Stainless steel why is not easy to rust?

Stainless steel why is not easy to rust? Stainless steel is easy to rust and stainless steel composition has the very big relations. The composition of the stainless steel in addition to iron, chromium, nickel, and aluminum, silicon, etc. The general stainless steel contain chromium is generally not be less than 12%, high even to 18%. Steel with chromium after elements, can change the performance of the steel, such as an example the molecular structure of the steel more even, in steel surface are more likely to generate a dense layer of oxide film, so as to greatly improve the ability of stainless steel corrosion resistance. So stainless steel can resist fire, water and acid, alkali and all kinds of solution to its corrosion, not rust. The scientists found that, the internal structure of steel the uniform, all kinds of components is linked to the more closely, corrosion, the more difficult the invasion is, plus surface and a layer of oxide attached protective film, like to put on steel armor, nature is not easy to rust. Stainless steel why will rust? When stainless steel tube surface appear brown rusty spot (point), people by surprise: think "stainless steel is not rust, rust is not stainless steel, the likelihood is steel problems". Actually, this is the lack of understanding of stainless steel is a one-sided view wrong. Stainless steel in certain conditions will rust. Among them is the oxidation resistance of stainless steel atmospheric ability-stainless sex, also have in acid, alkali, salt is the medium of the corrosion of the ability-namely corrosion resistance. But the corrosion resistance of the size is with its steel itself chemical composition, and mutual status, the using conditions and environmental media types and change. Such as 304 steel pipe in dry, clean atmosphere, has the absolute good resistance to corrosion ability, but will move it to the coast, contains a lot of salt in the sea fog, will soon get rust; And 316 steel tube is good. Therefore, not any kind of stainless steel, in any environment can corrosion, not rust. Stainless steel is the formation of a surface by the very thin layer and strong close stable rich chromium oxidation film (a protective film), prevent the oxygen infiltration, continue to continue to oxidation and corrosion resistance of the ability to get. Once have some reason, this film was growing destruction, air or liquid oxygen will constantly seeping into or metal atoms constantly XiLi iron out, forming loose of iron oxide, metal surface also has been constantly rust. The surface film of the damage form many, daily life see more has the following kinds: 1. Save the stainless steel surface accumulate contain other metal elements of the metal particles of dust or alien attachments, in the humid air, adhesives and stainless steel the condensed water between, both a become a micro cells, causing the electrochemical reactions, protective film to sabotage, says "the electrochemical corrosion. 2. Stainless steel surface adhesion organic juice (such as melons, vegetables, noodles soup, phlegm, etc), with water oxygen cases, constitute organic acid, long time is organic acid corrosion of metal surface. 3. Stainless steel surface adhesion contains acid, alkali, salt material (such as decoration of wall buck, fluid of limewater spitting), cause local corrosion. 4. In air pollution (such as contains a lot of sulfur compounds, oxidation, carbon, nitrogen oxide atmosphere), encounter condensate, form sulfuric acid, nitric acid, acetic acid liquid point, cause chemical corrosion.