Weld repair of a high pressure generator rotor for Commonwealth Edison Co. Joliet Station {number_sign}29
- IFR Engineering Co., Sugar Grove, IL (United States)
- Commonwealth Edison Co., Downers Grove, IL (United States)
A 550 Mw, high pressure (BP) generator field developed a circumferential crack in the transition formed between the main rotor body (40 inch diameter) and shaft extension (23 inch diameter) at the collector ring end after 20 years of service. Metallurgical investigation of a sample from the HP rotor revealed that the crack initiated from low cycle fatigue in the thin ligament section formed between the edge of the pole slot and the edge of a 5/8 inch diameter bolt hole. It was determined that the crack initiated at the OD surface of the BP generator shaft and propagated to a radial depth of 3.1 inch. Tooling and fixtures were developed to support the weight of the rotor during machining, welding and post weld heat treatment operations. The repair consisted of machining the crack to removal using a narrow groove (approximate groove angle of 2 degrees per side) extending, 360 degrees around the circumference of the rotor. The narrow groove was weld restored using, the automatic gas tungsten arc welding, process. The filler metal for the weld deposit, an SFA 5.28 ER 100S-1, was selected to match the chemical and physical properties of the BP rotor material. The HP rotor was classified as an ASTM A469 Class 4 forging. By performing this repair, CECo saved approximately $1.5 million in generator field replacement costs and avoided 12 to 18 months of lost generation while waiting for the replacement HP generator field.
- OSTI ID:
- 94234
- Report Number(s):
- CONF-950414-; TRN: IM9538%%207
- Resource Relation:
- Conference: 57. annual American power conference, Chicago, IL (United States), 18-20 Apr 1995; Other Information: PBD: 1995; Related Information: Is Part Of Proceedings of the American Power Conference: Volume 57-I; PB: 874 p.
- Country of Publication:
- United States
- Language:
- English
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