Deep cryogenic tempering is not a coating or a surface treatment, but a one-time, permanent, irreversible process that penetrates completely through the entire material structure. Cryogenic tempering transforms the microstructure into a more uniform structure that is more durable, stronger, longer lasting, and more dimensionally stable. Deep cryogenic tempering can significantly reduce retained internal stresses on most alloys. Stress imparted unequally can in most alloys cause a decrease in strength and durability. Stress boundary areas are more susceptible to micro cracking, which can lead to premature fatigue and even eventual failure of the stressed part.
Residual stresses exist in all types of parts from engines to tooling.
The stress is introduced into the parts at the time of forging, casting, heat treating and final machining. As parts expand from the heat generated during operation, the retained stresses cause uneven expansion, increased dimensional instability, and increased wear as well as decreased performance. By cycling parts to ultra low temperatures for a prolonged period a very dense molecular state is created. It is this slow rate of temperature change that allows what is known as thermal compression and thermal expansion to occur, which is what actually effects the release of stress. The result is a dimensionally stabilized part, which will resist distortion and warpage increasing performance and durability.