Methods for preparation of sheets to be used for fabrication of a welded steel blank and fabricating a welded blank

A method for fabricating a welded blank, the method comprising the steps of:

• providing a pre-coated steel first sheet having a first steel substrate and a first pre-coating including a first intermetallic alloy layer in contact with the first steel substrate, the first intermetallic alloy layer topped by a first metal alloy layer of aluminum metal or aluminum alloy or aluminum-based alloy, the pre-coated steel first sheet comprising a first principal face, a first opposite principal face and a first secondary face;
• providing a pre-coated steel second sheet having a second steel substrate and a second pre-coating including a second intermetallic alloy layer in contact with the second steel substrate, the second intermetallic alloy layer topped by a second metal alloy layer of aluminum metal or aluminum alloy or aluminum-based alloy, the pre-coated steel second sheet comprising a second principal face, a second opposite principal face and a second secondary face;
• positioning the pre-coated steel first sheet and the pre-coated steel second sheet so that the first secondary face and the second secondary face face each other and define a median plane perpendicular to the first principal face and the second principal face;
• simultaneously ablating the first metal alloy layer and the second metal alloy layer with a first laser beam in a first peripheral zone and a second peripheral zone of the pre-coated steel first sheet and the pre-coated steel second sheet, respectively, on the first principal face and the second principal face closest to the median plane;
• and
• welding the pre-coated steel first sheet and the pre-coated steel second sheet in the first peripheral zone and the second peripheral zone with a second laser beam different from the first laser beam to create a weld along a plane defined by the median plane, the first secondary face and the second secondary face not being processed between the ablating and welding steps.