MIM418涡轮的射线检测及其缺陷分析

Inspection and Analysis of Defects in MIM 418 Superalloy Turbine Wheels

摘要:

采用不同的射线设备对注射成形的MIM418涡轮进行检测，并对缺陷进行了解剖，采用光学显微镜OM和扫描电镜SEM观察其形貌，和EDS确定其成分，采用MIM TAB 软件对涡轮不同部位的缺陷进行了统计分析，并研究了热等静压（HIP）对缺陷的影响。研究结果表明：胶片x射线设备比实时呈像具有更高的检测灵敏度，微焦点射线设备，不适用于MIM418涡轮得检测，X射线检测和缺陷形貌观察表明在涡轮心部易于形成裂纹，相比较心部，在叶片处的气孔型缺陷更多一些，采用HIP可大幅度降低气孔型缺陷，但裂纹并不能愈合。

Abstract:

In the present paper, some turbine wheels produced by metal injection molding (MIM) were subjected to x-ray inspection using different three x-ray equipment. An x-ray inspected turbine wheel was then cut and polished to observe defects by OM and SEM equipped with EDS. The defects existing in the blades and the center of the turbine wheels were analyzed statistically using MINI TAB software. The results show that, under the same testing condition, the film x-ray equipment has higher sensitivity than the real-time imaging x-ray. However, the microfocus x-ray testing is not suitable to the MIM418 turbine wheels due to low power. NDT and metallographic observation exposes that Maro-cracks are prone to forming in the center part of the turbine wheel, and the mi-cro-defect in term of porosity in the blade is higher than that in the center of the sintered turbine wheel, and decreases significantly after heat isostatic pressing (HIP).