Contact resistance is an important parameter in the control of electrical spot welding. Here, a large current is passed through two water cooled copper electrodes which also clamp the sheets to be welded [1]. The contact resistance should not be too high, otherwise too much current is diverted to previously formed, neighbouring spot welds, and can make nugget formation difficult to control in the early part of the welding cycle. However, if it is too low, nugget formation is not completed at the interface. Therefore, the parameters that affect the contact resistance must be known and it must be compatible with the welding conditions [2]. The present paper reports the relationship between contact resistance, force, and electrode shape. A series of experiments were carried out using aluminium and steel specimens with different thicknesses to measure the faying surface and electrode-workpiece contact resistances.

Volume Subject Area:
Materials Handling Engineering
Keywords:
Resistance spot welding, contact resistance, electrode force, electrode shape
Topics:
Contact resistance, Electrodes, Shapes, Welded joints, Welding
1.
James
P. S.
,
Chandler
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Evans
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Wen
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,
Browne
D. J.
,
Newton
C. J.
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1997
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The Effect of Mechanical Loading on the Contact Resistance of Coated Aluminum
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Materials Science & Engineering
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2.
Esme, U., 2002, “The Effect of Welding and Design Parameters on the Quality of the Resistance Spot Welding (RSW) Joints,” MSc Thesis, Cukurova University Institute of Natural and Applied Sciences, Turkey.
3.
Degarmo, E.P., Black, J.T., Kohser, R.A., 1988, “Materials and Processes in Manufacturing,” Macmillan Publishing Company, New York.
4.
Lantz, J., 2000, “Principles of Resistance Welding-Weld Heads, Electrodes and Quality,” Welding Design and Fabrication, April, pp. 46–49.
5.
Yeung, K.S., Thornton, P.H., 1999, “Transient Thermal Analysis of Spot Welding Electrodes,” AWS Welding Research, January, pp. 1–6.
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Crinon
E.
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Evans
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The Effect of Surface Roughness, Oxide Film Thickness and Interfacial Sliding on the Electrical Contact Resistance of Aluminum
,”
Materials Science and Engineering
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A242
, pp.
121
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128
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