TY - JOUR A1 - Steppan, Enrico A1 - Mente, Tobias A1 - Böllinghaus, Thomas T1 - Numerical investigations on cold cracking avoidance in fillet welds of high-strength steels N2 - Industry faces a growing demand for high-strength structural steels with yield strengths of up to 1,300 MPa in order to cope with increasingly higher strength requirements in engineering. Higher strength levels are achieved by a special coordinated production process and an adapted chemical composition. Nevertheless, disastrous damage cases with high-strength steels have occurred in the past. The sensitivity to mechanical property degradation by hydrogen increases dramatically with strength. This phenomenon leads to hydrogen-assisted cold cracking. T-joints with fillet welds made from one side with an included angle of 60° were examined for their cold cracking behavior. Based on the T-joint, a modified heat input, even interpass temperature, plate thickness, and length ones were examined. The diffusion behavior and the effectiveness of different post-weld heat treatments in joints were simulated. The results of post-weld heat treatments are illustrated in practical hydrogen removal heat treatment diagrams. It is noticed that the T-joint is subject to a very high risk of hydrogen-assisted cold cracking (HACC). Contrary to other joints, its most critical area for cracking is not the weld metal but the heat-affected zone surrounding area of the root pass. The simulation shows that HACC in the T-joint can only be avoided by applying a sufficient post-weld heat treatment. KW - High-strength structural steels KW - Hydrogen diffusion KW - Numerical simulation KW - Hydrogen-assisted cold cracking (HACC) KW - T joints KW - Fillet welds KW - Post-weld heat treatment KW - Hydrogen removal heat treatment diagramm (HRHT) PY - 2013 U6 - https://doi.org/10.1007/s40194-013-0036-4 SN - 0043-2288 SN - 1878-6669 VL - 57 IS - 3 SP - 359 EP - 371 PB - Springer CY - Oxford AN - OPUS4-27952 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mente, Tobias A1 - Böllinghaus, Thomas T1 - Heat treatment effects on the reduction of hydrogen in multi-layer high-strength weld joints KW - Cold cracking KW - Heat treatment KW - High strength steels KW - Hydrogen KW - Numerical simulation KW - Structural steels PY - 2012 SN - 0043-2288 SN - 1878-6669 VL - 56 IS - 7/8 SP - 26 EP - 36 PB - Springer CY - Oxford AN - OPUS4-26055 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Mente, Tobias A1 - Böllinghaus, Thomas ED - Udomkichdecha, W. ED - Mononukul, A. ED - Böllinghaus, Thomas ED - Lexow, Jürgen T1 - Numerical investigations on hydrogen-assisted cracking (HAC) in duplex stainless steels N2 - Duplex stainless steels have been used for a long time in the offshore industry, since they have higher strength than conventional austenitic stainless steels and they exhibit a better ductility as well as an improved corrosion resistance in harsh environments compared to ferritic stainless steels. However, despite these good properties the literature shows some failure cases of duplex stainless steels in which hydrogen plays a crucial role for the cause of the damage. Numerical simulations can give a significant contribution in clarifying the damage mechanisms. Therefore, a numerical model of a duplex stainless steel microstructure was developed enabling simulation of crack initiation and propagation in both phases. The phase specific stress strain analysis revealed that local plastic deformation occurs in both austenite and δ-ferrite already in the macroscopically elastic range. Altogether, phase specific hydrogen-assisted material damage was simulated for the first time taking into account all main factors influencing hydrogen assisted cracking process. The results agree well with experimental observations and thus allow a better insight in the mechanism of hydrogen-assisted material damage. T2 - 4th WMRIF Young scientists workshop CY - Boulder, CO, USA DA - 2014-09-08 KW - Hydrogen-assisted cracking (HAC) KW - Numerical simulation KW - FEM KW - Duplex stainless steel (DSS) KW - Mesoscale model PY - 2016 SN - 978-981-287-723-9 SN - 978-981-287-724-6 U6 - https://doi.org/10.1007/978-981-287-724-6_3 SP - 21 EP - 31 PB - Springer AN - OPUS4-35075 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -