Root concavity
Sucking in of the weld root inward results in a concave surface below the weld, which reduces the effective weld thickness and cross-sectional area.
Physical-Chemical Mechanism of Action
Pulling in of the weld root deforms the metal near the root, resulting in a concave surface below the weld. This impairs the strength and load-bearing capacity of the weld.
Metallurgical Relevance & Welding Risks
A local root concavity defect can reduce the effective weld thickness, affecting the mechanical properties and load-bearing capacity of the weld. This increases the risk of cracks and deformation under load.
Workshop Practice & Action Guidelines
To avoid root concavity, pay attention to correct welding direction and sufficient weld volume. Ensure the weld is straight and no uneven stresses develop. If root concavity is suspected, carry out a microscopic examination.