针对天钢4号板坯连铸机生产铸坯的纵裂纹缺陷,利用低倍分析、扫描电子显微镜以及测量技术,对铸坯试样和使用的设备部件进行了检测分析,揭示了纵裂纹产生的原因是铸机结晶器的锥度不稳定,导致结晶器窄边对铸坯凝固壳的支撑力降低,导致铸坯裂纹。在此基础上采取了有效措施,避免了天钢4号板坯连铸机生产的铸坯的纵裂纹缺陷。 Aiming at the longitudinal crack defects of slab produced by No.3 Slab Caster in Tiangang Iron and Steel Co., Ltd., By using low magnification analysis, scanning electron microscope and measuring technology, the slab samples and equipment components were tested and analyzed, The reason is that the taper of the mold caster is unstable, which leads to the decrease of the support force of the mold narrow side to the solidified shell of the slab, which leads to the crack of the slab. On this basis, effective measures have been taken to avoid the vertical crack defects of the slab produced by the No.4 Slab Caster.