Oxygen-induced pores
Oxygen-induced porosity occurs from the reaction of carbon and dissolved oxygen in the weld pool to form carbon monoxide. It impairs the load-bearing capacity of the weld.
Physicochemical mechanism of action
Carbon molecules react with dissolved oxygen in the molten weld pool to form carbon monoxide (CO). This process consumes oxygen and forms pores.
Metallurgical relevance & risks in welding
Oxygen-induced porosity reduces the strength and mechanical properties of the weld. It can lead to cracks and deformation, especially under load. A high number of pores can also reduce the toughness of the material.
Workshop practice & action instructions
To avoid oxygen-induced porosity, it is important to minimize the oxygen content in the weld pool. This can be achieved by good deoxidation, e.g., by using silicon or other deoxidizing agents. Sufficient cooling control and careful cooling of the weld also help reduce pore formation.