LASER WELDING METHOD FOR PRODUCING A SEMI-FINISHED SHEET METAL PRODUCT MADE OF HARDENABLE STEEL AND COMPRISING A COATING BASED ON ALUMINIUM OR ALUMINIUM-SILICON

摘要

The invention relates to a method for producing a tailoredhot-formable semi-finished sheet metal product. Steel sheetswith different material grades and/or thicknesses are joinedtogether in a butt joint by means of laser welding. At leastone of the sheets is made of press-hardenable steel and has analuminium- or aluminium-silicon-based coating. The steelsheets are welded to one another with a gap which is delimitedby the sheet edges to be welded together and which has anaverage width of at least 0.15 mm. Filler wire, substantiallyfree of aluminium, is introduced into the gap to such a degreethat the ratio of the volume of filler wire inserted into thegap to the volume of the steel sheet material melted by thelaser beam is at least 20%. The method does not require thecoating to be removed from the sheet edges to be welded.