Method for manufacturing a welded component with very high mechanical characteristics from a coated lamination sheet

A method for creating a welded steel part includes providing a first steel plate having a first base, a first intermetallic alloy layer on the first base and a first metal alloy layer on the first intermetallic alloy layer; providing a second steel plate having a second base, a second intermetallic alloy layer on the second base and a second metal alloy layer on the second intermetallic alloy layer; butt welding the first and second steel plates at a weld so as to melt material from at least the first base, the first intermetallic alloy layer, the second base and the second intermetallic layer to form a molten weld material; austenizing the welded steel plates at a temperature between Ac1 and Ac3+100 degrees C. for a time greater than or equal to 20 seconds; and cooling the welded steel plates so as to render a uniform microstructure to the weld.