Cryogenic processing in a nutshell is the improvement of metals and other materials by the use of ultra cold temps and extended time frames.
Cajun Cryogenics uses liquid nitrogen as its agent to reduce the temperature of the item to -315F. It is very important that the temperature is reduced very slowly. I use a 1/2 degree per minute ascent and descent rate. The slow descent/ascent ensures that thermal shock will not be an issue and affect the item processed. Most other cryo processors will descend and ascend a little quicker but I want to do everything I can to make sure that the best results possible are produced by Cajun Cryogenics. After the 13 hour or so descent the item is held at -315 for 24hours. After the soak the processor will ascend back to ambient temperature at 1/3 degree per minute. In some instances a mild temper is performed to relax any newly formed Martensite, this is only necessary for ferrous metals and is performed when a larger amount of retained Austenite is present.
The benefits that result from this process are substantial and start with the formation of eta carbides. Carbides are formed during the soak and help to make the metal tougher and more resistant to wear. Another thing that happens during the cryo soak is the transformation of the softer Austenite crystalline structure to the stronger Martensite crystalline structure. Steels are heat treated in order to transform Austenite to Martensite but all of the Austenite cannot be transformed with heat treating alone and depends on factors like barometric pressure, temperature, and humidity. Cryogenic processing will complete 99.8% of Martensitic transformation resulting in a tougher and more wear resistant material. The next benefit of cryogenic processing is the relief of residual stress, this is important and can make a big difference in the accuracy of your firearm. The amount of residual stress in a barrel is not consistent between even identical barrels. Most all barrels have some amount of residual stress left over from the manufacturing process. Internal stresses can affect the harmonics and vibrations of a barrel which will affect accuracy. Removing stress will reduce vibrations and contribute to the overall consistency of the barrel. Cryogenic processing will also positively impact the heat dissipation properties of metals as well and this can dramatically affect the accuracy of warm barrels. As a barrel warms the heat is dissipated un-evenly and causes warping in the barrel. This warping is responsible for a loss of accuracy normally called "walking or wondering". After cryogenic processing heat dissipates very evenly throughout the barrel and as a result walking is eliminated. The even heat dissipation is a result of the evening of the microstructure. Every shot down the barrel is just as accurate as the first cold bore shot. This is important as most rifles will demonstrate some amount of walking as the barrel warms. Simi autos like AR's will benefit from the superior heat dissipation properties as rapid firing occurs. As a barrel heats from rapid firing the rifling and throat becomes more susceptible to wear because of the softer metal. In addition the spring’s cycle life will increase substantially and be less likely to lose tension. Many customers notice this first particularly if the gun was well worn before processing, they notice that their springs have more tension. The springs will not gain more tension than they had new but if worn they will regain lost tension. Processing new springs will ensure that they will keep that tension for a much longer time.
The culmination of these benefits produce a firearm that will last much longer, be more accurate under adverse conditions, be stronger, run cooler and handle heat better, be less likely to corrode due to the smoothing of the metal surface, powder and other contaminates are less likely to build up in the barrel, the springs in the action and magazines will last longer and be less likely to lose tension, moving parts will be smoother, the gun will be more dependable and less likely to fail, If blued the finish will come out deeper and richer and the gun will be easier to clean.
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