Weld restoration of the first stage disc of a Westinghouse Model 501AA gas turbine
With the advancement of dimensional data retrieval systems, analytical tools and specialized welding techniques, along with sound metallurgical evaluation, repair technology has progressed to the point where turbonmachinery repairs can be structurally and metallurgically superior to the original design. A case in point is the weld repair of the Westinghouse Model 501AA first stage gas turbine disc. The surfaces of the disc had experienced severe corrosion damage, particularly in the fir tree blade attachment areas. The repair required a disc rim rebuild in which the circumferential root attachment area was removed by machining, restored using the mechanized Submerged Arc Welding (SAW) process and final machined to original design specifications. This paper will discuss the engineering effort used to restore the damaged gas turbine disc. Included in the engineering effort were the dimensional inspections used to restore the damaged gas turbine disc. Included in the engineering effort were the dimensional inspections used for generating machining drawings, finite element thermal and stress analyses, and a complete metallurgical evaluation to determine the appropriate weld filler material. The weld repair and heat treatment procedures will be outlined, as will be the final machining and final dimensional inspection. The materials used for this application provide excellent mechanical and metallurgical properties with improved corrosion and creep resistance for longer component life. The weld procedure has been standardized and has been performed successfully on several discs of similar design.
- OSTI ID:
- 405466
- Report Number(s):
- CONF-951208--
- Country of Publication:
- United States
- Language:
- English
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