大型GCr15锻件超声波检测密集型缺陷的成因

The Cause of Cluster of UT Indications of GCr15 Heavy Steel Forgings

摘要: 在超声波检测大型GCr15锻件(冶炼路径：EAF-LF-VD-铸锭-热送-锻造;首次生产锻比6∶1，改锻锻比为5∶1，直径 650 mm)过程中，探出纵向的超声波密集型缺陷。对其定位解剖，且用金相、扫描电镜和能谱分析等方法进行分析。结果表明：大型轴承钢锻材中心区域存在严重的碳偏析是导致GCr15锻件出现超声波的衰减与反射的原因。

Abstract: Means such as Macroetch Testing and Micrographic examination, SEM and XPS were used to analyze the cluster of UT indications of GCr15 Heavy steel Forgings (press rate: 4∶1,  650 mm). The results showed that the main cause of the cluster of indications was many segregated spots of(Fe3C，α-Fe) structure. The spots were herein defined as cluster of UT indications in the forgings.