ASNT NDT Library - AutomatedNonDestructiveEvaluationofSpotWeldsusingtheImagingAnalysesoftheResidualMagneticFluxDensi

Resistance spot welding is due to its high reliability and economy one of the most widely used welding methods in the automotive and railway industries. The high-quality assurance requirements in these areas call for reliable nondestructive testing (NDT) methods of the spot welds. The nugget is localized between the sheet metals and therefore not directly measurable from outside. This aspect continues to pose a major challenge for non-destructive quality assurance, especially due to the increasing diversity of used steel alloys in car body manufacturing. At the Technische Universität Dresden, Germany, the imaging analyses of the residual magnetic flux density has been developed for NDT of spot welds. Up until now, the manual evaluation of the measurement results is timeconsuming and subjective. In order to achieve greater reliability and to minimize evaluation times, an algorithm for automated evaluation has been developed. In order to evaluate the quality of the algorithm, the results are compared with NDT and destructive measurements of the same samples. For these samples, typical automotive steel combinations for spot welding were used. This paper will show the measuring concept of the imaging analyses of the residual magnetic flux density for NDT of spot welds and presents the high potential of using an automated non-destructive evaluation algorithm for NDT of spot welds.

(1) Deutscher Verband für Schweißen und verwandte Verfahren e.V., 2000, “Widerstandspunkt-, Buckel- und
Rollennahtschweißen von Stahlblechen bis 3 mm mit metallischen Überzügen.”, (Technical Bulletin), DVS
2920.
(2) Deutscher Verband für Schweißen und verwandte Verfahren e.V., 2017, “Prüfen von
Widerstandspressschweißverbindungen Zerstörungsfreie Prüfung.”, (Technical Bulletin), DVS 2916-5.
(3) Füssel, U., Mathiszik, C., and Zschetzsche, J., 2019, “Zerstörungsfreie Charakterisierung der
Anbindungsfläche beim Widerstandspress-schweißen durch bildgebende Analyse der Remanenzflussdichte.”,
(Non-destructive characterization of spot welds by imaging analysis of the residual magnetic flux density)
Schlussbericht. Technische Universität Dresden, Dresden.
(4) DIN Deutsches Institut für Normung e.V., 2015, “Widerstandsschweißen – Verfahren zum Punktschweißen
von niedriglegierten Stählen mit oder ohne metallischem Überzug.”, (Resistance welding – Procedure for spot
welding of uncoated and coated low carbon steels), ISO 14373.
(5) Reinhardt, T., 2018, “Erarbeitung eines Algorithmus zur automatisierten Auswertung der Messergebnisse der
bildgebenden Analyse der Remanenzflussdichte.”, (Development of an automated evaluation method for
measurement results of the imaging analysis of the residual magnetic flux density) Diplomarbeit. Technische
Universität Dresden, Dresden.
(6) DIN Deutsches Institut für Normung e.V., 2003, “Widerstandsschweißen - Zerstörende Prüfung von
Schweißverbindungen - Brucharten und geometrische Messgrößen für Widerstandspunkt-, Rollennaht- und
Buckelschweißungen.”, (Resistance welding - Destructive tests of welds - Failure types and geometric
measurements for resistance spot, seam and projection welds (ISO 14329:2003)), ISO 14329.
(7) Mathiszik, C., Reinhardt, T., Zschetzsche, J., and Füssel, U., 2018, “NDT of spot welds by imaging analysis of
the residual magnetic flux density – Investigation on the influence of electrode indentation on the measurement
results.”, Materials Testing Vol. 60 No. 12 2018: pp. 1179–1183. DOI 10.3139/120.111262.
(8) voestalpine Stahl GmbH, 2017, “chemische Analyse und mechanische Kennwerte der gelieferten
Versuchswerkstoffe für IGF 19.208.”, (chemical analysis and mechanical characteristics of the supplied
experimental materials for IGF 19.208).
(9) Metall Jobst, 2019, “Unlegierter Stahl DC04 W.-Nr. 1.0338: Techn. Info unleg. Stahl.”, URL
https://www.metall-jobst.de/media/pdf/17/d1/6d/dc04.pdf.
(10) Salzgitter Flachstahl GmbH, 2014, “22MnB5 Borlegierte Vergütungsstähle.”, Salzgitter.
(11) Kaars, J., Mayr, P., and Koppe, K., 2018, “Determining Material Data for Welding Simulation of
Presshardened Steel.”, Metals Vol. 8 No. 10 2018: p. 740. DOI 10.3390/met8100740.
(12) Wink, H.-J. and Krätschmer, D., “Charakterisierung und Modellierung des Bruchverhaltens von
Punktschweißverbindungen in pressgehärteten Stählen: Teil II - Simulation des Schweißprozesses.”. 11. LSDYNA
Forum.

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