What is the difference between tempered glass and heat strengthened glass?
Accordingly, is heat strengthened glass the same as tempered glass?
Heat-strengthened (HS) glass has been subjected to a specifically controlled heating and cooling cycle, and is generally twice as strong as annealed glass of the same thickness and configuration. Tempered glass is approximately four times stronger than regular annealed glass of the same thickness and configuration.
Similarly one may ask, what is the difference between heat strengthened and toughened glass?
To produce heat strengthened glass, the cooling is slower and the resultant compression in the glass is lower than fully tempered glass yet still higher than annealed glass. Because of the compression in the glass, heat strengthened glass is approximately twice as strong as annealed glass of the same thickness.
Heat Tempering. When glass is tempered, it is heated beyond its softening point of 600ºC , then the glass is cooled rapidly creating a higher surface compression and edge compression in the glass. The air-quench temperature, volume, and other variables cause a surface compression of at least 10,000 psi or 69 MPa.