Surface hardening is a process that strengthens only the outer layer of a metal while keeping the inner core tough and flexible. It improves wear resistance without making the entire material brittle. This technique is commonly used to increase durability in components that face friction, impact, and repeated stress.

Key Features:

• Selective Hardening: Only the surface layer is hardened. This allows the inner core to absorb shocks and avoid sudden failure. 
• Multiple Techniques: Methods such as carburizing, nitriding, induction hardening, and flame hardening are used based on the metal and the desired hardness depth.
• Improved Wear Resistance: The hardened outer shell significantly cuts down on frictional wear, helping components last longer in tough working conditions.

The importance of surface hardening lies in its ability to pair a tough interior with a wear-resistant exterior. This combination makes it perfect for gears, shafts, bearings, and automotive parts that need strength without losing fatigue resistance. By improving durability while reducing material costs, surface hardening remains an essential process in manufacturing, mechanical engineering, and modern machinery design.​