Outdoor solar support frames stay under rain, dust, sun, and changing temperature for a long time. That is why galvanized steel is commonly used for many ground and roof support systems. The zinc layer gives the steel a protective surface, so the frame can handle normal outdoor use better than bare steel. Another reason is that galvanized steel is easy to process into rails, posts, beams, clamps, and braces.
The parts can be drilled, cut, packed, and bolted together with common tools. For a project with repeated panel rows, this makes the frame easier to control from production to installation. The final choice still depends on the drawing, site condition, and local project rules, but galvanized steel remains a practical material for many solar mounting jobs. For daily use, simple details such as size, surface, packing, and storage can make later installation easier.