Lamellar tearing
A lamellar tear is a step-like crack in the material, parallel to the rolling plane. It results from high shrinkage-induced tensile stresses in the through-thickness direction.
Physical-Chemical Action Mechanism
A lamellar tear forms when the material contracts heavily during cooling and builds up high stresses. These stresses lead to tensile separations in the thickness direction, which propagate parallel to the rolling plane and appear step-like.
Metallurgical Relevance & Risks in Welding
A lamellar tear can cause severe mechanical loads and endanger the workpiece. It can also reduce the service life of components and lead to unwanted failures. With improper handling during welding, such as cooling too fast or too high a stress state, the likelihood of a lamellar tear increases.
Workshop Practice & Action Instructions
To avoid lamellar tears, it is important to ensure controlled cooling of the welded part. This can be achieved by using cooling water or cooling gas. The rolling plane should remain protected during welding and not directly hit the workpiece. Some tools like the lamellar tear protection ring can help minimize these stresses.