1998 Volume 38 Issue 10 Pages 1100-1106
The low frequency pulsed current was applied in submerged arc welding of structural steels. This process requires a proper welding flux selection. The effect of pulsed current on weld metal solidification and structural transformations was investigated on bead-on-plate tests using various parameters of pulsed current. The latent heat of solidification can affect the microstructure of weld metal as well as that of heat affected zone. Declination of primary grains in transition between pulses was recorded. Recrystalisation and in some cases also grain coarsening was observed in precedent pulses. In 0.5% Mo welds the M–A constituent was mostly decomposed. The submerged arc pulsed current welding was applied in real welds with success. The observed shrinkage was less by 30–40% and the notch toughness of weld metals was considerably higher. The geometrical characteristics of the weld, the microstructure and weld properties are found to be largely governed by the pulse welding parameters.
