ASME B16.47 Series B Welding Neck Flanges

ASME B16.47 Series B welding neck flanges are engineered for large-diameter industrial piping, covering pipe sizes from NPS26 to NPS60. They are widely adopted in high-pressure pipelines for oil & gas, chemical, power generation and water treatment industries.

This standard specifies unified outer diameters, bolt hole arrangements, sealing face dimensions and thickness tolerances for flanges. Compared with Series A, Series B features smaller overall outer diameters and fewer bolts, saving installation space and project costs.

Featuring a long neck welding structure, the flange neck is fully fused with pipes for even stress distribution, delivering outstanding resistance to high temperature, high pressure and cyclic alternating loads. Multiple sealing faces including raised face and ring joint are available. Forged materials such as A105, F22, 304 and 316L are applicable to meet NACE sulfur-resistant and high-temperature service requirements.

Manufactured in strict accordance with ASME dimensional standards, these flanges offer great interchangeability and easy assembly. They serve as the mainstream matching flange for overseas large long-distance transmission pipelines, storage tanks and heat exchange equipment.