Method for joining two blanks and blanks and products obtained
The present invention relates to a method for joining a first blank and a second blank, wherein at least one of the first and second blanks comprises at least a layer of aluminum or an aluminum alloy. In particular, the method comprises placing the first and second blanks for welding; laser welding the first and second blanks following a welding path thus forming a tailor welded blank, wherein the welding path combines a linear movement along a welding direction and oscillating movements substantially transverse to the welding direction and then hot deforming and quenching the tailor welded blank to form a component, wherein the welding is done without using a filler.
1. A method for joining a first blank and a second blank, wherein at least one of the first and second blanks comprises at least a layer of aluminum or an aluminum alloy, the method comprising:
placing the first and second blanks for welding,
laser welding the first and second blanks following a welding path, and
hot deforming and quenching the welded blanks to form a component, wherein:
the welding path combines a linear movement along a welding direction and oscillating movements substantially transverse to the welding direction, wherein the welding is done without using a filler, and
the oscillating movements of the welding path follow a continuous multiple circular loop pattern, advancing in the welding direction.
2. The method according to claim 1 , wherein the joining of the first blank and the second blank is selected from the group consisting of an edge-to edge butt-joining, an overlap joining, or a lap joining.
3. The method according to claim 2 , wherein the joining of the first blank and the second blank comprises an edge-to edge butt-joining to form a tailor welded blank.
4. The method according to claim 1 , wherein at least one of the first blank or the second blank comprises a steel substrate with a coating comprising the layer of aluminum or of an aluminum alloy, and wherein said steel substrate comprises an ultra high strength steel.
5. The method according to claim 1 , wherein the oscillating movement has a frequency between 400 Hz and 1500 Hz.
6. The method according to claim 5 , wherein the oscillating movement has a frequency between 700 Hz and 1000 Hz.
7. The method according to claim 1 , wherein the welding path has a width between 0.5 mm and 10 mm.
8. The method according to claim 1 , wherein the laser beam has a spot size ranging from 0.2 mm to 1 mm.
9. The method according to claim 1 , wherein the laser beam has a maximum power ranging from 0.5 kW to 10 kW.
10. The method according to claim 1 , wherein the power of the laser beam is dynamically controlled during the oscillating movement, and wherein a minimum power of between 10% and 50% of the maximum power is used.
11. The method according to claim 1 , wherein the linear movement along the welding direction is conducted by the laser at a rate ranging from 1 m/min to 10 m/min.
12. The method according to claim 1 , wherein the welded zone has substantially the same tensile strength as adjacent portions of the component.
13. The method according to claim 1 , wherein the aluminum coating is not completely or partially removed prior to welding.