Shot Peening
Shot blasting is a mechanical-thermal surface treatment where the surface is bombarded with hard balls. This increases fatigue strength and prevents cracks.
Physical-Chemical Mechanism of Action
Shot peening creates compressive residual stresses in the surface layer through bombardment with hard shot. These stresses influence the crystal structure and increase surface strength.
Metallurgical Relevance & Welding Risks
Shot peening increases endurance limit, protecting the material from cracks. Incorrect application, however, can lead to overstressing and the formation of microstructures that may impair toughness.
Workshop Practice & Action Guidelines
Use shot peening on steels with low fatigue strength. The shot should have a hardness of at least 50 HRC. The blasting pressure is typically 200 to 400 N/mm², and the blasting speed should be between 10 and 30 m/s.