Welded cans for beverages amount to over 1 million cans/year and take an important role in the field bf steel package industry. Under the intense competition among other materials, can cost reduction and high productivity, which usually lead to the worse weldability, must be overcome steadily.
Until recently, several authors reported that the static electric contant resistance between welded materials strongly influenced weldability. However, the static contact resistance could not be the index of the dynamic high speed welding. The weldability using high speed seam welder was hardly experimented and discussed quantitatively because the dynamic electric resistance could not be divided into the contact resistance and the bulk resistance.
In this report, the effects of the main parameters on weldability, namely tin coating weight, steel thickness and welding speed, were investigated in connection with the equivalent contact resistance by subtracting the calculated bulk resistance from the measured total resistance during high speed welding.
It made clear that the contact length between material and electrode correlates with the available welding current range. The weldability deteriorated with the decrease of tin coating weight and the decrease of steel thickness because of the increased contact resistance and with the increase of welding speed because of the increased discontinuity of HAZ pattern.
