Corrosion causes in steel pipe plants
If corrosion occurs in steel pipe, it will affect the application of steel pipe and increase the economic cost. Corrosion of steel pipe can be divided into four kinds, and the following will be a specific introduction for you.
1. Intergranular corrosion. It refers to corrosion along the dislocation, which destroys the connections between the crystals. This kind of corrosion is very harmful, it will make the steel pipe brittle or lose the compressive strength, very easy to lead to safety accidents. Intergranular corrosion is the key corrosion mode of martensitic steel pipe. It is due to the difference of the composition or in-situ stress between the dislocation zone and the crystallization, which leads to the obvious reduction of the electrode potential in the dislocation zone and the difference of electrode potential.
2. Symmetrical corrosion. This means that all the steel pipes exposed to the corrosive natural environment will have chemical changes and suffer symmetrical corrosion. This type of corrosion can accurately measure the corrosion rate and predict the corrosion level. According to the accurate measurement results, the safety performance and service life can be set. Therefore, in many types of corrosion, symmetrical corrosion is not a risk, the corrosion level of symmetrical corrosion is generally based on the quality of the steel pipe and the reduction of the thickness of the steel pipe to accurately measure and predict the analysis. In the unique natural environment, steel pipe symmetrical corrosion rate is very low, long service life, low maintenance cost.
3. Spot corrosion. It is a kind of corrosion damage that occurs in some areas of the metal surface of the steel pipe. After crevice corrosion occurs, it can quickly develop a tendency to go deep through the steel pipe. Point corrosion is very harmful, especially to various high-pressure vessels. After corrosion, it should be polished or painted immediately to prevent further corrosion.
