STUDY OF UNDERWATER WELDING PARAMETERS

Abstract

This work was undertaken to.provide a means of of welding steel in a water environment that was just as simple as the existing 'open waters technique but gave results intermediate between the open water and the 'dry chamber' ( a costly and cumbersome) technique. A small gas trapping shroud was developed by means of a waterproofing paint of a suitable type and thicknesS. This shroud kept the water away from the arc and weld-pool region and reduced its cooling rate which in turn reduced the tendency to form undercuts. Different types of flux coated electrodes were also investigated for their performance in underwater welding. Iron-oxide electrodes (E-422413), coated with lacquer paint, were found to give the best mechanical properties for the weld. The effect of superimposition of a magnetic field on the welding arc was also studied and it was found that the magnetic field refined the microstructure of the weld. The use of iron-oxide electrode with gas trapping shroud developed by lacquer paint at the electrode end and the superimposition of alternating transverse or axial magne-tic field resulted in surprisingly large increase in the welding speed and improvement in mechanical propertieu.