Surface Roughness Effect on Fatigue
Microscopic surface notches increase fatigue sensitivity by creating local stress peaks. Mechanical post-treatment reduces these effects.
Physical-Chemical Mechanism of Action
Microscopic surface notches on the material surface act as local stress concentrations. These lead to increased local stresses and thus to accelerated fatigue under cyclic loading.
Metallurgical Relevance & Welding Risks
High surface roughness can lead to increased fatigue susceptibility, which especially under high loads and long-term operating conditions results in cracks and failure. This is particularly critical in highly stressed components such as structural parts or machine elements.
Workshop Practice & Action Instructions
To reduce fatigue susceptibility, mechanical post-treatment should be carried out after welding. This can be achieved by polishing, sandblasting, or chemical corrosion treatment. One goal is to reduce surface roughness so that it falls below 3 µm. This can be achieved using special machines and processes such as polishing with fine polishing wheels or chemical corrosion treatment.