Attach the latest drawing revision and project specification
Long Weld Neck Flange Drawing Checklist
Long weld neck flange quotations depend heavily on drawing detail. Overall length, neck outside diameter, bore, weld transition, facing, material, heat treatment and inspection process should be visible before quotation review starts.
Key Points
Confirm length, neck OD, bore and weld transition detail
List pressure class, facing, material and heat treatment
Include NDT, document and third-party inspection requirements
Long Weld Neck Drawing Dimensions to Confirm
| Dimension item | What to send | Typical impact | Inspection note |
|---|---|---|---|
| Overall length | Full neck length from flange face to weld end | Controls forging blank length and machining time | Dimensional report required |
| Neck OD | Outside diameter along the long hub | Controls turning envelope and weight | Check taper or straight neck |
| Bore / schedule | Bore diameter or pipe schedule | Affects weld-end fit-up | Gauge bore after machining |
| Facing | RF, FF or RTJ | Changes final machining process | Confirm surface finish |
| Class | ASME Class 150 to 2500 or project pressure | Controls flange thickness and bolt pattern | High class may need RTJ/NDT |
| Material | A105, LF2, stainless or duplex | Controls heat treatment and certificate route | PMI for alloy grades |
Practical Checklist
- Latest drawing revision with units and tolerances
- NPS or DN, pressure class or PN, and bolt pattern
- Overall length, neck outside diameter and flange outside diameter
- Bore, weld-end transition and any wall thickness requirement
- Facing type such as RF or RTJ and surface finish notes
- Material grade, heat treatment and impact test requirement
- Quantity, destination country, packing and inspection document requirements
Common RFQ Mistakes
- Requesting a long weld neck flange price without a drawing
- Omitting overall length or neck outside diameter
- Leaving bore and weld transition unclear for high-pressure service
- Assuming standard ASME dimensions cover a custom high hub design
- Not stating NDT, impact test or third-party inspection before quotation
FAQ
What dimensions define a long weld neck flange drawing?
Overall length, neck outside diameter, bore and its tolerance, wall transition to the weld end, flange class and facing, plus the bolt pattern. LWN items are usually drawing-controlled, so the current revision must accompany the RFQ.
What is the difference between LWN and a standard weld neck flange?
A long weld neck has an extended cylindrical neck often used as a nozzle on vessels and exchangers, machined from a solid forging. A standard weld neck has a short tapered hub for butt-welding to pipe.
Which tests are typical for long weld neck flanges?
Dimensional report against the drawing, UT of the forging, MTC 3.1, and heat treatment records are common; vessels projects often add impact tests and third-party inspection. The scope should be fixed in the RFQ.
Send your RFQ or drawing directly to BLD Forge Direct.
Email quote@bldforgedirect.com with standard, drawing, material, quantity and inspection requirements.