Do Carbon Steel Pipes Need Pickling And Passivation Treatment?

Carbon steel pipes need pickling and passivation treatment. This treatment process can effectively remove the oxide scale and rust on the surface of carbon steel pipes, and form a stable passivation layer on the surface, thereby enhancing its corrosion resistance and extending its service life.

The role of pickling and passivation treatment

Pickling and passivation is a common surface treatment method suitable for metal materials such as iron, steel, and ferroalloys.

For carbon steel pipes, the main function of pickling and passivation is to remove the oxide scale and rust on the surface to prevent leakage, breakage and other problems caused by corrosion during transportation and use of the pipeline.

At the same time, pickling and passivation treatment can also form a stable passivation layer on the surface of the carbon steel pipe, further enhancing its corrosion resistance and extending its service life.

Carbon steel pipe pickling and passivation process

1. Preparation before pickling

Before pickling and passivation of carbon steel pipes, sufficient preparations need to be made.

First, inspect the surface of the carbon steel pipe to be treated, remove impurities such as oil, mud and sand on its surface, and ensure that the pickling liquid can fully contact the surface of the steel pipe. Secondly, according to the material and specifications of the carbon steel pipe, select the appropriate pickling liquid formula, and prepare the required pickling equipment and tools.

2. Pickling technology operation

The pickling operation is a key link in the pickling and passivation process of carbon steel pipes. Pour the prepared pickling liquid into the pickling tank, heat it to a suitable temperature, and then put the carbon steel pipe to be treated into the pickling tank.

During the pickling process, it is necessary to ensure that the pickling liquid can evenly cover the surface of the steel pipe, and ensure that all parts can be fully pickled through proper stirring or turning. At the same time, the pickling time should be controlled to avoid excessive corrosion of the steel pipe surface caused by too long pickling.

3. Passivation treatment

After the pickling is completed, the carbon steel pipe needs to be passivated. The purpose of the passivation treatment is to form a dense oxide film on the surface of the steel pipe to improve its corrosion resistance.

Place the pickled steel pipe in the passivation tank, add an appropriate amount of passivator, and control the passivation time and temperature. During the passivation process, regularly check the oxide film formation on the surface of the steel pipe to ensure its quality and uniformity.

4. Post-processing steps

After completing the passivation treatment, a series of post-processing steps are required.

First, rinse the surface of the carbon steel pipe with clean water to remove the residual pickling solution and passivator. Secondly, dry the steel pipe to ensure that the moisture on its surface is completely evaporated. Finally, conduct a quality inspection on the treated carbon steel pipe to ensure that it meets the relevant standards and requirements.

Advantages pickling and passivation treatment

1. Effectively remove the oxide scale and rust on the surface of carbon steel pipes, and improve the corrosion resistance of the pipeline.

2. Form a stable passivation layer, which can prevent the surface of the pipe from further oxidation or corrosion and extend the service life.

3. The passivation layer will not affect the physical properties of the liquid or gas in the pipeline, and will not affect its use effect;

Disadvantages pickling and passivation treatment

1. The process of pickling and passivation treatment is relatively complicated and needs to be operated under strict environment.

2. The chemical composition in the pickling agent may have an impact on the environment, and it needs to be treated and discharged after treatment.

3. The quality of the passivation layer is affected by many factors, such as the temperature, concentration, time, etc. of the treatment process, which needs to be strictly controlled.

Conclusion

Carbon steel pipes need to be pickled and passivated, which is also a common anti-corrosion measure used by pipeline manufacturers and customers. Pickling and passivation can effectively remove the oxide scale and rust on the surface of carbon steel pipes, and form a stable passivation layer on the surface of the pipe, enhance the corrosion resistance of the pipe, and extend the service life. In order to ensure the quality of the passivation layer, the processing process needs to be strictly controlled to ensure that the quality of the pipeline meets the requirements.