A fractured input shaft used in NASCAR racing was received for analysis to investigate the cause of failure. Results indicate the shaft fractured due to fatigue progression from an intergranular stress crack, initiated at a dot peen identification marking on the shaft.
A cracked nozzle sleeve stub from XXXX Vessel of the proprietary vaporizer system was analyzed to determine the cause of cracking.
Two blade samples of a cracked ******************* centrifugal blower impeller blade was submitted for metallurgical analysis of the cracks. The cracks in the submitted blade samples were found to have initiated at corrosion pits on the leading edge of the blades.
Two aluminized heater tubes were received for analysis to investigate the cause of failure. Unused tube material also was supplied for comparison. Results indicate that the tubes failed via hot oxidation corrosion at extreme temperatures.
Metallurgical Technologies, Inc. examined a failed superheater tube from XXXXXX X XXX Boiler #7. The ASME SA-213 Grade T11 tube had been in service for 6 to 8 years until failure. The mode of failure was short-term stress rupture due to significant overheating.
The four seized bearings submitted for metallurgical analysis were determined to have suffered deterioration of their grease to the point that it was inhibiting motion rather than enabling. The grease had turned to a thick (viscous) black sludge that was full of particulate. Electrical pitting was found in the seized bearings, especially the inner races. Signs of axial (thrust) loads were noted, mainly in the outer raceways. Larger arc strike regions were found on the balls.
A cracked 316Ti stainless steel preheater tube was analyzed to determine the failure mechanism. A second non-cracked tube section from a different elevation was also analyzed to determine the condition of the tube material.
A welded left front spindle/steering arm assembly that had fractured at the fillet weld joint between the steering arm and inner brake boss was received for analysis to determine the mode of failure.
Several concentrating still condenser tubes exhibiting pitting were received to determine the cause of pitting. Results indicate the tubes pitted initially from the inner diameter (ID) surface due to microbiological corrosion (MIC). MIC pitting initiated preferentially at the tube seam weld. Additional ID surface pits and significant pit enlargement of MIC pits due to chloride pitting were also observed. The chlorine is likely remains from the hydrochloric cleaning process
Corrosion is a phenomenon leading to exorbitant losses of materials, energy, and money by causing degradation of products, materials of construction, equipment, and necessitating increased maintenance.