Metal processing with altered properties

The processing methods for changing the properties of metals include heat treatment and surface treatment.
1. Heat treatment
A major feature of metals is the modification of their internal structure through heat treatment, which stimulates various characteristics.
The most well-known heat treatment is quenching and tempering. Many people have seen the scene of rapidly immersing the red burned knife into water during the process of making Japanese knives. This is called quenching, which is a heat treatment that hardens steel. However, only hardening can lead to the disadvantage of not being resistant to impact. Knives are no exception. If only quenched, they will crack like glass when subjected to impact. Therefore, in order to achieve moderate toughness, tempering treatment is also necessary. This enables the production of knives with both strength and high toughness.
Normalizing is a method of homogenizing metal structure and improving mechanical properties, which is a heat treatment carried out before processing the workpiece.
Annealing is a method of softening metals as much as possible, either before cutting or after some degree of plastic processing, before further processing.
Carburization quenching is a type of quenching that partially hardens the surface of steel by immersing carbon. Used in conjunction with carburized steel in cases where local strengthening is desired on the teeth of gears, power transmission shafts, etc. Centered around products made of steel and aluminum, it is widely used in automotive parts, aircraft parts, etc.
2. Surface treatment
Representative methods of surface treatment include electroplating and chemical treatment.
O Electroplating
It is a treatment of covering the metal surface with an extremely thin metal film. It has various functions such as preventing rust, achieving aesthetics, and hardening the surface. Generally, nickel, chromium alloy, zinc, etc. are commonly used. For general surface treatment, it is widely used in household items, automotive parts, etc.
O Formation treatment
Unlike electroplating, it is a method of changing the surface properties of metals through chemical treatment to give them various functions.
Phosphate coating treatment is a widely used method for preventing rust and spraying on substrates.
Chromate gloss treatment is also widely used for screws and other methods, which can prevent rusting by implementing it on galvanized steel.
Used for parts with strict rust requirements for use in automobiles, construction machinery, etc.