What is Cryogenic Processing?
There are no “official” definitions of the term cryogenic processing. Controlled Thermal Processing (CTP) considers the definition of the process to be:
“The modification of a material or component using cryogenic temperatures.”
Cold Treatments generally only go down to temperatures of 178ºK (-140ºF, -96ºC). This is because these temperatures were easily reached using dry ice and alcohol. Cryogenic treatments have been found to offer performance over and above that of cold treatments by studies performed by the Illinois Institute of Technology Research Institute for the US Army Aviation and Missile Command.
The word Cryogenics is derived from the Greek words ‘Kryos” (meaning cold) and “Genes” (meaning born). It was first seen around 1894 by a fellow named Kamerlingh Onnes to describe his Leiden Cryogenic Laboratory. He was a professor of Physics from 1882 to 1923 at the University of Liden. In 1904 he founded a very large cryogenics laboratory and invited other researchers to the location, which made him highly regarded in the scientific community. He was the first physicist to liquefy helium, doing so in 1908. By 1937, “cryogenics” was being freely used in relation to gases and their critical points. This usage in the 1930’s led to the definition of 120ºK as the upper limit of the cryogenic temperature range.
Since 1945, the increased use of “cold” in medicine and industry has resulted in higher temperatures being labeled as cryogenic. In our industry this has led to some problems, as heat treaters tend to call the -110ºF cold treatment to convert retained austenite to martensite a cryogenic treatment. It is not cryogenic, and it does not do the same thing.
Since there is no official definition of the process, the process parameters vary widely from one company to the next. Processes and equipment vary considerably from one company to the next.
Simply specifying “cryogenic treatment” is not sufficient.
One must be very careful when comparing results from one company to those of another. Controlled Thermal Processing has been in business since 1982. Our equipment is the best available. Where our cryogenic processing machinery use the latest vacuum insulated dewars and heat exchanger technology, we have competitors who pour raw liquid nitrogen on their customer’s expensive tooling. Our techniques are proven ones. For instance, Controlled Thermal Processing, Inc. processes parts for other “cryogenic processing” companies because our process and machinery works where theirs fail.