Safety problems of stainless steel sheet

Stainless steel plate since the beginning of the 20th century, has a history of more than 1 century. The stainless steel plate surface is smooth, has higher plasticity, toughness and mechanical strength, acid, alkaline gas, solution and other media corrosion. It is an alloy steel that does not rust easily, but is not absolutely rust free. Stainless steel plate refers to the atmosphere, steam and water and other weak medium corrosion of steel plate, and acid steel plate is acid, alkali, salt and other chemical corrosion medium corrosion of steel plate. However, we should also understand that stainless steel plates will rust and be corroded.

Here is the content list:

l  Rusting

l  corrosion

Rusting

Stainless steel has the ability to resist atmospheric oxidation, that is, the performance of stainless steel, but also has the ability to resist corrosion in the medium containing acid, alkali and salt, that is, corrosion resistance. However, its corrosion resistance depends on the chemical composition of the steel itself, the state of each other, the use conditions and the type of environmental media. But for some reason, this film is constantly destroyed, air or liquid neutralizing oxygen atoms will continue to infiltrate or metal iron atoms continue to precipitate out, forming a relatively loose iron oxide is stainless steel rust. General stainless steel is very easy to rust in the environment of high air humidity, high pH in the air or high pH solution. Of course, the steel smelting process will also affect the corrosion resistance of stainless steel, smelting technology is good, advanced equipment, advanced process, alloy element proportion control is good, the high proportion of impurities removal, billet cooling temperature control is good and not easy to rust, if the surface damage is easy to rust.

Corrosion

The corrosion resistance of stainless-steel plate mainly depends on its alloy composition (chromium, nickel, titanium, silicon, aluminum, manganese, etc.) and the internal organizational structure, the main role is chromium element. Chromium has very high chemical stability, can form a passivation film on the surface of the steel, so that the metal is isolated from the outside world, protect the steel plate from oxidation, increase the corrosion resistance of steel plate. After the destruction of the passivating film, the corrosion resistance decreases. Following are the corrosion conditions:

l  Stainless steel surface deposited with dust containing other metal elements or similar metal particles of the attachment, in the humid air, the attachment and stainless-steel condensate between the two together into a micro battery, triggered an electrochemical reaction, the protective film is damaged, called electrochemical corrosion.

l  Stainless steel surface adhesion of organic juice (such as vegetables, noodle soup, sputum, etc.), in the case of water and oxygen, constitute organic acids, long time is the corrosion of organic acids on the metal surface.

l  Stainless steel surface adhesion contains acid, alkali, salt substances (such as decoration walls of alkali, limestone splashing), causing local corrosion.

l  In the polluted air (such as containing a large amount of sulfide, carbon oxide, nitrogen oxide atmosphere), in case of condensate, the formation of sulfuric acid, nitric acid, acetic acid liquid point, cause chemical corrosion above circumstances can cause the destruction of stainless steel surface protective film caused by corrosion.

Stainless steel plate is generally stainless steel plate and acid-proof steel plate. At the beginning of this century, the development of stainless steel plate for the development of modern industry and scientific and technological progress has laid an important material and technical foundation. There are many kinds of stainless steel plates with different performances. Although stainless steel plate has certain safety problems, it is still the first choice of many steels.