Abstract: The mechanism of surface longitudinal cracks of 200 mm x 1 260 mm cast slab of 1.5% ~ 2.5% Al steel 20Mn23AlV has been studied. The results show that the surface longitudinal crack of steel 20Mn23AlV cast slab is related to the denaturation of mold flux. The mold flux added 5.49% Li₂O can greatly improve the stability of the physical and chemical indexes of the mold flux during the casting process, and it is favourable to reduce the occurrence probability of cast slab longitudinal surface crack from 23.8% to below 0.3% .

摘要： 研究了 1.5%～2.5% Al的20Mn23AlV钢200 mm × 1260 mm铸坯表面纵裂纹产生机理。结果表明:20Mn23AlV表面纵裂纹与结晶器保护渣变性有关。保护渣渣中加入5.49%的Li₂O大幅提高了该钢种浇注过程保护渣理化指标的稳定性,且有利于将该钢种连铸坯表面纵裂发生几率由23.8%降至0.3%以下。

关键词: 铸坯, 纵裂, 保护渣变性, 高铝钢20Mn23AlV