What’s the difference between FLANGES of ANSI B16.47 series A and series B

American standard flange ANSI B16.47 has two series, namely A series and B series. American standard flange also has an ANSI B16.5 standard number. Generally speaking, the flange size of B16.5 is less than 24. Inch, B16.47 flange is larger than 24 inch.
B16.47 A series is actually the name obtained after MSS SP44 standard flange is added to the American standard flange system, and B series is the name obtained after API 605 standard flange is added to the American standard flange system. This is MSS SP44, API Relationship between 605 flange and ANSI B16.47.
As for whether the A series flanges and B series flanges can be used universally, the answer is definitely not universal. This should be determined at the engineering design stage whether to choose A series or B series flanges, and A series and B series with the same pressure and size Flange, A series flange outer diameter, disk thickness, bolt hole diameter must be larger than B series, but the number of holes is less than B series, which results in a result, flanges of the same pressure size, B series is cheaper than A series Many, more economical, lower single weight, and lower redundancy conditions. Generally speaking, the selection of A series may require more requirements for the project to meet the requirements, the B series is more economical, the B series is slightly more used for ordinary pipelines, and the A series is slightly more used for gas pipelines. The two are generally not interchangeable.
The domestic standards SH3406 and HG20615 are derived from the ANSI B16.47 B series, which is the API 605 flange standard.
The above is the connection and difference between ANSI B16.47 A B series flanges.
Thanks for reading.