Why anneal glass

This makes annealing a vital step in the production of strong, stable, and heat-resistant glass. From a physical perspective, glass is a highly unusual material. But the molecules in glass obey a different set of rules: they are, by definition, disordered. We say that glass is an amorphous solid. Crystalline solids and amorphous solids i. When crystalline solids are heated, they undergo a spontaneous phase transition at their melting temperature.

Instead, it very gradually tends toward a more liquid state. Glass is worked and formed at very high temperatures, where its viscosity is low. When it is allowed to cool rapidly supercool , the glass becomes stiffer and stiffer as the disordered molecules simply become more fixed in their positions. As this happens, internal stresses can become trapped in the solidifying glass. The result is extremely brittle glass that can shatter easily.

The process of annealing enables the elimination of internal stresses, producing strong and durable glass suitable for widespread application. Essentially, annealing is the process of cooling glass in a controlled manner to reduce internal stresses in the finished glass. Lowering the temperature of glass from its annealing temperature very slowly means that there is sufficient time for heat to distribute itself evenly, and molecules have sufficient time to find their most stable positions within the cooling glass.

Tempered glass cannot be drilled or cut without shattering. All fabrication needs to be done while the glass is in the softer, annealed condition. Annealed glass can be cut, drilled, notched and edge finished. Tempering is only done once the shaping and fabrication is complete. Annealed Glass , sometimes called standard glass is a softer glass that has been thermally treated and then slowly cooled to relieve any internal stresses.

Annealed glass tends to break into longer, jagged shards which can cause significant injury. When not at work, Adam can be found jogging the streets of Pittsburgh, golfing, working on his new home, or cheering on the Pittsburgh Pirates, Penguins, and Buffalo Bills.

The Annealing Process In glass manufacturing, a special type of furnace, called a lehr, is used for the annealing process. Controlled glass annealing: Ensures material consistency Minimizes stresses Prevents spontaneous breakage To learn more about glass basics, download our eBook:. Explore by Authors. Illuminated Applications. Scientific Fundamentals. Recent Posts. Search Search. Custom Solutions.