Ugh.
I usually don't "guess" about comments, so please let others correct me if this is wrong ....
Oxy-acetylene burning is an oxidation cycle cutting + melting method to remove steel or iron or cast iron. The iron is heated red-white hot with the inner part of the burner, then excess oxygen is added to the molten area through the outer "ring" of burner openings to "blow away" the melted iron and melt more iron into the molten pit by Fe + O2 high-intensity "combustion" (oxidation) ... The cut is made by both processes: the burning (heat) only melts the rion; the physical "push" of the melted iron away from the solid remaining iron is by the excess oxygen forced at high volumes into the melted pool of iron..
Carbon arc burning uses air pressure to 'blow away" the melted steel under the rod, but it uses the current going from the rod to the steel to melt the steel so it can be physically "pushed" away from the cut to continue the cut. But the melting itself is not combustion (as in oxy-acet burning and cutting) but the electric arc.
Thus, it is my opinion, but nor my specific knowledge nor experience that carbon arc could be used on th electrically conductive metals. NOT aluminum, since that would contaminate the cut area.