Intermittent Lack of Fusion
Tamed lack of fusion occurs when the weld metal and base metal do not fully fuse. This leads to a missing mechanical connection.
Physical-Chemical Mechanism of Action
During welding, a continuous metallic bond normally forms between the weld metal and base metal. In the case of tamed lack of fusion, however, a gap or missing fusion remains, resulting in an incomplete mechanical connection.
Metallurgical Relevance & Welding Risks
Tamed lack of fusion can lead to cracks and fractures in the weld. Mechanical strength and stress-bearing capacity are reduced, which can be dangerous especially under high loads. Additionally, corrosion can occur at the missing connection points.
Workshop Practice & Instructions
To avoid tamed lack of fusion, careful preparation of the weld joint is required. Make sure there are no dirt or paint residues before welding. Use appropriate shielding gas or shields to support fusion. In severe cases, an additional weld pass may be necessary.