Views: 0 Author: Site Editor Publish Time: 2024-06-05 Origin: Site
The material selection of metering pump must be corrosion resistant. Corrosion has always been one of the dangers of chemical equipment. If you are not careful, it will damage the equipment, causing accidents and even disasters. According to relevant statistics, about 60% of the damage to chemical equipment is caused by corrosion. Therefore, the selection of chemical pumps should pay attention to the scientific nature of material selection, and stainless steel is generally considered to be the 1 general-purpose material. It is dangerous to store stainless steel in any medium and environment.
1. nitric acid general metal is mostly rapidly corrosion damage, stainless steel is widely used nitric acid resistant material has good corrosion resistance, all concentrations of nitric acid at room temperature, 1 is worth mentioning that the corrosion resistance of molybdenum-containing stainless steel (316, 316L) to nitric acid is not only no better than ordinary stainless steel (such as 304,321), sometimes even worse. High temperature nitric acid, usually titanium and titanium alloy.
2. Most metal materials are not resistant to hydrochloric acid corrosion (including all kinds of stainless steel), molybdenum high silicon iron can also be used in hydrochloric acid at 50C and 30%. On the contrary, most non-metallic materials and metal materials have good hydrochloric acid corrosion, so lined rubber pumps and plastic pumps, such as polypropylene fluoroplastics, are a good choice for conveying hydrochloric acid.
3. As one of the strong corrosive media, sulfuric acid is 1 important industrial raw material and is widely used. Different concentrations of sulfuric acid corrosion material temperature difference, sulfuric acid concentration is greater than 80%, the temperature is lower than 80 ℃, carbon steel and cast iron have good corrosion resistance, but not suitable for high-speed sulfuric acid flow, not suitable for ordinary stainless steel valve materials; such as 304(0 Cr18Ni9), 316(0 Cr18Ni12Mo2Ti) sulfuric acid is also of limited use. Therefore, the pump valve for conveying sulfuric acid is usually made of high silicon cast iron (difficult casting and machining) and high alloy stainless steel (alloy 20). Fluoroplastics has a good sulfuric acid distance, and the use of lining fluorine pump (F46) is the 1 more economical choice.
4. ammonia (ammonia hydrogen oxide), most metals and non-metals in liquid ammonia and ammonia corrosion is very slight, only copper and copper alloy is not suitable for use.
5. Sodium hydroxide (sodium hydroxide) steel is widely used in sodium hydroxide solution, the concentration is below 80 and 30%. Many factories still use ordinary steel at 100 and 75%, although corrosion increases, but the economy is good. The corrosion resistance of ordinary stainless steel in alkaline solution has no obvious advantage compared with cast iron, as long as a small amount of iron is allowed, and does not recommend the use of stainless steel. In high temperature alkaline solution, titanium and titanium alloy or high alloy stainless steel is used.
6. Acetic acid is one of the corrosive substances in organic acids. Ordinary steel is severely corroded by acetic acid at all concentrations and temperatures. Stainless steel is an excellent acetic acid resistant material, molybdenum-containing 316 stainless steel, can also be applied to high temperature and dilute acetic acid vapor. High alloy stainless steel or fluorine plastic pump can be used for high temperature and high concentration acetic acid or other demanding corrosive medium.
7. The common alcohol media of alcohols, ketones, esters and ethers include methanol, ethanol, ethylene glycol, ethanol, ketoacetone and butanone. The methyl, ethyl and ether media of various media include methyl ether, ethyl ether, butyl ether, etc. They are basically non-corrosive materials and can be used to make reasonable choices according to the nature of the medium and the relevant requirements of specific uses. It is worth noting that ketones, esters, and ethers are dissolved in various rubbers to avoid errors in the selection of sealing materials.
8. salt water (sea water) ordinary steel in sodium chloride solution and seawater, salt water corrosion rate is not high, generally require the use of paint protection; all kinds of stainless steel has a very low corrosion rate, but may be due to local corrosion caused by chloride ions, generally 316 stainless steel is better.
The above content is to give you a detailed explanation of the effect of different materials on the metering pump, I believe everyone has further study and understanding. If you want to know more information, please continue to pay attention to us.
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