Final answer:
Steels can be hardened through heat treatment, but some steels are only case hardened due to their high carbon content. Case hardened steel has many uses, including gears and bearings, tools and cutting implements, automotive components, firearms, and railway and aerospace industry applications.
Step-by-step explanation:
Steels can be hardened through a process known as heat treatment. This involves heating the steel to a specific temperature and then rapidly cooling it, typically by quenching in oil or water. This process changes the microstructure of the steel, making it harder and more resistant to wear and deformation.
Some steels are only case hardened because they have a high carbon content, which makes them too brittle to be fully hardened. Case hardening involves adding carbon to the outer layer of the steel through a process called carburizing or through the use of a high-carbon alloy. This forms a hard surface while keeping the core of the steel tough and ductile.
Five uses for case hardened steel include:
- Gears and bearings: Case hardened steel is used in the manufacture of gears and bearings because of its high wear resistance and toughness.
- Tools and cutting implements: Case hardened steel is used to make tools such as drill bits, hammers, and chisels, as it provides a hard and durable cutting edge.
- Automotive components: Case hardened steel is used in the manufacture of various automotive components, including crankshafts, camshafts, and gears.
- Firearms: Some gun components, such as barrels and slides, are made from case hardened steel to enhance their surface hardness and durability.
- Railway and aerospace industry: Case hardened steel is used in the construction of railway tracks, wheels, and aerospace components, where high strength and wear resistance are required.