Methods for joining two blanks and blanks and products obtained

Abstract

Methods for joining a first blank and a second blank, at least one of the first and second blanks comprising at least a layer of aluminum or of an aluminum alloy or a layer of zinc or of a zinc alloy. The method comprises selecting a first portion of the first blank to be joined to the second blank, and selecting a second portion of the second blank to be joined to the first portion, and welding the first portion to the second portion. The welding comprises using a filler metal laser beam and a welding laser beam, and displacing both laser beams in a welding direction to melt and mix a filler wire material with the melted portions of the two blanks. The present disclosure further relates to blanks obtained by any of these methods and to products obtained from such blanks.

1 . A method for joining a first blank and a second blank, wherein one or both of the first blank and the second blank comprises a steel substrate with a coating of aluminum or aluminum alloy, and wherein the first and the second blanks are square butt-jointed, a first portion being an edge of the first blank and a second portion being an edge of the second blank, the method comprising:
 selecting the first portion of the first blank to be joined to the second blank, and selecting the second portion of the second blank to be joined to the first portion;   melting the first portion and the second portion, while supplying a filler wire to a weld zone using a first laser beam and a second laser beam, wherein   the first laser beam melts the filler wire in the weld zone during welding, and   the first portion and the second portion of the blanks are melted and mixed with the melted filler wire using the second laser beam.   
     
     
         2 . The method according to  claim 1 , wherein using the second laser beam comprises displacing the second laser beam in an oscillating manner to mix the first portion and the second portion of the blanks with the melted filler wire. 
     
     
         3 . The method according to  claim 1 , wherein using the second laser beam comprises using a twin-spot laser beam to melt the first portion and the second portion and to mix the first portion and the second portion of the blanks with the melted filler wire. 
     
     
         4 . The method according to  claim 1 , wherein the first laser beam generates a spot having a size substantially corresponding to a diameter of the filler wire and the second laser beam generates a spot or a twin-spot having a size substantially corresponding to a size of the weld zone. 
     
     
         5 . The method according to  claim 1 , wherein the first and second laser beams are generated by a single laser head. 
     
     
         6 . The method according to  claim 1 , wherein the first laser beam is generated by a first laser head and the second laser beam is generated by a second laser head. 
     
     
         7 . The method according to  claim 1 , wherein the first laser beam generates one spot and the second laser beam generates one or more spots and the first and second laser beams generate spots arranged substantially in line with a welding direction. 
     
     
         8 . The method according to  claim 1 , wherein using the second laser beam comprises generating a twin-spot comprising spots, and wherein the spots of the twin-spot are arranged substantially perpendicularly to a welding direction. 
     
     
         9 . The method according to  claim 8 , wherein the spots of the twin-spot either precede or follow the spot of the first laser beam in the welding direction. 
     
     
         10 . The method according to  claim 1 , wherein using the second laser beam comprises generating a twin-spot comprising spots, wherein the spots of the twin-spot and the spot of the first laser beam are arranged collinearly, and wherein the spot of the first laser beam is arranged between the spots of the twin-spot. 
     
     
         11 . The method according to  claim 1 , wherein the filler wire comprises gammagenic elements. 
     
     
         12 . The method according to  claim 1 , wherein the steel substrate of one or both of the first and the second blank is an ultra-high strength steel. 
     
     
         13 . A method for forming a product, the method comprising:
 forming a blank according to the method of  claim 1  for joining a first blank and a second blank,   heating the blank, and   hot deforming and subsequent quenching of the heated blank.