Finish & Appearance
The inspection of finish and appearance is done with an unmagnified visual inspection. This inspection is performed by fully observing all parts and pieces of a hot-dip galvanized product to ensure all necessary components and specifications have been met. The purpose of the visual inspection is to identify any surface conditions, both inside and out, and check all contact points, as well as welds, junctions, and bend areas. The visual inspection should be completed at the galvanizing facility before the part is shipped.
The appearance of the hot-dip galvanized coating can vary from piece to piece, and even section to section of the same piece. Common appearances for hot-dip galvanized steel immediately after galvanizing include bright and shiny, spangled, matte gray, and/or a combination of these. There are a number of reasons for the non-uniform appearance; however, it is important to note appearance has no bearing on the corrosion protection of the piece. Furthermore, in time, after exposure to the environment, all galvanized coatings will take on a uniform matte gray appearance. This section will overview the reasons for differences in appearance.
When inspecting the finish of the hot-dip galvanized coating, a variety of surface conditions may be observed. Several factors can affect the finish of the coating some can be controlled by the galvanizers while others cannot. This section will review a number of possible conditions visible on the galvanized coating. Some of these surface conditions are rejectable, as they will seriously lower the corrosion protection, while others have little or no effect on the corrosion performance and are acceptable.