How to identify whether the galvanized sheet material

If there is a colored film on the surface of the material that is clearly visible to the naked eye, then you can be sure that it is galvanized, and that is the passivation film.

If there is no colored passivation film, then add a drop of hydrochloric acid on the material, to see if there is no gas (or to see if there is zinc on the surface of the material by the acid to dissolve the mark), note that the reaction speed is very fast, a second to judge. If it takes several seconds for the mark to appear, it is certainly not galvanized, or the zinc layer is extremely thin.