Abstract:
Al assisted alloying of carbon steel in Submerged Arc Welding (SAW) by Al-Cr-Ti-Cu
unconstrained metal powders is applied. A base case without metal powder additions is compared to
two metal powder addition schedules, Al-Cu-Ti and Al-Cu-Ti-Cr. Al powder is used as a deoxidiser
element to control the oxygen partial pressure at the weld pool–molten flux interface to ensure that
most of the Ti and Cr metal powder is transferred into the weld pool and that the weld metal ppm O
is controlled within acceptable limits of 200 to 500 ppm O. The likely sequence of alloy melt formation
is deduced from the relevant alloy phase diagrams. The effect of Fe addition into the initial Al-Cu-Ti
and Al-Cu-Ti-Cr alloy melt is illustrated in thermochemical calculations. Increased metal deposition
productivity with metal powder addition in SAW is confirmed. The metal deposition rates increased
by 19% and 40% when Al-Cu-Ti and Al-Cu-Ti-Cr powders were applied at the same weld heat input
used in the absence of metal powder additions.
