Turbine rotors are among the most critical and highly stressed components in steam power plants. Although relatively few instances of catastrophic rotor bursts have occurred, they have resulted in lengthy forced outages and severe economic penalties to the affected utilities. To forestall the possibility of a catastrophic burst, utilities will retire the rotors affected, generally to the original equipment manufacturer's (OEM's) recommendations. The criteria and methodology for determining which rotors should be retired are proprietary and vary among manufacturers. If utilities could extend the life of these rotors by 10-20 years, then substantial savings would be made. The principal method for extending their life is weld repair and over the last 20 years, there has been a substantial increase in the number of repairs combined with the complexity of repair adopted. This project was designed to evaluate the relationship between microstructure and properties of welds on ex-service steam turbine rotor steels, after applying appropriate welding parameters and weld bead deposition sequence to minimise heat input and produce acceptable microstructures. From the project work, it is clear that the LP, IP and HP ex-service rotor forgings selected were representative of UK manufactured rotor forgings. Although never intended for weld repair, NP have demonstrated their ability to repair these steels successfully and produce weldments with acceptable microstructures and mechanical properties.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:638208 |
| Date | January 1999 |
| Creators | Mitchell, K. C. |
| Publisher | Swansea University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
Page generated in 0.0062 seconds