Nominal pressure of the valve

Generally, the nominal pressure rating corresponding to US standard 150LB is 2.0 MPa, while that corresponding to 300LB is 5.0 MPa

Reply to 1# Yellow River Water Comes from the Heavens: The standards applied are different; when making a selection, it is also necessary to pay attention to the flange details of the valve, otherwise connection problems may occur. What the original poster is referring to is the use of American standards; what we usually talk about as *standards or industry standards

The conversion relationship between nominal pressure and pounds (LB): MPa 1.6-2.0, 2.5-5.0, 6.3, 10.0, 13.0, 15.0, 25.0, 42.0; MPa classes: 150, 300, 400, 600, 800, 900, 1500, 2500; LB. PN and Class are both methods used to express pressure; the difference lies in the reference temperature at which the corresponding pressures are defined. The PN system used in Europe refers to pressures at 120°C, whereas the Class system used in the United States refers to pressures at 425.5°C. Therefore, in engineering conversions, it is not sufficient to simply perform pressure conversions; for example, the pressure corresponding to Class 300# based on mere pressure conversion would be 2.1 MPa. However, when the operating temperature is taken into account, the corresponding pressure increases, and according to the material’s temperature resistance tests, it is equivalent to 5.0 MPa. There are two systems for valves: one is the \"nominal pressure\" system, represented by Germany (including China), which is based on the allowable operating pressure at normal temperatures (100 degrees in China and 120 degrees in Germany). One is the “temperature-pressure system” represented by the United States, which is based on the allowable operating pressure at a certain temperature. In the U.S. temperature and pressure system, with 150LB based on 260 degrees, all other grades are based on 454 degrees. For a 25-grade carbon steel valve rated at 150 pounds per square inch (150 psi = 1 MPa), the allowable stress at 260 degrees is 1 MPa; whereas at room temperature, the allowable stress is much higher, around 2.0 MPa. Therefore, generally speaking, the nominal pressure class corresponding to US standard 150LB is 2.0 MPa, that corresponding to 300LB is 5.0 MPa, and so on. Therefore, the nominal pressure and temperature-pressure class cannot be arbitrarily changed using pressure conversion formulas.

The moderator is absolutely right; it’s just that the signature at the end is too obscene, haha

Reply to 4# Chinese cabbage5: Thank you very much for your helpful advice: handshake

I learned more things today and made progress

I’ve learned it, thank you:):time:I’ve learned it

Thanks to the guy on floor 4 for his guidance; I’ve learned from it. Thank you