FLANGE STANDARD LIBRARYAX FORGE · SPEC SHEET
SPEC SHEETNo. 398
ASME B16.5 · ASME B16.5-2025

B16.5 Class 400 22″ Weld Neck

DN550Weld NeckDimensions mmWeight kg
ASME B16.5 · 22″ (DN550) · Class 400 · Weld Neck FlangeASME B16.5 · 22″ (DN550) · Class 400 · Weld Neck Flange O.D. D 838.2 Bolt circle K 743.0 24ר44.5 Raised face Ø 641.4 Thickness C 73.2 RF height f 6.4 Length H 171.5 Hub Ø A 641.4 Weld end Ø 558.8 Both views share one scale (1:13); schematic only Unit: mm

Schematic — drawn from the table, not to scale for inspection.

SymbolItemValue
DOutside diameter838.2mm
CFlange thickness / blind thickness73.2mm
D2Raised face diameter641.4mm
fRaised face height6.4mm
KBolt circle diameter743mm
nNumber of bolt holes24pcs
dBolt hole diameter44.5mm
AHub diameter641.4mm
HHub length / overall length171.5mm
BWelding-end diameter558.8mm

Pressure–temperature ratings · Class 400 · Group 1.1

≤ 38 °C68.0 bar50 °C66.4 bar100 °C62.3 bar150 °C60.1 bar200 °C58.4 bar250 °C56.0 bar300 °C53.2 bar325 °C51.6 bar350 °C50.2 bar375 °C48.5 bar400 °C46.2 bar425 °C38.3 bar450 °C30.6 bar475 °C23.3 bar500 °C15.4 bar538 °C7.7 bar

Source: Table 2-1.1 (printed p. 25) — pressure–temperature ratings for Group 1.1 materials, SI units; Group 1.1.

Material and notes

Base material: ASTM A105 (North America, Middle East, South-East Asia)

Rating: ASME classes are not fixed pressures. For ASTM A105 (material group 1.1) the ASME B16.5-2025 ambient rating is 285 psi (19.6 bar) at Class 150, 740 psi (51.0 bar) at Class 300, 985 psi (68.0 bar) at Class 400, 1,480 psi (102.0 bar) at Class 600, 2,2…

Tolerances / marking: Tolerances, facing finish, material and marking requirements: ASME B16.5-2025 Sections 6 and 7.

Notes / special requirements

Work order Inspector Date Travels with the part; file after inspection