Targeted Surface Recrystallization

So, targeted surface layer recrystallization is basically nothing more than controlled soft annealing of the near-surface zone. This relieves the stresses and work hardening caused by previous processing like drilling or drawing. It prevents cracks and makes the component tough again. You heat the edge zone specifically and then let it cool slowly and evenly. It's important to keep the temperature tightly controlled so the structure can recrystallize anew and uniformly. You do this right after mechanical processing, before you continue welding or loading the part.