Localized Fusion Defect
A local lack of fusion is a point interruption of the fusion bond at the weld edges, caused by torch instability or magnetic arc blow. This results in a missing bond and increases the risk of cracks.
Physical-Chemical Mechanism of Action
A local lack of fusion occurs when the arc is unstable or magnetic blow disrupts the molten pool. This results in a lack of bonding between the metal particles at the weld faces.
Metallurgical Relevance & Welding Risks
A local lack of fusion increases the risk of cracks and brittleness in the weld. The lack of bonding can lead to a weak spot that is prone to bending or cracking under mechanical load.
Workshop Practice & Action Instructions
To avoid lack of fusion, ensure arc stability and minimize magnetic blow. Use appropriate shielding and perform careful pre-cleaning of the workpieces. If lack of fusion is detected, repair or re-welding is required.