At our factory, quality is our top priority. As such, we ensure to give our clients excellent products that will serve them for a long time. This is one of the major reasons why we do heat soak testing for glass. Generally, when the glass is being produced, there is a reaction between Nickel and Sulphur that leads to the accumulation of Nickel Sulfide in the glass. The Nickel is obtained from the raw materials and components that touch with the molten glass during the production process. The Sulphur comes about because it is present in fuels.
When the glass is tempered, the nickel sulfide that has accumulated may bring about some major problems. If present, nickel sulfide causes tempered glass to fracture spontaneously. This is one of the major reasons why we carry out heat soak testing.
Keep in mind that nickel sulfide only affects tempered glass. During the toughening process, the glass is heated to about 600 degrees and cooled instantly with air under intense pressure. If nickel sulfide is present in the tempered glass, it causes some instability. These impurities are unable to return to their normal state during the cooling process. This causes some stress on the glass, making it break.
Heat soak testing, therefore, is mainly a destructive test that requires us first to put the tempered glass into a heat soak oven. The toughened glass is then subjected to temperatures of approximately 555 degrees for two hours. If the glass contains nickel sulfide, it is guaranteed to break when brought under these temperatures.
So far, it has been established that on average, the incident of critical nickel sulfide inclusions is:
• 1 inclusion in 11,000 pounds of glass for ordinary tempered glass EN 12150
• 1 inclusion in 882,000 pounds of glass for heat soak tempered glass to EN 14179
Understanding this mechanism (heat soak testing) has allowed us to eliminate glass panes that have a higher probability of breaking. Moreover, more and more people are looking for toughened glass. When you come to us, it is advisable to ask for tempered glass that has undergone heat soak testing.