Fatigue Fatigue Striation
Fatigue Striations are microscopic grooves on the fracture surface that run perpendicular to the direction of fatigue crack propagation. Each band corresponds to the plastic deformation process of one load cycle.
Physical-Chemical Mechanism of Action
Fatigue Striations occur from repeated plastic deformation of the material under load. With each load cycle, a new ridge forms that is perpendicular to the direction of fatigue crack growth.
Metallurgical Relevance & Welding Risks
Fatigue Striations can appear at too high stress levels or if cooling after welding is too slow. They increase the risk of fatigue failure because they make the material more prone to micro- and macroscopic cracks.
Shop Practice & Action Items
To avoid Fatigue Striations, keep stress levels in check and cool fast after welding. If needed, use a higher load cycling frequency or raise the temperature in the weld zone.