Electrode Tip Diameters for Different Thickness Workpieces in Resistance Spot Welding
Keywords:Electrode Tip Diameters, Resistance Spot Welding, Heat Balance
In resistance spot welding, especially the welding of metals with different thicknesses but with the electrode with the same diameter, it resulted in both sides of the workpiece had unbalanced melting. It was due to the metals in both sides had the resistance to the electric flow differently the metal on the side with less thickness was melted more, making the incomplete melting. Sometimes there was the penetrating melting through the thinner workpiece side. Accordingly, there was the study of the electrode tip diameters for workpieces with different thicknesses in resistance spot welding. There was a trial of welding carbon steel ASTM A36 with the thickness of 1 mm and 2 mm, the electrode tip diameters of 6.5 and 8 mm were chosen, the welding current 5000, 5500 and 6000 Amp, the working period 45 cycles and the pressing force 1,600 N. The welding began with first using the same-diameter electrode tip, then with different-diameter tips. From the study result, it could be concluded that the use of the electrode tip with the diameter 8 mm in contact with the workpiece side 1 mm and the diameter 6.5 mm with 2-mm thickness gave the perfect welds. It was because the resistance of electric flow and the heat was balanced, making it had maximum tensile strength.
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