2090 – 11 – Using Quenching

1m

When manufacturers quickly cool metal seconds after it’s been soaked at an extreme temperature, it is called quenching. When metal is cooled so fast, the crystal structure of austenite, or F-C-C, doesn’t have time to form as it moves into the crystal structure of the ferrite, or BCC, phase. Instead, it forms the B-C-T crystal structure of martensite.
Quenching typically strengthens and hardens steel. It can be performed using a wide variety of liquids, like fresh water, saltwater, or different oils. Oil cools the metal much slower than saltwater, which cools quickest. The faster the metal cools, the harder the steel will be. But quick cooling goes hand-in-hand with the possibility of distortions being formed in the metal.