Lack of Fusion
Lack of fusion defects are incomplete connections between weld metal and base material or between weld beads, resulting in missing stress, reduced strength, and increased risk of cracking.
Physical-Chemical Mechanism
Lack of fusion defects arise from incomplete diffusion of atoms between weld metal and base material or between individual weld beads. This prevents homogeneous stress distribution and leads to local stress failures.
Metallurgical Relevance & Risks in Welding
Lack of fusion can cause cracks, deformation, and reduced service life of the weld. They increase the risk of hot cracking and failure under mechanical loading.
Workshop Practice & Procedures
To avoid lack of fusion, pay attention to correct welding direction, a homogeneous weld pool, and sufficient heat input. Use appropriate filler material and ensure the weld cools over a sufficient period.