Hybrid butt-lap joint, and method of production
View Patent ↗Lap joints and butt joints can be used for braze-welding metals together, particularly metal sheet materials. Disclosed herein are hybrid joints that include features of both lap joints and of butt joints, that are suitable for braze-welding together articles and workpieces, particularly sheets, composed of different metals including aluminum and steel. Methods for braze-welding such hybrid joints are also disclosed.
1 . A method for producing a hybrid butt-lap braze-welded joint between a steel workpiece and an aluminum workpiece, each of which comprise two faces and at least one edge surface, the method comprising the steps of:
a) positioning the steel workpiece and the aluminum workpiece for edge-to-edge contact with one another, thereby to provide a steel/aluminum butt region between an edge of the steel workpiece and an edge of the aluminum workpiece;
b) positioning a second aluminum workpiece flush across the steel/aluminum butt region on one side of the steel and aluminum workpieces, so that the second aluminum workpiece overlaps in contact both with a portion of one face of the steel workpiece and a portion of one face of the aluminum workpiece adjacent the steel/aluminum butt region; and
c) braze welding along the steel/aluminum butt region, on a side of the steel and aluminum workpieces opposite the second aluminum workpiece.
2 . The method of claim 1 , wherein step c) of braze welding comprises feeding molten filler wire to the steel/aluminum butt region, a portion of the molten filler wire being forced between the steel workpiece and the aluminum workpiece to produce a braze-welded butt joint.
3 . The method of claim 1 , wherein at least a portion of the second aluminum workpiece adjacent the aluminum workpiece melts during step c) of braze welding, thereby to form a welded joint between the aluminum workpiece and the second aluminum workpiece.
4 . The method of claim 1 , wherein step c) of braze welding comprises at least one of gas metal arc welding (GMAW), cold metal transfer arc welding, gas tungsten arc welding (GTAW) with adding wire, laser welding with adding wire, and hybrid or combined laser-arc welding.
5 . The method of claim 1 , wherein step c) of braze welding comprises combined laser-arc braze-welding by combined application of a laser and a gas metal arc welding torch to at least the steel/aluminum butt region.
6 . The method of claim 5 , wherein a laser beam of the laser is directed to at least one of:
the edge of the aluminum workpiece and
the interface between the steel workpiece and the second aluminum workpiece.
7 . The method of claim 1 , wherein in step c) of braze welding comprises gas metal arc braze-welding, wherein a welding torch applies filler wire to the steel/aluminum butt region.
8 . The method of claim 7 , wherein the welding torch applies the filler wire to the edge of the aluminum workpiece.
9 . The method according to claim 8 , wherein the welding torch applies filler wire at an angle of 1-10 degrees compared to perpendicular to the steel workpiece.
10 . The method of claim 9 , wherein the welding torch applies filler wire at an angle of 2-5 degrees compared to perpendicular to the steel workpiece.
11 . The method of claim 7 , wherein the welding torch employs argon shielding gas.
12 . The method of claim 7 , wherein the welding torch applies the filler wire to the steel/aluminum butt region in a weaving motion from the aluminum workpiece side towards the steel workpiece side.
13 . The method of claim 1 , wherein the distance between the edge of the steel workpiece and the edge of the aluminum workpiece at the steel/aluminum interface is from 0-5 mm.
14 . The method of claim 13 , wherein the distance between the edge of the steel workpiece and the edge of the aluminum workpiece at the steel/aluminum interface is from 0-2 mm.
15 . The method of claim 1 , wherein the second aluminum workpiece has a thickness of 0.3-2 mm.
16 . The method of claim 15 , wherein the second aluminum workpiece has a thickness of 0.5-1.5 mm.
17 . The method of claim 1 , wherein the steel workpiece is a steel sheet.
18 . The method of claim 1 , wherein the aluminum workpiece is an aluminum sheet.
19 . The method of claim 1 , wherein the steel workpiece comprises a zinc surface layer.
20 . The method of claim 1 , wherein the method further comprises the step of:
d) welding on a same side of the steel and aluminum workpieces as the second aluminum workpiece, to lap braze weld the second aluminum workpiece and the steel workpiece together.
21 . The method of claim 1 , wherein step c) of braze welding comprises feeding molten filler wire to the steel/aluminum butt region, a portion of the molten filler wire being forced between the steel workpiece and the second aluminum workpiece by capillary action to produce a brazed lap joint between the steel workpiece and the second aluminum workpiece.