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Why is stainless steel bars of pipe rust?aren't you buy stainless steel is not stainless steel?
Mar 12, 2017

Why is stainless steel rust? 

Stainless steel has the ability of resistance to atmospheric oxidation –we call the stainless, also has in the medium containing acid, alkali, salt corrosion – we call the ability of corrosion resistance.But the ability to resist corrosion was changed by the chemical composition of steel itself, and the proessing of state, using conditions and environmental medium type etc. For example,As 304 steel bar or tube, in dry, clean atmosphere, have absolute good corrosion resistance, but it will be moved to the coastal areas, in contains a great deal of sea salt fog, will soon be rusty;But 316 steel bar or316 tube is good.So,not any kind of stainless steel, in any environment corrosion, no rust.  

Stainless steel is not easy to rust because the finish of stainless steel formed on the surface of a layer of a very thin and fine and stable solid rich chromium oxide film (protective film), prevent oxygen to infiltration, continue to oxidation,and ability to resist corrosion.Once some reason caused this film has been continuously destroyed,oxygen atom in the air or liquid oxygen will constantly infiltration or metallic iron atom separation out unceasingly, forming loose iron oxide, the metal(stainless steel) Surface are also constantly rust. 

There are so many kinds of way to damage and distroy the oxide film,distroy the protective film,below are the ways in daily living has the following kinds: 

  1. Deposited on the surface of the stainless steel contain other metals attached or heterogeneous metal particles of dust of the content, in the humid air,attachments and condensed water between the stainless steel, will both together as a micro battery, triggers the electrochemical reaction, protective film is damaged, to call the electrochemical corrosion.

  2. The stainless steel surface adhesion organic fluids (such as melon seeds, noodle soup, sputum, etc.), under the condition of water,oxygen,formed organic acid, if time is long the organic acid will do the metal corrosion of stainless steel surface.

  3. The stainless steel surface adhesion containing acid, alkali, salt substances (e.g., decorate the walls of caustic soda, stone splash water,even sweat etc), cause local corrosion.

  4. When the stainless stand Where there is pollution in the air (e.g., contains a lot of sulfur, carbon oxide, atmospheric nitrous oxide), encounter condensation water, formation of sulfuric acid, nitric acid, acetic acid, liquid, chemical corrosion.

The above situation can be caused by the destruction of the stainless steel surface protective film cause corrosion. So, in order to ensure the surface of the permanent bright metal, will not be rust: 

  1. Decorative stainless steel surfaces must often sweep clean, remove attachments, eliminate the cause of external factors.

  2. The coastal areas to use material 316 stainless steel, 316 material corrosion resistance to sea water.

  3. Some chemicals stainless steel bars or tube on the market not accords with relevant national standards, such as nickle,chrome contents is lower So can also cause rust.

Therefore, when you buying stainless steel,please choose reputable manufacturer product carefully such as Shaanxi Ruiyang company,specially produce and supply stainless steel bars(stainless steel round bars,stainless steel flat bars,stainless steel angle bars,stainless steel square bars,stainless steel hex bars),stainless steel pipes(stainless tube,stainless steel seamless pipe,stainless round tube,stainless steel rectangular tubing,stainless steel square tubing,welded stainless steel tube)and others customed. 

Quality Assure:

1)Basic control(chemical components control) Guarantee of the chemical components:smelting and direct-reading spectrum test could guarantee the material chemical components is right for the clients’ requirements 

2)Process control:follow the process chart adding our workers’ care 

3)Inspection control:visual inspection and with inspection tools 


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