RESISTANCE SPOT WELDING MANUFACTURE AND METHOD OF FORMING SAME
A method of forming a resistance spot welding manufacture includes sandwiching a third metal layer between first and second metal layers to form a workpiece. The second layer has a surface defining an embossed region. The first layer has a first thickness, the third layer has a third thickness, and the second layer has a second thickness that is less than the first and third thicknesses so that a ratio of the first thickness to the second thickness is greater than about 2:1. The method includes positioning the workpiece between a first and second electrode so that the workpiece is disposed in electrically-conductive relationship with the first and the second electrodes, and applying an electrical current through the first electrode to concurrently melt the first and third layers and the surface at the embossed region to join the first and second layers to the third layer and form the manufacture.
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This application is a divisional application of U.S. patent application Ser. No. 13/009,134, filed on Jan. 19, 2011, which is hereby incorporated by reference in its entirety.
TECHNICAL FIELDThe present disclosure generally relates to a resistance spot welding manufacture, and more specifically, to a resistance spot welding manufacture including metal layers joined by a weld joint.
BACKGROUNDResistance spot welding may be used to join metal layers. In general, resistance welding is a joining process in which metal may coalesce at faying interfaces between the metal layers via resistance heating from the passage of electric current under applied force.
In particular, resistance spot welding may be used to join three metal layers so that a middle metal layer is sandwiched between two outer metal layers. For such workpieces, certain industrial welding specifications often require that a thickness ratio between the two outer metal layers should not be more than 1:2, and that a thickness ratio between the middle metal layer and any of the two outer metal layers should not be more than 1:3. Uniform heat distribution between each faying interface generally enhances weld quality and strength for such workpieces.
SUMMARYA method of forming a resistance spot welding manufacture includes sandwiching a third metal layer between a first metal layer and a second metal layer to thereby form a workpiece. The second metal layer has a faying surface defining an embossed region and disposed adjacent the third metal layer. The first metal layer has a first thickness, the third metal layer has a third thickness, and the second metal layer has a second thickness that is less than each of the first thickness and the third thickness so that a ratio of the first thickness to the second thickness is greater than about 2:1. The method also includes positioning the workpiece between a first electrode and a second electrode so that the workpiece is disposed in electrically-conductive relationship with each of the first electrode and the second electrode. In addition, the method includes applying an electrical current through the first electrode to concurrently melt each of the first metal layer, the third metal layer, and the faying surface at the embossed region to join each of the first metal layer and the second metal layer to the third metal layer and thereby form the resistance spot welding manufacture.
In one embodiment, sandwiching disposes the third metal layer adjacent and in contact with each of the first metal layer and the faying surface. Further, positioning aligns the workpiece between the first electrode and the second electrode along an axis perpendicular to the faying surface through the embossed region. In addition, applying forms a weld joint between the first metal layer, the third metal layer, and the faying surface at the embossed region.
In another embodiment, a method of forming a resistance spot welding manufacture includes sandwiching a third metal layer between a first metal layer and a second metal layer to thereby form a workpiece. The second metal layer has a faying surface disposed adjacent the third metal layer and defining a plurality of embossed regions each spaced apart from one another. The first metal layer has a first thickness, the third metal layer has a third thickness, and the second metal layer has a second thickness that is less than each of the first thickness and the third thickness so that a ratio of the first thickness to the second thickness is greater than about 2:1. The method also includes positioning the workpiece between a first electrode and a second electrode so that the workpiece is disposed in electrically-conductive relationship with each of the first electrode and the second electrode. In addition, the method includes applying an electrical current through the first electrode to concurrently melt each of the first metal layer, the third metal layer, and the faying surface at each of the plurality of embossed regions to join each of the first metal layer and the second metal layer to the third metal layer and thereby form the resistance spot welding manufacture.
