Abstract:
A welding apparatus is presented that allows for a controlled welding of steel cord ends. The welding apparatus allows for a controlled welding path from welding period over post-weld period to complete cool-down. In the welding apparatus a direct current source is controlled over time by means of a programmable controller. By sensing the voltage over the clamps of the welding apparatus and using this as a further input to the programmable controller, a constant power dissipation between the clamps can be achieved in the post-weld period. An associated method for making the weld is described wherein during the post-welding period the electric power dissipated between the clamps is held constant. The welds obtained by this procedure have a favourable metallographic structure in that the heat affected zone has more than 50% of pearlite and/or bainite over the total area of that zone.