Continuous cooling transformation
![](http://upload.wikimedia.org/wikipedia/commons/thumb/2/2a/TRCS_S355.svg/400px-TRCS_S355.svg.png)
Continuous cooling transformation diagram of EN S355 (ASTM A-572 Grade 50, warranted yield stress 355 MPa) for welding (fast cooling, linear scale).
A continuous cooling transformation (CCT) phase diagram is often used when heat treating steel.[1] These diagrams are used to represent which types of phase changes will occur in a material as it is cooled at different rates. These diagrams are often more useful than time-temperature-transformation diagrams because it is more convenient to cool materials at a certain rate (temperature-variable cooling), than to cool quickly and hold at a certain temperature (isothermal cooling).
Types of continuous cooling diagrams[]
There are two types of continuous cooling diagrams drawn for practical purposes.
- Type 1: This is the plot beginning with the transformation start point, cooling with a specific transformation fraction and ending with a transformation finish temperature for all products against transformation time for each cooling curve.
- Type 2: This is the plot beginning with the transformation start point, cooling with specific transformation fraction and ending with a transformation finish temperature for all products against cooling rate or bar diameter of the specimen for each type of cooling medium.
![](http://upload.wikimedia.org/wikipedia/commons/thumb/8/88/TTT_diagram-20201211-constant_cooling_rate_transformations_in_steels.svg/300px-TTT_diagram-20201211-constant_cooling_rate_transformations_in_steels.svg.png)
TTT diagram for constant cooling rate transformations of an steel.
See also[]
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Wikimedia Commons has media related to Continuous cooling transformation diagrams. |
- Isothermal transformation
- Phase diagram
References[]
- ^ Transformation diagrams (CCT & TTT), archived from the original on 2008-04-18, retrieved 2008-04-17.
Categories:
- Diagrams
- Phase transitions
- Metallurgy
- Mechanical engineering stubs