Screw heat treatment
SCREWS HEAT TREATMENT
Some parts are made by processing materials into threads, while others are heat treated to increase strength and toughness. Heat treatment of threads is often performed on high-strength hexagonal bolts and hexagon socket bolts.There are four main types of heat treatment for threads: "normalizing", "annealing", "hardening", and "tempering".
What are "normalizing", "annealing", "hardening", and "tempering"?
|
NAME |
PROCESS |
EFFECT |
|
Normalizing (N) |
After heating steel to an appropriate temperature, it is cooled in the air. |
・Improves unevenness in the metal structure |
|
Annealing (A) |
The steel is heated to over 730°C and cooled slowly.
|
・Improves metal structure・Softens metal・Removes residual stress |
|
Hardening(Q) |
The steel is heated to over 730°C and rapidly cooled. |
・Hardens metal |
|
Tempering (T) |
The steel is heated to below 730°C and rapidly cooled. The lower the tempering temperature, the harder the steel will be. |
・Stabilizes the metal structure and creates toughness |
Steel
|
NAME |
PROCESS |
EFFECT |
Application |
|
Carburizing and quenching |
The steel is then quenched in a gas layer that gives it heat treatment, and then tempered (which takes an average of one hour). |
The surface hardness of the steel required for tapping screws is obtained. The hardened layer is called the carburized layer. |
SWCH12A~18A |
