中碳结构钢厚板边裂分析与优化

Analysis and Optimizing of Edge Crack of Heavy Medium Carbon Plates

45号中碳结构钢板边部裂纹属于常见表面缺陷,对钢板的成材率和效益有直接影响。通过取缺陷试样进行金相分析,发现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。

The edge crack of 45 medium carbon structural steel plate is a common surface defect, which has a direct impact on the yield and benefit of steel plate. Defect samples were analyzed through metal-lographic methods, and the surface crack of 45 medium carbon structural steel plate with dense oxidation dots and obvious oxidation characteristics was found. It was confirmed that there were cracks before the slab enters the heating furnace. Further analysis of defect samples showed that the cracks had appeared in the high temperature stage of continuous casting, that is, they origi-nated in the mold. The optimization and improvement for first cooling system and mold powder were carried out, and the edge crack defects were reduced to less than 1%, which verified the re-liability of the analysis results and the effectiveness of the measures.