Carbon Steel

[flano]

Could anyone tell me the difference between the following steel alloys how they are formed etc : Martensite,Austenite, Bainite, Cemetite, Pearlite and Ferite.Thank you.

[amarillis]

Martensite: The hard constituent produced when steel is cooled from the hardening temperature at a speed greater than its critical cooling rate. Martensite is an acicular phase when seen in the microstructure of steel.
Austenite: The solid solution of carbon in gamma (face centred cubic) iron.
Bainite: An acicular aggregate of ferrite and carbide particles formed when austenite is transformed on cooling at temperatures in the intermediate (200-450oC) range, i.e. above the martensite and below the pearlite range.
Cemetite: An iron carbide (Fe3C) constituent of steel. It is hard, brittle and crystalline. Steel which has cooled slowly from a high temperature contains ferrite and pearlite in relative proportions varying with the chemical composition of the steel. Pearlite is a lamellar structure of ferrite and cementite.
Pearlite: A lamellar constituent of steel consisting of alternate layers of ferrite (alpha-iron) and cementite (iron Carbide Fe3C) and is formed on cooling austenite at 723oC. This produces a tough structure and is responsible for the mechanical properties of unhardened steel.
Ferrite: The solid solution of carbon in body-centred cubic iron, a constituent of carbon steels.

[flano]

Aramrillis you big legend. I didn't think I'd get an answer on this one. That clears up some college study anyway. Thanks a mill

[amarillis]

Glad to help flano, it got the old brain cells working for a little while too!