What Is A Corrosion-resistant Pump, And What Corrosion-resistant Materials Are There?

What is a corrosion-resistant pump? A corrosion-resistant pump is a type of pump pump, but the liquid it transports is not water. The pH value of the water is neutral and the corrosion is not high. However, when the liquid pH value is high or low, it involves the corrosion of acid and alkali liquids. Generally, civil water pumps use a very high one-time damage rate, mainly because overflow components have no corrosion-resistant materials, and are severely damaged when corrosion occurs.There are many materials for anti-corrosion pumps, which are roughly divided into metal corrosion-resistant pumps and non-metal corrosion-resistant pumps.Corrosion has always been one of the dangers of headaches in chemical equipment. If you are not careful, you can damage the equipment at the least, and cause accidents or even cause disasters at the worst.There is usually a misunderstanding that stainless steel is a good material, and it is very dangerous to bring out stainless steel pumps regardless of the medium and environmental conditions.The following is a key point for choosing corrosion-resistant pump materials for some commonly used chemical media: 1. 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 lined rubber pumps and plastic pumps (such as polypropylene, fluoroplastic, etc.) are the best choices for transporting hydrochloric acid.2. Acetate is one of the highly corrosive substances among organic acids. Ordinary steel will seriously corrode in acetic acid at all concentrations and temperatures. Stainless steel is an excellent acetic acid-resistant material. Molybdenum-containing 316 stainless steel can also be suitable for high temperature and dilute acetic acid steam.For high-temperature and high-concentration acetic acid or other corrosive media, high-alloy stainless steel pumps or fluoroplastic pumps can be used.3. Sulfuric acid is one of the strongly corrosive media, and 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 pump and valve materials; ordinary stainless steels such as 304 (0Cr18Ni9) and 316 (0Cr18Ni12Mo2Ti) also have limited uses 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 fluorine-lined pump F46 is a more economical choice.4. Nitric acid Generally, metals are rapidly corroded and damaged in nitric acid. Stainless steel is a 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.5. Alkali (sodium hydroxide) Steel is widely used in sodium hydroxide solutions below 80℃ and 30% concentrations. Many factories still use ordinary steel at 100℃ and 75%. Although corrosion increases, it has good economicality.The corrosion resistance of ordinary stainless steel to alkali liquid has no obvious advantages compared to cast iron. It is not recommended to use stainless steel as long as a small amount of iron is allowed to be mixed into the medium.For high-temperature alkali liquids, titanium and titanium alloys or high-alloy stainless steel are mostly used.The company's general cast iron pumps can be used in low-concentration alkali liquids at room temperature, and various stainless steel pumps or fluoroplastic pumps can be used when special requirements are required.6. Alcohols, ketones, esters, and ethers Common alcohol media include methanol, ethanol, ethylene glycol, propanol, etc., ketone media include acetone, butanone, etc., and ester media include various methyl esters, ethyl esters, etc., and ether media include methyl ether, ethyl ether, butan ether, etc. They are basically not corrosive and common materials are applicable. When selecting, reasonable choices should be made based on the properties of the medium and related requirements.It is also worth noting that ketones, esters and ethers are soluble in a variety of rubbers, so they avoid errors when choosing sealing materials.7. Ammonia (ammonia hydroxide) Most metals and non-metals have very mild corrosion in liquid ammonia and ammonia water (ammonia hydroxide), and only copper and copper alloys are not suitable for use.Most of the company's products are suitable for the transportation of ammonia and ammonia water.8. Brine (seawater) The corrosion rate of ordinary steel is not too high in sodium chloride solution, seawater and salt water, and generally requires coating protection; various types of stainless steel also have very low uniform corrosion rates, but local corrosion may be caused by chloride ions, and 316 stainless steel is usually better.The company's various chemical pumps have 316 material configurations.