Thesis (M.Sc.) - Cairo University - Faculty of Engineering - Department of Metallurgical Engineering

In this study, the influence of variation in the shielding gas composition on the mechanical properties and corrosion resistance of steel 316L was investigated. Seven different shielding gas compositions in addition to pure CO₂ were studied in this work using flux cored arc welding (FCAW) process. For bead-on-plate specimens, all the specimens appeared satisfactory under x-ray. It showed less spatter except using Ar/N 97/3 and Ar/CO₂/N 82/15/3 shielding gases which resulted in higher number of spatter. Furthermore, for complete real welded joints, conditions 100% CO₂, Ar/CO₂ 75/25, Ar/CO₂ 80/20 and Ar/O₂ 98/2 showed low porosity beside success by tensile test. Increase of carbon dioxide percentage lead to increase the depth of penetration. It led also to decrease in hardness, impact values and ferrite content. All specimens showed near values in corrosion resistance. So, it is recommended to use 100% CO₂, Ar/CO₂ 75/25, Ar/CO₂ 80/20 and Ar/O₂ 98/2 for welding steel 316L by flux cored arc welding

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