1.Cast iron
1.Gray cast iron is the most commonly used type of cast iron, and the national standard code is ht. Generally clean water pumps (diesel engine water pumps) use this material for the pump body, impeller, pump cover, suspension, etc., and usually use three brands: ht150, ht200, ht250. ht150 is used for non-main parts such as base and gasket, ht200 is used for pump body, pump cover, suspension, etc., ht250 is used for impeller, mouth ring, shaft sleeve, etc. The manifestations of gray iron are different in different countries. For example, Japan’s code is fc, Germany’s code is gg, and America’s is first-class.
2.Ductile iron is a cast iron with better overall performance. The country standard code is QT. Because its mechanical properties are close to those of steel, its casting performance and processing performance are better than steel, so it is often 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 etc., the impeller of the water pump is currently used with the material, and the cut type open impeller has superior cost performance. The DIN standard for ductile iron is GGG, and the US is ductile iron.
In addition, there are corrosion-resistant cast iron-high-silicon cast iron, wear-resistant cast iron-white cast iron, high-toughness cast iron-malleable cast iron, etc. Due to some difficulties in processing, not many products are used.
2.Cast steel
Due to the high strength of cast steel, usually when the pressure is > 1.6mpa, the pressurized parts are mostly cast steel. The national standard code is zg, and the most commonly used brand is zg230-450. Japanese and Americans usually use cs to mean cast steel.
3.Stainless steel
The most widely used stainless steel is austenitic stainless steel, such as 0Cr18Ni9, 1Cr18Ni9Ti, 0Cr18Ni12Mo2Ti, etc. Except for a small amount of media such as hydrochloric acid and dilute sulfuric acid, austenitic stainless steel is an excellent corrosion-resistant material. 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 often used as materials for pump shafts and bushings. The corresponding code for Japan and the United States is SS420. In addition, high-alloy stainless steel (20 alloy) and double stainless steel are also ideal corrosion-resistant materials.
4.Carbon structural steel
It is generally 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 section steels. The most representative high-quality carbon steel is 45 steel, which is widely used in 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 used in pumps are mainly used for sealing, such as PTFE, fluororubber, nitrile rubber, etc. Among them, PTFE is used in chemical pump seals and mechanical seals due to its excellent corrosion resistance and high temperature resistance. It is suitable for almost all chemical media up to 250°C. Its disadvantage is high hardness and difficult assembly. big.
Fluorine rubber is also a good temperature-resistant and corrosion-resistant material. The upper limit of temperature resistance is 160°C. When the user has no special requirements, the sealing ring of this material is recommended for chemical pumps; nitrile rubber is mainly used for static sealing of oil-resistant or water-resistant media.
