Use of magnetic are oscillation for grain refinement of gas tungsten arc welds in alpha-beta titanium alloys

In an effort to refine the weld metal grain structure in a-p titanium alloy s, gas tungsten are welding was carried out, during which transverse oscill ations of the are were induced through the use of an alternating external m agnetic field. At optimum values of oscillation amplitude and frequency in both the alloys investigated, considerable refinement of the fusion zone gr ain structure was achieved. This could be attributed to factors that includ e enhanced fluid flow, reduced temperature gradients, and a continually cha nging weld pool size and shape owing to the action of the imposed magnetic field. The reduction in the prior beta grain size was shown to result in a notable increase in fusion zone tensile ductility. Post-weld annealing incr eased ductility in all cases, but the magnetically treated material continu ed to show a higher elongation than that of the untreated material even aft er post-weld heat treatment.