NDE and Proposed Weld Overlay Procedure to Repair Shaft
When a Hydroelectric Turbine Shaft was Found Exhibiting Flaws, we were Asked to Perform an Engineering Evaluation.
The shaft had been removed and sent to an outside shop for refurbishment and installation of two new sleeves (upper and lower). Initial machining in the area of the Turbine Guide Bearing (lower sleeve position) uncovered a “knurled” surface just below the outermost shaft material – possibly indicative of a spray or weld metal build-up type of repair.
After reviewing the NDE results and determining the material of the shaft, we recommended to rebuild the shaft using a weld overlay method called Submerged Arc Welding (SAW). This is a mature, proven technology which has been employed frequently to repair both high speed rotors and low speed shafts. Part of this recommendation included further machining as described above to clean up the “near surface” inclusions prior to the weld overlay. In addition to supervising the SAW procedure, we performed a fracture mechanics analysis to determine the expected life of the shaft.
O’Donnell Consulting Engineers Performs Weld Troubleshooting / Consulting on Equipment including Shafts, Vessels, Piping and Heat Exchanger
Related Projects
– Weld Repair of Mis-machined Cast Turbine Blades
– Metallurgical Evaluation of a Damaged Compressor Bearing
– Failure Analysis of Cracked Cylinder Liner
Related Services
– Materials & Metallurgical Consulting
– Mechanical Engineering Services
Resources
– Tom O’Donnell, PE
– Blog: Failure Analysis Basics
– Publications: Pressure Vessels, Welds, Fatigue, Elevated Temperature
– Portfolio of Engineering Projects