The resistance spot welding manufacture and method allow for joining of thick and thin metal layers having different thicknesses. For example, the method joins thick-thick-thin metal layer combinations to form the resistance spot welding manufacture having acceptable weld strength and performance. In particular, for the method, the embossed region optimizes resistance heating at the faying surface and therefore generates sufficient heat for the weld joint to penetrate the faying surface of the second metal layer, i.e., the thin metal layer. The method enables resistance spot welding of challenging metal layer combinations such as workpieces having a ratio of the first thickness to the second thickness of greater than about 2:1 and/or a ratio of the third thickness to at least one of the first thickness and the second thickness of greater than about 3:1. Further, the method enables concurrent resistance spot welding of each of the first metal layer, the second metal layer, and the third metal layer, without, for example, employing dual force welding operations, electrodes having differing size or shapes, and/or subsequent resistance spot welding of the second metal layer to a workpiece including a previously-joined first metal layer and third metal layer. Moreover, the method allows for resistance spot welding of resistance spot welding manufactures including bare and zinc coated metal layers.
The above features and advantages and other features and advantages of the present disclosure are readily apparent from the following detailed description of the best modes for carrying out the disclosure when taken in connection with the accompanying drawings.
Referring to the Figures, wherein like reference numerals refer to like elements, a resistance spot welding manufacture is shown generally at 10 in
As shown in
Referring again to
As further shown in
Referring again to
As best shown in
As used herein, the terminology “embossed region 22” refers generally to an area of increased roughness on the faying surface 20. That is, the embossed region 22 may include peaks and/or valleys carved or molded in relief with respect to the faying surface 20. For example, referring to
Therefore, referring again to
Referring to
Referring again to
The third metal layer 12 may also be formed from any suitable metal according to the desired application of the resistance spot welding manufacture 10. For example, the third metal layer 12 may be formed from steel, such as, but not limited to, high strength steel. Further, the third metal layer 12 has a third thickness 54 that is greater than the second thickness 52. Depending upon the desired application of the resistance spot welding manufacture 10, the third thickness 54 may be from about 1.5 mm to about 3 mm for automotive applications. In addition, in one variation, the third thickness 54 may be greater than the first thickness 50. Therefore, the third metal layer 12 may be characterized as a “thick” layer as compared to the second metal layer 16, which may be characterized as a “thin” layer. As such, as shown in
Referring to
In another variation, a ratio of the third thickness 54 to at least one of the first thickness 50 and the second thickness 52 is greater than about 3:1. For example, the first metal layer 14 may have a first thickness 50 of about 3.5 mm, the third metal layer 12 may have a third thickness 54 of about 1.6 mm, and the second metal layer 16 may have a second thickness 52 of about 0.4 mm. For this variation, the ratio of the first thickness 50 to the second thickness 52 may also be greater than about 2:1.
As set forth above, each of the first metal layer 14, the second metal layer 16, and the third metal layer 12 may be formed from steel. The steel may include carbon and other alloying elements. Further, such alloying elements, especially carbon, may contribute to the strength of the steel. Unlike the first metal layer 14 and the third metal layer 12, which may be characterized as “thick” as set forth above, formability may be more important than strength for the second metal layer 16, which may be characterized as “thin”. Therefore, the amount of carbon and/or other alloying elements present in the second metal layer 16 may be less than an amount of carbon and/or other alloying elements present in either of the first metal layer 14 and the third metal layer 12. Consequently, the second metal layer 16 may have a lower melting point temperature as compared to the respective melting point temperatures of either of the first metal layer 14 and the third metal layer 12. In addition, as set forth above, the second metal layer 16 may be, for example, a vehicle body side (not shown), may require comparatively more corrosion-resistance, and may include a zinc coating for protection. The zinc coating may also further reduce the resistance heating generated at the faying surface 20 between the second metal layer 16 and the third metal layer 12.
