When you think of heat treating companies, you may think about modern steel that’s heated to high temperatures and then quenched with special processes that create a superior product in many ways. Although this is a major part of heat treatment services, some also use cryogenic hardening to enhance the properties of metal. How can exposing metals to low temperatures help? Let’s examine the process more closely to see.
What Does Cryogenic Mean?
Cryogenics became a popular term in the late 20th Century, as some people tried to look beyond modern science for health cures. By freezing the body (or head) to extremely low temperatures, it may be possible to thaw them out far into the future, when a cure or remedy for a disease has been found. However, extreme cold has many more uses today.
Cold Then Hot
When heat treating companies use cryogenic hardening, they cool metals to as low as two hundred and thirty-eight degrees below the zero point (Fahrenheit). That is one hundred and fifty below on the Celsius scale.
Cooling off the metal must be a slow process. This is often done with gas from liquid nitrogen. It’s very important to cool slowly to eliminate thermal stress. The metal is then kept at a very low temperature (about minus 300F) for about 24 hours. Next, the chilled metal is then heated to around 300F. This is a temperature change of about 600 degrees and reduces brittleness caused by freezing.
Benefits
Cryogenic hardening produces near perfect grain structures for hardened steel. There are very few imperfections. Corrosion resistance increases and so does durability (wear resistance). Also, an even grain structure reduces the effects of stress on hardened steel. These benefits are retained even through the machining process. When you choose heat treating companies offering cryogenic services, you receive some of the highest quality products.
