TY - CONF A1 - Kromm, Arne A1 - Rhode, Michael A1 - Mente, Tobias A1 - Czeskleba, Denis A1 - Wilhelm, Eugen A1 - Kannengießer, Thomas T1 - Residual stresses and hydrogen assisted cracking in thick walled submerged arc weld joints for offshore applications N2 - Offshore wind turbines continuously increase in size and weight and demand adequate offshore foundations concepts like monopiles, tripods or jackets. These components are typically submerged arc welded (SAW) high-strength thick steel plates like the S420ML. During welding, the occurrence of delayed hydrogen assisted cracking (HAC) must be anticipated. HAC is a critical combination of the local hydrogen concentration within a susceptible microstructure under certain mechanical load, i.e., the occurring (welding) residual stresses. The welding sequence of the thick-walled plates complicate the residual stress distribution due to the necessary repeated thermal cycling, i.e., welding seam / layer deposition to fill the joint. For that purpose, SAW with two-wire-technique was used to weld a specially designed and prototype-like mock-up of a real component with a thickness of 50 mm, filled with 22 passes and a seam length of 1,000 mm. Additional welded stiffeners simulated the effect of a high restraint, to stimulate critical HAC conditions. The residual stresses were determined by a robot XRD goniometer. A least square regression analysis of the sin²ψ-law by using multiple ψ- and φ-tilts was applied. Tensile residual stresses up to the yield limit are found both in the weld metal and in the heat-affected zone. Numerical modelling allowed the qualitative estimation of the hydrogen diffusion in the weld, enabling the determination of critical conditions for the formation of HAC. In a future step, a structural simulation will allow the assessment of the welding residual stresses and the comparison to the XRD-values. T2 - International Conference on Residual Stresses ICRS-11 CY - Nancy, France DA - 27.03.2022 KW - Welding KW - X-ray diffraction KW - Hydrogen KW - Cracking KW - Offshore steel PY - 2022 AN - OPUS4-54576 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -