TTT diagram
The TTT diagram shows phase development of metals during cooling or isothermal holding. It helps select appropriate welding processes and avoid microstructure problems.
Physicochemical Mechanism of Action
The CCT diagram (Continuous Cooling Transformation diagram) shows how metals undergo phase transformations at various times and temperatures. It visualizes the cooling or isothermal holding of metals and their microstructure development.
Metallurgical Relevance & Welding Risks
The CCT diagram is crucial for selecting the right welding process to achieve specific microstructural goals. Incorrect cooling can lead to undesirable structures such as martensite, which causes hardness and crack susceptibility. Conversely, the diagram helps optimize the welding process.
Workshop Practice & Action Instructions
To use the CCT diagram effectively in the workshop, follow these steps:
1 Temperature Control: Ensure that cooling or isothermal holding occurs exactly at the specified temperatures and times.
2 Microstructure Analysis: Use the diagram to achieve the desired microstructure and avoid potential risks like martensite formation.
3 Welding Process Selection: Choose welding processes that are compatible with the metal and the desired microstructure development.