Case hardening or surface hardening is an industrial process that is used to toughen the surfaces of metals. The process aims to create a hard surface that is tough and resilient to high pressures, while maintaining a soft core that imparts agility ensuring that the object is able to absorb shocks. This process is accompanied by a process of seeping the metal object in a carbon rich alloy so that the surface is layered with an alloy of the metal with high-carbon content. In a more common process iron is often layered with carbon to form steel. In the hardening process for steel, again, the object is carburized in a way that the outer layer retains more carbon than the center.
The process of case hardening is extremely specialized and industry specific. There are a number of industries that require metal objects with enhanced tensile strength and this particular process of heat treatment is carried on for such objects after they have been crafted and given their final shape and form. Often the process is carried on only over a part of the surface of an object that requires added strength and durability. However, there are some additional uses of this process, where unshaped metal bars are hardened and are then used for pattern welding or other similar processes.
The case hardening process finds wide application across industries like the firearms industry where there is a continuing demand for tough metal that can render highly accurate functioning in high pressure and high-temperature atmospheres. Case hardened metals are used to manufacture objects like fireplace equipments, kitchen utensils that go through a lot of wear and tear, wrought iron wash-pans, etc. Again, the automotive industry uses case hardened metal especially to strengthen metal auto parts that are used for suspension and other purposes.
The construction industry deploys the process to manufacture a variety of girders, metal panels, metal doors, etc for enhanced performance and to impart the capability to withstand greater load and pressure. Also, camshafts, special-purpose and self-drilling screws, etc are heat-treated using this procedure to obtain durability and tensile strength. The different application of this particular heat treatment process across industries can be summarized as below:
- The process is of utmost importance in the industry for energy generation, where it is primarily used to make gear wheels, and some other constituent parts that undergo heavy wear and tear. For instance, hydroelectric power stations, steam turbine gears, propeller drives in drilling rigs, and wind turbines, all require metal parts that are strong and highly durable.
- The transportation industry widely requires metal parts for all kinds of vehicles that can withstand years of wear and tear in an internal combustion engine.
- In the general mechanical industry objects like steel rolling devices, heavy load transmissions, forging press, construction cranes and other earth moving equipments, etc require metals with immense fatigue resistance.
- Screws across the industries, especially the self drilling version, requires immense strength under pressure and are hence hardened through this process. The process of hardening screws however is simpler than that of hardening other complex mechanical gears. They can be repetitively heated and cooled to gain a hardened surface.
This process of hardening is extremely effective and hence also very popular. There are several professional agencies offering case hardening services in the industry.