Test Type: Failure Analysis
A manufacturer of turbine engines was experiencing problems with one line of turbines. Something was causing the blades to brake loose causing catastrophic failure. The investigation centered on a new brand of bearings that were being used. The manufacturer of the bearings claimed that they were high-grade stainless steel, however, analysis by Scanning Electron Microscopy (SEM) proved otherwise.
A cross-section of the bearing was analyzed so that the O-ring and the metal would be visible. In the photograph above can be seen dark spots throughout the metal. These are places of high carbon content. Stainless steel does not contain these abnormalities. Furthermore, the circled area is rust pitted metal.
The cause of the failure in the engines was insufficiently manufactured bearings. These bearings are water-cooled and had a tendency to rust. The pitting allowed the cooling water to penetrate the turbine chamber. It only takes a few drops of water to break turbine fins that are traveling over 10,000 revolutions per minute and cause the catastrophic failures.
Test Type: Stain Analysis
On occasion it is important to identify stains. Ink, rust, paint, food and blood are only the tip of the iceberg. By utilizing numerous techniques such as Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectrometry, and physical chemistry we can determine the source of the discoloration.