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{electrochemical corrosion
The corrosion phenomenon of stainless steel at high temperature is mentioned earlier. Next, let's talk about the corrosion of stainless steel at room temperature. It is necessary to know that temperature has a great relationship with the oxidation resistance of stainless steel, because the surface oxidation temperature of different stainless steel is different, so the correct selection of stainless steel should be considered at what temperature, and then consider other aspects of the performance and requirements. Here, we should have a little understanding of stainless steel, stainless steel is conditional. So, how does the electrochemical corrosion happen? First of all, it should be known that the elements of the material world and the composition of the compounds have different electrode potential (electrode potential), that is to say, there is an electrode potential between different substances. Once a solution or electrolyte is used to enrich two substances, a battery circuit is created to form a micro current. This means that electrical corrosion is a common phenomenon.304 tubo de acero inoxidable sin soldadura OD10mm
Some factors of point corrosion321 tubo de acero inoxidable hecho en China
(1) inclusions on the surface of stainless steel: there are inclusions on the surface, such as oxide, sulfide, silicate and so on. If the surface is accompanied by a water solution, the water is electrolyzed between two substances, the water is produced by the micro current, the water electrolysis is hydrogen ion and hydrogen oxygen ion, and the hydrogen and oxygen ions can react with chromium to become chromium hydroxide and corrode.
2. Rough surface of stainless steel: there are rough surfaces such as pitting or pitting on the surface. The rough surface is easy to deposit the suspended particles in the air (dust), and the dust adsorbs the water in the air. Thus, the water is present. The water is electrolyzed under the electrode potential of the two material, and the hydrogen and oxygen ions are decomposed, and the hydrogen and oxygen ions are corrupted with chromium.
Chlorine ion environment: when the surface of stainless steel is in the atmosphere of chloride ion, the chloride ion selectively destroys the surface passivation film. The selectivity is because there are inclusions, rough points, composition segregation and mechanical properties difference on the surface of the stainless steel. Chlorine ions are electrolytes, chloric ions and oxygen can produce hypochloric acid, hydrogen oxygen ions and chromium. The chromium hydroxide is formed by reaction. Once the passivation film is destroyed, the corrosion concentration will occur, also known as pitting corrosion.Sch 40 soldado redondo tubo de acero inoxidable precio
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| Beitrag vom 25.06.2018 - 10:56 |
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