Lamellar Tear
A lamellar tear is a layer-like separation of the base material parallel to the plate surface, caused by high through-thickness shrinkage stresses and non-metallic inclusions. It can lead to cracks and distortion.
Physical-Chemical Mechanism of Action
A lamellar tear forms through separation of the base material into layered structures parallel to the plate surface. This happens under high through-thickness shrinkage stresses and due to non-metallic inclusions like oxygen gases or dirt particles introduced during the plate forming process.
Metallurgical Relevance & Welding Risks
A lamellar tear can lead to cracks and distortion in the weld. The layered structure can change how stress is distributed in the material, creating local stress concentrations and thus crack initiation. This increases the risk of hot cracking and distortion in the finished part.
Shop Practice & Actions
To avoid lamellar tearing, control the plate forming process to minimize through-thickness shrinkage stresses. Do this by optimizing plate temperature and thoroughly cleaning the material surface. When welding, make sure the weld is done in a shielded environment to minimize non-metallic inclusions like oxygen gases or dirt particles.