Method of resistance spot welding aluminum alloy workpieces

1. A method of resistance spot welding aluminum alloy workpieces together, the method comprising;

providing a welding electrode having a weld face;

shaping the weld face of the welding electrode to have a radius of curvature ranging between approximately 20 millimeters (mm) and 40 mm, inclusive;

texturing the weld face after shaping to provide the weld face with a peak-to-valley surface roughness ranging between approximately 2 micrometers (μm) and 50 μm, inclusive;

performing resistance spot welding with the welding electrode to form a plurality of resistance spot welds between overlapping aluminum alloy workpieces; and

dressing the weld face to re-establish a radius of curvature of the weld face that ranges between approximately 20 mm and 40 mm, inclusive, and to remove a depth of material from the weld face sufficient to remove contamination build-up on the weld face from performing resistance spot welding.

2. The method as set forth in claim 1 , further comprising texturing the weld face to provide the weld face with a peak-to-valley surface roughness ranging between approximately 2 μm and 50 μm, inclusive, after dressing of the weld face.

3. The method as set forth in claim 1 , further comprising texturing the weld face again to provide the weld face with a peak-to-valley surface roughness ranging between approximately 2 μm and 50 μm, inclusive, after resistance spot welding is performed with the welding electrode but before dressing of the weld face.

4. The method as set forth in claim 3 , wherein texturing the weld face again is performed after 10 to 20 individual resistance spot welds are performed.

5. The method as set forth in claim 1 , wherein the weld face of welding electrode is shaped to have a radius of curvature of approximately 25 mm.

6. The method as set forth in claim 1 , wherein the weld face is textured after shaping to provide the weld face with a peak-to-valley surface roughness ranging between approximately 5 μm and 10 μm, inclusive.

7. The method as set forth in claim 1 , wherein less than 100 individual resistance spot welds are formed with the welding electrode between overlapping aluminum alloy workpieces before the weld face is dressed to re-establish a radius of curvature of the weld face that ranges between 20 mm and 40 mm, inclusive, and to remove a depth of material from the weld face sufficient to remove contamination build-up on the weld face from the aluminum alloy workpieces.

8. The method as set forth in claim 1 , wherein between 10 and 100 individual resistance spot welds are formed between overlapping aluminum alloy workpieces before the weld face is dressed to re-establish a radius of curvature of the weld face that ranges between 20 and 40 mm, inclusive, and to remove a depth of material from the weld face sufficient to remove contamination build-up on the weld face from the aluminum alloy workpieces.

9. The method as set forth in claim 1 , wherein dressing the weld face removes a depth of material of the welding electrode ranging between approximately 25 μm and 250 μm, inclusive.

10. The method as set forth in claim 1 , wherein the dressing the weld face removes a depth of material of the welding electrode ranging between approximately 50 μm and 150 μm, inclusive.

11. The method as set forth in claim 1 , wherein performing resistance spot welding comprises bringing the welding electrode to a weld site surface of an aluminum alloy workpiece, wherein the weld face makes surface-to-surface abutment with the weld site surface and the roughness of the weld face and its abutment with the weld site surface under clamping pressure facilitates the flow of electrical current through oxide layers at the weld site surface and at least limits excessive heat generation thereat during electrical current flow.

12. A method of resistance spot welding aluminum alloy workpieces together, the method comprising:

providing a welding electrode having a weld face, wherein the weld face has a radius of curvature ranging between approximately 20 mm and 40 mm, inclusive;

texturing the weld face to provide the weld face with a surface roughness;

performing resistance spot welding with the welding electrode to form a plurality of individual resistance spot welds between overlapping aluminum alloy workpieces, wherein, during formation of each individual resistance spot weld, the textured weld face makes surface-to-surface abutment with a weld site surface of an aluminum alloy workpiece, and the surface roughness of the weld face and its abutment with the weld site surface under clamping pressure facilitates the flow of electrical current through oxide layers at the weld site surface and at least limits excessive heat generation thereat during electrical current flow;

dressing the weld face to re-establish a radius of curvature of the weld face that ranges between approximately 20 mm and 40 mm, inclusive, and to remove a depth of material from the weld face sufficient to remove contamination build-up on the weld face from performing resistance spot welding; and

texturing the weld face to provide the weld face with a surface roughness after dressing of the weld face.

13. The method as set forth in claim 12 , wherein the surface roughness achieved by each texturing step ranges between approximately 2 μm and 50 μm, inclusive.

14. The method as set forth in claim 12 , wherein dressing the weld face is removes a depth of material of the welding electrode ranging between approximately 25 μm and 250 μm, inclusive.