Absorption of Oxygen into Iron Weld Metal in Ar-CO₂ Gas Mixture Welding Atmosphere

Absorption of Oxygen into Iron Weld Metal during Arc Welding (Report 2)

Abstract

Pure iron was welded in controlled arc atmosphere. Effects of the welding conditions and the partial pressure of carbon dioxide in Ar-CO₂ welding atmosphere on the oxygen content of iron weld metal were systematically studied.
The results are summarized as follows:
1. The oxygen content of iron weld metal decreases with increasing welding current and increases with increasing arc voltage.
2. The oxygen content of iron weld metal increases with the partial pressure of carbon dioxide in Ar-CO₂ welding atmosphere. The oxygen content of iron weld metal in Ar-CO₂ welding atmosphere is smaller than that in Ar-O₂ welding atmosphere.
3. The carbon content of iron weld metal increases with the partial pressure of carbon dioxide in Ar-CO₂ welding atmosphere. The carbon content of iron weld metal is about 0.027 wt.% under the welding current of 250 A in carbon dioxide welding atmosphere.
4. The high partial pressure of carbon dioxide, blow holes are observed in iron weld metal.
5. Behaviour of oxygen absorption into iron weld metal is discussed by using equilibrium data.