Free Online Education Articles

Vari-Cold Cryogenic Treatment Process

The Vari-Cold cryogenic process, developed by Cryotron, is a unique, cost effective and cryogen-efficient two-phase procedure. The Vari-Cold™ process is based on a pre-determined thermal cycle that involves cooling of the tools/parts in a cryogenic chamber.

Vari-Cold utilizes the ramping benefits of ultra-cold nitrogen gas in conjunction with the deep-cryogenic “soak” benefits provided by the use of liquid nitrogen. Materials are cooled to cryogenic temperatures with nitrogen gas, utilizing precisely controlled temperature profiles, then slowly introduced to liquid nitrogen for the duration of the soak period.

The liquid-phase provides the most efficient and uniform deep-cryogenic soak, at a consistent temperature of -320°F, which is impossible to achieve with gas alone. Following the pre-determined soak period the cryogenic chamber is allowed to return very slowly to ambient temperature. The Vari-Cold cycle requires up to 72 hours to complete. Operator involvement during the process is minimal.

This procedure of precisely controlled temperature profiles avoids any possibility of thermal shock or stress that is experienced when tools or parts are subjected to abrupt temperature changes. Though liquid nitrogen is used as a refrigerant, no material is introduced to the liquid until it has been slowly cooled to cryogenic temperatures by ultra-cold nitrogen gas.

Cryotron chambers remain 100% moisture free during the entire Vari-Cold process, and it is not necessary to apply de-oxidants to materials prior to treatment.

In most instances the cryogenic cycle is followed by a heat tempering procedure; and as all materials do not have the same chemical constituents, the tempering procedure varies according to chemical composition, thermal history and/or a tool’s particular service application.

Tempering is conducted in a separate Cryotron Batch Oven, designed for the purpose.

To learn more about The Vari-Cold Process, please visit cryotron.com/vari-cold.htm” target=”_blank Cryotron (Canada) Ltd.

Submitted by:

austinculley.com/ Austin Culley works part-time for Cryotron (Canada) Ltd.