![\"gas](\"https:\/\/www.mdaturbines.com\/wp-content\/uploads\/2018\/08\/1-e1534252885628-221x300.jpg\" "\\"gas")
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An x-ray inspection was performed on the components in their as-received condition. No areas of concern were detected, and no clogging was observed on the cooling holes.<\/p>\n
An FPI inspection was performed to look for the presence of cracks. The area around the shroud radius was also evaluated for cracks.\u00a0 No major areas of concern were found during the preliminary FPI inspection.<\/p>\n
The condition of the internal coating was deemed acceptable and in good condition to operate for one more service interval. The external coating protected the external surfaces and was recommended for removal to allow a good FPI inspection of the hot gas-path surfaces.<\/p>\n
![\"gas](\"https:\/\/www.mdaturbines.com\/wp-content\/uploads\/2018\/08\/2-300x179.png\" "\\"gas")
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Microhardness readings taken at several blade locations showed a significant drop in the base material hardness where parts had been exposed to higher temperatures. These areas also showed significant degradation to the gamma prime structure under inspection by a Scanning Electron Microscope.<\/p>\n
Hardness values after heat treatment demonstrated that the GTD 111 responded well to the process and the overall blade hardness values were improved.<\/p>\n
For heat treatment, our experts utilize a vacuum heat treat furnace, where we control the heating and cooling of metals to alter their physical and mechanical properties.\u00a0 The specific heat treatments selected for a set of parts depend on a number of factors.\u00a0 Several separate heat treatment cycles are conducted throughout the course of repair including \u00a01) pre-weld solution heat treatment, 2) post-weld stress relief heat treatment, 3) coating diffusion, and 4) precipitation hardening (or aging) heat treatment.<\/p>\n
![\"vacuum](\"https:\/\/www.mdaturbines.com\/wp-content\/uploads\/2018\/08\/3-300x200.jpg\")
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Samples were removed from the blades for stress rupture testing and in the as-received condition did not meet the minimum expected strength requirements for GTD 111. The samples tested after heat treatment exceeded the minimum requirements.<\/p>\n
After the repair heat treatment, the stress rupture test results improved by roughly 100 test-hours (tested @ 1600F \/ 50KSI). This demonstrates that the repair heat treatment was able to rejuvenate the parts sufficiently to operate for one more service interval.<\/p>\n
In conclusion, our experts evaluated each component in the as-received condition and in the post-repair heat-treated condition. Improvements in the alloy mechanical properties were evaluated to determine if the two sets are candidates for a Life Time Extension (LTE) repair.\u00a0 Once established as candidates for Life Time Extension, our Experts employed repair practices to further extend the useable life of the components.<\/p>\n
MD&A\u2019s available Gas Turbine services range from full turnkey major inspections to rotor unstacking, gas turbine alignment, and control services. MD&A is a global full-service OEM alternative for services, parts, and repairs.<\/p>\n
Call our MD&A San Antonio Service Center, or our Gas Turbine Parts Service Facility today at +1 (210) 256-5000.<\/p>\n
Also, be sure to sign up for our MD&A Insight e-newsletter<\/a> delivered quarterly. Get our turbine-generator expert\u2019s case studies and tips! Fill in the sign-up form and SUBSCRIBE!<\/p>\n<\/h3>\n