TY - CONF A1 - Thomas, Maximilian A1 - Kromm, Arne A1 - Kannengießer, Thomas A1 - Weidemann, Jens A1 - Vollert, Florian A1 - Gibmeier, Jens T1 - Analyse des Heißrissverhaltens beim Schweißen neuartiger LTT-Zusatzwerkstoffe N2 - Solidification cracking of metals is a well-researched topic in the field of welding science. A material’s susceptibility to solidification cracking can be tested using numerous different specialized test procedures, one of which is the Modified Varestraint-/Transvarestraint test (MVT). It was developed at BAM in 1982 and is internationally standardised. Over the decades, this test has been extensively used to characterise the solidification cracking resistance of many different materials. The present study was conducted to further investigate the influences of the standardised MVT testing parameters, as well as the characteristics of evaluation methods on the results. Several different high alloyed martensitic LTT (low transformation temperature) filler materials, CrNi and CrMn type, were used. In previous pilot studies, these alloys have shown a rather distinctive solidification cracking behaviour (Fig. 1). During testing, energy input per unit length and bending speed were varied (especially the latter is usually kept at standard values), in addition to the most commonly altered factor - total deformation. First, the effects of different process parameter sets on the solidification cracking response were measured using the standard approach - microscopic analysis of the specimen surface. It was found that not all parameter changes had the expected outcome. For the Cr8Ni6 and Cr11Mn5 filler materials, influences of energy input per unit length and welding speed were in direct opposition. In order to investigate those apparent contradictions, µCT scans of MVT specimens were made. The results consistently show sub surface cracking, to significant, yet varying extents. Different primary solidification types were found using WDX-analysis, an aspect that is believed to be the main difference between the CrNi- and CrMn-type materials and their cracking characteristics. Results show that when it comes to testing of modern high-performance alloys, one set of standard MVT testing parameters might not be equally suitable for all materials. Also, to properly accommodate different solidification types, sub-surface cracking has to be taken into account. T2 - Votragsreihe MDDK an der OvGU Magdeburg CY - Magdeburg, Germany DA - 05.06.2019 KW - Schweißen KW - Heißrisse KW - LTT PY - 2019 AN - OPUS4-48177 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Thomas, Maximilian A1 - Vollert, F. A1 - Weidemann, Jens A1 - Gibmeier, J. A1 - Kromm, Arne A1 - Kannengießer, Thomas T1 - On the Accuracy of Standard Analysis Methods for (Trans-) Varestraint Solidification Cracking Testing N2 - Solidification cracking of metals is a well-researched topic in the field of welding science. A material’s susceptibility to solidification cracking can be tested using numerous different specialized test procedures, one of which is the Modified Varestraint-/Transvarestraint test (MVT). It was developed at BAM in 1982 and is internationally standardised. Over the decades, this test has been extensively used to characterise the solidification cracking resistance of many different materials. The present study was conducted to further investigate the influences of the standardised MVT testing parameters, as well as the characteristics of evaluation methods on the results. Several different high alloyed martensitic LTT (low transformation temperature) filler materials, CrNi and CrMn type, were used. In previous pilot studies, these alloys have shown a rather distinctive solidification cracking behaviour. First, the effects of different process parameter sets on the solidification cracking response were measured using the standard approach. Subsequently, μCT scans were performed on the specimens. The results consistently show sub surface cracking, to significant, yet varying extents. Different Primary solidification types were found using WDX-analysis, an aspect that is regarded to be the main difference between the CrNi- and CrMn-type materials and their cracking characteristics. Results show that when it comes to testing of modern high-performance alloys, one set of standard MVT testing parameters might not be equally suitable for all materials. Also, to properly accommodate different solidification types, sub-surface cracking has to be taken into account. T2 - 72th International Assembly of the International Institute of Welding (IIW) CY - Bratislava, Slovakia DA - 08.07.2019 KW - Heißriss KW - Erstarrungsriss KW - Hot Cracking KW - Solidification Cracking KW - MVT KW - Varestraint KW - Low Transformation Temperature KW - LTT PY - 2019 AN - OPUS4-48752 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Thomas, Maximilian A1 - Vollert, F. A1 - Weidemann, Jens A1 - Gibmeier, J. A1 - Kromm, Arne A1 - Kannengießer, Thomas T1 - Über die Zuverlässigkeit von Standard-Analyseverfahren bei der Erstarrungs-rissprüfung nach dem (Trans-) Varestraint-Verfahren N2 - Für moderne Hochleistungswerkstoffe scheinen Standardparameter der Erstarrungsrissprüfung mittels MVT-Test in vielen Fällen ungeeignet. Dieser Vortrag erläutert die charakteristischen Besonderheiten der betrachteten Werkstoffe, und zeigt überdies alternative Analysemethoden auf, mit denen fehlerhafte Einschätzungen von Erstarrungsrissanfälligkeiten vermieden werden können. T2 - BDDK Uni Madgeburg CY - Magdeburg, Germany DA - 28.11.2019 KW - Erstarrungsriss KW - MVT PY - 2019 AN - OPUS4-49845 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Thomas, Maximilian A1 - Vollert, F. A1 - Weidemann, Jens A1 - Gibmeier, J. A1 - Kromm, Arne A1 - Kannengießer, Thomas A1 - Schaupp, Thomas T1 - On the accuracy of standard analysis methods for (trans-) varestraint solidification cracking testing N2 - Solidification cracking of metals is a well-researched topic in the field of welding science. A material’s susceptibility to solidification cracking can be tested using numerous different specialized test procedures, one of which is the Modified Varestraint-/Transvarestraint test (MVT). It was developed at BAM in 1982 and is internationally standardised. Over the decades, this test has been extensively used to characterise the solidification cracking resistance of many different materials. The present study was conducted to further investigate the influences of the standardised MVT testing parameters, as well as the characteristics of evaluation methods on the results. Several different high alloyed martensitic LTT (low transformation temperature) filler materials, CrNi and CrMn type, were used. In previous pilot studies, these alloys have shown a rather distinctive solidification cracking behaviour. During testing, energy input per unit length and bending speed were varied (especially the latter is usually kept at standard values), in addition to the most commonly altered factor - total deformation. First, the effects of different process parameter sets on the solidification cracking response were measured using the standard approach - microscopic analysis of the specimen surface. It was found that not all parameter changes had the expected outcome. For the Cr8Ni6 and Cr11Mn5 filler materials, influences of energy input per unit length and welding speed were in direct opposition. In order to investigate those apparent contradictions, μCT scans of MVT specimens were made. The results consistently show sub surface cracking, to significant, yet varying extents. Different primary solidification types were found using WDX-analysis, an aspect that is believed to be the main difference between the CrNi- and CrMn-type materials and their cracking characteristics. Results show that when it comes to testing of modern high-performance alloys, one set of standard MVT testing parameters might not be equally suitable for all materials. Also, to properly accommodate different solidification types, sub-surface cracking has to be taken into account. T2 - IIW Intermediate Meeting: Commission II-A CY - Miami, FL, USA DA - 12.03.2019 KW - LTT filler material KW - Solidification cracking KW - Modified Varestraint-/Transvarestraint test KW - μCT PY - 2019 AN - OPUS4-47611 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -