Corrosion can be divided into wet corrosion and dry corrosion two categories. Wet corrosion refers to the corrosion of metal materials in the presence of water. Dry corrosion refers to corrosion in dry gas in the absence of liquid water. Because the atmosphere generally contains water and chemical production often deal with various aqueous solutions, wet corrosion is the most common, but the harm caused by dry corrosion during high temperature operation can not be ignored.

The following points for some common chemical media to talk about corrosion resistance centrifugal pump selection:

1. sulfuric acid medium as one of the strong corrosive medium sulfuric acid is a very wide range of important industrial raw materials. Sulfuric acid with different concentrations and temperatures has great difference in corrosion to materials. Carbon steel and cast iron with concentrated sulfuric acid with concentration above 80 and temperature less than 80 ℃ have good corrosion resistance, but it is not suitable for high-speed flowing sulfuric acid, which is not suitable for pump valve materials. Ordinary stainless steel such as 3040 Cr18Ni9 and 3160Cr18Ni12Mo2Ti are also of limited use to sulfuric acid medium. Therefore, the pump valve for conveying sulfuric acid is usually made of high silicon cast iron and difficult to process, high alloy stainless steel alloy 20, but its processing is difficult and expensive, so it is not favored by people. Fluoroplastic alloy has good sulfuric acid resistance. It is a patented material of Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences. The patented technology introduced by our company in 1985 was the first to use it to develop and produce corrosion-resistant chemical pumps. Experiments by Chinese Academy of Sciences have proved that there is no chemical medium that can react with it. Therefore, using fluorine-lined pump F46 is a more economical choice. The applicable products of Sanchang Company include IHF fluoroplastic chemical pump, FSB fluoroplastic centrifugal pump, IGF fluorine-lined pipeline pump, PF corrosion-resistant centrifugal pump, CQB-F fluoroplastic magnetic pump, etc.

2. Hydrochloric Acid Medium Most metal materials are not resistant to hydrochloric acid corrosion, including various stainless steel materials containing molybdenum and high silicon iron, which can only be used for hydrochloric acid below 50 ℃ and 30 ℃. In contrast to metal materials, most non-metallic materials have good corrosion resistance to hydrochloric acid, so lined rubber pumps and plastic pumps such as engineering plastics and fluoroplastics are the best choice for conveying hydrochloric acid. Sanchang company applicable products are fluorine plastic chemical pump series can be.

3. Nitric acid General metal mostly in nitric acid is rapidly corroded stainless steel corrosion-resistant centrifugal pump is the most widely used nitric acid centrifugal pump has good corrosion resistance to all concentrations of nitric acid at room temperature. It is worth mentioning that the corrosion resistance of molybdenum stainless steel such as 316, 316L to nitric acid is not better than that of ordinary stainless steel such as 304, 321 and sometimes even worse. For high temperature nitric acid, fluoroplastic alloy materials are usually used. The applicable products of Sanchang Company include IHF fluoroplastic chemical pump, FSB fluoroplastic centrifugal pump, IGF fluorine-lined pipeline pump, PF corrosion-resistant centrifugal pump, CQB-F fluoroplastic magnetic pump, etc.

4. Acetic acid is one of the most corrosive substances in organic acids. Ordinary steel will seriously corrode stainless steel in all concentrations and temperatures of acetic acid. It is an excellent acetic acid resistant material. Molybdenum-containing 316 stainless steel can also be applied to high temperature and dilute acetic acid vapor. For high temperature and high concentration acetic acid or containing other corrosive media and other harsh requirements can choose high alloy stainless steel magnetic pump or fluorine plastic chemical pump such as CQB type stainless steel magnetic pump, CQ type magnetic drive pump, stainless steel pipeline centrifugal pump, stainless steel chemical pump.