Effect of Electromagnetic Stirring on Weld Pools.
Research and development rept.,
DAVID W TAYLOR NAVAL SHIP RESEARCH AND DEVELOPMENT CENTER ANNAPOLIS MD SHIP MATERIALS ENGINEERING DEPT
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Autogenous gas tungsten arc welds were made perpendicular to the rolling direction on a single heat of Ti-6al-4V alloy. A commercial electromagnetic arc control system producing a transverse magnetic field that enabled the arc to be rotated at frequencies ranging from 0 to 35 Hz. Control welds were made without arc rotation. Two series of welds were made with the rotating arc, one at a welding speed of 1.7 mms and the second at a welding speed of 3.4 mms. The frequency of arc rotation was varied from 1 to 35 Hz while all other welding variables were maintained constant. Metallographic examination was performed transverse and parallel to the longitudinal axis of the weld to determine the effect of arc rotation on the size of the columnar grains associated with titanium welding, the depth of penetration, and the width fo the weld bead. In general, increasing the frequency of arc rotation over the range studied had no effect on the area, major axis or minor axis of the columnar grains for either of the welding speeds employed. For the series which employed a welding speed of 1.7 mms the depth of penetration decreased initially and then increased to the depth of the control series. Conversely, the weld bead width increased initially with the introduction of arc rotation. With a welding speed of 3.4 mms, arc rotation had a detrimental effect on the weld bead contour.
- Metallurgy and Metallography
- Fabrication Metallurgy