Controlled Dry Cryogenic Process

What is a controlled dry cryogenic process?
Cryogenics, a product of aerospace research, refers to temperatures below (-280°F). A dry process means that material to be treated is not exposed to any cryogenic liquids, which eliminates the risk of thermal shock. The material is frozen through a thermo-dynamic refrigeration cycle. Controlled simply states that the entire process is performed according to a precise, prescribed time table. The material is cooled slowly, held for prolonged period of time, 20-60 hours, and allowed to return to room temperature slowly.

The treated material maintains its original size and shape throughout the cryogenic process. Although a material is stronger at lower temperatures, following treatment, they show no change in yield of tensile strength. The treated material does become less brittle but without losing hardness. What does change most significantly and considerably is an increase in the material's toughness, stability and wear resistivity.

In contrast to various other surface treatments, the dry cryogenic treatment is a one time only process and affects the material through and through. Re-sharpening or redressing of worn tools does not destroy the effects of the treatment. Tools may be new or used, sharp or dull.

Source: http://www.300below.com/press/magazine-articles/the-promise-of-cryo.html