45号钢厚板表面边裂原因分析与控制

Analysis and Optimizing of Surface Edge Crack of 45#Heavy Plates

通过取缺陷试样进行金相分析,发现45号钢板表面裂纹区域氧化圆点密布、氧化特征明显,确定其铸坯进入加热炉之前已经存在裂纹,而进一步取铸坯缺陷试样分析可知,裂纹在连铸高温阶段已经出现,即起源于结晶器内,针对结晶器一冷水、保护渣等进行了优化改进并持续实施,使边裂缺陷下降至1%以内,验证了分析结果的可信和措施的有效性。

Surface cracks of 45#heavy plates with dense oxidation dots and obvious oxidation characteristics were observed and analyzed by adopting metallographic methods.It was confirmed that cracks appeared before the slab entered the heating furnace.Further analysis of defect samples of slabs showed that the cracks appeared in continuous casting with high temperature,that is to say originated in moulds.By optimizing and improving the first cooling system and mould powder,edge crack defects rate reduced to less than 1%,which verified the reliability of the analysis results and the effectiveness of the measures in practice.