Steel structure corrosion picture sharing: The corrosion of the steel structure around the heating furnace is still quite severe.

I would like to ask everyone, how to repair the steel structure corrosion to this extent?

First is emergency reinforcement, then demolition and reconstruction.

How does this corrosion occur? How to prevent

This should be due to the reduction in the life of the anti-corrosion surface caused by the radiated heat energy around the furnace body. Before repairing, you need to check whether there is any repairable value. Generally, the design margin of steel structures in this position is relatively large. If the corrosion exceeds a certain margin, forget it. It can also be repaired by sandblasting these parts in place and replacing all the fixing bolts.

Mainly caused by high-temperature corrosion, superimposed by various corrosion mechanisms such as water vapor corrosion, our 1021 or 811 can be used for high-temperature anti-corrosion

The best strategy is to find the root cause of corrosion.

Analysis of the causes of metal corrosion and coating damage 1. Environmental corrosion We know that when the fuel is burned, the hydrogen (H2) and oxygen (O2) combine to form water vapor (H2O), and most burners use steam atomization, so the flue gas in the furnace contains a large amount of water vapor. In addition, the sulfur (S) in the fuel generates sulfur dioxide (SO2) after combustion, and a small amount of SO2 is further oxidized into sulfur trioxide (SO3). The sulfur trioxide combines with the water vapor in the flue gas to form sulfuric acid (H2SO4). When the flue gas comes out of the desulfurization tower, it contains a lot of sulfur oxides and a large amount of moisture, which is easily converted into an aqueous solution of sulfuric acid, which will create a highly corrosive environment and intensify the corrosion of nearby metals. In addition, the exhaust temperature of desulfurization flue gas cannot reach the requirement of above 85°C, and the exhaust gas will not float too far and land nearby, which will aggravate metal corrosion. 2. Analysis of the cause of coating damage. It can be seen from the scene and pictures that the anti-corrosion coating is thin, so the anti-permeability of the coating is not good. The anti-corrosion coating is intact in the initial stage, but due to the thin impermeability of the paint film, the corrosive medium first destroys the coating from the surface of the paint film, and this period of time is relatively short. Once the paint film is damaged, the corrosive medium will spread on the metal surface and the inner surface of the paint film, directly corroding the metal. Because this phenomenon is more harmful than metal without anticorrosion. Because when moisture or water vapor comes into contact with the metal surface under the paint film, the moisture is not easy to evaporate, and electrochemical corrosion will occur for a long time and become more destructive. As can be seen from the above pictures, especially Figure 1, it can be seen that the surface of the paint film is intact, but the underneath is not a metal surface but a metal oxide layer. In addition, there are certain quality problems in terms of the construction quality of the anti-corrosion coating. Figure 2 uses glass fiber cloth as the reinforcing layer, but the mesh of the glass fiber cloth is exposed and the surface is uneven. It is better not to add such glass cloth. In short, the corrosion of the steel structure near the desulfurization tower by acid gas is relatively serious. Therefore, some appropriate anti-corrosion materials should be selected with appropriate construction. This can be used for many years at a time.

1. Insufficient rust removal before anti-corrosion construction, 2. Poor anti-penetration performance of the paint film, 3. Corrosion from environmental media, 4. Water vapor corrosion, 5. Alternating temperature and alternating dry and wet conditions. Anti-corrosion under this working condition is relatively simple. You can use our 711, 811, 1021, or 1041.

It looks chilling, and I haven’t done any preventive maintenance at ordinary times. The key to whether it is eugenic is to control the initial coating construction process.