When the stainless steel tube surface appear brown rust (point) when people are surprised: "the stainless steel does not rust, rust is stainless steel, steel may be a problem". In fact, this is a one-sided view of the lack of understanding of the stainless steel. Stainless steel will rust under certain conditions.
Stainless steel has the ability to resist oxidation of the atmosphere --- that is, not rust, but also has the acid, alkali, salt in the medium of corrosion resistance capacity --- that is, the corrosion resistance of. But its corrosion resistance is the size of steel with its own chemical composition, increase mutual status, conditions of use and environmental changes in the type of media. Such as the 304 steel pipe, in the dry clean atmosphere, have absolutely excellent anti-corrosion ability, but it will be moved to the beach area, with large amounts of sea salt fog, will rust quickly; and the good performance of 316 steel pipe. Therefore, not any kind of stainless steel, can in any environment corrosion, no rust.
Stainless steel is a very thin layer formed on the surface and the stability of the fine solid chromium rich oxide film (protective film), to prevent the infiltration of oxygen atoms, to oxidation, and the ability to obtain anti-corrosion. Once there are some reasons, this film was constantly destroyed, air or liquid oxygen atoms will continue to infiltrate or metal atoms of iron to keep out from the loose formation of iron oxide, the metal surface will be continuously corroded. This kind of surface film is destroyed in the form of a lot of daily life more than the following are the following:
1, stainless steel multistage pump stainless steel surface deposited dust or heterogeneous metal particles containing other metal elements of the attachment, in the humid air, condensed water and adhesion between the stainless steel, the two together into a micro battery, causing the electrochemical reaction, the film has been destroyed, called electrochemical corrosion.
2, stainless steel surface adhesion containing acid, alkali and salts (such as wall decoration, soda lime water splash), caused by local corrosion.
3, stainless steel multistage pump stainless steel surface adhesion of organic juice (such as vegetables, soup, sputum), oxygen in the water under the circumstances, a long time, organic acid, organic acid on the surface of metal corrosion.
4, stainless steel multi-stage pump in the contaminated air (such as containing a large amount of sulfur dioxide, carbon dioxide, nitrogen oxide atmosphere), in case of condensation of water, sulfuric acid, nitric acid, acetic acid liquid point, causing chemical corrosion.
All the above conditions can cause the damage of the surface protective film of the stainless steel. So, in order to ensure that the metal surface permanent light, not to be corroded, we suggest that:
1, must often clean the stainless steel surface cleaning, remove attachments, eliminate the external factors that lead to modification.
2, the coastal area to use 316 stainless steel pipe material, 316 material can resist the corrosion of sea water.
3, some stainless steel tubes in the market can not meet the corresponding national standards, up to 304 material requirements. So it will cause rust, which requires the user to carefully choose a reputable manufacturer of products.