SS400钢连铸板坯在生产检验中常出现表面纵裂缺陷。对有裂纹的连铸板坯进行了高温塑性试验、低倍、金相组织和夹杂物分析。结果表明,钢水中硫含量高、钢中存在夹杂物、连铸板坯坯壳厚度不均匀、结晶器锥度和矫直温度不合理均可引起连铸板坯表面纵裂。提出了避免连铸板坯产生表面裂纹的措施。 SS400 steel continuous casting slab often appear in the production of surface longitudinal cracking defects. The cracked continuous casting slab was subjected to high temperature plasticity test, low magnification, microstructure and inclusions analysis. The results show that the high sulfur content in the molten steel, inclusions in the steel, continuous casting slab shell thickness unevenness, mold taper and straightening temperature can cause unreasonable longitudinal slab surface cracking. Proposed to avoid the continuous casting slab surface cracking measures.