<p>A major drawback of fusion welding is the residual distortion field, which adversely affects the serviceability of assembled structures such as ship hulls. In the shipbuilding industry, predicting welding-induced distortions is a critical step in the design cycle, offering valuable insights for welding engineers to prevent or mitigate them through both preventive and corrective measures. Despite all efforts, such distortions cannot be entirely avoided, and post-weld mitigation techniques are often necessary. In this paper (part 2), the flame straightening process of the grillage structure assembled in the accompanying paper (part 1) was simulated using the finite element inherent strain method (FE-ISM). In the first step, the inherent strain field generated by a triple-nozzle oxyacetylene torch was derived using finite element thermo-elasto-plastic analysis (FE-TEPA) and a DFLUX subroutine in the ABAQUS/CAE software. By applying the equivalent thermal strain method (ETSM) with a two-layer laminated composite shell element, artificial coefficients of linear thermal expansion were calculated for each layer. In the second step, using the restart analysis technique, the inherent strain components were incorporated into the FE-ISM model of the prior welding process. Employing the simultaneous double-line heating technique, eight different heating sequences were designed to evaluate the impact of prioritizing the straightening order of either the peripheral or central weld lines on the skin plate. Simulation results indicated that the straightening process should begin with the central weld lines, followed by the peripheral ones, to achieve maximum effectiveness in reducing the out-of-plane distortions of the skin plate. Finally, the optimal assembly process was validated through experimental measurements.</p> Graphical Abstract <p></p>