Principle: After quenching, rolling mill rolls contain a large amount of unstable residual austenite and residual internal stresses from heat treatment. Deep cryogenic treatment (–180 to –190°C) converts the residual austenite into stable martensite, simultaneously precipitating fine, dispersed carbides and relieving internal stresses. This is a supplementary process following quenching, not a replacement for quenching and tempering.

Key Benefits:

1. High dimensional stability: Reduces post-treatment deformation by eliminating residual austenite and releasing thermal stresses. The rolls resist gradual deformation and dimensional drift under prolonged cycles of heating and pressure, ensuring precise plate thickness control, minimizing scrap, and making them ideal for high-precision rolling mills.

2. Significantly improved wear resistance: Grain refinement combined with the precipitation of numerous fine carbides increases wear resistance by 30%–100%. This reduces surface wear, scratches, and roll sticking, extending the operational interval between regrinds and decreasing downtime for roll maintenance.

3. Enhanced fatigue, spalling, and thermal cracking resistance: Under alternating rolling loads, the risk of surface spalling, pitting, and thermal cracking is reduced, increasing overall service life by 50%–200% and lowering spare parts procurement costs.

4. Slight increase in hardness without loss of toughness: Hardness improves by approximately 5–15 HRC while maintaining or even improving toughness, reducing the risk of roll breakage and scrapping.