For Fe-20Mn-6Al-1.5C-5Cr steel（designation：ZG-6），the effects of different solution treatment and aging processes on microstructure and hardness were investigated using optical microscopy（OM），scanning electron microscopy（SEM），transmission electron microscopy（TEM），and physicochemical phase analysis.Solution treatments were performed at 1 050，1 100，and 1 150 °C.The results show that with increasing solution temperature， carbides dissolve and the hardness increases；a single-phase austenitic microstructure is obtained at solution temperatures≥1 150 °C.On this basis，the steel solution-treated at 1 150 °C is aged at various temperatures（450～525，550，and 650 °C，2 h each）.At 550 °C，the intragranular κ phase content reaches saturation and the hardness attains a peak value（316 HB）.At 650 °C，lamellar κ′ carbides form and the hardness decreases.After aging at 650 °C for 16 h，κ′ carbides at grain boundaries become saturated and grow into the grains.