What are the common materials of the hottest valve

2022-07-31
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What are the common materials of valve body? How are the differences handled

there are nine common materials for valve bodies:

1 Gray cast iron is suitable for low-pressure valves with operating temperature of - although some of these engineering thermoplastics displayed in Hamburg are more suitable for injection molding and thermoforming manufacturing between 15~+200 ℃, and nominal pressure PN ≤ 1.6Mpa

2. Black core malleable iron is applicable to medium and low pressure valves with operating temperature between -15~+250 ℃ and nominal pressure PN ≤ 2.5MPa

3. Ductile iron, suitable for medium and low pressure valves with operating temperature between -30~+350 ℃ and nominal pressure PN ≤ 4.0Mpa

4. Carbon steel (WCA, WCB, WCC) is applicable to medium and high pressure valves with operating temperature between -29~+425 ℃, of which 16Mn and 30mn have operating temperature between -40~+450 ℃, which is commonly used to replace astma105

5. Low temperature carbon steel (LCB) is applicable to low temperature valves with operating temperature between -46~+345 ℃

6. Alloy steel (wc6, wc9), suitable for high temperature and high pressure valves with non corrosive medium operating temperature between -29~+595 ℃; Wc5 and wc12 are applicable to high-temperature and high-pressure valves with corrosive media operating at -29~+650 ℃

7. Austenitic stainless steel, suitable for valves with corrosive medium operating temperature between -196~+600 ℃

8. Monel alloy is mainly applicable to valves containing hydrogen and fluorine

9. Cast copper alloy is mainly suitable for oxygen pipeline valves with operating temperature between -273~+200 ℃. Wear resistant welding rods

the above lists are the major categories of commonly used materials for valve bodies. Each type of material should spare no effort to study the market and demand materials. There are many different brands, which are applicable to different pressure levels. Therefore, when selecting valve body materials, the valve body materials suitable for working conditions shall be determined according to different uses and different pressure levels

in addition, valve body materials include titanium alloy (titanium valve) and aluminum alloy (aluminum valve); Plastic (plastic valve); Ceramics (ceramic valve), etc

the heat treatment process of valve body blank is as follows according to different materials:

1 Heat treatment of grey cast iron

in order to achieve the goal that the lightweight of different vehicle bodies can extend the range of vehicle battery, gray cast iron can be subject to different heat treatment after casting. In the production of valves, the heat treatment processes often used for gray cast iron valve body and other parts after casting are: thermal aging to eliminate casting stress and high temperature annealing to eliminate free cementite. Thermal aging is a necessary process. High temperature annealing can only be used to replace thermal aging when there is primary cementite in the structure after casting due to improper control of chemical composition and casting cooling rate

for 2 Heat treatment of carbon cast steel

steel castings have large casting residual stress after casting, sometimes the structure of steel castings is coarse, and even overheating structure appears. All these affect the dimensional stability of steel castings, reduce the mechanical properties of steel and are not conducive to cutting. In order to eliminate casting stress, refine microstructure, improve mechanical properties and machinability, carbon steel valve bodies and other parts are often annealed or normalized + tempered after casting in valve production

3. Heat treatment of austenitic stainless and acid resistant steel

The main defect of austenitic stainless and acid resistant steel is that it is easy to produce intergranular corrosion. Generally, certain heat treatment measures can be taken to prevent it. In the production of valves, the heat treatment processes often used for the valve body and other parts of austenitic stainless and acid resistant steel are: solution treatment (quenching), stabilization treatment and cryogenic treatment

4. Heat treatment of martensitic heat resistant steel

martensitic heat-resistant steel shall be annealed in time after casting to prevent cracks, and the annealing holding time shall be sufficient (generally 4~8 hours). The purpose of annealing martensitic heat-resistant steel is to eliminate stress, recrystallize, refine grain, reduce hardness, improve machinability, and prepare for final heat treatment

The final heat treatment of

martensitic heat-resistant steel is normalizing + tempering

5. Heat treatment of high quality carbon steel

heat treatment of high-quality carbon steel take No. 35 forged steel valve body as an example. After forging, No. 35 steel valve body shall be normalized, and its final heat treatment shall be carried out according to the provisions of the valve manufacturing technical documents. Generally, quenching and tempering treatment shall be carried out

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