Method for producing a welded metal blank and thus obtained welded metal blank

A method for producing a welded metal blank comprising the steps of:

• cutting at least a first initial metal sheet from a first metal strip and a second initial metal sheet from a second metal strip;
• joining at least the first initial metal sheet and the second initial metal sheet by welding so as to obtain an initial welded metal blank having an initial contour, the initial welded metal blank comprising a weld joint joining the first and the second initial metal sheets;
• and
• cutting the initial welded metal blank by a process involving metal melting so as to obtain at least one final welded metal blank having a final contour, the at least one final welded metal blank comprising a first metal blank portion and a second metal blank portion joined by a weld joint portion consisting of a portion of the weld joint obtained during the joining step,
• wherein the first initial metal sheet and the second initial metal sheet comprise a steel substrate,
• wherein at least one of the first initial metal sheet and the second initial metal sheet comprises, on at least one main face of the substrate, a precoating comprising an intermetallic alloy layer and a metallic alloy layer extending atop the intermetallic alloy layer, the metallic alloy layer being a layer of aluminum, a layer of aluminum alloy or a layer of aluminum-based alloy,
• wherein the at least one final welded metal blank has a thickness comprised between 0.8 mm and 5 mm and comprises a peripheral edge surface resulting from the cutting of the initial welded metal blank, the peripheral edge surface extending from one main face of the at least one final welded metal blank to the other, and
• wherein the cutting step carried out on the initial welded metal blank is a laser cutting step, the laser cutting being carried out in such a way that it results directly in a surface fraction of aluminum on a substrate region of the peripheral edge surface directly resulting from the laser cutting operation greater than or equal to 9% and a surface fraction of aluminum on the bottom half of the substrate region of the peripheral edge surface directly resulting from the laser cutting operation is greater than or equal to 0.5%.