Calcium inclusion modification
Calcium inclusion modification reduces anisotropy in steel welds by transforming elongated sulfides into globular calcium oxides and sulfides. This improves mechanical properties.
Physicochemical mechanism of action
Calcium reacts with elongated sulfides in the molten pool to form globular calcium oxides and sulfides. This changes the microstructure and minimizes anisotropy of mechanical properties.
Metallurgical relevance & risks in welding
Without calcium inclusion modification, elongated sulfides can cause anisotropy, impairing mechanical properties and potentially causing cracking. The modification improves toughness and hardness of the weld.
Workshop practice & instructions
Use calcium in the weld pool to minimize elongated sulfides. A typical calcium content is 0.05–0.1%. Carefully monitor the temperature and time of the weld to achieve an optimal microstructure.