射线照相检测研究TC4钛合金铸件热等静压缺陷演变

Defects Evolvement of TC4 Titanium Alloy Castings by Radiographic Inspection

通过射线照相检测对TC4钛合金铸件内部常见缺陷及其在热等静压前后的演变进行分析,结果表明:TC4钛合金铸件内部大部分闭合孔洞类缺陷经热等静压均可消除,内部缺陷底片上显示消失;少量的夹杂类和非闭合孔洞类缺陷未压合,在底片上与热等静压前缺陷显示基本一致;个别缩孔缺陷部分压合或表面压陷,极少量的大尺寸缩孔缺陷压缩变形为线性缺陷,在底片上缺陷显示形态发生变化。由于线性缺陷的结构特征在射线照相检测时易导致影像对比度下降,进而影响缺陷的检出率,因此应在热等静压前对易产生缩孔部位进行射线照相检测并将大尺寸缩孔清除补焊,避免热等静压后缩孔压缩变形造成缺陷漏检。

In this paper,the defects evolvement of TC4 titanium alloy castings before and after hot isostatic pressing（HIP） was analyzed by radiographic inspection.The results show that most of the closed holes in castings can be eliminated by HIP and the defects will disappear on the film.A small number of inclusions and unclosed defects cannot be eliminated,and the display of the defects is nearly the same as before HIP.Few shrinkage cavity defects were partially compressed or their surface was crushed.Few large shrinkage cavity defects were deformed into linear defects,and their display on the film also changed.The structure of linear defects reduces the contrast of the images of radiographic inspection,and thus affects the detection rate of linear defects,so shrinkage cavity defects should be detected before the HIP and large size shrinkage cavities should be eliminated by repair welding to avoid the defects non-detection.