Effect of Types of Calcium-Containing Cored Wires on the Inclusion Modification by Calcium Treatment

Calcium treatment experiments with equal calcium amounts using different calcium-containing cored wires are carried out in the laboratory to investigate the effect of calcium wire types on the modification of inclusions. Inclusions change from Al2O3(-MgO) to calcium aluminates with the feeding of calcium wires; however, the modification degrees are different. The CaO content in inclusions increases to 25.8, 34.5, and 31.0 wt%, respectively, at 1 min after the addition of pure Ca, SiCa, and AlCa. The calcium yield is the highest when using SiCa wire and is the lowest under the use of pure Ca wire. The difference in calcium yield is attributed to the increasing effect of Si or Al on the solubility of calcium in molten steel. When calcium treatment is performed using SiCa and AlCa wires, the local Si and Al content around calcium bubbles would be large, which can promote the dissolution of calcium into steel and increase the yield of calcium. From the perspective of improving calcium yield, calcium treatment with SiCa or AlCa wires is better than that with pure Ca wires. However, steel grade, ladle capacity, and calcium treatment parameters should be further considered in the actual selection of calcium-containing cored wires.