High-hub butt-weld connections with a pipe-matched bore
We supply weld neck flanges for wholesale piping and project flange schedules. The tapered hub meets the pipe through a butt weld, with the bore and weld-end thickness selected for that pipe. Material grade, pressure class and sealing face remain part of the same flange item.
| Flange form | Forged weld neck flange with tapered hub |
|---|---|
| Carbon grade | ASTM A105 selection |
| Stainless selections | 304L and 316L material designations under the specified ASTM A182 grade |
| Sealing face | FF, RF or RTJ on the selected flange |
| Pressure class | Selected Class 150, 300, 600, 900, 1500 or 2500 flange configuration |
| Pipe interface | Ordered bore, wall/schedule and butt-weld preparation |
These factory catalog dimensions identify the flange body and raised-face geometry for the listed Class 150 sizes.
| NPS (in.) | Flange OD (mm) | Hub-base diameter (mm) | Raised-face OD (mm) | Flange thickness (mm) |
|---|---|---|---|---|
| 1/2 | 89 | 30.2 | 35.1 | 11.2 |
| 2 | 152 | 77.7 | 91.9 | 19.1 |
| 6 | 279 | 192.0 | 215.9 | 25.4 |
| 12 | 483 | 365.3 | 381.0 | 31.8 |
| 24 | 813 | 663.4 | 692.2 | 47.8 |
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Selected Class 150 RF entries from our weld neck flange catalog, in its published millimeter rounding. The order drawing retains the required bore, weld-end detail and adopted flange specification for each pipe schedule.
Carbon and stainless flange items retain their material specification and grade. The ordered pipe material, service conditions and welding requirements establish the matching selection and required material records.
Class is the flange rating designation. The applicable material group and service temperature establish its permitted pressure under the adopted standard, with the gasket and bolting chosen for the same joint.
A flat face, raised face and ring-joint groove use different mating and gasket arrangements. The scheduled face type remains with the flange class, surface detail and matching equipment connection.
The machining drawing identifies the pipe-side bore and remaining hub-end thickness. The mating pipe dimensions are reviewed at that same weld datum before the bevel is prepared.
The tapered hub provides a transition from the pipe-end section into the flange body. Its length and profile are retained as part of the selected weld neck pattern and connection envelope.
The sealing face and butt-weld end are separate prepared surfaces. Face protection remains in place during handling, while the weld preparation follows the released joint detail and fabrication procedure.
Each line identifies size, class, material, face and pipe wall or bore. Repeated flange sizes can therefore retain different pipe-end preparations without merging their item numbers.
The equipment flange supplies the mating class, face and bolt pattern. The spool drawing adds the pipe-side weld datum and installed face position, giving the fabricator both ends of the connection.
Checks retain bore, weld-end preparation and hub geometry against the ordered pipe interface. The record identifies the drawing revision and the flange item measured.
The required face form and surface detail are compared with the selected gasket arrangement. Protective covers preserve the sealing surface and RTJ groove where specified.
Material identification and required records remain linked to the flange class, size and bore selection. Different wall preparations keep separate item references through dispatch.
Packing supports the flange body and separates sealing faces. Hub-end protectors preserve the weld preparation and prevent adjacent flanges from striking the bevel.
Flanges of the same NPS/class but different pipe bores retain separate quantities and marks. The receiver can match each high-hub item to its spool or pipe schedule.
Our offer lists the material, class, face and bore of each flange. Required records, additional machining, protection and shipment terms appear with that defined selection.
Yes. The pipe wall or required bore establishes the hub-end interface. Retaining that value beside NPS, class and material lets the machine preparation and receiving identity follow the same pipe selection.
The two forms use different weld and axial datums. A replacement layout compares the flange face position, hub length and pipe cutting point, then releases the corresponding weld detail.
The mating ring groove, flange class and size identify the ring designation and joint arrangement. Ring material and hardness are selected with the flange material and service specification, and appear as a separate gasket item where supplied.
Class 150 is a rating designation. The adopted pressure-temperature table for the actual flange material establishes the allowed pressure at the service temperature; the complete joint also retains its specified gasket and bolting.
The large-diameter order names the applicable standard and series or its released drawing. ASME B16.47 addresses NPS 26–60 steel flange families; the selected series, face and bore stay explicit on the quotation.
A revised bore is accepted with the remaining hub section, weld-end detail and applicable flange design requirements reviewed together. The accepted revision updates the machining drawing and material/item identification before the flange is prepared.
Other items in the same product category.
Send NPS, class, material, face and pipe wall or required bore with quantities. Include the adopted specification, equipment flange details and required records. We return an itemized flange and machining offer with packing and delivery terms.