Cleaning and prep
Your parts must be properly cleaned before zinc can bond with them. A heated alkali solution, followed by a mild acidic bath removes dirt, contaminants, rust, and mill scale from the surface of the steel. Epoxies, vinyls, paints, or welding slag that cannot be removed during this process must be removed by sandblasting. Parts that have prior hot-dipped features must have the old zinc stripped. We are happy to make arrangements for any situation.
During the true galvanizing step of the process, the material is completely immersed in a bath of molten zinc.
While immersed in the kettle, the zinc reacts with the iron in the steel to form a series of metallurgically bonded zinc-iron intermetallic alloy layers, commonly topped by a layer of impact-resistant pure zinc.
Once the fabricated items’ coating growth is complete, it is withdrawn slowly from the galvanizing bath, and the excess zinc is removed by draining, vibrating, and/or centrifuging.
The metallurgical reaction will continue after the materials are withdrawn from the bath, as long as it remains near bath temperature. Galvanized articles are cooled either by immersion in a passivation solution or water or by being left in open air.
inspection and finishing
The inspection of hot-dip galvanized steel is simple and quick. The two properties of the hot-dip galvanized coating most closely scrutinized are coating thickness and appearance/surface condition. A variety of simple physical tests can be performed to determine thickness, uniformity, adherence, and appearance.
Products are galvanized according to long-established, accepted, and approved standards of ASTM. These standards cover everything from the minimum coating thicknesses required for various categories of galvanized items to the composition of the zinc metal used in the process.