Patent EP0153149A2 successfully refreshed from Google Patents.
EP0153149A2
Expired / Lapsed
EP
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Metal pretreatment for resistance spot welding of aluminum
Assignee: Rio Tinto Alcan International Ltd
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Filing: 1985-02-14
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Granted: —
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Expires: 2005-02-14
Abstract
Abstract A process is described for preparing aluminium sheet for resistance welding, which increases the useful life of the welding electrodes used for welding the thus prepared sheet. The process comprises the steps of: (a) treating both surfaces of the sheet portion to be welded to remove the non-uniform mill finish oxide layer and provide clean surfaces, and (b) providing a thin oxide layer on one cleaned surface and a thicker oxide layer on the other cleaned surface of said sheet, thereby creating a differential in oxide thickness between the surfaces of the sheet and hence a differential in surface resistance.
Inventors
- 👤 Gino Luigi Leone
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-07 04:02
CPC Classifications
C; C25; C25D; C25D11/00; C25D11/02; C25D11/04; B; B23; B23K; B23K11/00; B23K11/34
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
84 words
A method of preparing an aluminum sheet for the resistance welding thereof comprising the steps of: (a) treating both surfaces of the sheet portion to be welded to remove the non-uniform mill finish oxide layer and provide clean surfaces, and (b) providing a thin oxide layer on one cleaned surface and a thicker oxide layer on the other cleaned surface of said sheet, thereby creating a differential in oxide thickness between the surfaces of the sheet and hence a differential in surface resistance. ,
Claim 2
Independent Claim
84 words
A method of preparing an aluminum sheet for the resistance welding thereof comprising the steps of: (a) treating both surfaces of the sheet portion to be welded to remove the non-uniform mill finish oxide layer and provide clean surfaces, and (b) providing a thin oxide layer on one cleaned surface and a thicker oxide layer on the other cleaned surface of said sheet, thereby creating a differential in oxide thickness between the surfaces of the sheet and hence a differential in surface resistance. ,
Claim 3
Dependent Claim
26 words
The method of claim 1 wherein the differential in oxide thickness is provided by subjecting at least said other surface of said sheet to anodizing treatment.
Claim 4
Dependent Claim
37 words
The method of claim 2 wherein a thin oxide layer is formed on both cleaned surfaces and thereafter one of said thin oxide layer covered surfaces is subjected to anodizing treatment to form a thicker oxide layer.
Claim 5
Dependent Claim
20 words
The method of claim 3 wherein the surface not being subjected to anodizing treatment is protected by an electroplating tape.
Claim 6
Dependent Claim
39 words
The method of claim 2 wherein one cleaned surface is subjected to a very light anodization to form a thin oxide layer and the other cleaned surface is subjected to a heavier anodization to form a thicker oxide layer.
Claim 7
Dependent Claim
41 words
The method of claim 1 wherein the thin oxide layer has 0 a thickness in the range of about 20 to 200 A, and the thicker oxide layer has a thickness in the range of about 0 110 and 1500 A.
Claim 8
Dependent Claim
22 words
The method of claim 6 wherein the differential in oxide 0 thickness is in the range of about 90 to 1480 A.
Claim 9
Dependent Claim
20 words
The method of claim 6 wherein the differential in oxide thickness is in the range of 150 to 600 A.
Claim 10
Dependent Claim
21 words
The method of claim 6 wherein the differential in oxide thickness is in the range of about 300 to 400 A.
Claim 11
Dependent Claim
122 words
A resistance welding process for joining aluminum sheet members comprising the steps of: (1) removing the non-uniform mill finish oxide layer from said sheet portions to be welded, (2) providing a very thin oxide layer on one surface and a thicker oxide layer on the other surface after the removal of the mill finish, thereby creating a differential in oxide thickness between the surfaces of the sheet members, (3) bringing said sheet members into resistance joining relationship with the very thin oxide layer situated to contact the welding electrodes, (4) bringing said electrodes into forced contact with the sheet members, and (5) passing sufficient electric current between said electrodes to locally fuse said sheet members together and provide a resistance welded joint.
Claim 12
Dependent Claim
122 words
A resistance welding process for joining aluminum sheet members comprising the steps of: (1) removing the non-uniform mill finish oxide layer from said sheet portions to be welded, (2) providing a very thin oxide layer on one surface and a thicker oxide layer on the other surface after the removal of the mill finish, thereby creating a differential in oxide thickness between the surfaces of the sheet members, (3) bringing said sheet members into resistance joining relationship with the very thin oxide layer situated to contact the welding electrodes, (4) bringing said electrodes into forced contact with the sheet members, and (5) passing sufficient electric current between said electrodes to locally fuse said sheet members together and provide a resistance welded joint.
Claim 13
Dependent Claim
17 words
The method of claim 10 wherein at least the thicker oxide layer is formed by anodizing treatment.
Claim 14
Dependent Claim
14 words
The method of claim 10 wherein both oxide layers are formed by anodization treatments.
Claim 15
Dependent Claim
22 words
The method of claim 10 wherein the differential in 0 oxide thickness is in the range of about 90 to 1480 A.
Claim 16
Dependent Claim
20 words
The method of claim 13 wherein the differential in oxide thickness is in the range of 150 to 600 Å.
Claim 17
Dependent Claim
22 words
The method of claim 13 wherein the differential in 0 oxide thickness is in the range of about 300 to 400 A.
Claim 18
Dependent Claim
47 words
The method of claim 10 wherein the oxide thickness on the surfaces situated to contact the electrodes is in the range of about 20 to 200 A and the oxide thickness on the surfaces to be welded is in the range of about 110 to 1500 Å.
References Cited (Backward Citations)
No citation records indexed.
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