Super duplex stainless steels were welded using a new flash butt welding technology of temperature controlling. Flash butt welding consists of two stage processes. First stage is a flashing action. The specimen produced a flashing or arcing across the interface of the two butting ends of the specimens. Fine particles of metals near the surface were burned out towards the opposing surface of the specimen irregularity and then the melted particles were deposited on the surface. The second stage is a resistance welding. The solid state bonding was performed in the region around the deposited particles. The cross sectional microstructure of the weld bond region was observed using a scanning electron microscopy. The microstructure showed two regions : a deposited fine particles region and a solid state bonding region. The grain growth was hardly observed in the weld region and the heat-affected zone. The impact energy increased with increasing heating time up to 1373K because of the increasing fine grained deposited metal.