Weld Neck Flange RF 12" Class 900 — ASME B16.5
Weld Neck Flange RF 12" Class 900 to ASME B16.5: outside diameter 610 mm, flange thickness, min 79.4 mm, raised face diameter 381 mm, raised face height 6.4 mm, bolt circle (pcd) 533.4 mm; approx. weight 154.1 kg.
Dimensions of Weld Neck Flange RF 12" Class 900
| Symbol | Dimension | Value |
|---|---|---|
| O | Outside diameter | 610 mm (24.016 in) |
| tf | Flange thickness, min | 79.4 mm (3.126 in) |
| R | Raised face diameter | 381 mm (15.000 in) |
| f | Raised face height | 6.4 mm (0.252 in) |
| W | Bolt circle (PCD) | 533.4 mm (21.000 in) |
| n | Number of bolt holes | 20 |
| h | Bolt hole diameter | 38.1 mm (1.500 in) |
| d | Stud bolt size | 1-3/8" |
| Y | Length through hub | 200 mm (7.874 in) |
| A | Hub diameter at weld (pipe OD) | 323.9 mm (12.752 in) |
| B | Bore (Sch 40) | 303.3 mm (11.941 in) |
| m | Approximate weight | 154.1 kg (339.73 lb) |
SKU TSH-FLANGE-WN-B165-900-12 · Standard ASME B16.5 · weight: Calculated from nominal dimensions, carbon steel (ρ 7850 kg/m³)
Purchase description
FLANGE, WELD NECK, RAISED FACE, 12" (DN 300), CLASS 900, BORE SCH 40, ASTM A105N, ASME B16.5
Available materials: ASTM A105N, ASTM A350 LF2 Cl 1, ASTM A182 F304/304L, ASTM A182 F316/316L, ASTM A182 F11 Cl 2, ASTM A182 F22 Cl 3, ASTM A182 F51 (Duplex), ASTM A182 F53 (Super Duplex), ASTM A694 F52 / F60, IS 2062 E250 (plate).
Bolting and gasket
20 stud bolts 1-3/8" UNC × 270 mm (10.75") with 40 heavy hex nuts — ASTM A193 B7 studs + A194 2H heavy hex nuts. Gasket: Spiral wound 12" Class 900, ASME B16.20, SS316 + graphite, CS outer ring, SS inner ring.
Additional data
| Facing | Raised face 6.4 mm, 3.2–6.3 µm Ra serrated |
Same size, other ratings
Other sizes — Weld Neck, Class 900
Frequently asked questions
What are the main types of pipe flanges?
Weld neck (WN), slip-on (SO), blind (BL), socket weld (SW), threaded (THD), lap joint (LJ) and plate flanges. Special types include orifice, long weld neck, reducing flanges and spectacle blinds.
When should I use a weld neck flange instead of a slip-on?
Use weld neck flanges for high pressure, high or cycling temperature, and lines with vibration or fatigue loading. The tapered hub and full-penetration butt weld spread stress smoothly. Slip-on flanges are cheaper and easier to align, but their fatigue life is roughly one third of a WN.
What does Class 150, 300 or 600 mean on a flange?
The ASME class is a pressure-rating designation, not a pressure in psi. The allowable pressure depends on the material group and temperature. A Class 150 A105 flange is rated 19.6 bar at 38 °C but 13.8 bar at 200 °C.
Is a 150# flange rated for 150 psi?
No. A Class 150 carbon-steel flange is rated about 285 psi (19.6 bar) at ambient temperature, and about 170 psi (11.7 bar) at 260 °C. The "150" is a class number.