JOURNAL OF POLYTECHNIC-POLITEKNIK DERGISI, cilt.21, ss.543-552, 2018 (ESCI İndekslerine Giren Dergi)
In this study, Grade A ship steel was joined at both the atmospheric conditions and underwater at various depths through shielded metal arc welding method using paraffin coated shielded rutile type electrode conforming to E 6013 standard. In order to determine the mechanical properties of welded joints hardness and tensile tests were carried out. In addition, microstructural examinations were performed on the welded specimens in order to observe structural the changes and transformations occurring in the welding zone. The hardness test results showed that the highest hardness values are seen for the weld metal and these are followed by heat affected zone (HAZ) and base material. After the tensile tests, it was seen that all the specimens fractured at the meld metal and that strength of the joints lower than that of base material. It was observed from the microstructural examinations that first passes are fine grained isotropic while the last passes are fine grained columnar. In addition, martensitic transformation due to rapid cooling was seen in the specimens joined at underwater. When the experimental results are generally evaluated, it is seen that the specimens joined through underwater arc welding method exhibited 30 % lower elongation and 12 % lower tensile strength than those joined at the atmospheric conditions.