APPLICATION OF PLASMA MIG HYBRID WELDING TO DISSIMILAR JOINTS BETWEEN COPPER AND STEEL

Plasma MIG hybrid welding was developed several decades ago. This welding method is known to be suitable for aluminium. But cases of practical use were not reported so much. The combination of plasma and MIG arcs has recently been noticed again as a process appealing for heat source and arc phenomenon. Therefore, we examined the practical application, while the effectiveness of the plasma MIG hybrid welding was confirmed. This time, the result of examining the applicability to the copper contaminant welding is reported. The plasma MIG hybrid welding torch is coaxial with the MIG electrode placed in the centre, and the ring electrode in which the plasma arc is generated at the circumference. First, the weldability of copper was examined in order to confirm the basic characteristics of plasma MIG hybrid welding. The process was very effective for the application to the welding of copper in order to contribute not only to plasma preheating the base material but also stabilizing the MIG arc. Next, it was shown that copper-carbon steel dissimilar metal welding was possible by justifying the welding parameters. On the basis of these results, plasma MIG hybrid welding was applied to the copper-carbon steel contaminant welding of large structures for the nuclear waste storage, and the result was good.