Assessment of service induced microstructural damage and its rejuvenation in turbine blades

Koul, A. K.; Castillo, R.

doi:10.1007/bf02645208

Cited by 100 publications

(45 citation statements)

References 28 publications

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“…Surface microstructure of a component plays an important role in governing response of an engineering component against various surface degradation mechanisms, including corrosion, wear, stress-corrosion cracking, fatigue, corrosion-fatigue, hydrogen embrittlement etc (Yamashita et al, 1997, Koul et al, 1988, Ghosh et al, 2010, Ghosh et al, 2011, Etienne et al, 2010, Mandal et al, 2007, Liu et al, 1992. The procedure adopted for fabrication of a component (involving machining, welding and heat treatment) as well as its service conditions (stress, temperature, ambiance etc.…”

Section: Introductionmentioning

confidence: 99%

“…The procedure adopted for fabrication of a component (involving machining, welding and heat treatment) as well as its service conditions (stress, temperature, ambiance etc. greatly influence its surface microstructure (Yamashita et al, 1997, Koul et al, 1988, Ghosh et al, 2010, Ghosh et al, 2011. Therefore, non-destructive characterization of surface microstructure of as-fabricated and in-service components is very important parameter to assess their suitability to function and residual life in a given service environment (Dobmann et al, 1997, Sagar et al, 2005, Nanekar et al, 2004, Frank et al, 2000, Mathew et al, 2010, Rai et al, 2004, et al, Rai et al, 1999.…”

Section: Introductionmentioning

confidence: 99%

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Non-destructive Micro-structural Characterization of Metallic Specimens with a Portable X-ray Diffraction based Residual Stress Analyzer

Ganesh

Nagpure

Kaul

et al. 2015

SET

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Non-destructive characterization of surface microstructure of an engineering component is an important parameter to assess its fitness to function in the given service conditions. The paper describes various case studies performed in authors' laboratory involving use of portable X-ray diffraction based residual stress analysis system to examine and understand the micro-structural state of the investigated surface. A significant decrease in full width at half maximum (FWHM) of gamma(311) diffraction peak from about 4.2° in the cold worked state to about 2.5° in the annealed/surface melted state was recorded for austenitic stainless steel. In case of 0.4% carbon steel there is sharp increase in FWHM of alpha(211) diffraction peak from about 2° in the as received condition to about 5-6° in the laser hardened condition. Crystallographic texture developed during electro-plating of chromium on stainless steel, could be detected from the strong intensity of alpha (211) peak of chromium at about 19° to the surface normal with respect to all other X-ray inclination angles (ѱ) during residual stress measurement. The results show that FWHM and intensity variation of the diffraction peak are two sensitive parameters for characterization of surface microstructure. Change in FWHM has been used to detect machining-induced cold deformation and evolution of re-crystallized grains in austenitic stainless steel and formation of hard martensite in laser transformation hardened ferritic steel. Variation in the intensity of diffracted peak with respect to X-ray inclination angle provided valuable information regarding crystallographic texture in hard chrome plated deposits.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Non-destructive Micro-structural Characterization of Metallic Specimens with a Portable X-ray Diffraction based Residual Stress Analyzer

Ganesh

Nagpure

Kaul

et al. 2015

SET

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“…The implementation of the rejuvenating procedures, such as solution-and-aging heat treatment and Hot Isostatic Pressing (HIP) has proven to be able to restore even severely overaged blade microstructure and properties to a virtually ''as-new'' condition ( Ref 1,4,[7][8][9][10][11]. They are currently employed successfully throughout the industry.…”

Section: Introductionmentioning

confidence: 99%

“…Extensive studies have shown that a prolonged thermal and stress exposure causes ''overaging'' of the microstructure (c¢-phase coarsening and coalescence, formation of continuous secondary M 23 C 6 carbide films on the grain boundaries, primary MC carbide degeneration, TCP phase formation), which has detrimental effects on the componentÕs properties and, consequently, service life (Ref [1][2][3][4][5][6].…”

Section: Introductionmentioning

confidence: 99%

A Comparison of Aging Kinetics of New and Rejuvenated Conventionally Cast GTD-111 Gas Turbine Blades

L'vova¹

2007

J. of Materi Eng and Perform

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Two industrial gas turbine blades made from a conventionally cast Ni-base superalloy GTD-111, one new and the other rejuvenated, were removed from the same machine after a particular operational cycle for an examination in order to determine the effect of rejuvenation on the materialÕs behavior during service. It was found that service-induced changes in the microstructure, such as c¢-phase coarsening and coalescence, excessive grain-boundary secondary M 23 C 6 carbides formation, and primary MC carbides decomposition, were noticeably more advanced in the rejuvenated blade. The stress-rupture life of the rejuvenated blade decreased significantly compared to that of the new blade after the same number of hours in service. The cause of this decrease appears to be related to a release of additional amounts of carbon and carbideforming elements into the matrix during rejuvenating heat treatment as a result of the primary MC carbide decomposition.

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“…No all-inclusive statement can be made concerning the most desirable type and morphology of carbides [10,11]. In general optimum high temperature properties are obtained when M 23 C 6 is present as discrete particles distributed uniformly along the GBs [12][13][14].…”

Section: Introductionmentioning

confidence: 99%

Evolution of Grain Boundary Precipitates in a Directionally Solidified Ni-base Superalloy during High Temperature Creep

Wang¹,

Liu²,

Zhang³

et al. 2012

Superalloys 2012 (Twelfth International Symposium)

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Assessment of service induced microstructural damage and its rejuvenation in turbine blades

Cited by 100 publications

References 28 publications

Non-destructive Micro-structural Characterization of Metallic Specimens with a Portable X-ray Diffraction based Residual Stress Analyzer

Non-destructive Micro-structural Characterization of Metallic Specimens with a Portable X-ray Diffraction based Residual Stress Analyzer

A Comparison of Aging Kinetics of New and Rejuvenated Conventionally Cast GTD-111 Gas Turbine Blades

Evolution of Grain Boundary Precipitates in a Directionally Solidified Ni-base Superalloy during High Temperature Creep

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