Surface roughness
Surface roughness influences fatigue strength because irregularities promote cracking. The rougher the surface, the shorter the service life.
Physical-Chemical Mechanism of Action
Surface roughness consists of microscopic irregularities on the surface of a material. These irregularities can act as anchor points for cracks that propagate under mechanical stress.
Metallurgical Relevance & Welding Risks
High surface roughness increases the likelihood of fatigue fractures and cracks. This can lead to earlier degradation of components, especially under repeated loading.
Workshop Practice & Action Instructions
To reduce surface roughness, mechanical polishing procedures should be applied after welding. This can be achieved through gentle abrasion or chemical polishing agents. A target value for the roughness number (Ra) should be below 3.2 μm to ensure good fatigue strength.