Influence of Covered Electrode Type on Underwater Pad Weld Quality in High-Strength Low-Alloy Steel

Abstract

Water as a welding environment generates significant challenges affecting the quality of welded structures. The purpose of this study was to investigate the effect of the type of covered electrode (three for underwater works and three for air welding) on the quality of the padding welds made on high-strength low-alloy steel in wet welding conditions. The S355J2C+N structural steel was selected for tests. As filler materials six different covered electrodes were chosen. Tests were conducted in similar conditions – fresh tap water (temperature 20℃) at 150 mm depth. After surfacing, the specimens were subjected to visual testing. Subsequently, macroscopic examinations and Vickers HV10 hardness measurements were performed.. It was proved that the grade of covered electrode has a significant influence on the quality and hardness of pad welded structures. Underwater electrodes, which are covered with different hydrophobic coatings, can reduce the occurrence of welding imperfections. It was shown that hardness of underwater welded structures with covered electrodes for air welding may be similar to structures made with the use of electrodes for underwater works. Moreover, it was stated that type of covered electrode may generate 130-140 HV10 lower hardness in heat-affected zone (HAZ).