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.

Pipe flanges

Pipe flanges

There are many different flange standards to be found worldwide. To allow easy functionality and inter-changeability, these are designed to have standardised dimensions. Common world standards include ASA/ANSI (USA), PN/DIN (European), BS10 (British/Australian), and JIS/KS (Japanese/Korean).

In most cases these are not interchangeable (e.g. an ANSI flange will not mate against a JIS flange). Further, many of the flanges in each standard are divided into “pressure classes”, allowing flanges to be capable of taking different pressure ratings. Again these are not generally interchangeable (e.g. an ANSI 150 will not mate with an ANSI 300). These pressure classes also have differing pressure and temperature ratings for different materials. Unique pressure classes for piping can also be developed for a process plant or power generating station; these may be specific to the corporation, engineering procurement and construction (EPC) contractor, or the process plant owner.

The flange faces are also made to standardized dimensions and are typically “flat face”, “raised face”, “tongue and groove”, or “ring joint” styles, although other obscure styles are possible.

Flange designs are available as “welding neck”, “slip-on”, “boss”, “lap joint”, “socket weld”, “threaded”, and also “blind”.

ASME standards (U.S.)

ASME type flange on a gas pipeline

Pipe flanges that are made to standards called out by ASME B16.5 or ASME B16.47 are typically made from forged materials and have machined surfaces. B16.5 refers to nominal pipe sizes (NPS) from ½” to 24″. B16.47 covers NPSs from 26″ to 60″. Each specification further delineates flanges into pressure classes: 150, 300, 400, 600, 900, 1500 and 2500 for B16.5; B16.47 delineates its flanges into pressure classes 75, 150, 300, 400, 600, 900.

The gasket type and bolt type are generally specified by the standard(s); however, sometimes the standards refer to the ASME Boiler and Pressure Vessel Code (B&PVC) for details (see ASME Code Section VIII Division 1 – Appendix 2). These flanges are recognized by ASME Pipe Codes such as ASME B31.1 Power Piping, and ASME B31.3 Process Piping.

Materials for flanges are usually under ASME designation: SA-105 (Specification for Carbon Steel Forgings for Piping Applications), SA-266 (Specification for Carbon Steel Forgings for Pressure Vessel Components), or SA-182 (Specification for Forged or Rolled Alloy-Steel Pipe Flanges, Forged Fittings, and Valves and Parts for High-Temperature Service). In addition, there are many “industry standard” flanges that in some circumstance may be used on ASME work.

Other countries

Flanges in other countries also are manufactured according to the standards for materials, pressure ratings, etc. Such standards include DIN, BS, and/or ISO standards.