1. Sulfuric acid As one of the strong corrosive media, sulfuric acid is an important industrial raw material with a very wide range of uses. The corrosion of sulfuric acid with different concentrations and temperatures is quite different. For concentrated sulfuric acid with a concentration above 80% and temperature less than 80℃, carbon steel and cast iron have good corrosion resistance, but it is not suitable for high-speed flowing sulfuric acid. It is not suitable for use as a material for pump valves; ordinary stainless steels such as 304 (0Cr18Ni9) and 316 (0Cr18Ni12Mo2Ti) have limited use for sulfuric acid media. Therefore, pump valves for transporting sulfuric acid are usually made of high-silicon cast iron (difficult to cast and process) and high-alloy stainless steel (alloy 20). Fluoroplastics have better resistance to sulfuric acid, and fluorine-lined valves are a more economical choice.
2. Acetic acid is one of the most corrosive substances in organic acids. Ordinary steel will be severely corroded in acetic acid at all concentrations and temperatures. Stainless steel is an excellent acetic acid resistant material. 316 stainless steel containing molybdenum is also suitable for high temperature and Dilute acetic acid vapor. For demanding requirements such as high temperature and high concentration of acetic acid or containing other corrosive media, high alloy stainless steel valves or fluoroplastic valves can be selected.
3. Hydrochloric acid Most metal materials are not resistant to hydrochloric acid corrosion (including various stainless steel materials), and high-silicon ferro-molybdenum can only be used in hydrochloric acid below 50°C and 30%. Contrary to metal materials, most non-metal materials have good corrosion resistance to hydrochloric acid, so rubber valves and plastic valves (such as polypropylene, fluoroplastics, etc.) are the best choice for transporting hydrochloric acid.
4. Nitric acid. Most metals are rapidly corroded in nitric acid. Stainless steel is the most widely used nitric acid resistant material. It has good corrosion resistance to all concentrations of nitric acid at room temperature. It is worth mentioning that stainless steel containing molybdenum (such as The corrosion resistance of 316, 316L) to nitric acid is not only inferior to ordinary stainless steel (such as 304, 321), and sometimes even inferior. For high temperature nitric acid, titanium and titanium alloy materials are usually used.
Post time: Sep-26-2021