Duplex stainless steelsDuplex stainless steels are renowned for their excellent corrosionCorrosion resistance and high strength. However, during welding, the microstructuralMicrostructural morphologyMorphologies and phase transformationPhase transformation remain crucial concerns, particularly regarding the significant impact of WidmanstättenWidmanstätten austenite precipitation on performance. In this study, the WidmanstättenWidmanstätten austenite of different steel grades was classified under different laser beam weldingLaser beam welding conditions, and a serial sectioning method was used toJoining reconstruct the 3D modeling of the WidmanstättenWidmanstätten austenite microstructureMicrostructure. It clarified the differences of the WidmanstättenWidmanstätten austenite in welds based on nitrogen contentNitrogen content and different welding conditions. Furthermore, in contrast to 2D, 3D observations better reveal the morphological and arrangement variations of WidmanstättenWidmanstätten austenite within the same region across different cross-sections. In 3D observations, most of the WidmanstättenWidmanstätten austenite appeared connected, while in 2D observations, they seemed to be separated. By comparing, it was also demonstrated that a specific relationship exists between the granular austenite within ferrite grains and the precipitated WidmanstättenWidmanstätten austenite at the grain boundaries.