Investigation of the microstructural and mechanical properties of welding joints made with underwater electrodes

In this study, the metallurgical properties of all-weld-metal, which welded underwater and atmospheric conditions by using rutile-based electrodes and low alloy S355J2+N steel plates, were investigated. Underwater welding process were performed at a depth of 4 meters in the open sea with paraffin coated GeKaTec UW E7014 underwater electrodes that specially developed according to the AWS A5.35 standard for the first time in Turkey. The welded plates were firstly subjected to non-destructive tests according to the AWS A5.35 standard. Then, tensile test, Charpy-V impact test, hardness test and microstructure examinations were carried out to determine the mechanical properties and to identify the effects of sea water on the microstructural transformation. The results showed that there was no significant change in the yield and tensile strengths of the welds performed in both environments. However, compared to the welds performed at atmospheric conditions, it was observed that the welds performed underwater were 6-8% harder and the Charpy impact values obtained at-2 degrees C together with the % elongation values were lower by 48% and 22%, respectively. As a result, it has been observed that welds made underwater met with the requirements of AWS A5.35 standard quality Level 1.