Discoloration on Laser Welds of AISI 321 Tubes
-
A. Neidel
,
J. Rockel
completed a training as State Certified Technical Assistant for Metallography and Physical Material Analysis at Lette-Verein in Berlin. After a few years at Siemens AG in the high voltage department, she is now an employee in the laboratory of the Siemens Gas Turbine Plant in Berlin. Her main areas of work are various preparation methods of metallic components, damage analysis, structure characterization, especially with regard to heat treatment, as well as assessments of welded joints and various coatings.
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.
Abstract
In this contribution, a fabrication problem is discussed, related to Laser Beam Welding (LBW). Strictly speaking, the case study presented herein does not constitute a failure as such, since the subject components never made it to component service. In the narrow sense of the word, a component failure happens if and when a part does no longer serve its proper function. This is definitely not the case in the study put forward in this paper. However, one could argue that a product that cannot be marketed for lack of certain properties, or because of certain shortcomings, is rendered worthless for the manufacturer and this, in turn, could be considered a failure. In this case study, the issue of discoloration on the surfaces of welded austenitic stainless steel is discussed. This is a well-known and well-researched fabrication problem. Dependent upon service conditions of affected parts, discoloration might be detrimental to the normally outstanding corrosion resistance of this class of high-alloy steels.
Kurzfassung
In dieser Arbeit wird ein mit dem Laserstrahlschweißverfahren (Laser Beam Welding, LBW) in Zusammenhang stehendes Fertigungsproblem diskutiert. Streng genommen ist der hier vorgestellte Fall nicht mit einem Versagensfall als solches gleichzusetzen, da die entsprechenden Bauteile niemals im Einsatz waren. Im engeren Sinn des Worts handelt es sich um ein Bauteilversagen bzw. einen Ausfall, falls und sobald ein Teil nicht mehr seine ordnungsgemäße Funktion erfüllt. Bei der in diesem Beitrag vorgestellten Untersuchung ist das definitiv nicht der Fall. Man könnte allerdings argumentieren, dass ein Hersteller eines Produkts es als Ausfall ansehen könnte, wenn sein Produkt, das mangels bestimmter Eigenschaften oder aufgrund bestimmter Mängel nicht vertrieben werden kann, wertlos wird. Diese Untersuchung beschäftigt sich mit dem Problem der Anlauffarben auf Oberflächen von geschweißtem rostfreiem austenitischem Stahl. Dabei handelt es sich um ein bekanntes und gut untersuchtes Fertigungsproblem. Anlauffarben können sich, je nach Einsatzbedingungen der entsprechenden Teile, negativ auf die normalerweise hervorragende Korrosionsbeständigkeit dieser Klasse von hochlegierten Stählen auswirken.
About the authors
completed a training as State Certified Technical Assistant for Metallography and Physical Material Analysis at Lette-Verein in Berlin. After a few years at Siemens AG in the high voltage department, she is now an employee in the laboratory of the Siemens Gas Turbine Plant in Berlin. Her main areas of work are various preparation methods of metallic components, damage analysis, structure characterization, especially with regard to heat treatment, as well as assessments of welded joints and various coatings.
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.
References / Literatur
[1] Ehrich, T.: Personal communication, Berlin, September 22, 2020Search in Google Scholar
[2] Bruck, J.: Personal communication, Berlin, September 22, 2020Search in Google Scholar
[3] Reinkensmeier, I.: Personal communication, Berlin 2013Search in Google Scholar
[4] Neidel, A., Fischer, B.: Internal Report BLN MT/2020/0602, Berlin, September 24, 2020Search in Google Scholar
[5] Hoffmann, R.: Personal communication, Berlin, September 22, 2020Search in Google Scholar
[6] ASM Handbook, Vol. 11: Failure Analysis and Prevention, Sixth printing, American Society for Metals, Handbook Committee, 1998Search in Google Scholar
[7] VDI-Richtlinie VDI 3822Search in Google Scholar
[8] Neidel, A. (Hrsg.): Handbuch Metallschäden. 2. Auflage, Carl Hanser Verlag München Wien 2012Search in Google Scholar
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Articles in the same Issue
- Inhalt
- Editorial
- Editorial
- Characterization and comparison of cobalt-base and nickel-base alloys with iron-base intermetallic hard alloys used in wear protection
- Characterization of microstructure and magnetic properties of 3D printed bonded magnets made by fused deposition modeling
- Microstructural analysis of the cast and melt-spun high entropy noble alloy Ag20Pd20Pt20Cu20Ni20
- Failure Analysis
- Discoloration on Laser Welds of AISI 321 Tubes
- Picture of the Month
- Picture of the Month
- News
- News
- Meeting Diary
- Meeting Diary
