Method for producing iron-carbon-manganese austenitic steel sheet having excellent delayed crack resistance, and steel sheet thus produced

摘要

An austenitic steel sheet excellent in resistance to delayed cracking, the composition of said steel comprising, in weight: 0,35% ‰ C ‰ 1,05%, 15%‰ Mn ‰ 26%, Si ‰ 3%, Al ‰ 0,050%, S ‰ 0,030%, P‰ 0,080%, N ‰ 0,1%, at least one metallic element X chosen among vanadium, titanium, niobium, molybdenum, chromium:0,050% ‰ V ‰ 0,50%, 0,040% ‰ Ti ‰ 0,50%, 0,070% ‰ Nb ‰ 0,50%, 0,14%‰ Mo ‰ 2%, 0,070% ‰ Cr ‰ 2 % and optionally, one or several elements chosen among 0,0005% ‰ B ‰ 0,010%, Ni ‰ 2%, Cu ‰ 5%,the remainder being iron and unavoidable impurities inherent to fabrication, including hydrogen, the quantity X p of said at least one metallic element under the form of carbides, nitrides or carbonitrides being, in weight : 0,030% ‰ V p ‰ 0,40%, 0,030%‰ Ti p ‰ 0,50%, 0,040% ‰ Nb p ‰ 0,40%, 0,14%‰ Mo p ‰ 0,44%, 0,070% ‰ Cr p ‰ 0,6%, the hydrogen content H max designating the maximal hydrogen content that can be measured from a series of at least five specimens, and the quantity X p , in weight, being such that