1. Grey cast iron is the most commonly used cast iron, and the national standard code is HT. Generally, this material is used to clean the pump body, impeller, pump cover and suspension of the water pump (diesel engine water pump). Generally, three brands are used: HT150, HT200 and 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. Different countries have different forms of gray iron. For example, Japan's code is FC, Germany's code is GG, and the United States is first-class.
2. Nodular cast iron is a kind of cast iron with better comprehensive properties. The national standard code is QT. Because its mechanical properties are close to steel and its casting and processing properties are better than steel, it is usually used as a substitute for cast steel. The most commonly used brands are: QT450-10, QT500-7 and QT600-3. Due to the limitation of casting, the impeller of water pump is used together with materials at present, and the cutting open impeller has superior cost performance. The DIN standard of nodular cast iron is GGG, and the United States is nodular cast 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, few products are used.
Two. Cast steel
Because of the high strength of cast steel, usually when the pressure is & gt; 1.6Mpa, the pressure parts are mostly cast steel. The national standard code is ZG, and the most commonly used brand is zg230-450. Japanese and American usually use CS to express cast steel.
3、 Stainless steel
The most widely used stainless steel is austenitic stainless steel, such as 0Cr18Ni9, 1Cr18Ni9Ti, 0Cr18Ni12Mo2Ti, etc. In addition to a small amount of medium 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. In Japan and the United States, SS304, SS316 and SS316L are usually used 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
Generally divided into ordinary carbon structural steel and high-quality carbon structural steel. The most representative common 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 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
The non-metallic materials used for pumps are mainly used for sealing, such as PTFE, Viton, NBR, etc. Among them, PTFE is used for chemical pump seal and mechanical seal because of 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 difficult assembly. Big.
Fluororubber is also a good temperature and corrosion resistant material. The upper limit of temperature resistance is 160 ℃, when the user has no special requirements, the chemical pump is recommended to use the sealing ring of this material; NBR is mainly used for static sealing of oil or water resistant medium.