1. Cast iron
Gray cast iron is the most commonly used cast iron. The national standard code is HT. Many water pumps use this material for the pump body, impeller, pump cover, suspension, etc. Different countries have different ways of expressing gray iron, for example, the code name of Japan is FC, the code name of Germany is GG, and the code name of the United States is Class
2. Ductile iron is a kind of cast iron with better comprehensive performance, and its national standard 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. Due to the limitation of casting and other reasons, the impeller of some water pumps will use this material. the
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 the difficulty in processing, the use is limited.
2. Cast steel
Due to the high strength of cast steel, usually when the pressure is greater than 1.6Mpa, cast steel is mostly used for pressure-bearing parts. Its national standard code is ZG, and the most commonly used grade is ZG23 0-450. Japan and the United States usually use CS to indicate cast steel.
3. Stainless steel
Except for a few media such as hydrochloric acid and dilute sulfuric acid, stainless steel is an excellent corrosion-resistant material and 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 steel, such as 2Cr13 and 3Cr13, has better mechanical properties than austenitic stainless steel, and is usually used as the material for pump shafts and bushings. The corresponding code in Japan and the United States is SS420. In addition, high-alloy stainless steel (alloy No. 20) and double-phase stainless steel are also ideal corrosion-resistant materials.
4. Non-metallic materials
Non-metallic materials for pumps are mainly used for sealing, such as polytetrafluoroethylene, fluororubber, nitrile rubber, etc. Among them, polytetrafluoroethylene is used for the gasket of chemical pumps and the static seal of mechanical seals because of its excellent corrosion resistance and high temperature resistance. It is suitable for almost all chemical media within 250 ° C. Its disadvantages are 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 preferably 160°C. When the user has no special requirements, it is recommended to use the sealing ring of this material for chemical pumps; and nitrile rubber is mainly used for oil resistance or Static sealing in clear water medium
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