Root defect
Root defects are irregularities in the weld root, such as incomplete penetration or missing root reinforcement. They compromise the leak tightness and integrity of the weld.
Physical-Chemical Mechanism of Action
Root defects occur when not enough energy is introduced into the materials during the welding process. This leads to incomplete penetration or a lack of root structure formation. The incomplete bonding of metals at the root can allow oxygen in, which can lead to corrosion and cracking.
Metallurgical Relevance & Risks in Welding
Root defects compromise the tightness of the weld, which can lead to leaks or cracks. They can also impair mechanical properties such as strength and toughness. In severe cases, this can lead to a complete failure of the component.
Workshop Practice & Action Guidelines
To avoid root defects, it is important to ensure that the welding energy is sufficient and evenly distributed. This can be achieved by correct setting of welding parameters such as voltage, current, and time. Careful pre-treatment of the workpiece and adequate cooling are also crucial. In case of suspicion, the weld structure should be inspected with a microscope.