium ions (K+) contained in the salt replace the smaller diameter sodium ions (Na+) contained in the surface of the glass, causing compressive stresses to build up across the surface and edges.

The mechanical flexural strength properties of chemically toughened glass are five to ten times higher than those of thermally toughened glass subjected to the same force. This particular manufacturing process also increases impact resistance: thermally toughened glass has an impact resistance with a steel ball that is almost double that of standard float glass; but the impact resistance of chemically toughened glass is five times that of standard float glass, guaranteeing absolute flatness without any visual distortion.

All types of standard float glass can be chemically toughened. Green glass usually undergoes less ion exchange than the others. Coated glass and glass with a different chemical composition to standard float glass are not chemically toughenable. The parameters of the chemical tempering process may vary depending on the type of glass and the required specifications.

By means of chemical tempering, glass with a minimum thickness of 0.5 mm can be tempered. Even glass with a special geometrical shape can be chemically tempered, maintaining a high optical quality.