Austenitic stainless steel plate

There is provided a precipitation-strengthened stainless steel plate having a chemical composition: by mass %, C: 0.01 to 0.10%; Si: 0.02 to 3.0%; Mn: 0.02 to 2.0%; Ni: 20 to 30%, Cr: 14 to 25.0%; Mo: 1.0 to 4.0%; Cu: 0.01 to 2.0%; Co: 0.01 to 0.5%; V: 0.1 to 1.0%; B: 0.001 to 0.01%; N: 0.02% or less; Ti: 2.0 to 5.0%; Al: 0.002 to 5.0%; Ti+Al: 3.3 to 6.0%; and the balance being Fe and impurities, the precipitation-strengthened stainless steel plate having a Vickers hardness Hv of 300 or higher, wherein the number density γ′: Ni 3 (Al, Ti), which is an intermetallic compound, is 0 to 5/μm 2 . As a heat resistant component material, the precipitation-strengthened stainless steel plate is less expensive than conventional Ni-based alloys such as NCF625 and NCF718, and more excellent in high temperature properties than a precipitation-strengthened heat-resistant stainless steel such as SUH660.