Why do carbon steel pipes need to be sprayed with black paint?

Why do carbon steel pipes need to be sprayed with black paint?

Carbon steel material is an iron-carbon alloy, and its surface is susceptible to oxidation and rust. It generally contains a small amount of silicon, manganese, sulfur, and phosphorus. Generally, the higher the carbon content in carbon steel, the greater the hardness and strength, but the lower the plasticity. In order to protect the surface of the steel from oxidation, a layer of black paint will be sprayed before leaving the factory.

Carbon steel pipes (CS pipe) will be corroded by chemical media, water vapor, oxygen, and microorganisms during long-term use, especially in corrosive environments such as seawater, which are more prone to corrosion damage. In order to extend the service life, it is necessary to treat carbon steel pipes with anti-corrosion.

Compared with stainless steel pipes, carbon steel pipes are more prone to rust and corrosion. Carbon steel pipes are generally required to be sprayed with a layer of black paint before leaving the factory. Spraying black paint has the following purposes:

1. Anti-oxidation. Black paint can effectively shield the erosion of sunlight and rain, prevent oxygen in the air from directly contacting the steel surface, thereby improving rust resistance.

2. Improve aesthetics. The black paint surface looks smoother and more beautiful, and it is also to better meet the requirements of customers.
3. Distinguish the types of steel. Different types of steel will be sprayed with different colors of paint for easy distinction.

What are the advantages of black paint?

1. Wear resistance. Black paint has a high wear resistance and can protect the surface of steel.
2. Corrosion resistance. Black paint is not easily corroded by chemicals and has strong corrosion resistance.
3. Water resistance. Black paint can shield and absorb moisture in the air and has good water resistance.
4. Weather resistance. Black paint can withstand erosion under various weather conditions and has good weather resistance.

Application occasions of black paint:

1. General internal occasions. Suitable for general indoor occasions, such as the walls of buildings and beams and columns of houses.
2. Storage in warehouses. Since black paint can shield light, rain and other factors, the effect of black paint is excellent when storing items in warehouses.
3. Machinery manufacturing industry. Since important parts of machinery are often made of carbon steel, spraying black paint can protect mechanical parts from rust, thereby increasing the service life of the machinery.

Precautions for spraying black paint:

1. Corrosion is easy in hot and humid areas. In a hot and humid environment, black paint is prone to corrosion, so it is not suitable for use in such climatic conditions.
2. Environmental protection issues. The ingredients in black paint may pollute the environment, so environmental protection issues must be paid attention to during the construction process.
3. Be cautious when using. If used improperly, the effect of black paint will be greatly reduced and may also cause safety accidents.

Conclusion:

A layer of black paint is sprayed on carbon steel pipes before leaving the factory to protect the surface from oxidation and improve rust resistance. Black paint is very suitable for general internal occasions and storage in warehouses, and is also widely used in industries such as machinery manufacturing. However, it is easy to corrode in a hot and humid environment, and attention should also be paid to environmental protection and use issues.

Read more: Carbon steel pipe painting standards or Black Carbon Steel Pipe