Study and Application of Electrical Resistivity and Other NDT Techniques for Flaw Detection in Powder Metal Parts

摘要

Nondestructive testing of powder metal parts is often challenging due to the porous and non-uniform nature of the material. However, a few techniques including electrical resistivity, resonant inspection and eddy current have shown promising results over the past few years. In this study, a review of the main concepts and key features of these techniques is first presented. Secondly, it investigates extensively for density measurement and crack characterization the electrical resistivity technique using a four point probe on test samples made under well controlled laboratory conditions. This NDT technique has been chosen because it is probably the only technique capable of testing various sizes of cracks in both green and sintered parts. Third, a comparative study is carried out on these techniques establishing their capacity to detect cracks in different locations of a typical P/M component produced industrially. These industrial parts have finally been tested by metallographic examinations.