Abstract
In an oxidizing gas welding atmosphere of Ar-CO2-O2 gas mixture, oxygen absorption behavior by steel weld metal has been investigated metallurgically, using a popular Fe-Si-Mn electrode wire and two types of base metal, that is, pure iron and rolled steel for welded structure. The oxygen content in steel weld metal is controlled by the partial pressure of oxygen, and the partial pressure of carbon-dioxide has the both different effects of gain and decrease of the oxygen content. The silicon and manganese contents in steel weld metal depend on the degree of deoxidation reaction. Thus, the more the oxygen in steel weld metal, the less the silicon and manganese content. The carbon content in steel weld metal decreases as the result of the deoxidation reaction and increases depending on the absorption of carbon from the CO2 in welding atmosphere. Finally, the diagram of oxygen, silicon, manganese and carbon cuntent of steel weld metal have been produced as the function of the ternary welding atmosphere of Ar-CO2-O2.
