连铸坯的中心偏析和疏松缺陷形态经轧制后会发生演化，合理选择轧制压缩比可以达到减轻或消除铸坯缺陷的效果。利用宏观检验、硬度测试、金相检验和密度测定等方法对典型的合金钢和普碳钢两种300 mm厚连铸坯经不同压缩比轧制后其中心偏析和疏松缺陷的形态演化进行了分析。结果表明：在常规轧制工艺下，当轧制压缩比小于4时，连铸坯仅在板厚的上、下1/3厚度位置发生明显塑性变形，中心部位的偏析和疏松缺陷形态不会发生变化。压缩比达到5以上时，1.5级的中心疏松缺陷才得以轧合，但1.5级的中心偏析缺陷只能适度减轻。

The segregation and shrinkage in the centre of the continuous casting billet can be evolved and deformed after rolling. The defect in the casting blank can be reduced and eliminated by using proper rolling compression ratio. The two kinds of 300 mm thick continuous casting billets of typical alloy steel and carbon steel rolled with different ratios. And the shape of the segregation and shrinkage in the continuous casting billet was analyze by using macro examination,hardness testing,metallographic examination and densitometry. The results showed that when the compression ratio was less than 4,plastic deformation can be found in the depth of 1/3 thickness from the surface of the casting blank under routine rolling process and the segregation and shrinkage in the centre can not be improved;when the compression ratio was larger than 5,the shrinkage in the centre(grade 1.5) can be rolled into conjunction,but the segregation in the centre can be reduced only.