Automatic Gouging by Air Caobon-Arc Method (Report 2)

An Application to Circumferential Weld of Pipe

Abstract

Mild steel was welded in pressurized CO₂ atmospheres in the pressure range from I to 30 atm using a solid wire of 1.6 mm dia. The effect of ambient pressure on the melting rate of electrode wire, and the geometry, chemical compositions and mechanical properties of weld metals were studied.
The results obtained are as follows:
1) The melting rate of an electrode wire increases with the increase of ambient pressure up to a certain pressure.
2) The bead width decreases with the increase of ambient pressure.
3) The penetration depth and fused area of base metals increase with increasing the ambient pressure up to a certain pressure.
4) The melting rate of electrode wire and bead geometry appear to be affected with the metal transfer mode of electrode wire in pressurized CO₂ atmospheres.
5) Oxygen content of weld metals increase with the increase of ambient pressure.
6) The charpy impact values of weld metals decrease with increasing the ambient pressure.