Annealing marking is a special type of laser etching for metals. The heat effect of the laser beam causes an oxidation process underneath the material surface, resulting in a color change on the metal surface.t the same time, marking with the laser ensures constant high-quality results. Durable marking Laser etching is permanent and at the same time resistant to abrasion, heat and acids. Depending on the laser parameter settings, certain materials can also be marked without damaging the surface.