耐候钢连铸工艺的改进

分析耐候钢连铸出现的问题,认为凝固时应力过大和磷铜元素偏析造成晶界脆化是出现铸坯纵裂的主要原因;结晶器中喂稀土丝恶化保护渣性能,影响结晶器与坯壳间的润滑与传热,并使热流不均匀是连铸漏钢的主因。采用钙处理代喂稀土丝工艺,以及减缓连铸一、二次冷却强度,改进保护渣后,连铸缺陷获得极大改善。

IMPROVEMENT ON THE CC PROCESS OF WEATHER RESISTANT STEEL

The problems met during the CC process of weather resistant steel were ana- lyzed , the appearance of longitudinal crack on the cast slab was mainly caused by the large stress and the brittle crystal boundary due to the segregation of Cu and P elements during solidification. The feeding RE wire in the mould worsened the property of casting powder which affected the lubricating and heat conducting between the mould and the slab shell, moreover, the uneven heat flow resulted the break out. The quality of CC slab can be improved effectively by the measures of Ca treatment replacing the feeding RE wire, the reduction of the first and second cooling strength during the CC process and improvement of the property of casting powder.