C&N industrial Group, pipe, fitting and flanges manufacturers,fbe epoxy and pe coating for pipeline since 1991,with brand C&N huitong ,C&N hongcheng.
ASME B16.9 Collar
A collar — sometimes called a backing ring or Van Stone ring — is a loose steel ring used together with a lap-joint stub end. Unlike a standard weld-neck flange, the collar is not welded to the pipe. It simply slides over the stub end’s lap face and is drawn tight by the flange bolts, while the stub end itself — not the collar — forms the actual pressure-containing surface. This construction lets the pipe spool be rotated freely to align bolt holes on site, which is a major advantage on long pipeline runs, lined-pipe systems, and any project where field alignment matters more than a fixed, welded connection.
Specifications
| Size range | ½″ – 24″ NB (DN15 – DN600) |
| Wall thickness / schedule | Sch 5S, 10S, 40S, 80S, and heavier on request |
| Flange rating compatibility | ANSI Class 150 (other ratings available on request) |
| Connection type | Loose-fit, bolt-secured (non-welded) — used with a separately welded lap-joint stub end |
| Manufacturing process | Forged, cast, or machined from bar/plate stock |
| Reference standards | ANSI/ASME B16.9, ASME B16.28, MSS-SP-43 |
Typical Applications
- Lined pipe systems (PTFE / PFA / rubber-lined, glass-lined) where the collar protects the liner by keeping bolt-up torque off the process-wetted surface
- Long pipeline sections and tie-ins, where bolt-hole rotation on site avoids re-cutting or re-welding pipe
- Heavy oil and bitumen processing, where lined or corrosion-resistant piping is common and welded flange connections aren’t practical
- Refinery, petrochemical, acid handling, and water treatment piping using lap-joint stub end + backing ring assemblies
Materials & Standards
C&N Hongcheng supplies collars in carbon steel (ASTM A234 WPB and equivalent), stainless steel (ASTM A403 WP304/304L/316/316L), and alloy steel (ASTM A234 WP5/WP9/WP11/WP22), sized from ½″ up to 24″ NB. Dimensions follow ANSI/ASME B16.9 practice for 150# lap-joint flange assemblies, cross-referenced against ASME B16.28 and MSS-SP-43. Every batch ships with mill test certificates per EN 10204 3.1 / 3.2, with 3.2 third-party certification available on request.
Collar vs. Weld-Neck Flange — What’s the Difference?
A weld-neck flange is welded directly to the pipe and cannot rotate once installed. A collar-and-stub-end assembly separates these two jobs: the stub end is welded to the pipe and handles the process contact, while the collar is a free ring that only handles the bolt load. Because the collar isn’t fixed in place, installers can spin it to line up bolt holes without touching the weld — useful wherever field tolerances are tight or the pipe material (e.g. lined pipe) shouldn’t be re-welded after fabrication.
ASME b16.9 collar dimensions weight
| Dimensions (mm) | Approx. Weight by Schedule (kg) | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| NPS (inch) | DN | OD "D" (mm) | G – Dia. of lap (mm) | h – Height (mm) | R – Fillet radius (mm) | Sch 5S | Sch 10S | Sch 40S | Sch 80S |
| 1/2 | 15 | 21.34 | 34.92 | 5 | 3 | 0.01 | 0.02 | 0.03 | 0.04 |
| 3/4 | 20 | 26.67 | 42.86 | 6 | 3 | 0.03 | 0.03 | 0.04 | 0.06 |
| 1 | 25 | 33.40 | 50.80 | 8 | 3 | 0.04 | 0.07 | 0.08 | 0.11 |
| 1 1/4 | 32 | 42.16 | 63.50 | 8 | 5 | 0.05 | 0.08 | 0.11 | 0.15 |
| 1 1/2 | 40 | 48.26 | 73.00 | 10 | 6 | 0.06 | 0.11 | 0.15 | 0.20 |
| 2 | 50 | 60.32 | 92.10 | 10 | 8 | 0.08 | 0.14 | 0.20 | 0.28 |
| 2 1/2 | 65 | 73.02 | 104.80 | 12 | 8 | 0.15 | 0.22 | 0.37 | 0.50 |
| 3 | 80 | 88.90 | 127.00 | 12 | 9 | 0.19 | 0.27 | 0.50 | 0.70 |
| 3 1/2 | 90 | 101.60 | 139.70 | 12 | 9 | — | — | — | — |
| 4 | 100 | 114.30 | 157.20 | 14 | 11 | 0.25 | 0.35 | 0.70 | 1.00 |
| 5 | 125 | 141.30 | 185.70 | 16 | 11 | 0.50 | 0.65 | 1.25 | 1.80 |
| 6 | 150 | 168.27 | 215.90 | 16 | 12 | 0.65 | 0.80 | 1.70 | 2.60 |
| 8 | 200 | 219.07 | 269.80 | 18 | 12 | 0.95 | 1.30 | 2.80 | 4.30 |
| 10 | 250 | 273.05 | 323.80 | 20 | 12 | 1.50 | 1.80 | 4.00 | 5.50 |
| 12 | 300 | 323.85 | 381.00 | 20 | 12 | 2.00 | 2.40 | 5.00 | 6.60 |
| 14 | 350 | 355.60 | 412.70 | 25 | 12 | 2.50 | 2.95 | 5.90 | 7.90 |
| 16 | 400 | 406.40 | 469.90 | 25 | 12 | 3.60 | 4.00 | 8.10 | 10.8 |
| 18 | 450 | 457.20 | 533.40 | 25 | 12 | 4.00 | 4.60 | 9.20 | 12.3 |
| 20 | 500 | 508.00 | 584.20 | 25 | 12 | 5.10 | 6.00 | 10.2 | 13.7 |
| 22 | 550 | 558.80 | 641.30 | 25 | 12 | — | — | — | — |
| 24 | 600 | 609.60 | 692.10 | 25 | 12 | 8.15 | 9.30 | 14.0 | 18.6 |
Notes: Weights are approximate, based on steel density 8 kg/dm³. “—” indicates data not available for that size. Applicable standards: ASME/ANSI B16.9, ASME B16.28, MSS-SP-43, BS4504, BS1560, BS10.
Why Source Collars from C&N Hongcheng?
As a non-standard item, collars are often left off the shelf entirely by regional suppliers — buyers usually end up waiting on a custom quote. C&N Hongcheng keeps common sizes and materials in stock at our Dammam 3rd Industrial Zone warehouse in Saudi Arabia, so regional customers can get fast delivery on collars alongside the flanges and stub ends they’re already ordering, without a separate lead time.
Contact us for a quote today!
