Case Hardening & Through Hardening

Case Hardening

• Low carbon
• Develops hard case with a ductile core
• Alloys with under .30% carbon
• Maintains good shock resistance
• Usually carburized to achieve a high surface hardness
• Example: 8620

Through Hardening

• Medium to high carbon
• Achieves a greater depth of hardness
• Alloys with .40% or more carbon
• Quenched and tempered for high strength and hardness
• Example: 4340