Mechanisms of Improving Creep Rupture Lives by Re-Heat-Treatments

Dennison, J.P.; Wilshire, B.

doi:10.1016/b978-0-08-022138-0.50093-9

Cited by 2 publications

(2 citation statements)

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“…Full rejuvenation processing of components has a long history of success in the turbine industry. As early as 1979, repair companies, such as Liburdi Turbine Services, began to publish papers and implement rejuvenation repairs on turbine components made of X750 and U500 [4,19]. Shortly thereafter, full rejuvenation cycles were developed for IN700, IN738, and U520 superalloys [20,21].…”

Section: Service Experiencementioning

confidence: 99%

“…The first studies showing that the creep life of superalloys could be extended were performed on Nimonic 80 during the 1960's [2]. Further studies during the 1970's, examining the effects of heat treatments on higher strength alloys, showed that it was possible to achieve substantial restoration of creep properties through the use of appropriate heat treatment cycles [3,4]. The term "rejuvenation" was first adopted in 1977, when the techniques, including hot isostatic pressing, were first used to restore service exposed turbine blades to a serviceable condition [5].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Practical Experience With the Development of Superalloy Rejuvenation

Liburdi¹,

Lowden²,

Nagy³

et al. 2009

Volume 4: Cycle Innovations; Industrial and Cogeneration; Manufacturing Materials and Metallurgy; Marine

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Material degradation is one of the primary causes of gas-turbine hot section component retirement. This is characterized by microstructural aging and subsequent loss of creep strength. Under the same temperature conditions, the longer components remain in service, the more microstructural degradation occurs. This can be evaluated both through microscopy and stress-rupture tests, quantifying the material strength under high temperature, constant load creep conditions. In an effort to extend component life and reduce replacement part costs, material rejuvenation processes have been developed and implemented over the past few decades. In total over 35 commercial superalloy rejuvenation processes were studied and it was found that many alloys can be successfully rejuvenated but others pose a greater challenge. Issues of grain growth in forged turbine components and recrystallization in single crystal components impose limits on rejuvenation processes and are areas of ongoing development. The feasibility, successes and limitations of material rejuvenation are reviewed in this paper with a particular focus on the following superalloys: GTD111, IN738, and Nimonic 115. Examples of microstructure and stress-rupture life of turbine components in both the service-exposed and rejuvenated condition are presented. Component microstructure is shown to be restored, and the stress-rupture life following rejuvenation is returned to a condition fit for continued service.

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Section: Service Experiencementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%