There are many myths and misconceptions about cryogenic processing. We will try to dispel some of those for you. Cryogenics is not a magic "cure-all" for metals, but when applied properly, results can be quite astounding.

The biggest issue we run across is people who have misapplied cryogenics, did not attain the results they were after, and concluded that cryogenics does not work. The problem stems from the fact that the limits of the part are being exceeded.

Example:

If you have a component that can only withstand 100,000 lb force, and you are applying a 200,000 lb force, you are exceeding the capability of that part. Nothing is going to help that, except for an ENGINEERING DESIGN CHANGE. Cryogenics will not do anything in this case.

Conversely, if you are operating WITHIN the designed parameters of the component, cryogenics WILL extend the life of that component. This is due in part to the fatigue resistance being increased.

Hardness vs. Strength

People often use these two interchangeably, even though they are two separate entities. Cryogenics can strengthen a material by removing the micro-flaws that initiate crack propagation, which are what cause wear and premature failure. In other words, the material performs as it was intended to in design.

"Hardness" is an independent material property, set by the initial heat-treatment of a steel. If the heat treatment is done correctly, the cryogenic process will not appreciably raise the hardness (Rockwell, Brinell, Vickers/Micro/Knoop).

However, if there is more than 10% retained austenite, you WILL see a change in the hardness, usually a point or two. If the heat-treat was extremely poor, the gains will be even higher. While this may be used as a "band-aid" for a bad heat-treat, it should NOT be substituted for proper heat-treatment and quality procedures.