Dynamic Recovery
Process of dislocation annihilation and arrangement into substructures during ongoing plastic deformation at elevated temperatures. It prevents excessive work hardening.
Dynamic recovery happens when the material is hot-deformed during welding. The dislocations in the structure rearrange and partially annihilate instead of piling up. If this doesn't work properly, the material becomes hard and brittle, the grain grows, and you risk cracks in the weld or in the component. Make sure the heat input is right and the material doesn't cool too quickly. If you notice the structure getting too hard, you need to adjust the temperature control or reduce the deformation during welding. When in doubt, rather weld the seam in multiple layers so the structure can recover in between.