Hot- dip galvanizing is one of the most commercial methods providing a long lasting corrosion resistance of iron and steel components in various environments. Once the zinc coating is applied, the finished product is inspected in order to ensure compliance with the standard specifications. Any galvanized product is expected to show long service life (typically for decades) without maintenance requirements. Several factors can affect the service life of galvanizing coating, the most important of which is the coating thickness. Adherence, appearance and finish are other parameters that should be assessed.
Most of the galvanizing defects are simply visible and easily recognized without any special equipment. ASTM A123, A153 and A767 standards cover the specification for hot-dip galvanizing coatings. One of the main advantages of galvanizing technique is that although some imperfections in appearance and surface finish might occur, the protection capability of the coating is still intact and in most cases, the product is not rejected.
Quality control is performed in following categories:
• Spray salt test
• Adherence test
• Surface quality including roughness and uniformity
• Coating specification and thickness
Please click the above links for more information regarding conventional methods of inspection and quality control of galvanized products.
