| 摘要 |
The invention relates to a duplex ferritic austenitic stainless steel having 40 - 60 volume % ferrite and 40 - 60 volume % austenite, preferably 45 - 55 volume % ferrite and 45 - 55 volume % austenite at the annealed condition, and having improved cold workability and impact toughness. The stainless steel contains in weight % less than 0,07 % carbon (C), 0,1 - 2,0 % silicon (Si), 3 - 5 % manganese (Mn), 19 - 23 % chromium (Cr), 1,1 - 1,9 % nickel (Ni), 1,1 - 3,5 % copper (Cu), 0,18 - 0,30 % nitrogen (N), optionally molybdenum (Mo) and/or tungsten (W) in a total amount calculated with the formula (Mo + ½W) < 1,0 %, optionally 0,001 - 0,005 % boron (B), optionally up to 0,03 % of each of cerium (Ce) and/or calcium (Ca), balance being iron (Fe) and evitable impurities in such conditions for the ferrite formers and the austenite formers, i.e. for the chromium equivalent (Creq) and the nickel equivalent (Nieq): 20 < Creq < 24,5 and Nieq > 10, where Creq = Cr + 1,5Si + Mo + 2Ti + 0,5Nb Nieq = Ni + 0,5Mn + 30(C+N) + 0,5(Cu+Co) |
