Overlap Defect

Physicochemical Mechanism of Action

During welding, the metal near the weld edge flows. If it cools too quickly or the temperature is too low, the metal remains unbonded and flows over the edge. This causes a sharp notch on the outside of the weld.

Metallurgical Relevance & Risks in Welding

Edge overlap results in a lack of metallurgical bonding, which can lead to cracks and breakage at the edge of the weld. This increases susceptibility to hot cracking and reduces mechanical strength.

Workshop Practice & Instructions

To avoid edge overlap, ensure sufficient melting time and controlled cooling. Use a suitable backing (e.g., a backing strip) and ensure the weld edge is clean. For heavy steels, higher melting temperature or slower cooling may help.