Patent ID: 8268101

Claim:
A method for continuous manufacture of an austenitic stainless steel strip having an offset yield strength Rp 0.2 of greater than or equal to 600 MPa, an ultimate tensile strength Rm of greater than or equal to 800 MPa, an elongation A 80 of greater than or equal to 40%, a mean size of austenite grains smaller than or equal to 4 μm and a surface gloss, measured at an illumination angle of 60°, of greater than 50; consisting essentially of: cold rolling an austenitic stainless steel strip comprising, in wt %: 0.025≦C≦0.15%, 0.20<Si≦1.0%, 0.50≦Mn≦2.0%, 6.0≦Ni≦12.0%, 16.0≦Cr≦20.0%, Mo≦3.0%, 0.030≦N≦0.16%, Cu≦0.50%, P≦0.50%, S≦0.015%, if necessary, 0.10≦V≦0.50% and 0.03≦Nb≦0.50% with 0.10≦Nb+V≦0.50% the rest being iron and possible impurities resulting from smelting, the cold rolling being effected with working cylinders having an arithmetic average roughness Ra of smaller than or equal to 0.15 μm; subjecting the cold-rolled strip to a heat treatment in an annealing furnace, inside which there prevails an atmosphere that is oxidizing toward iron, in order to obtain a strip covered with a layer of oxide, the said heat treatment being adjusted so as to bring about partial recrystallization of the steel to obtain a strip whose recrystallized volume fraction is between 60 and 75%; and pickling the strip that has been subjected to the heat treatment, using at least one acid pickling solution capable of completely eliminating the said oxide layer as a function of its thickness and its nature, without etching the grain boundaries of the steel.