Metal Heat Treatment: 4 Main Processes

1. Induction Hardening
   Surface Hardening by Electromagnetic Induction
   Uses high-frequency electromagnetic induction to generate heat directly on the metal surface, followed by rapid quenching.
    Key Advantages
   Extremely fast heating
   Precise localized hardening
   Hard surface with tough core
   Reduced distortion
   Ideal for mass production
    Common Applications
   Shafts
   Gears
   Sprockets
   Rollers
   Pins
   Machine Parts

2. Annealing
Metal Softening Process
A heat treatment process where metal is heated to a specified temperature and then slowly cooled inside the furnace.

Purpose
Reduce hardness
Improve ductility
Relieve internal stress
Improve machinability and formability
Benefits
Prevents brittleness
Reduces cracking risk
Refines metal structure
 Common Applications
Forming
Bending
Machining
Pre-machining processes

3.Quenching
Rapid Cooling Hardening Process
Metal is heated to a specific temperature and then rapidly cooled in water, oil, or another quenching medium.

 Purpose
Increase hardness
Improve wear resistance
⚠ Important Considerations
Excessive cooling speed may cause brittleness
Distortion or cracking can occur
 Common Applications
Tool Steel
Dies
Blades
Industrial Machine Parts

4.Tempering
Reheating After Hardening
After quenching, metal becomes very hard but also brittle.
Tempering reheats the material at a lower temperature to balance hardness and toughness.

 Results
Reduces brittleness
Improves toughness
Relieves internal stress
Extends service life
Common Applications
Quenched Steel
Tool Steel
Automotive Parts
Industrial Components