Causes of corrosion of seamless carbon steel pipes

In the whole process of the application of seamless carbon steel pipe, if the seamless carbon steel pipe corrodes, it may affect the normal application of the project, so what is the reason for the corrosion of the seamless carbon steel pipe?

1. Pitting corrosion. It refers to a form of local corrosion damage on the metal surface of seamless carbon steel pipes. After crevice corrosion occurs, it can rapidly develop into a deep and through seamless steel pipe. Pitting corrosion is very dangerous, especially for various high-pressure vessels. After corrosion has occurred, it should be sanded or painted immediately to prevent further corrosion.

2. Uniform corrosion. This means that all seamless pipes exposed to corrosive environments undergo chemical changes and suffer from uniform corrosion. This corrosion can accurately measure its corrosion rate and predict its corrosion degree. Based on precise measurements, its safety performance and lifetime can be set. Therefore, in many types of corrosion, uniform corrosion does not pose a risk, and the degree of corrosion of uniform corrosion is generally accurately measured and predicted based on the quality of the seamless steel pipe and the reduction in the thickness of the seamless steel pipe. In addition to the unique natural environment, the uniform corrosion rate of the seamless steel pipe is very low, the service life is long, and the maintenance cost is low.

3. Intergranular corrosion. It refers to corrosion along dislocations, breaking the connections between crystals. It will make the seamless steel pipe brittle or lose its compressive strength, which can easily cause safety accidents. Intergranular corrosion is the main corrosion mode of martensitic seamless steel pipe. This is because the dislocation region is different from the crystal composition or ground stress, which leads to a significant decrease in the electrode potential of the dislocation region, which in turn causes a difference in electrode potential.

4. Fatigue corrosion. It refers to the damage of seamless steel pipes under the action of corrosive substances and alternating ground stress, which is characterized by corrosion pits and many cracks. Significantly lowers the fatigue limit of seamless steel tubes, leading to premature rupture. The corrosion fatigue of seamless steel pipe is not the fatigue of mechanical equipment, it does not have a certain fatigue strength. As the frequency of the circulatory system increases, the fatigue limit decreases.

Therefore, the corrosion of seamless steel pipes can be divided into these four types, and the appropriate solution should be selected according to the specific situation.