1、 Hot dip galvanizing process
Zinc has corrosion resistance, and as a method of sacrificing yang to protect negative metals, the lifespan of zinc immersion depends on the resistance and corrosion rate of its corroded zinc coating. The zinc layer thickness of hot-dip galvanizing is generally 6 μ Above m, the interface between zinc and iron forms a layer of zinc iron alloy, which improves the adhesion of the zinc layer. Foreign countries have conducted atmospheric exposure tests on hot-dip galvanized coatings under different environmental conditions. From the inspection results, hot-dip galvanizing can meet the requirements for the operating life of cable trays.
Due to its corrosion resistance, high performance, and price ratio, hot-dip galvanized steel bridges are widely used both domestically and internationally. The difficulty of deformation caused by hot-dip galvanizing requires consideration in the construction of cable trays and galvanizing technology. Other types of coated cable trays have poor UV resistance and are prone to rusting, resulting in large areas of coating blistering and peeling. They are generally not suitable for outdoor use.
2、 Electrogalvanizing process
For cable trays without special requirements, compared to hot-dip galvanizing, electrogalvanizing has a simpler technology and lower cost. After passivation treatment, electrogalvanizing can significantly improve its anti-corrosion function. The galvanized layer is generally at 6 μ Around m, therefore it is not suitable for occasions with high requirements for corrosion resistance lifespan.
Our country has issued standards for electrogalvanizing, such as GB/T13912-2002, JT/T281-95, GB2694-81, etc. When selecting electroplated coatings, the thickness of the coating and the strong adsorption capacity of the coating are different. Through corrosion resistance tests, different demands for target selection are also different. The manufacturers currently producing galvanized cable trays in China are also different when referring to national standards. Choosing electroplated nickel alloy or high passivation treatment after galvanizing can significantly improve the corrosion resistance of the bridge.
3、 Powder spraying process.
PVC materials are generally powder coatings, polyester powders, or anti-corrosion powders, with a coating thickness of approximately 60 μ M. Electrostatic spraying has the function of beautiful appearance and resistance to chemical corrosion. However, compared to metal coatings, their adhesion is low, and their resistance to dirt and wear is poor. Suffering from a simple external impact can cause local coatings to fall off, causing corrosion of internal steel and forming large areas of coating blistering and peeling. Cable trays using UV coating are generally not suitable for outdoor use.
4、 Apply anti rust paint.
Larger scale components, due to the limitations of galvanizing equipment conditions, can generally only be treated by applying anti rust paint. This certainly has advantages such as low cost and convenient operation, but its anti-corrosion performance is poor. Its engineering lifespan is short, and in order to ensure the quality of the project, it is generally not suitable for use.
Regardless of the high humidity or high sulfur dioxide index in coastal areas, aluminum alloy cable trays are now widely used in the country. The material of the cable tray is aluminum alloy, and the atmospheric exposure test results show that the cable tray has obvious advantages in corrosion resistance, especially when using anodized alumina for corrosion, the effect is very good.