Overlap
Weld overlap is cold weld metal that lies on the surface of the base metal without fusion. This creates a sharp notch at the weld edge and increases crack susceptibility.
Physical-Chemical Mechanism of Action
Weld overlap occurs when weld metal is pressed onto the base material without melting it. The weld metal lays over the surface and deforms to form the overlap.
Metallurgical Relevance & Risks in Welding
The sharp notch at the weld toe can lead to cracking, especially when the material is under mechanical stress. The lack of fusion also means that no improvements in mechanical properties occur through diffusion or crystal structure changes.
Workshop Practice & Instructions
Use weld overlap for low-stress applications and when quick assembly is required. Make sure the weld metal is well positioned and pressed to achieve a uniform overlap. Avoid using this technique in areas with high mechanical stress.