Abstract: In order to study the influence of brittleness transforms aging time on impact properties of the 22Cr duplex stainless steel,impact properties of 22Cr steel with different heat treatment,including solution treatment,solution and brittle temperature spot aging treatment,were investigated.The results show that the original sheet and samples after solution treatment at 1 050 ℃ have excellent impact toughness,the impact energy of them are higher than that of 280 J,the fracture surfaces are dimples.Aging at 850 ℃ leads the significant decrease of the impact properties,and the impact energy of the samples at room temperature decrease from 60 J to 5 J with the ageing time from 0.5 h to 2 h.With increasing of the ageing time,the fracture surfaces are cleavage.Aging at 475 ℃ makes clearly decrease of the impact properties,the dimples with local cleavage areas are found on the fracture surface of specimens after ageing at 475 ℃.