TY - CONF A1 - Rethmeier, Michael A1 - Suwala, Hubert ED - Wieland, H.-J. ED - Brockmann, S. T1 - Development of a test method for determining the cracking susceptibility of resistance spot welded high strength steel sheets T2 - SCT2014 - 4th International conference on steels in cars and trucks CY - Braunschweig, Germany DA - 2014-06-15 KW - Resistance spot welding KW - Advanced high strength steel KW - Welding cracks KW - Susceptibility to cracking KW - Hot cracking KW - Test method PY - 2014 SN - 978-3-514-00813-7 SP - 483 EP - 490 PB - Verl. Stahleisen GmbH CY - Düsseldorf AN - OPUS4-32548 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rethmeier, Michael A1 - Suwala, Hubert ED - Bleck, W. ED - Raabe, D. T1 - Influence of crack-imperfections on mechnical properties of resistance spot welded ferritic-austenitic steel sheet combinations T2 - 2nd HMnS -2nd International conference on high manganese steels 2014 CY - Aachen, Germany DA - 2014-08-31 KW - Resistance spot welding KW - Frequency KW - Stiffness KW - Advanced high strength steels KW - FeMn-steels KW - Cracking KW - Defects PY - 2014 SP - A-107, 1-5 AN - OPUS4-32549 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Myrach, Philipp A1 - Jonietz, Florian A1 - Meinel, Dietmar A1 - Suwala, Hubert A1 - Ziegler, Mathias T1 - Calibration of thermographic spot weld testing with X-ray computed tomography N2 - The paper presents an attempt for the calibration of an active thermography method that is suitable for the non-destructive evaluation of spot welds. Nowadays, the quality of spot welds is commonly characterised by the application of random chisel tests, which are time consuming, expensive and destructive. Recently a non-destructive testing method by means of active thermography was proposed that relies on the fact that the mechanical connection formed by the spot weld also serves as a thermal bridge between the two steel sheets joined in the welding process. It is shown in this paper that this thermal bridge can be thermographically characterised by extracting a measure for the spot weld diameter and hence the quality of the spot weld. The determination of the absolute value of the diameter hereby relies on a calibration of the testing system, which is performed by means of X-ray computed tomography in this study. The experiments were carried out using different experimental approaches, namely transmission as well as reflection geometry wSetup in reflectionith laser illumination. A comprehensive evaluation of samples produced using different welding currents, hence different quality, was carried out in order to validate the thermographic results. KW - Thermography KW - Spot welds KW - Spot welding KW - Computed thomography KW - Non-destructive testing PY - 2017 U6 - https://doi.org/10.1080/17686733.2017.1281554 SN - 1768-6733 SN - 2116-7176 VL - 14 IS - 1 SP - 122 EP - 131 PB - Taylor & Francis CY - London AN - OPUS4-40180 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -