Surface roughness
Surface roughness describes the irregularities on the surface of a material, resulting from the manufacturing process. It affects the reliability of surface inspections.
Physicochemical mechanism of action
Surface roughness results from mechanical processes such as grinding, polishing, or embossing. It consists of microscopic height variations on the surface.
Metallurgical relevance & risks in welding
High surface roughness can increase corrosion risk because water and air penetrate better into micropores. It also affects weld quality: unevenness can cause inconsistent weld penetration and lead to lack of fusion.
Workshop practice & instructions
Before welding, workpieces should be cleaned with a fine abrasive. Surface roughness should be measured (e.g., with a roughness profilometer) and reduced if needed. A target value for many applications is a roughness of 0.8 µm or less.