Metal cryogenic treatment, also known as cryogenic processing or cryogenic tempering, is a specialized thermal treatment process that involves subjecting metal objects to extremely low temperatures, usually below -100 degrees Celsius (-148 degrees Fahrenheit) or even lower. The purpose of this treatment is to enhance the mechanical and physical properties of the metal by inducing changes in its microstructure. The process typically involves cooling the metal gradually to the desired temperature and holding it there for an extended period before slowly bringing it back to room temperature. Here are the key aspects of metal cryogenic treatment:
Objective:
The primary goal of metal cryogenic treatment is to improve the metal's wear resistance, hardness, and overall mechanical properties.
The process can be applied to various metals, including steels, alloys, and tool steels.
Process Steps:
Cooling: The metal object is gradually cooled to cryogenic temperatures using specialized cryogenic chambers or liquid nitrogen. The cooling process is carefully controlled to avoid thermal shock.
Soaking: The metal is held at the cryogenic temperature for an extended period, known as the soaking or dwell time. This allows for the completion of transformations within the metal's microstructure.
Gradual Warming: After the soaking period, the metal is slowly brought back to room temperature. This gradual warming helps prevent thermal stress and ensures a more uniform transformation.
Microstructural Changes:
During the cryogenic treatment, changes occur in the metal's microstructure, such as the transformation of retained austenite to martensite, precipitation of fine carbides, and reduction in residual stresses.
These changes contribute to improvements in hardness, wear resistance, dimensional stability, and overall durability.
Benefits:
Increased Hardness: Cryogenic treatment can lead to increased hardness of the metal, providing better resistance to wear and abrasion.
Improved Wear Resistance: The transformation of microstructure