Carbon steel is the most common metal in industrial and structural welding. Trailers, equipment frames, structural beams, gates, fences, ag implements, and most steel buildings are carbon steel. Welding carbon steel is what most welders do most days.
We weld carbon steel with MIG, stick, and flux-core depending on the conditions and the joint. Cleanliness, rod or wire selection, and proper preheat on thicker sections are what make the welds hold.