Pitting Corrosion
Pitting corrosion is a local corrosion form on passivated metal surfaces caused by chloride ions. It forms cavities growing in depth and leads to wear and cracking.
Physikalisch-chemischer Wirkmechanismus
Pitting corrosion occurs when chloride ions react on the surface of a passivated metal (such as steel). These ions breach the passive layer and form cavities that grow in depth. Oxygen molecules are generated, which continue to react with the metal and cause corrosion.
Metallurgical Relevance & Welding Risks
Pitting corrosion can lead to wear and cracks in the weld seam. It impairs the strength and service life of the material. In the workshop, it can arise from missing surface treatment or insufficient drying.
Werkstattpraxis & Handlungsanweisungen
To avoid pitting corrosion, workpieces should be thoroughly dried and cleaned after welding. Use necessary surface treatment methods such as phosphating or chromating. Pay attention to the correct selection of welding materials and processes to maintain the passivity of the metal.