FLANGE STANDARD LIBRARYAX FORGE · SPEC SHEET
SPEC SHEETNo. 463
ASME B16.5 · ASME B16.5-2025

B16.5 Class 2500 1½″ Weld Neck

DN40Weld NeckDimensions mmWeight kg
ASME B16.5 · 1½″ (DN40) · Class 2500 · Weld Neck FlangeASME B16.5 · 1½″ (DN40) · Class 2500 · Weld Neck Flange O.D. D 203.2 Bolt circle K 146.1 4ר31.8 Raised face Ø 73.2 Thickness C 44.5 RF height f 6.4 Length H 111.3 Hub Ø A 79.2 Weld end Ø 48.3 Both views share one scale (1:6.4); schematic only Unit: mm

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

SymbolItemValue
DOutside diameter203.2mm
CFlange thickness / blind thickness44.5mm
D2Raised face diameter73.2mm
fRaised face height6.4mm
KBolt circle diameter146.1mm
nNumber of bolt holes4pcs
dBolt hole diameter31.8mm
AHub diameter79.2mm
HHub length / overall length111.3mm
BWelding-end diameter48.3mm
—Approximate weight11.3kg

Pressure–temperature ratings · Class 2500 · Group 1.1

≤ 38 °C425.1 bar50 °C414.9 bar100 °C389.1 bar150 °C375.4 bar200 °C365.1 bar250 °C349.7 bar300 °C332.6 bar325 °C322.3 bar350 °C313.7 bar375 °C303.4 bar400 °C288.6 bar425 °C239.4 bar450 °C191.4 bar475 °C145.7 bar500 °C96.0 bar538 °C48.4 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