Surface hardening
Surface hardening is a process by which the surface of a metal is hardened using heat treatment. The process can be divided into many different types, including high temperature and low temperature treatments, chemical treatments, plating and so on.
High temperature treatments involve the direct application of heat. These treatments impart a hardened outer layer on the metal by changing the chemical composition and crystalline structure of the metal. These treatments can be either direct or indirect, depending on the method used. Examples of high temperature treatments are carburizing, nitriding, flame hardening and induction hardening. They are usually used to harden steels and carbide tools.
Low temperature treatments also involve the application of heat, but in a more controlled manner. These treatments involve the differential hardening of a metals surface, which can be done by either heating and quenching (a specific process involving heating the metal and then abruptly quenching it in water or oil) or by flame or induction hardening. This process results in a hardened outer layer on the metal, while maintaining the soft inner core.
Chemical treatments are used to harden the surface of metals by changing the chemical composition of the metal. Common chemical treatments include chromium and nitride plating, electrolytic plating and electrolytic hardening. These treatments leave a hardened layer on the surface of the metal, and can be used for both ferrous and non-ferrous metals.
Plating is another method used to harden metal surfaces. It involves the application of a thin layer of metal onto the surface of the metal, which adds strength and hardness to the surface. This process can be used on both ferrous and non-ferrous metals, and is often used for decorative or functional purposes.
Surface hardening can be used to improve the wear and fatigue resistance of a metal. It can also be used to improve the surface finish of the metal and to protect it from corrosion. The choice of type of treatment depend on the type of metal to be treated, and the intended application of the finished product.
