What reason is 316 stainless steel angle bar rust?

316 stainless steel angle bar as matrix is beyond 60%, for complex high alloy steel, nickel, molybdenum and other alloying elements, its biggest characteristic is corrosion resistant ability strong, but not rust stainless steel is not absolute. In coastal areas, or some severe air pollution in local truly, when the chloride ion content in the air is larger, disclosed in stainless steel appearance atmosphere could have some rusty spot, but only the rust stain appearance, not erosion inside stainless steel substrate. On the ocean, 304 stainless steel angle bar, there is no 316 stainless steel angle bar corrosion resistant performance is good.

Stainless steel angle bar under the condition of must also will rust. Stainless steel has arrived when atmospheric oxidation ability - that is, stainless, and have in acid, alkali, salt corrosion medium is not easy to - corrosion resistance. But its corrosion resistant ability of intrusive is with its own chemical composition of steel, and each form, use conditions and types of medium and modifying. Stainless steel is to rely on the appearance of a layer of thin and solid precision constant rich chromium oxide film (protective film), avoiding continuous oxygen atoms of continuous infiltration and oxidation, and corrosion resistance ability. Once you have a reason, make the make the appearance of membrane destroyed will constitute a rusty spot.
Stainless steel angle bar rust form has the following several reasons:
A.. Deposited on stainless steel angle bar surface or heterogeneous metal particles of dust of other metal elements attachments, in the humid air, vapour, both between the attachments and stainless steel together as a micro battery, motivated by the electrochemical reaction, maintain membrane have been damaged, called the electrochemical corrosion.
B. stainless steel angle bar adhesion appearance with organic matter (such as melon seeds, noodle soup, sputum, etc.), oxygen in water conditions, composed of organic acid, long time is organic acid corrosive to metal surface.
C. stainless steel angle bar adhesion appearance with acid, alkali, salt substances (e.g., decorate the walls of caustic soda and lime water splash), a department of corrosion.
D. where there is pollution in the air (e.g., contains a lot of sulfur, carbon oxide, atmospheric nitrous oxide), stainless steel angle bar in water vapor, sulfuric acid, nitric acid, acetic acid, liquid, provoked chemical corrosion.
5. Appearance is stainless steel angle bar weapon damage, and then destroy the appearance of a protective film.
"Accordingly, stainless steel angle bar is not rust is not absolute, but a relative and conditional. Such as; 304 stainless steel angle bar, 316 stainless steel angle bar. Until the current is not under any circumstances not rust stainless steel Angle, but, still can only correct use and protection of persistent stick to the light and do not rust.
Source: Zhejiang Yaang Pipe Industry Co., Limited (www.yaang.com)