马钢小异形坯表面纵裂纹控制工艺研究

A Study of Control Process of Surface Longitudinal Cracks of Small Beam Blank in Ma'anshan Iron and Steel Co. Ltd.

针对马钢小异形坯表面纵裂纹指数较高的问题,对小异形坯轧后裂纹与保护渣组成进行分析,且对结晶器内流场与温度场进行模拟。结果表明,保护渣变性以及小异形坯管式结晶器流场与传热不均是导致小异形坯表面纵裂纹的主要原因。针对小异形坯表面纵裂纹产生的特点,开发小异形坯保护浇注工艺以及优化结晶器均匀传热工艺,可使小异形坯表面纵裂纹指数由100 mm/m以上降至30 mm/m以下,轧后裂纹修磨率也由4%左右下降至1%以下。

In view of the problem of high surface longitudinal cracks index of small beam blank in Ma’anshan Iron and Steel Co.Ltd.,the longitudinal cracks after rolling and the composition of mold powder were analyzed,and the flow and temperature distribution in the mold were simulated.The results indicate that,the main causes of longitudinal cracks of the small beam blank are mold powder properties altered during casting,and uneven flow and heat transfer of the beam blank tubular mold.According to the characteristics of longitudinal cracks of small beam blank,the protection and pouring process of small beam blank were developed,and the tubular mold were redesigned which made heat transfer homogeneously.The surface longitudinal crack index is reduced from above 100 mm/m to less than 30 mm/m.The grinding ratio after rolling is significantly reduced from about 4%to below 1%after process optimization.