Abstract: 316H stainless steel with 300 mm thickness electroslag ingot forging billet rolled to steel plate with 50 mm thickness, the original grains sizes of grade 5, 6, 7 and 9 were selected. Solution tests were carried out at 1000 ℃ for 60 min and 120 min, 1050 ℃ for 30 min and 60 min, and 1100 ℃ for 20, 40 and 60 min. The results show that obtaining a fully recrystallized hot-rolled microstructure with uniform grains is a necessary condition for obtaining solution microstructure with uniform grain. For hot-rolled mixed crystals or partially recrystallized microstructure, a solution microstructure with unifor grain cannot be obtained by solution treatment. For the hot-rolled steel plate with uniform grains, by reasonably matching the solution temperature and time, the grains can grow uniformly. The reasonable solution system of the 316H stainless steel plate with thickness of 20-50 mm is solution at 1050 ℃ for 30-60 min, and at 1100 ℃ for 20-40 min , the solution time can be adjusted according to the hot-rolled microstructure and user needs to obtain the ideal grain size level.

Key words: 316H stainless steel, solution treatment, grain size