OXYGEN ABSORPTION AND OXIDE INCLUSION OF IRON WELD METAL DURING ARC WELDING.

Pure iron plates were welded using pure iron electrode wire in a controlled arc atmosphere. Effects of the oxidizing gas partial pressure in the welding atmospheres of Ar-O//2 and Ar-CO//2 gas mixture and welding conditions on the oxygen contents and the nonmetallic inclusions of the iron weld metals were systematically studied. In Ar-O//2 welding atmosphere, the oxygen contents and the inclusions of the iron weld metals increase with increasing the oxygen partial pressure, but the oxygen contents become constant value at about 0. 26 wt. % in high oxygen partial pressure atmosphere. In Ar-CO//2 welding atmosphere, the oxygen contents and the inclusions of the iron weld metals increase with increasing the carbon dioxide partial pressure. The oxide inclusions seemed to be FeO. Behavior of the oxygen absorption into the iron weld metal is discussed using thermodynamic data.