Referring again to
In addition, for the variation of the faying surface 20 defining the plurality of embossed regions 22 as shown in
A method of forming a resistance spot welding manufacture 10 is now described with reference to
Referring again to
Further, referring to
Although not shown in
Referring again to
Without intending to be limited by theory and described generally with reference to
In contrast, since each of the first metal layer 14 and the third metal layer 12 is thicker than the second metal layer 16, and may have a higher carbon content and corresponding lower melting point temperature than the second metal layer 16, each of the first metal layer 14 and the third metal layer 12 may exhibit relatively higher resistance to the electrical current 40. Such relatively higher resistance to the electrical current 40 generates higher resistance heating during resistance spot welding at the interface 32 as compared to the faying surface 20. The embossed region 22 compensates for such differences in resistance heating at the interface 32 and the faying surface 20. That is, the embossed region 22 minimizes skewed formation of the weld joint 18 towards the first metal layer 14 and the third metal layer 12, and instead promotes penetration of the weld joint 18 into the faying surface 20 by increasing resistance heating at the faying surface 20. Consequently, a desired joining, i.e., fusion, of each of the first metal layer 14 and the second metal layer 16 to the third metal layer 12 may be achieved via the strong weld joint 18.
With continued reference to
Therefore, the resistance spot welding manufacture 10 and method allow for joining of thick and thin metal layers 12, 14, 16 having different thicknesses 50, 52, 54. For example, the method joins thick-thick-thin metal layer combinations to form the resistance spot welding manufacture 10 having excellent weld strength and performance. In particular, for the method, the embossed region 22 of the faying surface 20 optimizes resistance heating at the faying surface 20 and therefore generates sufficient heat for the weld joint 18 to penetrate the faying surface 20 of the second metal layer 16, i.e., the thin metal layer 16. The method enables resistance spot welding of challenging metal layer combinations such as workpieces having a ratio of the first thickness 50 to the second thickness 52 of greater than about 2:1 and/or a ratio of the third thickness 54 to at least one of the first thickness 50 and the second thickness 52 of greater than about 3:1. Further, the method enables concurrent resistance spot welding of each of the first metal layer 14, the second metal layer 16, and the third metal layer 12, without, for example, employing dual force welding operations, electrodes having differing sizes or shapes, and/or subsequent welding of the second metal layer 16 to a workpiece including a previously-joined first metal layer 14 and third metal layer 12. Moreover, the method allows for resistance spot welding of resistance spot welding manufactures 10 including bare and zinc coated metal layers 12, 14, 16.
While the best modes for carrying out the disclosure have been described in detail, those familiar with the art to which this disclosure relates will recognize various alternative designs and embodiments for practicing the disclosure within the scope of the appended claims.
Claims
1. A method of forming a resistance spot welding manufacture, the method comprising:
- sandwiching a third metal layer between a first metal layer and a second metal layer to thereby form a workpiece;
- wherein the second metal layer has a faying surface defining an embossed region and disposed adjacent the third metal layer;
- wherein the first metal layer has a first thickness, the third metal layer has a third thickness, and the second metal layer has a second thickness that is less than each of the first thickness and the third thickness so that a ratio of the first thickness to the second thickness is greater than about 2:1;
- positioning the workpiece between a first electrode and a second electrode so that the workpiece is disposed in electrically-conductive relationship with each of the first electrode and the second electrode; and
- applying an electrical current through the first electrode to concurrently melt each of the first metal layer, the third metal layer, and the faying surface at the embossed region to join each of the first metal layer and the second metal layer to the third metal layer and thereby form the resistance spot welding manufacture.
2. The method of claim 1, wherein said positioning aligns the first electrode and the second electrode with the embossed region.
3. The method of claim 1, wherein said positioning aligns the workpiece between the first electrode and the second electrode along an axis perpendicular to the faying surface through the embossed region.
4. The method of claim 3, wherein said positioning disposes the workpiece adjacent and in contact with each of the first electrode and the second electrode.
5. The method of claim 3, wherein said positioning includes disposing the first metal layer adjacent and in contact with the first electrode and disposing the second metal layer adjacent and in contact with the second electrode.
6. The method of claim 1, wherein said sandwiching disposes the third metal layer adjacent and in contact with each of the first metal layer and the faying surface.
7. The method of claim 1, wherein said sandwiching includes disposing the third metal layer between the first metal layer and the embossed region such that the third metal layer is disposed adjacent and in contact with each of the first metal layer and the second metal layer.
