Study of the effect of shielding gas composition on the mechanical weld properties of steel ST 37-2 in gas metal arc welding

In this study, the influence of variation in the shielding gas composition on the weld properties of the steel ST 37-2 was investigated. The influence of four different shielding gas compositions was studied in this work. After accomplishing some mechanical and metallographic tests, it was found that the absorbed energy in the Charpy impact test first increases then remains constant with increase of the amount of carbon dioxide in the shielding gas composition. The amount of inclusions decreases and the Widmanstatten ferrite volume fraction increases with increase of the carbon dioxide percent in shielding gas. On the other hand, the depth of the fusion zone in GMAW increases with increase of the carbon dioxide in shielding gas.