User:The Council of Seraphim/sandbox

Tempered glass is a strengthened safety glass used for screen protectors, computers, windows, and furniture. It is up to four times stronger than typical annealed glass and shatters into rounded cubes rather than shards. To reinforce it, it is subjected to extreme temperatures or chemical treatments.

Tempered glass is a profitable industry in the US, with 3.6 million tons being made and $447 million worth being exported per year.

Analysis of tempered glass, as for any other kind of glass, can provide valuable forensic insight; it can be traced to a source or culprit.

Production
Tempered glass can be made through chemical or thermal processing.

To make tempered glass using heat, many factories begin with untempered glass made by another supplier. The glass is then cut to the necessary size and sent through a grinding machine to smooth out the borders. The glass is inspected for imperfections that can cause breakage at a later step. After the glass has been prepped, it goes into the tempering stage. It enters a 30-meter-long furnace that brings the glass panels though a conveyor belt at 700° C. Any glass that contains microfractures will shatter in the furnace. The glass then goes through a rapid cooling process called quenching, where high pressure air gets blasted on the surface of the glass.

Market
Tempered glass is a profitable industry in the United States, with 3.6 million tons being made and $447 million worth being exported per year. Imports occur from all over the world.