HOT-ROLLED AND COATED STEEL SHEET FOR HOT STAMPING, HOT-STAMPED COATED STEEL PART AND METHODS FOR MANUFACTURING THEREOF

Abstract

A process for manufacturing a hot-rolled and coated steel sheet, with a thickness between 1.8 mm and 5 mm, comprising obtaining a semi-finished product having the following composition: 0.04% ≤ C ≤ 0.38%, 0.40% ≤ Mn ≤ 3%, 0.005% ≤ Si ≤ 0.70%, 0.005% ≤ Al ≤ 0.1%, 0.001% ≤ Cr ≤ 2%, 0.001% ≤ Ni ≤ 2%, 0.001% ≤ Ti ≤ 0.2%, Nb ≤ 0.1%, B ≤ 0.010%, 0.0005% ≤ N ≤ 0.010%. 0.0001% ≤ S ≤ 0.05%, 0.0001%, ≤ P ≤ 0.1%, Mo ≤ 0.65%, W ≤ 0.30%, Ca ≤ 0.006%, hot rolling to a final temperature FRT, to obtain a hot-rolled steel product with a thickness between 1.8 mm and 5 mm, then cooling to a winding temperature T coil Satisfactory: 450 °C ≤ T coil ≤ T coilmax , T coilmax=650-140×fγ and T coilmaxexpressed in degrees Celsius and fy denoting the austenite fraction just before winding, and winding to obtain a hot-rolled steel substrate, pickling and coating of the hot-rolled steel substrate with aluminum or an aluminum alloy by continuous immersion in a bath, to obtain a hot-rolled and coated steel sheet comprising a hot-rolled steel sheet and a layer of aluminum or aluminum alloy. an aluminum alloy coating, with a thickness between 20 and 33 µm, on each face of the hot-rolled steel sheet.