Abstract: Hot-rolled 2205 duplex stainless steel was taken as the raw material and solid-solution treated at 1000-1350 ℃ for 30 min.X-ray diffraction (XRD),optical microscope (OM),scanning electron microscope (SEM) and microhardness tester were employed to measure the microstructure and microhardness of the solution-treated 2205 duplex stainless steels.The results show that with the increase of solution treatment temperature,the fraction of ferrite increases and the fraction of austenite decreases,both the recrystallization and grain growth occur,the difference in content of each element including Cr,Mo,and Ni in the two phases is reduced.The ferrite and austenite content is basically equivalent when solution treated at 1050 ℃.The microhardness increases with the increase of solution treatment temperature,and it increases abruptly at 1150 ℃ to 1200 ℃.In order to obtain a lower hardness for subsequent cold processing,the solution treatment temperature of the 2205 duplex stainless steel should be controlled at 1000-1150 ℃.

Key words: 2205 duplex stainless steel, solid-solution temperature, microstructure, microhardness