ASME B16.5 · ASTM A105 · stock and made to order
8″ Class 300 Slip-On Flange — ASTM A105
8″ Class 300 slip-on flange to ASME B16.5, machined from ASTM A105 forging. Outside diameter 380 mm, thickness 39.7 mm, 12 bolt holes on a 330.2 mm circle, approximate weight 26 kg. Available with raised face, flat face or ring-type joint finish.
Size
8″ / DN200
Pressure class
Class 300
Outside diameter
380 mm
Flange thickness
39.7 mm
Bolt circle
330.2 mm
Approx. weight
26 kg
Full dimensions — 8″ Class 300
| NPS | DN | OD | Thickness | RF Ø | Bolt circle | Bolts | Weight |
|---|---|---|---|---|---|---|---|
| 2″ | 50 | 165 mm (6.5″) | 20.7 mm (0.81″) | 92.1 mm (3.63″) | 127 mm (5″) | 8 × Ø19 | 3.2 kg |
| 4″ | 100 | 255 mm (10.04″) | 30.2 mm (1.19″) | 157.2 mm (6.19″) | 200 mm (7.87″) | 8 × Ø22.2 | 10 kg |
| 6″ | 150 | 320 mm (12.6″) | 35 mm (1.38″) | 215.9 mm (8.5″) | 269.9 mm (10.63″) | 12 × Ø22.2 | 17.7 kg |
| 8″ (this size) | 200 | 380 mm (14.96″) | 39.7 mm (1.56″) | 269.9 mm (10.63″) | 330.2 mm (13″) | 12 × Ø25.4 | 26 kg |
| 12″ | 300 | 520 mm (20.47″) | 49.3 mm (1.94″) | 381 mm (15″) | 450.8 mm (17.75″) | 16 × Ø31.8 | 52 kg |
Dimensions in millimetres; bolt hole diameter applies to through-holes. For stud length, gasket and bolt selection, see the assembly note below.
What Class 300 means in service
ASME B16.5 Class 300 is a pressure class, not a single pressure number: the allowable pressure falls as temperature rises. For ASTM A105 in material group 1.1 the rating is 740 psi (51 bar) at 38 °C (100 °F), and the applicable value must be read from the pressure–temperature tables in B16.5 for the actual design temperature. The 8″ Class 300 slip-on flange in this page is therefore specified by size and class, and the gasket, bolting and pipe schedule are selected to match.
The 12 bolts on a 330.2 mm circle are sized to develop the gasket seating load without over-stressing the flange ring. Use the bolt hole diameter of Ø25.4 mm with a bolt one size smaller, and follow the cross-pattern tightening sequence in ASME PCC-1 for a leak-free joint.
Material and finish options
| Option | Specification | When to choose it |
|---|---|---|
| Carbon steel | ASTM A105 / A105N | General oil, gas, water and steam service |
| Low temperature | ASTM A350 LF2 | Service down to −46 °C with impact testing |
| Stainless | ASTM A182 F304/F316L | Corrosive, hygienic or marine atmosphere |
| Alloy | ASTM A182 F11/F22/F91 | High-temperature refinery and power piping |
| Duplex | ASTM A182 F51/F53 | Chloride-bearing and offshore service |
Inspection and delivery
- Dimensional inspection against the B16.5 table for this size and class
- Heat number stamped on the rim; EN 10204 3.1 certificate issued
- PMI on stainless and alloy heats; UT/RT on request
- Anti-rust oil, plywood case or pallet, with packing list and MTC
- Typical lead time 7–15 days for A105 stock sizes, 20–30 days for alloys
Other sizes in Class 300
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8″ Class 300 Slip-On Flange
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