Material selection for Desmi gear pumps and Rotan pumps

Material Selection for DESMI ROTAN Gear Pumps

According to statistics, approximately 60% of chemical pump failures are caused by corrosion. 

Therefore, when selecting a chemical process pump, scientific material selection is paramount. 

There is a common misconception that stainless steel is a "universal material," requiring stainless 

steel pumps to be used regardless of the medium or environmental conditions. This is highly dangerous.

1. Acetic acid: This is one of the most corrosive organic acids. Ordinary steel will be severely corroded in acetic acid at all concentrations and temperatures. Stainless steel is an excellent material for acetic acid-resistant chemical process pumps. Molybdenum-containing 316 stainless steel is also suitable for high temperatures and dilute acetic acid vapor. For demanding requirements such as high-temperature, high-concentration acetic acid or other corrosive media, high-alloy stainless steel chemical process pumps or chemical process pumps made of fluoroplastics can be selected.

2. Hydrochloric Acid: Most metals are not resistant to hydrochloric acid corrosion (including various stainless steels). Molybdenum-containing

 high-silicon iron can only be used in hydrochloric acid below 30% at temperatures of 50°C. In contrast, most non-metallic materials have 

good corrosion resistance to hydrochloric acid. Therefore, rubber-lined pumps and plastic chemical process pumps (such as polypropylene

 and fluoroplastics) are the best choices for transporting hydrochloric acid.

3. Nitric Acid: Most metals are rapidly corroded and damaged in nitric acid. Stainless steel is the most widely used material for nitric 

acid-resistant chemical process pumps, offering excellent corrosion resistance to all concentrations of nitric acid at room temperature.

 It is worth noting that molybdenum-containing stainless steels (such as 316 and 316L) are not only not as resistant to nitric acid as 

ordinary stainless steels (such as 304 and 321), but sometimes even worse. For high-temperature nitric acid chemical process pumps, 

titanium and titanium alloys are commonly used.

4. Sulfuric acid. As one of the most corrosive media, sulfuric acid is an important industrial raw material with a wide range of applications.

 Sulfuric acid has significant corrosion effects on materials at different concentrations and temperatures. Carbon steel and cast iron offer 

good corrosion resistance for concentrated sulfuric acid with concentrations above 80% and temperatures below 80°C. However, they 

are not suitable for high-speed sulfuric acid chemical process pumps. Ordinary stainless steels such as 304 (0Cr18Ni9) and 316 

(0Cr18Ni12Mo2Ti) also have limited use in sulfuric acid media.

Therefore, chemical process pumps used to transport sulfuric acid are typically manufactured from high-silicon cast iron (which is 

difficult to cast and process) or high-alloy stainless steel (Alloy 20). Fluoroplastics have excellent resistance to sulfuric acid, making 

fluorine-lined chemical process pumps (F46) a more economical option.

To learn more, please click：https://www.dfinsewagepump.com/DESMI-ROTAN-Gear-Pumps.html