Galvanized square tubes are widely used, mainly in curtain walls, construction, machinery manufacturing, solar panel supports, and steel structure projects, especially extensively in curtain walls and construction applications. So, how should we differentiate them when purchasing?
Iron Hero Industry now teaches you several points to differentiate between hot-dip galvanized square tubes and cold-dip galvanized square tubes.
One, appearance-wise. Cold galvanized square tubes have a smooth and shiny surface. Compared to cold galvanized square tubes, hot galvanized square tubes have a slightly rougher exterior.
Secondly, observe the color. Under a certain angle of sunlight, cold galvanized square tubes exhibit a yellowish-green, light blue, or slightly iridescent color. Hot galvanized square tubes, under the same angle of sunlight, appear silver white.
Thirdly, zinc coating thickness. There is a significant difference in galvanizing processes between cold galvanized square tubes and hot galvanized square tubes. The corner edges of cold galvanized square tubes are prone to "electrical burn," resulting in a dark coloration and a thicker zinc layer. In the concave corners, current dead zones are easily formed, leading to a thinner zinc layer in this area, and the inner wall of the cold galvanized square tube has no zinc coating attached. The overall cold galvanized square tube has no zinc nodules or lumps, but the zinc layer is relatively thin, with the outer wall zinc layer thickness ranging from 5μm to 10μm. Hot galvanized square tubes have zinc coatings on both the inner and outer walls, featuring watermarks and some zinc nodules, but with a thicker overall zinc layer, with the zinc layer thickness on both the inner and outer walls exceeding 70μm.
The above methods can also be applied to identify galvanized angle steel, both cold and hot dipped, as well as cold and hot dipped channel steel, and other galvanized steel products.