Air Products can provide liquid nitrogen and supply systems for cryogenic treatment, cryo-tempering, and shrink fitting down to -300°F (-184°C). Cryo-treating with subsequent tempering can improve material properties resulting in stress relief, plus increased toughness and wear resistance. Our cryogenic liquid nitrogen cools metal parts inside treatment chambers to optimize final properties, such as hardness and wear resistance, through transformation of retained austenite into martensite.
Air Products offers a variety of technical services for cryogenic nitrogen treatment processes. Our applications engineers can work with you to understand your cryo-treating, cryo-tempering, and shrink fitting operations to recommend improvements that can help you optimize gas use and improve product quality.
Why would I want to cryogenically treat tool steels? Does it really affect the microstructure?
After austenitizing and quenching, tool steels are sometimes subjected to cold treatment at approximately –80°C (-112°F), followed by tempering. Primarily, the cold treatment is done to increase strength, improve dimensional or microstructure stability, and improve wear resistance. These benefits are due to the transformation of retained austenite to martensite. Some studies show that lowering the cold treatment temperature below –100°C (-148°F) does not significantly increase the amount of retained austenite-to-martensite transformation—therefore, it does not result in additional benefits. However, other studies show that compared to cold treatment (–80°C / -112°F), cryogenic treatment (–190°C / -310°F) further improves wear resistance.