Effects of corrosion of different water quality on stainless steel sewage pumps

Corrosion has always been one of the most headaches for water pumps. If you are not careful, you can damage the equipment at the least, and 

cause accidents or even cause disasters at the worst. According to relevant statistics, about 60% of the damage to chemical equipment is caused 

by corrosion. Therefore, when selecting chemical pumps, you must first pay attention to the scientific nature of the material selection.

There is usually a misunderstanding that stainless steel is a "universal material". It is very dangerous to bring out stainless steel regardless of the

 medium or environmental conditions. The following is a key point of material selection for some commonly used chemical media:

1. Sulfuric acid

As one of the strongly corrosive media, sulfuric acid is an important industrial raw material with a wide range of uses. Sulfuric acid at different 

concentrations and temperatures has great corrosion resistance to materials. For concentrated sulfuric acid with concentrations above 80% and 

temperatures less than 80℃, carbon steel and cast iron have good corrosion resistance, but it is not suitable for high-speed flowing sulfuric acid 

and is not suitable as a material for pump and valves.

Ordinary stainless steels such as 304 (0Cr18Ni9) and 316 (0Cr18Ni12Mo2Ti) are also of limited use for sulfuric acid media. Therefore, pumps and valves 

for conveying sulfuric acid are usually made of high silicon cast iron (casing and processing difficult) and high alloy stainless steel (alloy No. 20). 

Fluoroplastics have good sulfuric acid resistance, and using a fluorine-lined pump (F46) is a more economical choice. The company's suitable products

 include: IHF fluorine-lined pump, PF (FS) strong corrosion-resistant centrifugal pump, CQB-F fluorine-plastic magnetic pump, etc.

2. Hydrochloric acid

Most metal materials are not resistant to hydrochloric acid corrosion (including various stainless steel materials), and high molybdenum-containing 

ferrosilicon can only be used for hydrochloric acid below 50℃ and below 30%. In contrast to metal materials, most non-metallic materials have good 

corrosion resistance to hydrochloric acid, so lining rubber pumps and plastic pumps (such as polypropylene, fluoroplastic, etc.) are the best choices for 

transporting hydrochloric acid. The company's suitable products include: IHF fluorine-lined pump, PF (FS) strong corrosion-resistant centrifugal pump, 

CQ polypropylene magnetic pump (or fluoroplastic magnetic pump), etc.

3. Nitric acid

Generally, metals are rapidly corroded and damaged in nitric acid. Stainless steel is the most widely used nitric acid-resistant material and has good 

corrosion resistance for all concentrations of nitric acid at room temperature. It is worth mentioning that the corrosion resistance of molybdenum-containing 

stainless steel (such as 316, 316L) to nitric acid is not only not better than that of ordinary stainless steel (such as 304, 321), but sometimes even worse.