Abstract
The effect of electromagnetic stirring on the microstructure of fully austenitic stainless steel weld metal was investigated. The parameters examined to achieve the grain refinement were magnetic field intensity, the frequency of alternately stirring and relative distance from an electrode to magnetic field center. Bead-on-plate TIG welds were made in the conditions that welding current was 60A and travel speed was 3 cm/min. A significant decrease in the grain size of weld metal could be achieved when the electrode was located 1 to 2 cm apart from the magnetic field center to welding direction and the stirring frequency was 0.5 to 1 Hz.
It was the most likely that remelting of a primary dendrite arm by stirred molten metal played a main role of the grain refinement of weld metal, and both the existence of fragments separated from a primary dendrite arm and the increase in constitutional supercooling ahead of solid-liquid interface due to molten-metal stirring assisted the weld metal in grain-refining.
