Hot-rolled and coated steel sheet for hot-stamping, hot-stamped coated steel part and methods for manufacturing the same

Abstract

A method for manufacturing a hot-rolled and coated steel sheet having a thickness between 1.8 mm and 5 mm. The method contains the steps of providing a semi-product having a composition containing: 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 with a final rolling temperature FRT, to obtain a hot-rolled steel product having a thickness between 1.8 mm and 5 mm, then cooling down to a coiling temperature Tcoil satisfying: 450° C.≤Tcoil≤Tcoilmax with Tcoilmax=650-140×fγ, Tcoilmax being expressed in degrees Celsius and fγ designating the austenite fraction just before the coiling, and coiling to obtain a hot-rolled steel substrate, pickling and coating the hot-rolled steel substrate with Al or an Al alloy by continuous hot-dipping in a bath, to obtain a hot-rolled and coated steel sheet containing a hot-rolled steel sheet and an Al or an Al alloy coating, having a thickness between 10 and 33 μm, on each side of the hot-rolled steel sheet.

Dependencies are inferred from the claim text.