Effects of Oscillation on Impact Property of Weldments

摘要

The present paper deals with effects of oscillation on impact property of mild steel weldments. Mild steel plates were welded at different frequencies and amplitudes of longitudinal and transverse oscillation. Frequencies and amplitudes of oscillations were varied in the ranges of 0 to 400 Hz and 0 to 40 um respectively. Impact test specimens were made out of the stationary and oscillatory welded workpieces and were tested on Izod testing machine. The absorbed energy of the welds prepared under oscillatory (longitudinal and transverse) conditions show significant increase in comparison to absorbed energy of stationary prepared welds. It was observed that 80 Hz-40 um and 400 Hz-5um oscillatory condition gave best results, at 80 Hz and 400 Hz frequencies respectively. At lower frequency higher amplitude and at higher frequency lower amplitude produce maximum percentage increase. However, best results are obtained at 400 Hz-5um oscillatory condition where the percentage increase in absorbed energy may be attributed to grain refinement which is caused by the initiation of dendrite fragmentation and grain detachment mechanisms in the weld pool because of its oscillation.