The processing principle of half strengthened glass is similar to that of physically tempered glass, and the difference between the glass is not visible on the surface. The heating temperature is about 650 ℃, the tempered glass cools quickly, the half strengthened glass cools more slowly, making the half strengthened glass strength between tempered glass and ordinary glass. However, the crack of half strengthened glass rupture extends from the point of initiation to the side, similar to annealed glass, the fragments are larger, so half strengthened glass does not belong to the safety glass, half strengthened glass has the advantage of better flatness than tempered glass, while its thermal stability and strength is also better than annealed glass.
The special stress structure of half strengthened glass allows the fragments to remain in the frame when it is damaged, unlike tempered glass that falls off completely in granular form when broken, gaining time for glass replacement. You can choose to install half strengthened glass in scenarios where you want the glass not to shatter completely in the event of an accident and where personal safety is not involved. Or use the flatness of the half strengthened glass, the use of laminated process processing, so that two pieces of half strengthened glass into safety glass, its flatness and stack difference will be much better than the tempered laminated glass.
The surface stress of half strengthened glass is: 24-69Mpa, while the surface stress of tempered glass is above 90Mpa.
What are the characteristics of tempered and half strengthened tempered glass?
Safety: broken in small blunt particles, will not cause great harm to the human body.
High strength: generally 4 times and more than the strength of ordinary glass.
Deflection: 3-4 times greater than ordinary glass.
Thermal stability: Tempered glass has good thermal stability. Tempered glass withstands 2.5-3 times the temperature difference of annealed glass (up to 200°C). It can meet the environmental cold and heat changes considered in the building, indoor and outdoor shading of sunlight, thermal shock of heating or air conditioning, etc.
The biggest disadvantage of tempered glass is that it is easy to self-explode, and the larger the tempered glass area corresponding to the higher the risk of self-exploding.
So how to deal with the danger of self-explosion of tempered glass? The first is to make heat soak test (that is, heat soaking treatment),put the tempered glass into a hot soaking furnace to treat the equipment with high temperature and high pressure, and detonate due to uneven internal stress and potential self-explosion factors of the tempered glass. Reduce the self-explosion rate of tempered glass.
2. Half strengthened glass
Safety: It does not meet the standard of safety glass and does not belong to safety glass.
Strength: generally 2 times or more than that of ordinary glass.
Thermal stability: The thermal stability of half strengthened glass is better than ordinary glass.
Half strengthened glass has a low self-explosion rate, but the biggest regret is that it cannot be used as safety glass. If you want to choose half strengthened glass, you can only do lamination process on it to make it into safety glass.