Novel generations of shipbuilding steels have outstanding toughness due to the improved steel producing processes. Their microstructure mainly consists of ferrite and bainite, while the presence of acicular ferrite has a role in high impact energy of the welded joint. This research aims to analyze the effect of multipass welding on weld characteristics of S500 shipbuilding steel. A Gleeble 3500 simulator machine is used to produce the welding thermal cycles by the Rykalin-3D model on 70 \(\times\) 10 \(\times\) 10 mm samples manufactured in transversal direction from a submerged arc welded joint of 16 mm plate. Temperatures for the simulations were set at 1350 °C for the coarse-grained zone forming in the weld metal (CGHAZ-W), 815 °C for the intercritical zone (ICHAZ-W), and a combination of these peak temperatures for the intercritically reheated coarse-grained zone (ICCGHAZ-W). The examined t8/5 interval was 5–30 s. The weld properties were examined by microstructural examination, hardness test, and instrumented Charpy V-notch impact toughness test. The impact energy values of subzones were below the unaffected weld metal. Longer cooling time resulted in lower impact energy in ICHAZ-W. However, this tendency was not observed in CGHAZ-W. ICHAZ-W and ICCGHAZ-W resulted in the lowest impact toughness, which was indicated by the large unstable crack propagation.
