| 摘要 |
The invention relates to a double-annealed steel sheet, the composition of which comprises, the contents being expressed as weight percentage, 0.20% ≤ C ≤ 0.40%, 0.8% ≤ Mn ≤ 1.4%, 1.60% ≤ Si ≤ 3.00%, 0.015% ≤ Nb ≤ 0.150%, Al ≤ 0.1%, Cr ≤ 1.0%, S ≤ 0.006%, P ≤ 0.030%, Ti ≤ 0.05%, V ≤ 0.05%, B ≤ 0.003%, N ≤ 0.01%, the rest of the composition consisting of iron and unavoidable impurities resulting from the production, the microstructure consisting, in surface area proportions, of 10% to 30% of residual austenite, of 30% to 60% of annealed martensite, of 5% to 30% of bainite, of 10% to 30% of fresh martensite and of less than 10% of ferrite. It also relates to the method for manufacturing same and also to the use of such a sheet. |
