T.T.T

[ankur bhattacharjee]

Write short note on T.T.T curves.

[India Hindi Blog Information]

T.T.T (Time-Temperature-Transformation) diagram also known as S-curve, C-curve, Bain's curve or isothermal transformation diagram shows the relationship between temperature and time take for a decomposition transformation to take place in a metal when the transformation is isothermal, i.e transformation is allowed to occur at constant temperature. 

Iron-carbon equilibrium diagram can only be used for study of steels cooled under equilibrium conditions. The phases and resulting micro-structure for a given composition and temperature can be obtained only under equilibrium conditions. 

However in products of transformation. At higher rates of cooling some meta-stable phases may be formed. Which does not found any place in Fe-C equilibrium diagram, such as martensite . Thus a T.T.T diagram, relates the transformation of austenite to the time and temperature conditions to which it is subjected. T.T.T diagram are most useful in the heat treatment of steel.