Surface hardening is a process carried out to make the surface of a material harder and more durable. This process can be accomplished through various methods.
Here are some commonly used surface hardening techniques:
1. Induction Hardening:
• The material is heated through electromagnetic induction.
• Surface temperature rapidly increases and is then cooled.
• This process results in increased hardness on the surface.
2. Oxygen Gas Carburizing (Oxygen Lancing):
• Oxygen gas is directed onto the material's surface to heat it.
• The surface oxidizes and hardens at high temperatures.
• This method is often used for hardening steels.
3. Carbon Gas Carburizing:
• The material is exposed to carbon-containing gases.
• Carbon diffusion occurs on the surface, resulting in hardening.
• It is commonly used for surface hardening of steels.
4. Hot-Dip Galvanizing:
• Metal material is immersed in a bath containing molten zinc.
• Zinc adheres to the surface, forming a protective coating.
• This process enhances material protection and durability.
5. Annealing:
• Hardened material is heated to a specific temperature and then slowly cooled.
• This process reduces internal stresses, improving material durability.
6. Phosphate Coating:
• The material is dipped into or sprayed with a phosphate solution.
• Phosphate coating helps protect the surface from corrosion.
7. Surface Spraying:
• The surface is coated using a specialized spraying gun.
• The coating material either hardens or protects the surface.
The choice of surface hardening method depends on the type of material, its intended use, and the environment it will be exposed to. The selection should be made considering expertise and material properties.