1. Sulfuric acid medium: As one of the strong corrosive media, sulfuric acid is an important industrial raw material with a wide range of uses. Sulfuric acid with different concentrations and temperatures has a large difference in corrosion of materials. For concentrated concentrations with concentrations of more than 80%and less than 80 ° C, carbon steel and cast iron have good corrosion resistance, but it is not suitable for high -speed flow sulfuric acid. It is not applicable to the material of the pump valve; ordinary stainless steel such as 304 (0CR18NI9) and 316 (0CR18NI12MO2TI) are also limited to sulfuric acid medium. Therefore, the pump valve that transports sulfuric acid is usually manufactured with high silicon cast iron (casting and processing difficulty) and high alloy stainless steel (alloy 20). Fluor plastic has good sulfur resistance, and the use of fluorine -lining pump valve (F46) is a more economical choice.
2. Medium hydrochloric acid medium: Most metal materials are not resistant to corrosion of hydrochloric acid (including various stainless steel materials), and molybdenum high -silicon iron can also be used only for 50 ° C and 30%of hydrochloric acid. Contrary to metal materials, most non -metallic materials have good corrosion resistance to hydrochloric acid. Therefore, inner lining rubber pumps and plastic pumps (such as polypropylene, fluoroplastics, etc.) are good choices for transporting hydrochloric acid.
3. Nitric acid medium: Generally, most metals are quickly corroded and destroyed in nitric acid. Stainless steel is a widely used nitrogen -resistant material. It has good erosion resistance for all concentrations of all concentrations at room temperature. For example, 316, 316L) is not only better than ordinary stainless steel (such as 304, 321), and sometimes not as good as ordinary stainless steel. For high temperature nitric acid, titanium and titanium alloy materials are usually used.
