Liquid Metal Embrittlement in Narrow Gap Welds
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A. Neidel
joined the Gas Turbine Plant of Siemens‘ Energy Sector in 1984 and first underwent vocational training there. As a materials testing technician, one of the first fields of her professional endevours was steam turbine service, namely remaining lifetime assessment by means of the replica technique. She is a metallographer and one of the principal failure analysts in the materials testing laboratory. Her main fields of expertise comprise microstructural analyses of steel and iron castings.
Apprenticeship as a materials testing technician at the welding institute SLV Berlin-Brandenburg. After that, she studied materials science at the Berlin Institute of Technology. She graduated with a masters degree in materials science in 2012. Since November 2012 employment as engineer at the Metallography Laboratory of the Siemens Gas Turbine Works in Berlin. She has been appointed laboratory manager within the Berlin Testing Center of the Large Gas Turbine Engineering Group in 2014. Her main fields of expertise comprise failure analysis and microstructural investigations using the field emission scanning electron microscope.
Abstract
Failure analysts are sometimes surprised to find well-known metallurgical failure mechanisms at work in completely unexpected places. This contribution is an eloquent example for just such an incidental convergence of well-known failure mechanism and fabrication process where it was not reported to have previously occurred. Liquid Metal Embrittlement (LME) was observed in Narrow Gap Welds (NGW) produced for Welding Procedure Qualification (WPQ). The embrittling liquid metal was copper in this case. It is believed to have originated from copper backing used for weld pool protection. It was recommended to replace copper backing with ceramic weld pool protection.
Kurzfassung
Von Zeit zu Zeit werden Schadensanalytiker vom Auftreten allgemein bekannter metallurgischer Fehlermechanismen an völlig unerwarteter Stelle überrascht. Die vorliegende Arbeit präsentiert ein anschauliches Beispiel für einen solchen Fall, bei dem zufällig ein allgemein bekannter Fehlermechanismus bei einem Fertigungsprozess wirkt, über dessen Auftreten zuvor noch nicht berichtet wurde. In im Rahmen der Verfahrensprüfung (Welding Procedure Qualification, WPQ) hergestellten Engspaltschweißnähten (Narrow Gap Welds, NGW) konnte Flüssigmetallversprödung (Liquid Metal Embrittlement, LME) festgestellt werden. In diesem Fall handelte es sich beim versprödend wirkenden Flüssigmetall um Kupfer. Es wird davon ausgegangen, dass es von der zur Schweißbadsicherung eingesetzten Kupferunterlage stammt. Empfohlen wurde, die Kupferunterlage durch eine keramische Schmelzbadsicherung zu ersetzen.
About the authors
joined the Gas Turbine Plant of Siemens‘ Energy Sector in 1984 and first underwent vocational training there. As a materials testing technician, one of the first fields of her professional endevours was steam turbine service, namely remaining lifetime assessment by means of the replica technique. She is a metallographer and one of the principal failure analysts in the materials testing laboratory. Her main fields of expertise comprise microstructural analyses of steel and iron castings.
Apprenticeship as a materials testing technician at the welding institute SLV Berlin-Brandenburg. After that, she studied materials science at the Berlin Institute of Technology. She graduated with a masters degree in materials science in 2012. Since November 2012 employment as engineer at the Metallography Laboratory of the Siemens Gas Turbine Works in Berlin. She has been appointed laboratory manager within the Berlin Testing Center of the Large Gas Turbine Engineering Group in 2014. Her main fields of expertise comprise failure analysis and microstructural investigations using the field emission scanning electron microscope.
References / Literatur
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Artikel in diesem Heft
- Contents
- Editorial
- Editorial
- Material-property correlations for a high-alloy special steel
- Impact of surface preparation on the formation of deformation-induced α‘-martensite in a metastable austenitic steel
- Liquid Metal Embrittlement in Narrow Gap Welds
- Picture of the Month
- Picture of the month
- News
- News
- Meeting diary
- Meeting diary
Artikel in diesem Heft
- Contents
- Editorial
- Editorial
- Material-property correlations for a high-alloy special steel
- Impact of surface preparation on the formation of deformation-induced α‘-martensite in a metastable austenitic steel
- Liquid Metal Embrittlement in Narrow Gap Welds
- Picture of the Month
- Picture of the month
- News
- News
- Meeting diary
- Meeting diary
