1. Cast iron (1). Gray cast iron is the most commonly used type of cast iron. The national standard code is HT. Generally, the pump body, impeller, pump cover, suspension, etc. of the clean water pump are made of this material, and three grades are usually used: HT150, HT200, HT250. For the non-main parts such as the base and the backing plate, the HT150 is mostly used, and the HT200 is used for the pump body, the pump cover and the suspension, and the HT250 is used for the impeller, the ring ring and the bushing. The representation methods of gray iron are different in different countries. For example, the code name is FC in Japan, the code in GG in Germany, and the class in the United States. (2). Ductile iron is a kind of cast iron with better comprehensive performance. The national code is QT. Because its mechanical properties are close to steel, and its casting performance and processing performance are better than steel, it is usually used as a substitute for cast steel. The most commonly used brands are: QT450-10, QT500-7, QT600-3. Due to the limitation of casting and the like, the impeller of the water pump is currently used with the material, and the cutting type open impeller is superior in cost performance. The DIN standard for spheroidal graphite cast iron is GGG, and the US is for Ductile iron. In addition, there are corrosion-resistant cast irons – high-silicon cast iron, wear-resistant cast iron – white cast iron, high-toughness cast iron – malleable cast iron, etc. Due to the difficulty in processing, there are not many products used.
2, Cast steel Because the strength of cast steel is high, usually when the pressure is >1.6Mpa, the pressure parts are mostly cast steel, the national standard code is ZG, the most commonly used grade is ZG23 0-450. Japan and the United States usually use CS to represent cast steel.
3, Stainless steel The most widely used stainless steel is austenitic stainless steel, such as 0Cr18Ni9, 1Cr18Ni9Ti, 0Cr18Ni12Mo2Ti and so on. Austenitic stainless steel is an excellent corrosion-resistant material in addition to a small amount of medium such as hydrochloric acid and dilute sulfuric acid. It is the most commonly used corrosion-resistant material for chemical pumps. Japan and the United States usually use SS304, SS316, SS316L to represent austenitic stainless steel. Martensitic stainless steels such as 2Cr13 and 3Cr13 have better mechanical properties than austenitic stainless steels and are commonly used as materials for pump shafts and bushings. The corresponding codes for Japan and the United States are SS420. In addition, high alloy stainless steel (20 alloy) and double stainless steel are also ideal corrosion resistant materials.
4. Carbon structural steel is usually divided into ordinary carbon structural steel and high quality carbon structural steel. The most representative ordinary carbon structural steel is Q235, which is widely used in various steel plates and sections. The most representative high-quality carbon steel is 45 steel, which is widely used for pump shaft materials without corrosion requirements.
5. Alloy steel The most representative alloy steel is 40Cr, which is usually used for high strength pump shaft materials.
6. Non-metallic materials Non-metallic materials for pumps are mainly used for sealing, such as PTFE, fluororubber, and nitrile rubber. Among them, PTFE is used for chemical pump seals and mechanical seals due to its excellent corrosion resistance and high temperature resistance. It is suitable for almost all chemical media at 250 °C. Its disadvantages are high hardness and assembly difficulty. Big. Fluororubber is also a good temperature and corrosion resistant material. The upper temperature limit is 160 °C. When the user has no special requirements, the chemical pump recommends the seal of the material; while the nitrile rubber is mainly used for oil resistance or Static seal when clear water medium.