Abstract:

In order to overcome the low stability of the underwater wet welding due to the effect of water and pressure,the reciprocal of the difference coefficient of arc voltage was taken as the measurement index of arc stability,and some wet welding experiments were carried out in an underwater hyperbaric chamber. Then,according to the reciprocal of the difference coefficient as well as the voltage waveforms of the wet and the in-air welding at different
parameters,the arc stability of shallow-wet and in-air flux-cored arc welding was quantitatively discussed. The results show that,within the range of welding parameters in the experiments,the arc stability of wet welding has a negative correlation with the current but a positive correlation with the voltage,and the CTWD value should be optimized to achieve the maximum arc stability. Moreover,it is found that the arc stability of underwater shallow-wet welding degrades with the increase of welding speed,while that of atmospheric in-air welding almost keeps unchanged,that the wet welding is of narrower range of acceptable welding parameters,and that higher welding voltage should be selected in wet welding for the purpose of improving the arc stability at constant welding current.

Key words: wet welding, arc stability, flux-cored arc welding, difference coefficient