Microstructural Degeneration
Microstructure degeneration is the coarsening of the metal microstructure due to inadequate thermal process control. This leads to reduced toughness and increased susceptibility to cracking.
Physicochemical mechanism of action
Microstructure degeneration occurs when the metal does not cool quickly enough during cooling. This prevents proper grain formation and leads to irregular coarsening of the crystal structure.
Metallurgical relevance & risks in welding
Microstructure degeneration increases the susceptibility to cracking because the metal is less tough. It can also lead to poorer mechanical strength and reduced stress capacity. This particularly affects scale resistance and the service life of the weld.
Workshop practice & action instructions
To avoid microstructure degeneration, it is crucial to implement a correct cooling strategy. This includes:
• An adequate cooling rate after welding (e.g., by using cooling water or cooling gas).
• Adherence to the specified cooling times and temperatures.
• Avoiding too fast cooling, which can lead to irregular grain growth.