Thermal spray zinc, aluminum anti-water coating typical application

[China Aluminum Industry Network] Steel structure factory buildings, steel box girder bridges, TV towers, building antennas, transmission substations, steel poles and other outdoor steel structures, these steel components are exposed to the atmosphere due to long-term exposure to climate change and sun and rain. Leaching, the rapid oxidation of the surface, resulting in a layer of ferric oxide, seriously affecting the strength and service life of steel structures. In order to prevent the oxidation of the surface of the steel structure, paint protection has generally been used in the past, and its anti-corrosion period is generally 3-5 years. Therefore, regular maintenance and maintenance are required. A common method is to copy and paint the paint, which consumes a lot of manpower and material resources. The steel structure is now protected by zinc spray and aluminum spray. The anti-corrosion service lasts for more than 30 years without maintenance. If the paint is sealed with zinc-aluminum coating, the anti-corrosion period will be longer.

The surface of the steel structure can only play the role of anode protection after spraying zinc and spraying aluminum, so as to achieve the purpose of long-term corrosion protection of steel structures. Therefore, many major projects and municipal projects in the country are designated to adopt this technology. Such as: Longer Three Gorges Gate of the Yangtze River, Shanghai Oriental Pearl TV Tower, Yangpu Bridge Main Protector, Guangzhou City Inner Ring Elevated Steel Beam, Steel Structure Aerial of Shanghai Securities Building, Pudong Airport Road Gonggou Gas Explosion Pipeline, Shanghai South Bridge 500,000 kilowatts Substation And so on, to ensure a hundred years of major projects.

1. Water-resistant corrosion-resistant coating Steel-made water gates are the main steel structures that control the amount of water in hydroelectric stations and reservoirs. Some of them are long-term submerged in water and the surface is subject to microbial attack (such as the adsorption of nails and their excrement is acidic). The other part is exposed to the atmosphere for a long time, especially on the waterline. It is affected by surfing and floating objects on the water surface. At the same time, it is affected by rising tides and low tides. The surface of the steel structure often alternates between wet and dry, and is particularly prone to rust. The use of zinc wire spraying and aluminum spraying has now greatly improved the corrosion resistance of steel gates, which is 5 to 6 times longer than the original paint process.

Second, spray zinc, aluminum spray process and similar process performance comparison (hot dip galvanizing process)

1, hot dip galvanizing process pretreatment using pickling, phosphating process, the workpiece surface will have acid, lye residue, leaving the hidden danger of corrosion, so that the hot dip galvanized layer is easy to produce shedding. The zinc spray and aluminum spray process pretreatment adopts sandblasting process, so the surface of the workpiece is very clean and rough, and the surface is sprayed with zinc and no corrosion from the inside will be generated after aluminum spraying, so that the zinc layer will not fall off.

2, hot dip galvanizing process has a certain temperature, about 440 °C or so, so the workpiece will be deformed after hot-dip; and spray zinc, aluminum spraying process is very low temperature, the workpiece surface temperature <80 °C, so the workpiece is not deformed .

3, the use of hot-dip galvanizing process, the workpiece by the plating tank length × width × height restrictions; while the use of zinc spray, aluminum spray process is no limitation on the workpiece.

4, using hot-dip galvanizing process, there are still field repair problems. When welding, loading and unloading, and transportation damages are installed on the site, repairs can only be performed with paint, thus creating a technological breakthrough. If zinc spraying or aluminum spraying is adopted, the site can be repaired by spraying zinc or aluminum, avoiding a breakthrough in the process.

5. Since the pretreatment of the hot-dip galvanizing process adopts pickling and phosphating, the surface of the workpiece has no roughness, and the coating has poor adhesion. The pretreatment of spray zinc and aluminum spray process is sandblasting, Sa ≥ 2.5, so the surface roughness of the workpiece, the coating binding force is better. Tensile strength ≥ 0. 6kg/mm2.

6, hot-dip galvanizing process is very serious pollution of water quality, environmental protection issues are very prominent. Therefore, the hot spray zinc, aluminum spray process more widely.

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