TY - JOUR A1 - Falkenreck, Thora E. A1 - Böllinghaus, Thomas T1 - Blast resistance of high-strength structural steel welds JF - Welding in the World N2 - As consequence for increasing threats by IEDs (Improvised Explosive Devices) on vehicles, the blast resistance of the welded frames and bodies becomes increasingly important. Considering vehicle welds subjected to blasting, the real configurations of the joints in the structure and the position of the blast loads have to be considered. The present contribution thus focuses on a weld joint at the explosion endangered wheel well of a tactical truck. The high-strength steel welds were subsequently impacted by explosion loads within the upper range from those experienced in practical military operation to cause not only deformation, but also to investigate the ultimate fracture behaviour of the high-strength weld. The interaction between cooling time t8/5 and displacement, crack path as well as fracture surface was analysed. The analyses of the fracture surfaces revealed ductile overload failure and also the size of the dimples was influenced by the cooling time t8/5. As a prominent feature, these investigations showed that the crack path of such high-strength steel welds under blasting is less influenced by the final hardness level in the respective weld microstructures but much more affected by the hardness gradient at the fusion line and inside the Heat Affected Zone (HAZ). KW - Explosions KW - High strength steels KW - MAG welding KW - Cooling rate PY - 2016 DO - https://doi.org/10.1007/s40194-016-0307-y SN - 0043-2288 SN - 1878-6669 VL - 60 IS - 3 SP - 475 EP - 483 PB - Springer CY - Heidelberg, Germany AN - OPUS4-36378 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Steppan, Enrico A1 - Zhang, Lei A1 - Kannengießer, Thomas T1 - Influence of microalloy design on HAZ toughness of S690QL steel N2 - Three high strength Nb-, Ti- and Ti+V- bearing S690QL steels were welded to investigate and compare the effects of microalloy addition on HAZ toughness. Charpy V notch impact tests from three microalloyed welds under different cooling rates have been performed. Fractographic examination shows that several factors including large-sized grain, upper bainite or hard second phase, interact to determine the brittle fracture mode and impaired toughness of Nb bearing weld at high heat input. In contrast to this reduced toughness, Ti bearing welds exhibits satisfied toughness regardless of at a fast or slow cooling rate as a result of limited austenite grain and refined favourable intragranular acicular ferrite structure. Moreover, in the case of such refined structure as matrix, TiN particles are found to be irrelevant to the fracture process and crystallographic misorientation results also confirms that high angle boundaries between fine ferrites plates provide much effective barrier for crack propagation and contribute to improved toughness. T2 - 69th IIW Annual Assembly and International Conference CY - Melbourne, Australia DA - 10.07.2016 KW - Cooling rate KW - High strength steel KW - Microalloy elements KW - HAZ toughness KW - Microstructure PY - 2016 AN - OPUS4-39458 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -