Can flat-weld flanges be used for high-pressure pipelines?
Thread Content
Under normal circumstances, are flat-weld flanges allowed for high-pressure tanks or pipelines? What pressure level requires a butt weld flange?
Refer to the provisions on the types of flange sealing surfaces and their applicable ranges in Table 3.0.1, Section 3 of HG/T20592 or HG/T20614, and also consult the provisions on the selection of flange types in Table 26-7 on page P136 of Chapter 26 on piping design in the second volume of the \"Chemical Process Design Manual\"
Are there plate-type butt weld flanges for high pressure?
This post was last edited by Mr.R on 2019-7-10 at 15:48. By definition, pipes in which the gauge pressure of the medium inside is greater than or equal to 10 MPa and up to 42 MPa are considered high-pressure pipes. According to the specifications regarding pipe flange types and their applicable ranges in HG20592, the maximum allowable nominal pressure for plate-type butt weld flanges is PN40, which corresponds to 4.0 MPa; therefore, plate-type butt weld flanges cannot be used for high-pressure pipes.
HG/T20592 up to PN40
Why such an enthusiasm for flat flanges?
If it is within the allowable pressure range, plate butt weld flanges are inexpensive