Uncertainties in the Measurement of the Cleanliness of Steels
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S. Stücklin
Stephan Stücklin obtained his diploma in materials engineering from the Ecole Polytechnique Fédérale de Lausanne in 2001. An internship at Nippon Steel Corp. and a sales job at Nanosurf preceded his current position at Swiss Steel AG, where he is responsible for the metallography lab and the QM for the entire lab.
Abstract
Accredited metallography laboratories are required to estimate the uncertainty of the result of every test carried out. This presents a particular challenge in evaluating the cleanliness of a metal as usually a particle distribution – log-normal at best and represented by a tiny sample size – is truncated and split into discrete classes. Therefore, neither indirect (top-down) nor direct (bottom-up) methods succeed in estimating the uncertainty of cleanliness evaluations. For these reasons, such evaluations should be viewed through a process surveillance lens, particularly when discussing results or setting acceptance thresholds.
Kurzfassung
Akkreditierte Metallographielabors sind angehalten, für jede Prüfung die Messunsicherheit abzuschätzen und auf Anfrage anzugeben. Die Reinheitsgradprüfung stellt dabei eine Herausforderung dar, da im Normalfall eine bestenfalls log-normale Partikelverteilung abgeschnitten und diskretisiert wird. Zudem wird mit einer winzigen Stichprobe der Gesamtmenge gearbeitet. Daher lässt sich die Messunsicherheit der Reinheitsgradprüfung weder mit indirekten (top-down) noch direkten (bottom-up) Methoden abschätzen. Die Reinheitsgradprüfung hat dadurch eher den Charakter einer Prozesskontrolle, was bei der Diskussion von Prüfresultaten und der Festlegung von Grenzwerten mit in Betracht gezogen werden sollte.
About the author
Stephan Stücklin 
obtained his diploma in materials engineering from the Ecole Polytechnique Fédérale de Lausanne in 2001. An internship at Nippon Steel Corp. and a sales job at Nanosurf preceded his current position at Swiss Steel AG, where he is responsible for the metallography lab and the QM for the entire lab.
References / Literatur
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© 2016 Carl Hanser Verlag, München
Artikel in diesem Heft
- Contents
- Editorial
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- Determination of Fatigue Life and Failure Location of Vehicle Cylindrical LPG Fuel Tanks
- Coloured Metallography of Ti-6Al-4V Alloys Using Phtalocyanine Blue
- Sample Preparation of Worn Surfaces for EBSD Analysis
- Uncertainties in the Measurement of the Cleanliness of Steels
- Top-ten downloads / Picture of the month
- Top-Ten Article Downloads
- Picture of the Month
- PM-News
- PM-News
- Meeting diary
- Meeting Diary
Artikel in diesem Heft
- Contents
- Editorial
- Editorial
- Determination of Fatigue Life and Failure Location of Vehicle Cylindrical LPG Fuel Tanks
- Coloured Metallography of Ti-6Al-4V Alloys Using Phtalocyanine Blue
- Sample Preparation of Worn Surfaces for EBSD Analysis
- Uncertainties in the Measurement of the Cleanliness of Steels
- Top-ten downloads / Picture of the month
- Top-Ten Article Downloads
- Picture of the Month
- PM-News
- PM-News
- Meeting diary
- Meeting Diary
