Stainless vacuum pump is one of the most common corrosion-resistant vacuum pumps. EVP vacuum pump manufacturers have also introduced various corrosion-resistant vacuum pumps, including stainless steel vacuum pumps, to cope with various complex corrosion environments in chemical and pharmaceutical industries. But there are many kinds of stainless steel. What’s the difference between different stainless steel? Let EVP vacuum pump manufacturer introduce several kinds of stainless steel which may be involved in the vacuum system step by step for you.
First we need to know, what is stainless steel? In the application of stainless steel vacuum pump, how to achieve anti-rust and anti-corrosion?
Simply put, stainless steel refers to iron-based alloys with chromium content greater than 10.5%, stainless and corrosion resistance.
Stainless steel and corrosion resistance are relative, play a key role, is the alloy element chromium, due to the formation of chromium-rich oxide film (passivation film) on the metal surface, resulting in rust and corrosion resistance characteristics. At the same time, it is a kind of low carbon steel. Its stainless corrosion resistance decreases with the increase of carbon content.
Practice shows that in weak medium such as atmosphere, water and oxidizing medium such as nitric acid, the rust and corrosion resistance of steel increases with the increase of chromium content in steel. When chromium content reaches a certain percentage, the rust and corrosion resistance of steel will change abruptly, that is, from easy to rust, from corrosion resistance to corrosion resistance, and when chromium content reaches a certain percentage. When the amount increases to a certain value, its corrosion resistance tends to be stable.
Stainless steel has experienced a century of development since its invention. With the addition of more elements such as nickel and molybdenum, more than 100 kinds of industrial stainless steel have been formed. According to the different proportion of each element, its rust and corrosion resistance characteristics will also be different. Therefore, in the application field of stainless steel vacuum pumps, stainless steel vacuum pumps are different under different working conditions.
Therefore, the diversity of stainless steel also leads to many classification methods of stainless steel:
According to the structure, there are five types of stainless steel: martensite, austenite, ferrite, duplex stainless steel (austenite + ferrite) and precipitation hardening stainless steel.
According to the main chemical composition, it can be divided into two systems: chromium stainless steel and Chromium-Nickel Stainless steel.
According to the use, there are nitric acid resistant stainless steel, sulfuric acid resistant stainless steel, seawater resistant stainless steel and so on.
According to the types of corrosion resistance, it can be divided into pitting corrosion resistant stainless steel, stress corrosion resistant stainless steel and intergranular corrosion resistant stainless steel.
According to the functional characteristics, it can be divided into non-magnetic stainless steel, free cutting stainless steel, low temperature stainless steel, high strength stainless steel and so on.
Stainless steel has been widely used in various industries because of its excellent corrosion resistance, formability, compatibility and toughness in a wide temperature range.
Stainless vacuum pumps are widely used in our life. The materials of vacuum pumps on the market are also various.