Prevention method of corrosion of seamless carbon steel pipe

As we all know, seamless carbon steel pipe has better corrosion resistance, is a kind of pipeline resistant to weak acid substances such as steam, and is widely used in our daily life. However, if the seamless pipe is directly placed in a strong alkali or strong acid environment, corrosion will also occur. Therefore, in order to avoid not affecting the use in the later period, it is necessary to do anticorrosion work in advance and maintain it well, so that it can be reasonably applied in production and life.

When we clean seamless steel pipes, whether we use some weak acidic substances for cleaning, we need to pay attention to the content of acidic substances, because if the acidic substances are too strong, it may have a certain impact on our environment, so we It needs to be wiped clean with clean water after cleaning, and do not leave residues on its surface. Some people have a misunderstanding, thinking that since strong acid cannot be used, then strong alkali should be used! However, do not use strong alkaline substances to directly clean the oil stains, because it will make the surface sluggish. The correct way is to just place it in a dry environment, which can reduce corrosion.

In fact, for now, the use of seamless steel pipes is very extensive. Most of them are made of ordinary carbon structural steel, low-alloy structural steel or alloy structural steel by rolling, and are usually used in production and manufacturing.

Why do buried seamless steel pipes need anti-corrosion? Carbon seamless line pipes also need to be anti-corrosion. Buried steel pipes will corrode the outside of the pipes when exposed to water and acidic, saline-alkali soils. Some pipes without anti-corrosion will crack and corrode within a few years, which will directly lead to the outflow of liquid in the pipes, causing environmental pollution and resource loss. It is a kind of loss. 3PE is the external anti-corrosion of the pipeline, and its product materials are three kinds, one is epoxy powder, the other is adhesive, and the third is polyethylene (PE). The service life of this process is 3-5 times that of the steel pipe without anti-corrosion. According to relevant data, the service life is more than 50 years.

Several types of corrosion common to seamless pipes

1. Pitting corrosion. It refers to a form of corrosion damage that occurs in part of the metal surface of the seamless steel pipe. After crevice corrosion occurs, it can rapidly develop into a deep, through seamless steel pipe. Pitting corrosion is very dangerous, especially for various high pressure vessels. After corrosion occurs, it should be polished or painted immediately to prevent further corrosion.

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

3. Intergranular corrosion. It refers to corrosion along dislocations, which destroys connections between crystals. It will make the seamless steel pipe brittle or lose its compressive strength, which can easily lead to safety accidents. Intergranular corrosion is the key corrosion method of martensitic seamless steel pipe. It is because the dislocation area and the crystalline composition or ground stress are different, resulting in a significant reduction in the electrode potential in the dislocation area, which in turn results in a difference in electrode potential.

4. Fatigue corrosion. Refers to the damage of seamless steel pipes under the action of corrosive substances and alternating ground stress, characterized by corrosion pits and many cracks. Significantly reduces the fatigue limit of seamless steel pipes, resulting in premature rupture. Corrosion fatigue of seamless steel pipe does not mean fatigue of mechanical equipment, it does not have a certain fatigue strength. With the increase in the frequency of the circulatory system, the fatigue limit is reduced.

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.