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Metallurgical Failure Investigation of Combustion Chamber Leakage in a Heavy-duty Gas Turbine Engine

Schadensuntersuchung einer Brennkammerleckage in einer Großgasturbine
  • A. Neidel , T. Gädicke

    Tobias Gädicke was born in 1986 and joined the Siemens Energy Sector in 2005 as apprentice in the Berlin Gas Turbine Works. As materials testing technician, his main field of expertise is metallographic target preparation of laserdrilled holes in turbine blading. Also, he is expert in the field of portable metallography by means of the replica technique with both putty and replica foils which he regularly applies to microstructural analyses of large gas turbine casings made of ductile iron and steel castings. He is a lecturer in the DGM seminar on portable metallography. Metallurgical failure analysis of gas turbine engine hot gas path components are another field of expertise of his.

    , S. Riesenbeck and S. Wallich

    Sebastian Wallich was born in 1981 and joined the Berlin gas turbine plant in 2000 as an apprentice. He works as a materials tester in the metallographic laboratory where his area of expertise is, first and foremost, the metallographic investigation of components of large gas turbine housings made of cast iron and cast steel materials, but also the target preparation of laser drilled holes in turbine blades. His field of activity furthermore comprises failure analyses on power plant gas turbines. His latest field of technological endevour is industrial-scale computed tomography, that he mainly uses for quality control of additively manufactured components. He has been acting laboratory manager since October 2017.

From the journal Practical Metallography

Abstract

In this contribution, a case study is presented describing the failure of a combustion chamber assembly in a non-OEM (Original Equipment Manufacturer) gas turbine engine used for power generation. It showed how even advanced fabrication methods, such as Electron Beam (EB) welding, could trigger fatigue fracture, even if there are no material defects, no weld imperfections, no fabrication flaws, and even if everything is within specified limits. As is so often the case in component failures, the fact that failures occur anyway, despite the absence of out-of-spec material properties, and even though there were no fabrication flaws, is attributable to the design; which is often not sturdy enough to withstand unexpected dynamic loading.

Kurzfassung

Der vorliegende Beitrag präsentiert eine Fallstudie zur Beschreibung eines Schadensfalls, der in der Brennkammerbaugruppe einer nicht mit Originalteilen ausgerüsteten Turbine zur Stromerzeugung auftrat. Es zeigte sich, dass sogar fortschrittliche Fertigungsmethoden wie z. B. Elektronenstrahlschweißen (oder EB-Schweißen, electron-beam welding) Schwingbrüche einleiten können, auch wenn keine Materialfehler, Herstellungsfehler oder Unregelmäßigkeiten in den Schweißnähten vorliegen und sogar alle festgelegten Grenzwerte eingehalten wurden. Dennoch kommt es immer wieder zu Versagensfällen, auch wenn die Werkstoffeigenschaften den Spezifikationen entsprechen und keinerlei Herstellungsfehler vorliegen. In solchen Fällen ist das Bauteilversagen auf die konstruktive Gestaltung zurückzuführen, die oftmals nicht genügend Stabilität bietet, um einer unerwarteten dynamischen Beanspruchung standzuhalten.

About the authors

T. Gädicke

Tobias Gädicke was born in 1986 and joined the Siemens Energy Sector in 2005 as apprentice in the Berlin Gas Turbine Works. As materials testing technician, his main field of expertise is metallographic target preparation of laserdrilled holes in turbine blading. Also, he is expert in the field of portable metallography by means of the replica technique with both putty and replica foils which he regularly applies to microstructural analyses of large gas turbine casings made of ductile iron and steel castings. He is a lecturer in the DGM seminar on portable metallography. Metallurgical failure analysis of gas turbine engine hot gas path components are another field of expertise of his.

S. Wallich

Sebastian Wallich was born in 1981 and joined the Berlin gas turbine plant in 2000 as an apprentice. He works as a materials tester in the metallographic laboratory where his area of expertise is, first and foremost, the metallographic investigation of components of large gas turbine housings made of cast iron and cast steel materials, but also the target preparation of laser drilled holes in turbine blades. His field of activity furthermore comprises failure analyses on power plant gas turbines. His latest field of technological endevour is industrial-scale computed tomography, that he mainly uses for quality control of additively manufactured components. He has been acting laboratory manager since October 2017.

References / Literatur

[1] Neidel, A.; Gädicke, T.; Riesenbeck, S.; Wallich, S.: Internal Report BLN MT/2018/0533, Berlin, July 30, 2018Search in Google Scholar

[2] DIN EN ISO 13919Search in Google Scholar

Received: 2020-03-03
Accepted: 2021-10-11
Published Online: 2021-12-30

© 2021 Walter de Gruyter GmbH, Berlin/Boston, Germany

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