FLANGE STANDARD LIBRARYAX FORGE · SPEC SHEET
SPEC SHEETNo. 351
ASME B16.5 · ASME B16.5-2025

B16.5 Class 150 12″ Weld Neck

DN300Weld NeckDimensions mmWeight kg
ASME B16.5 · 12″ (DN300) · Class 150 · Weld Neck FlangeASME B16.5 · 12″ (DN300) · Class 150 · Weld Neck Flange O.D. D 482.6 Bolt circle K 431.8 12ר25.4 Raised face Ø 381.0 Thickness C 30.2 RF height f 1.5 Length H 112.8 Hub Ø A 365.3 Weld end Ø 323.9 Both views share one scale (1:7.6); schematic only Unit: mm

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

SymbolItemValue
DOutside diameter482.6mm
CFlange thickness / blind thickness30.2mm
D2Raised face diameter381mm
fRaised face height1.5mm
KBolt circle diameter431.8mm
nNumber of bolt holes12pcs
dBolt hole diameter25.4mm
AHub diameter365.3mm
HHub length / overall length112.8mm
BWelding-end diameter323.9mm
—Approximate weight36.3kg

Pressure–temperature ratings · Class 150 · Group 1.1

≤ 38 °C19.6 bar50 °C19.1 bar100 °C17.7 bar150 °C15.8 bar200 °C13.8 bar250 °C12.1 bar300 °C10.2 bar325 °C9.3 bar350 °C8.4 bar375 °C7.4 bar400 °C6.5 bar425 °C5.5 bar450 °C4.6 bar475 °C3.7 bar500 °C2.8 bar538 °C1.4 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