Root pore
Root porosity is a gas pocket at the weld root, caused by residual moisture or lack of root shielding gas. It narrows the critical weld cross-section and weakens component strength.
Physico-chemical mechanism of action
Root pore occurs when gases such as hydrogen or carbon dioxide cannot be excluded from the weld root. These gases form bubbles and constrict the weld cross-section.
Metallurgical relevance & risks when welding
Root pore can lead to component failure because it severely weakens the strength of the weld. It increases stress concentration and can lead to cracks or deformation in the component.
Workshop practice & instructions
To avoid Root pore, it is crucial to ensure effective shielding gas coverage during welding. The weld should be cooled in a dry condition, and the workpiece must be cleaned carefully before heating. In case of severe gas inclusions, post-treatment with argon or helium may be necessary.