JOINING METHOD OF DISSIMILAR METAL PLATES AND DISSIMILAR METAL JOINED BODY

• US 20110097594A1
• Filed: 10/21/2010
• Published: 04/28/2011
• Est. Priority Date: 10/23/2009
• Status: Active Grant

• Current Assignee: Klaus Schmidt, Mazda Motor Corporation
• Original Assignee: Klaus Schmidt, Mazda Motor Corporation
• Inventors: NISHIGUCHI, Katsuya, SASABE, Seiji, TANAKA, Koujirou
• Granted Patent: US 8,502,105 B2
• Time in Patent Office: Days
• US Class Current: 428/594
• CPC Class Codes: B23K 11/115 by means of two electrodes placed opposite one another on both sides of the welded parts
• CPC Class Codes: B23K 11/166 of galvanized or tinned materials
• CPC Class Codes: B23K 11/185 of aluminium or aluminium alloys
• CPC Class Codes: B23K 11/20 of different metals
• CPC Class Codes: B23K 11/24 Electric supply or control circuits therefor
• CPC Class Codes: B23K 2101/006 Vehicles
• CPC Class Codes: B23K 2101/18 Sheet panels
• CPC Class Codes: B23K 2101/34 Coated articles , e.g. plated or painted; Surface treated articles
• CPC Class Codes: B23K 2103/20 Ferrous alloys and aluminium or alloys thereof
• CPC Class Codes: C09J 2400/163 in the substrate
• CPC Class Codes: C09J 5/10 Joining materials by welding overlapping edges with an insertion of plastic material
• CPC Class Codes: Y10T 428/12347 Plural layers discontinuously bonded [e.g., spot-weld, mechanical fastener, etc.]

Abstract

The joining method of the present invention includes a lapping step of lapping the aluminum alloy plate (1) and the plated steel plate (2) via the adhesive (5), a pre-heating step of clamping both of the metal plates (1, 2) that have been lapped in the lapping step between a pair of electrodes (7, 7) for spot welding and applying pressure thereto, and applying a current between the pair of electrodes (7, 7), a cooling step of pressurizing, after the pre-heating step, both of the metal plates (1, 2) at a pressing force which is higher than that at the start of the pre-heating step in a state where conduction between the electrodes (7, 7) is stopped, and continuing this pressurization over a predetermined cooling time, and a welding step of pressurizing, after the cooling step, both of the metal plates (1, 2) at a pressing force which is higher than that at the start of the pre-heating step, and welding both of the metal plates (1, 2) by applying a current which is higher than the conduction current value in the pre-heating step between the pair of electrodes (7, 7). It is thereby possible to firmly join the dissimilar metal plates (1, 2) by combining adhesion due to an adhesive and spot welding.

Claims

1. A method of joining dissimilar metal plates of an aluminum alloy plate and a plated steel plate by means of adhesion of an adhesive and spot welding,

the method comprising:

a lapping step of lapping the aluminum alloy plate and the plated steel plate via the adhesive;

a pre-heating step of clamping both of the metal plates that have been lapped in the lapping step between a pair of electrodes for spot welding and applying pressure thereto, and applying a current between the pair of electrodes;

a cooling step of pressurizing, after the pre-heating step, both of the metal plates at a pressing force which is higher than that at the start of the pre-heating step in a state where conduction between the electrodes is stopped, and continuing this pressurization over a predetermined cooling time; and

a welding step of pressurizing, after the cooling step, both of the metal plates at a pressing force which is higher than that at the start of the pre-heating step, and welding both of the metal plates by applying a current which is higher than the conduction current value in the pre-heating step between the pair of electrodes.

2. The joining method of dissimilar metal plates according to claim 1,

wherein the pressing force of the electrodes is set to a first pressing force during a predetermined period from the start of the pre-heating step, the pressing force is increased to a second pressing force that is greater than the first pressing force in the middle of or at the end of the pre-heating step, and the pressurization is continued with the second pressing force until the completion of the cooling step and the welding step.

