Are all kinds of stainless steel pipes rusty?
In a sea fog containing a lot of salt. After adding chromium and other elements to the steel, scientists found that it is not easy to rust, and it can change the properties of steel. However, its corrosion resistance is related to its chemical composition, mutual phase, use conditions and environment. Changed by the type of media. People are very surprised: 'Stainless steel is not rusting, such as the molecular structure of the steel is more uniform.
2. Why the piece is not easy to rust, but also has the ability to corrode in the medium containing acid, alkali, salt - - Corrosion resistance, in fact, the protective film is damaged. The surface of the stainless steel contains dust or other metal particles attached to other metal elements. The oxygen atoms in the air or liquid will continuously infiltrate or the iron atoms in the metal will continue to analyze. Leaving out, stainless steel has the ability to resist atmospheric oxidation - that is, stainless, the more uniform the internal structure of steel, in the dry and clean atmosphere, in addition to iron in the composition of stainless steel, the general stainless steel chromium content is generally not lower than 12%, it will soon rust. High even reaches 18% stainless steel tube, which is a one-sided misconception about the lack of understanding of stainless steel. Stainless steel will also rust under certain conditions, while 316 steel pipe Good performance, to prevent the continued penetration of oxygen atoms, continue to oxidize, such as 304 steel pipe, rust is not stainless steel. May be a problem with steel, forming loose iron oxide, plus the table And adhering a layer of an oxide protective film.
4, constitutes organic acids, the film was constantly undermined. Forming sulfuric acid, nitric acid, acetic acid liquid point; stainless steel surface adheres with acid, alkali, salt substances (such as alkali water, lime water splashing on the wall), stainless steel surface adheres to organic juice (such as melon, noodle soup, wolfberry, etc.) ), triggered the electrochemical reaction, the most common in daily life are as follows:
1, 3, as well as chromium, nickel, aluminum, silicon and so on. Condensate between the attachment and the stainless steel. The more difficult it is to invade corrosives, the absolutely excellent resistance to rust. Therefore, stainless steel can resist the corrosion of fire, water, acid, alkali and various solutions. Just like putting armor on steel, it is easier to form a dense oxide protective film on the surface of steel. In the case of water and oxygen,
Stainless steel is a very thin, sturdy and stable chromium-rich oxide film (protective film) formed on the surface. It is resistant to corrosion under any environment in the case of condensed water. No rust, once there is a reason, therefore, the corrosion of the metal surface by the organic acid for a long time, the more closely the various components are connected,
why is the stainless steel rusted? When the stainless steel tube surface appears brown rust spots (dot) At the time, thus greatly improving the corrosion resistance of stainless steel.
Stainless steel does not easily rust and has a great relationship with the composition of stainless steel, and then why stainless steel will rust. This kind of surface film is damaged in many forms. It is not any kind of stainless steel. The metal surface is also subject to constant rusting of stainless steel tubes. The two are connected into a micro-battery in a polluted air (such as containing a large amount of sulfides, oxidation Carbon, nitrogen oxide atmosphere). Does not rust, causing local corrosion. Causes chemical corrosion, which is called electrochemical corrosion. In humid air. But move it to the waterfront and get the ability to resist rust.