8. The method of claim 1, wherein the second metal layer has a second surface spaced opposite the faying surface and defining an imprint aligned with the embossed region, and further wherein said sandwiching includes disposing the third metal layer between the first metal layer and the embossed region such that the imprint is spaced opposite the third metal layer.
9. The method of claim 1, wherein said applying forms a weld joint between the first metal layer, the third metal layer, and the faying surface at the embossed region.
10. The method of claim 9, further including penetrating the faying surface at the embossed region with the weld joint.
11. The method of claim 1, wherein said applying includes increasing resistance heating at the faying surface.
12. The method of claim 1, wherein said applying includes resisting flow of the electrical current at the embossed region.
13. The method of claim 1, further including defining a ratio of the third thickness to at least one of the first thickness and the second thickness to be greater than about 3:1.
14. The method of claim 1, further including selecting the first electrode to have a shape and size that is substantially the same as a shape and size of the second electrode.
15. The method of claim 14, wherein the first electrode and the second electrode are each formed from substantially the same material.
16. A method of forming a resistance spot welding manufacture, the method comprising:
- sandwiching a third metal layer between a first metal layer and a second metal layer to thereby form a workpiece;
- wherein the second metal layer has a faying surface defining an embossed region and disposed adjacent the third metal layer;
- wherein the first metal layer has a first thickness, the third metal layer has a third thickness, and the second metal layer has a second thickness that is less than each of the first thickness and the third thickness so that a ratio of the first thickness to the second thickness is greater than about 2:1;
- wherein said sandwiching disposes the third metal layer adjacent and in contact with each of the first metal layer and the faying surface;
- positioning the workpiece between a first electrode and a second electrode so that the workpiece is disposed in electrically-conductive relationship with each of the first electrode and the second electrode;
- wherein said positioning aligns the workpiece between the first electrode and the second electrode along an axis perpendicular to the faying surface through the embossed region; and
- applying an electrical current through the first electrode to concurrently melt each of the first metal layer, the third metal layer, and the faying surface at the embossed region to join each of the first metal layer and the second metal layer to the third metal layer and thereby form the resistance spot welding manufacture;
- wherein said applying forms a weld joint between the first metal layer, the third metal layer, and the faying surface at the embossed region.
17. The method of claim 16, wherein said sandwiching includes disposing the third metal layer between the first metal layer and the embossed region such that the third metal layer is disposed adjacent and in contact with each of the first metal layer and the second metal layer.
18. The method of claim 16, further including penetrating the faying surface at the embossed region with the weld joint.
19. A method of forming a resistance spot welding manufacture, the method comprising:
- sandwiching a third metal layer between a first metal layer and a second metal layer to thereby form a workpiece;
- wherein the second metal layer has a faying surface disposed adjacent the third metal layer and defining a plurality of embossed regions each spaced apart from one another;
- wherein the first metal layer has a first thickness, the third metal layer has a third thickness, and the second metal layer has a second thickness that is less than each of the first thickness and the third thickness so that a ratio of the first thickness to the second thickness is greater than about 2:1;
- positioning the workpiece between a first electrode and a second electrode so that the workpiece is disposed in electrically-conductive relationship with each of the first electrode and the second electrode; and
- applying an electrical current through the first electrode to concurrently melt each of the first metal layer, the third metal layer, and the faying surface at each of the plurality of embossed regions to join each of the first metal layer and the second metal layer to the third metal layer and thereby form the resistance spot welding manufacture.
20. The method of claim 19, wherein said applying includes resisting flow of the electrical current at each of the plurality of embossed regions.
Type: Application
Filed: Aug 15, 2013
Publication Date: Dec 12, 2013
Applicant: GM GLOBAL TECHNOLOGY OPERATIONS LLC (Detroit, MI)
Inventors: Chih-Chang Chen (Rochester Hills, MI), Michael J. Bland (Clarkston, MI), Daniel C. Hutchinson (Goodrich, MI)
Application Number: 13/967,712