Why Cryogenic Tempering?
The cryogenic tempering process for cast iron, steel, aluminum, cast iron, brass, copper, and other metal materials involves both cooling and heating the material. This cooling and heating process refines the grain structure and improves the general properties to make the material more useful in its intended role.
Cast iron and steel benefit from the cooling and heating processes involved in cryogenic tempering in two primary ways:
-reduction of internal stresses reducing the incidence of material warping, cracking, and spalling
-the creation and precipitation/distribution of micro-carbides called “eta carbides” through the base material, increasing wear resistance properties, improving surface quality by filling micro fissure/voids in the base material, and reducing the amount of material removal required to effectively sharpen tools.
Aluminum has alloying elements, but they generally exist outside of the aluminum grain in what is referred to as the “grain boundary.” Aluminum retains a large amount of internal stress and less than ideal alloy distribution. Stress relief is a primary benefit when cryogenically tempering aluminum, but the theory is that the alloying elements located in the grain boundaries are more evenly distributed and the grain boundaries are refined to make a more cohesive structure greatly improving all of aluminum’s beneficial properties.
Copper and its derivatives have alloying elements that exist in a fairly homogenous mixture, but there still exists internal stresses which cause cracking, warping, and in electrical applications, confused electrical pathways resulting in higher resistance to efficient electron flow. Over time and usage some microscopic thermal break down can occur resulting in increased electrical resistance within the material. When cryogenically tempered, stress relieving takes place for the physical benefit of structural items and electrical resistance is lowered, which lowers temperature build up in electrical parts. Specific benefits include welding tips and consumables last longer, circuit boards have less voltage drop and require less cooling, computer processors speed up, electric motors and generators become more efficient and electrical usage goes down.
Cryogenic tempering is a permanent process. It only needs to be done once. Only if the material is subject to destructively high temperatures would the material need to be re-processes, and only if the material was able to be salvaged at all.