We supply weld neck flanges to ASME B16.5 from 1/2″ to 24″, in Class 150 through Class 2500, forged from ASTM A105, with the welding end prepared to ASME B16.25. Every batch ships with an EN 10204 3.1 material test certificate issued against one heat number. Below is the size list, the dimensions we work to, and the paperwork that travels with the goods.
A high pressure line loads the joint at the weld, not at the hub face. Send us the size and class and we quote our weld neck flanges against your delivery window.
Size range: 1/2″ to 24″, Class 150 to 2500
- Sizes: 1/2″, 3/4″, 1″, 1-1/2″, 2″, 3″, 4″, 6″, 8″, 10″, 12″, 14″, 16″, 18″, 20″, 24″
- Pressure class: 150, 300, 400, 600, 900, 1500, 2500
- Face: raised face as standard; RTJ available where the specification calls for a ring joint
- Bore: machined to your pipe wall – Sch 40, Sch 80, Sch 160 and heavier on request
- Standard: ASME B16.5 for dimensions and marking
Sizes above 24″ to ASME B16.47 are available on request.
ASME B16.5 dimensions we work to
The table below covers Class 150 raised face, the sizes most enquiries cover. All figures in inches, to ASME B16.5.
| NPS | OD | Thickness | RF dia | PCD | Bolt holes | Hole dia | Hub length |
|---|---|---|---|---|---|---|---|
| 1/2 | 3.50 | 0.44 | 1.38 | 2.38 | 4 | 0.62 | 1.88 |
| 1 | 4.25 | 0.56 | 2.00 | 3.12 | 4 | 0.62 | 2.00 |
| 2 | 6.00 | 0.75 | 3.62 | 4.75 | 4 | 0.75 | 2.50 |
| 4 | 9.00 | 0.94 | 5.69 | 7.50 | 8 | 0.75 | 3.00 |
| 6 | 11.00 | 1.00 | 8.31 | 9.50 | 8 | 0.88 | 3.50 |
| 8 | 13.50 | 1.12 | 10.62 | 11.75 | 8 | 0.88 | 4.00 |
| 12 | 19.00 | 1.25 | 14.75 | 17.00 | 12 | 1.00 | 4.50 |
| 16 | 23.50 | 1.38 | 18.75 | 21.25 | 16 | 1.12 | 5.00 |
| 24 | 32.00 | 1.75 | 27.25 | 29.50 | 20 | 1.38 | 6.00 |
Class 300 changes only three columns for most sizes. Here are the figures our team uses most often:
| NPS | OD | Thickness | RF dia | PCD | Bolt holes | Hole dia | Hub length |
|---|---|---|---|---|---|---|---|
| 1/2 | 3.75 | 0.56 | 1.38 | 2.62 | 4 | 0.62 | 2.06 |
| 2 | 6.50 | 0.88 | 3.62 | 5.00 | 8 | 0.75 | 2.75 |
| 4 | 10.00 | 1.25 | 5.69 | 7.88 | 8 | 0.88 | 3.50 |
| 6 | 12.50 | 1.44 | 8.31 | 10.62 | 12 | 0.88 | 4.06 |
| 8 | 15.00 | 1.62 | 10.62 | 13.00 | 12 | 1.00 | 4.62 |
Check these numbers against your own copy of ASME B16.5 before you release the drawing. Class 600 and above carries a thicker hub and a different bolt circle – ask us and we send the full dimension sheet for the class you need.
What we measure before the crate closes
A drawing tolerance means nothing if nobody checks the piece. Before packing, we measure OD, flange thickness, bore and bolt circle on every piece against a gauge. Anything outside the tolerance goes back to the machine shop, not into the crate.
That is how we handle it on our side. On larger sizes we record the readings and send the check sheet with the shipment when your PO asks for it.
Welding end to ASME B16.25
The hub is machined to the ASME B16.25 contour – standard 37.5 degree bevel with a 1.6 mm root face. Wall thickness tapers into the pipe, so the bending stress sits at the weld where the material is thickest. Your welder gets a standard bevel and one WPS covers it.
We cut the rest of the spool to the same standard. Our 90 degree elbows use the same ASME B16.25 end, and so do our tees. If your procedure calls for a different angle, send the bevel drawing and we machine it that way.
ASTM A105 material and the EN 10204 3.1 MTC
A105 is the standard carbon steel for forged flanges. Typical values on the certificate read like this:
- Carbon 0.35% max
- Manganese 0.60-1.05%
- Silicon 0.10-0.35%
- Phosphorus 0.035% max, sulphur 0.040% max
- Tensile strength 485 MPa min (70 ksi)
- Yield strength 250 MPa min (36 ksi)
The EN 10204 3.1 material test certificate is issued against one heat number. We do not put two heats inside one shipment. Each flange carries the heat number stamped on the hub, and we check that stamp against the heat list piece by piece before loading. A piece with the wrong number comes out of the batch.
The certificate travels with the goods. We also send a scan before shipment so your inspector can read the chemistry and mechanicals while the goods are still at our facility.
Sizes the standard does not cover
Every project brings one item that the table does not have. A thicker hub, an odd bolt circle, a bore machined to a pipe nobody stocks. We handle non-standard bores and special dimensions through the custom route – send the drawing and we tell you whether it needs a new forging die or a machining programme.
Small quantity, mixed sizes, LCL shipment
Minimum quantity depends on size and class. Send the item and we quote the real figure for it. We do not ask you to take a container load of a single diameter.
Mixed lists run through our production facility constantly. Put eight sizes and four classes on one enquiry, we pull from stock, build one crate and load LCL. You pay for the crate space, not for a full 20-footer.
Lead time, packing and payment
Lead time depends on size, quantity and the production schedule. Stocked sizes and production slots are both available. We confirm the schedule before you place the order, not after payment.
Packing is standard export packing. Individual piece marking is available where your receiving team needs it.
Payment works either way: TT, deposit with the order and balance before loading, or LC at sight. Tell us which one your company runs and we prepare the proforma invoice accordingly.
FAQ
What sizes do you supply in weld neck flanges?
1/2″ to 24″ to ASME B16.5. Larger sizes to ASME B16.47 are available on request. Send the list and we confirm availability first.
Do you have a dimension table for Class 600 and above?
Yes. Class 600, 900, 1500 and 2500 each carry their own bolt circle and hub figures. Tell us the class and the sizes and we send the sheet.
Which standard covers the weld end?
ASME B16.25. We machine the standard 37.5 degree bevel with a 1.6 mm root face, and we follow your WPS if it asks for something else.
What comes with the shipment?
EN 10204 3.1 material test certificate per heat, packing list, and a dimensional check sheet if your PO requires one. Original documents go with the goods, scans go out before loading.
Can I order mixed sizes in one container?
Yes, and you do not need a full container. We consolidate mixed sizes into one crate and ship LCL.
Send us your size list – pipe size, class, wall thickness, quantity – and we send back price and lead time on every line.
Looking for weld neck flanges with EN 10204 3.1 MTC? Send your sizes to Mingyang Pipe Fittings for firm prices and lead times.