在车削加工45Mn2钢管时, 发现管壁中存在类似裂纹状的有金属光泽的“亮线”线条,通过宏观和微观形貌分析、力学性能测试、压扁试验和腐蚀试验等方法分析了钢管“亮线”的形成原因。结果表明:“亮线”的微观形貌由贝氏体组织构成, 是异于钢管基体的成分偏析带, 来源于连铸坯; 这种“亮线”是一种不允许存在的缺陷, 建议炼钢厂采取措施, 提高钢坯的质量, 杜绝“亮线”缺陷的发生。

The shining lines like cracks with metallic luster were found on pipe wall of 45Mn2 steel tube when lathe machining. Macro and micro structure inspection, mechanical properties testing, flatten testing and corrosion testing methods were used to analyze the formation cause of shining line defect. The results show that the microstructure of the shining line was bainite and it was line of chemical compositions segregation, which came from the continuously cast billet. The shining line was defect that should not exist. It was recommended that steel mill took measures to improve the quality of billets and put an end to the formation of shining line defect.