What Does Pearlite Mean?
Pearlite is a mixture of ferrite and cementite forming distinct layers or bands in slowly cooled carbon steels. Pearlite is an iron alloy that contains around 88% ferrite and 12% cementite.
Pearlite is known for being tough and it is used in a variety of applications, including:
- Cutting tools
- High-strength wires
Pearlite is both stronger and lighter than pure ferric steel. It is often used as wire, and pearlite cables play an important role in some bridges. As an insulating material, pearlite is used in refrigeration technology.
Corrosionpedia Explains Pearlite
Pearlite is a two-phased, lamellar (layered or plate-like) structure composed of alternating layers of alpha-ferrite and cementite that occurs in some steels and cast irons. Pearlite only forms under specialized conditions which must be controlled to create this alloy phase.
Ferrite or alpha iron (a-Fe) is a solid solution with iron as the main constituent with a body-centered cubic crystal structure. Cementite, also known as iron carbide, is a chemical compound of iron and carbon, with the formula Fe3C.
Pearlite is a common microstructure occurring in many grades of steels. It is hard and strong because of the layered structure, and is used in a variety of applications. Pearlite is wear-resistant because of a strong lamellar network of ferrite and cementite.
Eutectoid steel can, in principle, be transformed completely into pearlite; hypoeutectoid steels can also be completely pearlitic if transformed at a temperature below the normal eutectoid. Steels with pearlitic or near-pearlitic microstructure can be drawn into wires.
Such wires, often bundled into ropes, are commercially used as piano wires, ropes for suspension bridges, and as steel cord for tire reinforcement. It makes pearlite one of the strongest structural bulk materials on earth.