Oxygen Segregation in Cast Structures
Oxygen segregation in cast structures is the enrichment of oxygen and oxide residues at the edge of the solidification process, leading to local weak spots.
Physicochemical Mechanism of Action
Oxygen segregation occurs when oxygen reaches the surface during the final stages of cooling after casting. This process can be caused by air currents or incomplete deoxidation.
Metallurgical Relevance & Risks in Welding
Oxygen segregation leads to local weak spots in the cast structure, which can cause cracks or failures during welding. These weak spots are especially dangerous if they are located in stress zones.
Workshop Practice & Action Instructions
To avoid oxygen segregation, deoxidation should be carried out carefully during the casting process. This can be achieved by using deoxidizing agents. Additionally, controlled cooling and minimal air currents in the casting area are important. When welding, these weak spots should be located and repaired before continuing to weld.