The market demands more and more safety and glass should respond to the regulations to be considered suitable in some installations.
When the life of the persons risks to be compromised, glass should grant safety which does not mean that it does not break but it has to stay in place to allow persons to save themselves.
In the context of safety products required by the glass market, requiring features making the glass less likely to break, the chemical tempering of the glass has a fundamental role for its several benefits, among which the absence of surface distorsion and the high mechanical resistance, more robust than glass treated with other system. Chemical tempering has drawn high attention in the last five years, so much that insiders know more about the process and want to invest to grant production of special products in the future.
However, there is another important point in chemical tempering, the possibility to temper very thin glass up to 0.3mm with the purpose of lightening some projects such as windows for boats. Recently, the use of a third thin glass of 0.3mm into the insulated units, it is suitable to reduce weight and simplify transportation and installation.
Chemical tempering is a surface treatment made at a temperature under vitreous transition. Glasses are dipped into a bath with melted potassium salts at a temperature superior to 450°C for a period of 16 hours. Under these conditions, an exchange takes place between the potassium ions contained into the salts and the sodium ions at the surface of the glass. The introduction of potassium ions larger than the sodium ones, involves as a consequence, the establishment of residual stress characterized by a compressed tension on the surface compensated by stress tension inside the glass.
Process time can eventually be reduced to 4 or 8 hours by using special glass manufactured by the most important glass manufacturers.
Chemical tempering is not an alternative to the thermal one, both of them are fundamental for the construction of safety glass, they have different purpose process but they complete each other. Chemical tempering is for both flat and curved glass, thin and thick glass.
Our CT line does not require high consumption because once the due temperature has been reached, the machine uses only the 15% of the installed power to keep constant temperature.
Last but not least, the glass chemically tempered can be drilled and edge-shaped which represents another benefit of this process.
The chemical tempered glass cannot be considered safety glass because, when it breaks, it comes in sharp pieces as a monolithic glass. That’s why to be safety glass, it should be laminated later.
The quality of the potassium salts is a key matter for the result. RCN supplies pure salts at 99% with certificate of analysis for every lot delivered. This means to give a full service and a turn-key system to manufacture quality products.
To sum up, chemical tempering is not something obscure related to optical, small things or thin glass only. There is a lot of attention around this sytem and companies such AGC, Glastroesch and Schott have already chosen RCN’s machines for the production of special projects.
The glass industry is developing faster and diversification in production is a crucial matter for all the glaziers. In this view, chemical tempering plays an important role.
