Normalizing:
The casing is heated above the critical temperature and then cooled by air. Normalizing treatment helps to improve the strength and hardness of the casing and homogenizes its structure.
Effect: Increase strength and hardness, improve toughness, reduce stress, and improve processing performance.
Tempering:
The normalized casing is reheated to a lower temperature and then cooled. This process helps to adjust hardness and strength to obtain properties more suitable for specific uses.
Effect: Reduce hardness, improve the balance of toughness and strength, and reduce internal stress.
Austenitizing:
The casing is heated above the critical temperature and then cooled rapidly to form an austenite structure. This process increases the hardness of the casing.
Effect: Increases hardness, but may reduce toughness, so subsequent tempering is required to adjust properties.
Quenching:
The casing is heated above the critical temperature and then cooled rapidly to form hard martensite on the surface of the casing and austenite inside. This treatment increases the stiffness of the casing but may cause internal stresses.
Effect: Increases hardness, but may reduce toughness, requiring subsequent tempering to balance properties.