3. The joining method of dissimilar metal plates according to claim 2, wherein, prior to the pre-heating step, a pre-pressurization step of clamping the aluminum alloy plate and the plated steel plate between the pair of electrodes and applying pressure thereto is performed.

4. The joining method of dissimilar metal plates according to claim 3, wherein the pressing force in the pre-pressurization step is set to be greater than the first pressing force.

5. The joining method of dissimilar metal plates according to claim 1, wherein as the lapping step, in addition to lapping the aluminum alloy plate and the plated steel plate via the adhesive, a steel plate that is separate from the plated steel plate is lapped on an opposite surface of the plated steel plate to the aluminum alloy plate, and in the foregoing state, the aluminum alloy plate, the plated steel plate and the separate steel plate are mutually joined by performing the respective steps of the pre-heating step, the cooling step and the welding step.

6. The joining method of dissimilar metal plates according to claim 2, wherein

as the lapping step, in addition to lapping the aluminum alloy plate and the plated steel plate via the adhesive, a steel plate that is separate from the plated steel plate is lapped on an opposite surface of the plated steel plate to the aluminum alloy plate, and

wherein, in the foregoing state, the aluminum alloy plate, the plated steel plate and the separate steel plate are mutually joined by performing the respective steps of the pre-heating step, the cooling step and the welding step.

7. The joining method of dissimilar metal plates according to claim 3, wherein

as the lapping step, in addition to lapping the aluminum alloy plate and the plated steel plate via the adhesive, a steel plate that is separate from the plated steel plate is lapped on an opposite surface of the plated steel plate to the aluminum alloy plate, and

in the foregoing state, the aluminum alloy plate, the plated steel plate and the separate steel plate are mutually joined by performing the respective steps of the pre-heating step, the cooling step and the welding step.

8. The joining method of dissimilar metal plates according to claim 4, wherein

as the lapping step, in addition to lapping the aluminum alloy plate and the plated steel plate via the adhesive, a steel plate that is separate from the plated steel plate is lapped on an opposite surface of the plated steel plate to the aluminum alloy plate, and

in the foregoing state, the aluminum alloy plate, the plated steel plate and the separate steel plate are mutually joined by performing the respective steps of the pre-heating step, the cooling step and the welding step.

9. A dissimilar metal joined body in which an aluminum alloy plate and a plated steel plate are joined,

wherein a first joint part welded based on spot welding and a second joint part subject to adhesion with an adhesive exist between the aluminum alloy plate and the plated steel plate, and the first joint part is formed in an annular shape in a planar view.

10. The dissimilar metal joined body according to claim 9, wherein the periphery of the first joint part is surrounded by the second joint part.

11. The dissimilar metal joined body according to claim 9, wherein a weak joint part, with a thermolysis product of the adhesive remaining therein, exists more on the center side than the first joint part of an annular shape.

12. The dissimilar metal joined body according to claim 10, wherein a weak joint part, with a thermolysis product of the adhesive remaining therein, exists more on the center side than the first joint part of an annular shape.

13. The dissimilar metal joined body according to claim 9, wherein a steel plate that is separate from the plated steel plate is joined to an opposite surface of the plated steel plate to the aluminum alloy plate.

14. The dissimilar metal joined body according to claim 10, wherein a steel plate that is separate from the plated steel plate is joined to an opposite surface of the plated steel plate to the aluminum alloy plate.

15. The dissimilar metal joined body according to claim 11, wherein a steel plate that is separate from the plated steel plate is joined to an opposite surface of the plated steel plate to the aluminum alloy plate.

16. The dissimilar metal joined body according to claim 12, wherein a steel plate that is separate from the plated steel plate is joined to an opposite surface of the plated steel plate to the aluminum alloy plate.

17. The dissimilar metal joined body according to claim 13, wherein a nugget part is formed between the plated steel plate and the separate steel plate, and the nugget part does not come in contact with the aluminum alloy plate and is formed at a position which faces the first joint part.