Weld Mechanical and Electrical Properties

Is there a relationship netween weld mechanical and electrical properties? The basic conclusion is that low electrical resistances were found to correlate with high mechanical strengths of the welds.

weld strength versus resistance

Correlation between electrical resistance and tensile strength for welds produced with (blue markers) and without (red markers) spatial beam oscillation. [1]

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In some way we can relate this to the bolted joint:

  • bolted joint: increasing the force increases the contact area
  • welded joint: increasing the weld area and depth increases the weld strength
resistance vs force in a bolted joint

In a bolted electrical joint the resistance is inversely proportional to the force in the joint.

Schlegel et al [2] show this relationship for copper busbars.

Kaufmann et al [3] show maximum tensile load versus weld resistance for a copper to aluminium weld using green laser. They have used different weld patterns: correlation between tensile strength and electrical resistance for welds produced with linear stitched welding strategy (blue), circular beam oscillation (green), and vertical eight beam oscillation (red); error bars indicate the standard deviation; dashed line indicates the overall trend.

joint resistance versus weld tensile strength
Kaufmann et al [3]

What see in these references is a relationship between resistance and mechanical strength, showing that the mechanical strength could be used as a quality metric.

References

  1. Jarwitz, M.; Fetzer, F.; Weber, R.; Graf, T. Weld Seam Geometry and Electrical Resistance of Laser-Welded, Aluminum-Copper Dissimilar Joints Produced with Spatial Beam OscillationMetals 20188, 510.
  2. S. Schlegel, S. Grossmann, H. Löbl, M. Hoidis, U. Kaltenborn and T. Magier, “Joint Resistance of Bolted Copper – Copper Busbar Joints Depending on Joint Force at Temperatures beyond 105 °C,” 2010 Proceedings of the 56th IEEE Holm Conference on Electrical Contacts, Charleston, SC, USA, 2010
  3. Kaufmann, F.; Strugulea, M.; Höltgen, C.; Roth, S.; Schmidt, M. Seam, Properties of Overlap Welding Strategies from Copper to Aluminum Using Green Laser Radiation for Battery Tab Connections in Electric VehiclesMaterials 202316, 1069

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