Hot dip galvanizing is one of the effective methods to improve the atmospheric corrosion resistance of steel because of its excellent coating performance, long life, as a protective layer is substantially not been widely used in the maintenance of transmission towers, microwave towers, highway guardrail, lampposts long-term exposure to outdoor electrical fittings such as corrosion of steel parts. Hot-dip galvanizing layer surface defects such as missing many common quality plated, white striped feather pattern, coating thick, rough, gray, striped tears, Tortoise, crystal-like protrusions pattern, "white rust", with its influencing factors more, and relatively difficult to control. In this regard, you can start strengthening process control, combined with the necessary technical measures to improve the quality of hot galvanized surfaces.
Poor surface preparation is the main cause leakage plating (exposed iron). Steel factory, storage, transportation, processing inevitably stained with paint or mineral grease, welding parts sometimes smear testing is difficult to clean surfaces need special grease, etc., most businesses nor degreasing process, relying on the pickling to remove
surface impurities, which is likely to cause leakage plating (exposed iron). Another situation is due to the pickling process more concentrated pickling pieces, stacking intensive, weight and other factors, resulting in less pickling line and folders, or because of pickling salt concentration is too high so that the precipitation on the surface, trenches, no washing or washing is not complete, it is very easy to form a leak-plated, plated imaginary phenomenon. Furthermore, due to the aging of the solvent, failure, coupled with the work laid out in no time will the drying process, or the drying time is longer appear twice in the steel surface micro-oxidation, formation of acidic iron cover on the surface, but also very plated prone to leakage, especially at relatively high humidity climate and fog are more common. Such cases are often easily overlooked. Steel parts are often caused by poor state matrix coating gray surface defects, cracks and other turtles. Even in the galvanizing process is reasonable, stable, state of the steel parts of the matrix affect the zinc coating on the surface quality is also very prominent. Often due to the impact and chemical composition of the smelting process of rolling carbon, silicon, phosphorus and other elements of the steel substrate affecting certain factors to harmful elements segregation, which appears flaky gray coating on the coating surface, Tortoise, crystals obvious defects raised grain, grainy stripes, bark cracks.
In the welding of the coated section of the same path when the poles of different diameters, at the same temperature may enhance the speed and surface quality will be different conditions, such as dimples, orange peel-like wrinkles, mainly caused by the different materials. Once a stable layer is formed, the reason and no matter whether there is stability, stability will be preserved, in addition to having to support the formation of iron-rich layer on the surface of the depression conditions. By providing a large surface alloy layer growth area for the volume contraction, so that an adequate supply of iron required for the reaction, while zinc supply is difficult to access due to the depression of zinc reduced. Bumps or pits steel substrate surface pitting diffuse distribution, generally because of severe corrosion or excessive acid formation. For electrical fittings products, should be eliminated when machining left knife pattern, or by cloth polishing wheel and other measures to eliminate surface pitting pits.
