Abstract
Pure iron plates were welded using Fe-Si alloy electrode wires in a controlled arc atmosphere. The effects of silicon on the oxygen contents and non-metallic inclusions in the weld metals were investigated under various welding conditions in Ar-O2 and Ar-CO2 atmospheres. The oxygen contents of the Fe-Si weld metals decrease with an increasing welding current and increase with an increasing arc voltage at low oxidizing gas partial pressure. The traveling speed has not a marked effect on the oxygen contents of the Fe-Si weld metals at low oxidizing gas partial pressure. The oxygen contents of the Fe-Si weld metals increase with an increasing the partial pressure of oxidizing gases and decrease with an increasing silicon contents in the weld metals. The oxygen contents of the weld metals welded in Ar-CO2 are lower than those in Ar-O2. The nonmetallic inclusions in the Fe-Si weld metals increase with an increasing oxygen contents of the weld metals. The nonmetallic inclusions are silicon-dioxide accompanying with iron-oxide. Behavior of the oxygen absorption into the Fe-Si weld metals is discussed using thermodynamic data.
