Abstract：The microstructure evolution of intermetallic phases (σ phase and χ phase) in hot rolled 316L stainless steel during solution process was studied by means of scanning electron microscope (SEM), X-ray diffractometer (XRD) and electron backscatter diffractometer (EBSD). Meanwhile,the high temperature laser confocal microscope was used to observe the whole in-situ re-dissolution of intermetallic phases. The optimal solution temperature was determined. The results indicated that the phase transition process of γ+σ+χ→γ+σ+χ+α/FeCr→γ+α/FeCr occurred during solution process. The re-dissolution of intermetallic phases started at 1033.1℃ and ended at 1149.5℃. The re-dissolution time lasted for 21 seconds, and the optimum solution temperature for eliminating intermetallic phases was about 1150℃. Before the solution treatment, the morphology of banded structure distributed in the matrix was irregular, and the area percentages of χ phase and σ phase was 0.46% and 0.94%, respectively. After the solution treatment, the morphology of banded structure was uniform and mainly distributed in the form of ferrite and FeCr phase, while χ phase and σ phase were not observed.
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