Internal crack is the normal defect in hot-puncturing process,we can know internal crack is a complicated systematical problem by analyzing the causes of it.

• 内裂纹是钢管热轧穿孔中常见的缺陷,通过对内裂纹影响因素的分析,可以看出内裂纹问题实际上是个较为复杂的系统问题。