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Cryogenic Services Improve Wear Characteristics

Cryogenic processing is the deep chilling of tool steel so that the molecular of the metal is brought to cryogenic stillness in order to improve wear characteristics. CryoPlus, Inc. offers cryogenic services for the metalforming, stamping, tool & die, shearing, slitting, welding and punching industries, among others. Applications include metalcutting tools, blades, punches, dies, slitters, gun barrels, engine components and more.

The computer controlled process uses a prescribed schedule where the temperature is maintained at -300 °F for a particular time before slowly returning the parts to room temperature. Prior to the deep cryogenic step, many tool steels require a preconditioning step consisting of a short temper. After being subjected to the deep freeze, the materials must be tempered to about 300 °F. This temperature varies for different materials, and the processing time varies for different material cross sections.

The difference between deep and shallow cryogenic treatment should be considered. Taking a part to -120 °F for a short period of time, called shallow cryogenics, uses dry ice. This method does not transform all of the retained austenite to martensite and does not stress relieve. Deep cryogenics takes the parts to -300 °F for many hours as LN2 is pumped into a well insulated chamber at precise time intervals. "Beware of those processors who are dipping and dunking parts into a barrel of liquid nitrogen," said a company spokesperson. "This will cause stress and fracturing to the part. It must be done gradually and precisely so the metal will be stronger and will not become brittle."

Cryo processing increases abrasive wear resistance, raises the tensile strength and decreases brittleness with only one permanent treatment. It creates a denser molecular structure and closes the grains structure, resulting in a larger contact surface area that reduces friction, heat and wear. Cryogenic treatment changes the entire structure, not just the surface. Subsequent refinishing or regrinding operations do not affect the permanent improvements of the processing.

Cryo treating can be used for coated as well as uncoated tools. The coatings actually adhere better. Anodized surfaces or metals, such as aluminum, also obtain longer life. Cryo also creates a better conductor giving the metal better electrical conductivity.

When the cryo treated tool does wear, the degree of wear reportedly is less severe, slower and more uniform. Therefore, less material must be removed to re-sharpen it. Customers have reported a material removal rate of less than half the normal material removed in re-sharpening. Cryo treating reduces the cost of the product by having longer tool like, less scrap, fewer rejections and above all, less costly downtime.

Durability is the most important criterion used to define the quality of a gear. Cryogenic treatment provides an increase in fatigue life, load capacity and wear resistance of gears without an increase in weight or major modifications to component design. Potentially every gear that is heat treated is a candidate for the additional service of cryogenic treatment.

CryoPlus, Inc. has been certified as a Women's Business Enterprise by the Women's Business Enterprise National Council (WBENC).

For more information contact:

Kathi Bond

CryoPlus, Inc.

2429 North Millborne Rd.

Wooster, OH 44691


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