Discontinuous Recrystallization
Discontinuous recrystallization is the process where new, fine grains form in a deformed metal without completely eliminating the old grains. This leads to reduced hardness and improved toughness.
Physical-Chemical Mechanism of Action
During discontinuous recrystallization, new fine grains form in a deformed metal at the boundaries between old, large grains. This process occurs without complete melting of the material and without significant changes in chemical composition.
Metallurgical Relevance & Welding Risks
Discontinuous recrystallization is particularly important in welding, as it can reduce hardness and grain size. This improves toughness and mechanical properties of the weld. However, too fast cooling or excessive temperature during welding can prevent full recrystallization, leading to hardness problems and potential cracks.
Workshop Practice & Action Guidelines
To optimally utilize discontinuous recrystallization, it is important to cool the material in a protected environment after welding. This means the material should not be cooled in open air or under strong drafts. Controlled cooling can be achieved using furnaces or cooling pans. The exact temperature and time for cooling depend on the material and desired properties, but it is essential that the material is cooled slowly and continuously.