Failure of Connecting Clamps in Electrical Terminal Blocks
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A. Neidel
completed a training as State Certified Technical Assistant for Metallography and Physical Material Analysis at Lette-Verein in Berlin. He has worked in the metallographic laboratory of the Siemens Gas Turbine Plant (Siemens-Gasturbinenwerk) Berlin for more than a decade. The key areas of his work are failure analysis and microstructural examinations using the field emission scanning electron microscope.
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
The failure of fastening elements in electrical terminal blocks was attributed to various material-related causes. While the casehardened terminal screws broke due to hydrogen embrittlement, the material-related cause of the plastic deformations of the roof-shaped washers and the stripping of the threads of the square nuts are undersizing and an insufficient strength for this particular application.
Kurzfassung
Das Versagen von Befestigungselementen in elektrischen Anschlussklemmenblöcken wurde auf unterschiedliche werkstofftechnische Ursachen zurückgeführt. Während die einsatzgehärteten Klemmschrauben infolge Wasserstoffversprödung brachen, sind die werkstofftechnischen Schadensursachen der plastischen Verformungen der Dachkantscheiben und das Abstreifen der Gewinde der Vierkantmuttern Unterdimensionierung und für den Anwendungsfall eine zu geringe Festigkeit.
About the authors
completed a training as State Certified Technical Assistant for Metallography and Physical Material Analysis at Lette-Verein in Berlin. He has worked in the metallographic laboratory of the Siemens Gas Turbine Plant (Siemens-Gasturbinenwerk) Berlin for more than a decade. The key areas of his work are failure analysis and microstructural examinations using the field emission scanning electron microscope.
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
[1] Neidel, A.; Gädicke, T.; Fischer, B.: Interner Bericht BLN MT/2017/0620, Berlin, 26.10.2017Suche in Google Scholar
[2] DIN 562: Mai 2013: Vierkantmuttern, niedrige Form, Produktklasse BSuche in Google Scholar
[3] Lange, G. (Hrsg.): Systematische Beurteilung technischer Schadensfälle. Wiley-VCH, 2001Suche in Google Scholar
[4] Pohl, M.: Wasserstoff in metallischen Bauteilen – Eine systematische Übersicht. 39. VDI-Jahrestagung Schadensanalyse – Wasserstoff in metallischen Bauteilen. Würzburg, Germany, October 8 and 9, 2013Suche in Google Scholar
[5] ASM Handbook, Volume 11: Failure Analysis and Prevention. 6. Auflage, ASM International 1998Suche in Google Scholar
[6] Böttner, J.: Schäden durch Wasserstoff in Schrauben aus hochfesten Stählen. Konstruktion 7/8, July/August 2013, pgs. IW 8 – IW 9Suche in Google Scholar
[7] Paatsch, W.: Die Rolle des Wasserstoffs in der Galvanotechnik. Galvanotechnik 12, 2005Suche in Google Scholar
[8] DIN EN ISO 4042:2001 – Galvanische ÜberzügeSuche in Google Scholar
[9] DIN EN 14399-4:06-2006: Hochfeste planmäßig vorspannbare Schraubenverbindungen für den Metallbau – Teil 4: System HV – Garnituren aus Sechskantschrauben und -muttern; Deutsche Fassung EN 14399-4:2005Suche in Google Scholar
[10] Kühn, S.; Unterumsberger, F.; Pohl, M.: …Und wenn sich der Wasserstoff nicht nur im Tank befindet? Ingenieure untersuchen Gefahren durch Wasserstoff in hochfesten Stählen. Werkstoffprüfung Rubin Sonderheft 11, January 2013, pp. 74–8Suche in Google Scholar
[11] Troiano, R.: The role of hydrogen and other interstitials in the mechanical behaviour of metals. Trans. AIME, 1960, pp. 54–80Suche in Google Scholar
[12] Dennies, D. P.: Proposed Theory for the Hydrogen Embrittlement Resistance of Martensitic Precipitation Age-Hardening Stainless Steels such as Custom 455. Journal of Failure Analysis and Prevention, ASM International, June 2013, published by Springer.10.1007/s11668-013-9684-3Suche in Google Scholar
[13] Kühn, S.: Einfluss von diffusiblem Wasserstoff auf die mechanischen Eigenschaften von hochfesten Mehrphasenstählen unter Berücksichtigung der Kaltverfestigung. Dissertation Ruhr-Universität Bochum 2011Suche in Google Scholar
[14] Pohl, M.: Personal Communication, Bochum, October 24, 2017Suche in Google Scholar
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Artikel in diesem Heft
- Contents
- Editorial
- Editorial
- Machine learning for the classification of macroscale fracture surfaces
- Vibratory polishing of multiphase CuZn30//CuZn80 diffusion pairs for electron backscatter diffraction (EBSD) characterization
- Failure Analysis
- Failure of Connecting Clamps in Electrical Terminal Blocks
- Picture of the Month
- Picture of the Month
- People
- People
- News
- News
- Meeting Dairy
- Meeting Diary
Artikel in diesem Heft
- Contents
- Editorial
- Editorial
- Machine learning for the classification of macroscale fracture surfaces
- Vibratory polishing of multiphase CuZn30//CuZn80 diffusion pairs for electron backscatter diffraction (EBSD) characterization
- Failure Analysis
- Failure of Connecting Clamps in Electrical Terminal Blocks
- Picture of the Month
- Picture of the Month
- People
- People
- News
- News
- Meeting Dairy
- Meeting Diary
