Numerical Simulation Study of Welding Process of AH32 Ship Plate Steel

To finely optimize and synergistically control the welding efficiency along with the microstructural properties of AH32 steel plates, computational simulations via COMSOL Multiphysics software were employed. The objective was to assess the effect of varying t 8/5 cooling rates on the impact properties of AH32 ship plate steel. This theoretical analysis was further confirmed by practical welding experiments and evaluations of impact performance. The results indicated that the microstructure of the AH32 heat-affected zone (HAZ) primarily consists of bainite under the condition of t 8/5 = 5 s, and as t 8/5 increases, the microstructure transits into predominantly ferrite. In addition, we simulated the microstructural evolution across diverse HAZ regions, identifying a notably coarser microstructure in the vicinity of 0 ~ 1 mm near the fusion line. This observation was further validated by impact tests that showed decreased value in this specific area. The findings in this study not only confirm the precision of the COMSOL simulations but also offer authoritative guidance on the welding process design for AH32 steel plates. Moreover, it provides a strategic approach to predict changes in post-welding HAZ microstructure, thereby aiding the advancement of welding engineering for marine steel.