Due to its material characteristics, the biggest disadvantages of steel structure engineering are that it is easy to rust and has poor fire resistance. For steel structure projects, if corrosion is found and not dealt with, there will be great safety risks. In the event of a fire, the steel structure will quickly fail and collapse at high temperatures. If fire prevention treatment is not carried out, the fire resistance limit of the steel structure will only be about 15 minutes. It can be seen the importance of anti-corrosion and fire prevention measures for steel structure projects.
Steel structure anti-corrosion is related to many aspects such as cost, durability, maintenance and performance of the entire steel structure project. Of course, anti-corrosion measures for steel structure projects also vary depending on the environment in which they are used. If it is a steel structure project with a dry environment and low pollution, it does not require a high level of anti-corrosion; if it is a highly corrosive area with humidity, high salinity, offshore or chemical plants, special attention must be paid to anti-corrosion design.
The anti-corrosion methods for steel structure projects generally include the following. It is very necessary to choose the appropriate anti-corrosion method according to the project usage environment.
- The steel material itself is weathering steel with corrosion resistance. Generally used in steel structure projects with relatively high anti-corrosion environment requirements.
- Surface treatment of steel structures with hot-dip galvanizing and thermal spray aluminum composite coatings can make the anti-corrosion life of steel structures reach 20 to 30 years, or even longer. It is also the first choice for most steel structure projects now.
- Coating method, spraying paint or other anti-corrosion materials on the surface of the steel structure, the general corrosion resistance period is 5 to 10 years.
- Use cathodic protection for underground steel structures.
Weathering steel will also rust on the surface like ordinary steel, but it will not penetrate deep into the interior and has the anti-corrosion characteristics of copper or aluminum. Weathering steel is mainly used for steel structures that are exposed to the atmosphere for a long time, such as steel, vehicles, bridges, photovoltaics, and high-speed projects. It is also often used for outdoor sculptures and decoration of building exterior walls.
Hot-dip galvanizing and thermal spray aluminum composite coatings are currently used in most steel structure projects. They are reasonably priced and have good anti-corrosion effects. Steel components must first undergo surface treatment before anti-corrosion treatment. Oil dirt, burrs, coatings, spatter, and iron oxide scales should be carefully removed before and after rust removal, and then hot-dip galvanizing or thermal spraying aluminum treatment is required. If a good-looking color is required , and can also be sprayed with paint.
The coating method is actually the most commonly used spray painting method now. After surface treatment of steel components, primer and topcoat are sprayed. According to different needs, the paint thickness is different and the number of spraying times is also different. Depending on the paint brand and thickness, the price will be different, and the corresponding anti-corrosion life will also be different.
Choosing different anti-corrosion methods according to needs has a great impact on the service life of steel structure projects.