Pressure from different countries defining
150LB 300LB is Press grade standard from ANSI America.
It is equal to Chinese PN1.6MPa.
See the following:
1.Above description is based on Flange pressure grade,American standard is ANSI B16.5 B16.47
2.Class is similar to Mainland Pressure grade of PN,it is defined with a materials under a temperature’s
pressure allowance,so cannot defined for all materials under all temperature’s pressure value.
3. PSI is British measure unit.it is pound/squire inch,it can be conversion with Mpa
4. In HG standard, there are two sheets ( Europea and America) Steel Flange pressure-temperature
grade described material/pressure/ temperature connections.
PN and Class are all representing method.The difference is pressure corresponding temperature is different.
PN Euro system says pressure under 120℃,Class American says pressure under 425.5℃.
In engineering conversion,cannot easily defined by pressure.i.e: Class 300 simply equal to 2.1Mpa,
but consider to materials anti-temperature value,it is 5.0 Mpa. Valve has 2 systems,
one is German (China) under normal temperature of 100-120degree,named as NOMIRAL PRESSURE system,
another is American,it is defined under a fix temperature,named as TEMPERATURE PRESSURE system.
In America pressure system, 150LB is fixed temperature of 260 degree,but others are all fixed by 450degree.
150LB （150psi=1MPa）25# carbon steel valve’s stress is 1Mpa on temperature of 260degree,but in normal teperature,
stress is about 2.0 MPa.Normally ,we say America standard 150LB equals to 2.0 MPa,300LB nomiral pressure is 5.0MPa.
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