Plasma-MIG hybrid arc welding is a hybrid heating source welding method which is composed of plasma arc and MIG arc. During Plasma-MIG hybrid arc welding process, the interface behavior of copper and steel dissimilar alloy is investigated. The results show that electromagnetic stirring effect decreases and the heat input increases with the increase of outer plasma current in the hybrid arc welding process. The interface diffusion and interface thickness is controlled by the tradeoff of electromagnetic stirring effect degradation and heat input increase. The interface diffusion and interface thickness are controlled by decreasing the electromagnetic stirring force and increasing the heat input with the increase of plasma current in Cu/Fe plasma-MIG hybrid arc welding process.
In this paper,6 mm thick 2219-T6 aluminum alloy was joined by means of variable polarity tungsten-arc welding( VP-TIG) and the influence of gradient mismatches on VP-TIG joints is investigated. The average tensile strength of the joints reduces 32%,53% and 59%,when the mismatch of the joint was 0. 635 mm,1. 44 mm,1. 83 mm,respectively.Incomplete penetration,additional bending moment( Ma) and decrease of effective load region area are considered to explain this phenomenon. The fracture location of tensile specimens occurred at the weld zone( WZ) close to partial melt zone( PMZ),corresponding to a sharp decline of microhardness from PMZ to WZ. The original position of fracture is found at weld toe,where incomplete penetration forms due to the introduction of gradient mismatches.
