Deep Freezing/Cryogenic Treatment

Highly alloyed tool steels have a tendency to form potentially deleterious retained austenite after hardening.  For this reason, Cryogenic Treatment is used to transform this retained austenite into martensite.  Cryo Treatment is also used to promote dimensional stability prior to sensitive machining and grinding operations especially for certain aluminum components, and also as a stress relief operation.  

Capability

The majority of our Cryogenic treatment cycles are ran in one of our liquid nitrogen cryo-boxes for optimum process and lot control. Our largest cryo-box has a working dimension of 33” x 47” x 47”.  We also have the capability to cryogenically treat larger parts on demand.   

Process

Therm Tech uses liquid nitrogen as the cooling medium in our cryo boxes.   The material is taken down to the process specific freezing temperature and held at the deep freezing temperature for an extended period of time.  The cycle times and temperatures may vary depending on the part and the application, however most parts are taken to -120F ro -320F.  The lead time for this process is usually a day or so.

Recommendations

We often recommend cryogenic treatment process for parts when retained austenite is an existent or potential issue.  We are capable of Nitriding at temperatures down to -120F or even -320F.  Typical lead-times for these treatments are typically 1-2 days, but can be run overnight in cases of emergency.

Cryo Treatment may also be used on occasion to gain an additional rockwell “C” point of hardness after hardening.  Where cases wherein your part isn’t quite hard enough, adding a cryo-treatment operation to the heat treatment can make the difference!

Cryo Treatment is also used as an important part of shrink fitting operations.  Shrink Fitting is a process in which two parts are permanently stuck together by capitalizing on the thermal expansion properties of steel.  Shrink Fits are sometimes preferential to welding operations because shrink fitting does not necessarily involve any loss of properties or high temperatures.

Depending on individual product needs, we also offer Thermal-Cycling along with processes including but not limited to Vacuum Hardening and Oil Quench and Temper in order to meet any hardness or additional property requirements.

Contact a sales representative today to discuss cryogenic treatments for your tool and/or die products!