Oxygen Absorption and Oxide Inclusion of Iron Weld Metal during Arc Welding

Abstract

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-O2 and Ar-CO2 gas mixture and welding conditions on the oxygen contents and the nonmetallic inclusions of the iron weld mteals were systematically studied.The results are as follows:1. The mean temperature of the iron weld pool is about 1910 K.2. The oxygen contents and the inclusions of the iron weld metals decrease with increasing the welding current and increase with increasing the arc voltage.3. The oxygen contents and the inclusions of the iron weld metals decrease slightly with increaseing the traveling speed.4. In Ar-O2 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-CO2 welding atmosphere, the oxygen contents and the inclusions of the iron weld metals increase with increasing the carbon dioxide partial pressure. The oxide inclusions are seemed to be FeO.5. Behavior of the oxygen absorption into the iron weld metal is discussed using thermodynamic data.