Stainless Steel Long Welding Neck (LWN) Flanges
A long welding-neck (LWN) flange has a longer neck than a standard WN and is common on vessel and exchanger nozzles.
Specifications
Pressure class
ASME Class 150–2500 and all PN ratings (EN 1092-1, GB/T 9124); non-standard per drawing
Size range
All standard sizes, up to DN3000; ASME B16.5 to NPS24, larger per B16.47 or drawing
Standard
Flange face per standard + neck length per drawing; overall per drawing
Facing
RF as usual; FF / RTJ per drawing
Neck / pipe wall
Neck length / bore per drawing (not a standard WN neck table); bore matched to pipe or vessel
Bevel
LWN bevel per drawing
Grade
304/304L, 316/316L, 310S, 321, 2205, 2507
Forging material spec
ASTM A182 F304/F304L, F316/F316L, F321, F310, F51 (2205), F53 (2507)
Process
forged → solution annealed → machined and drilled → pickled and passivated
Inspection
MTR available on request; hydrotest/NDT and lead time per order
Marking
Hard stamping or ink marking, per standard or order
Certificates
ISO 9001/14001/45001, PED, DNV, BV, TÜV SÜD factory approvals; see this site’s Certificates page
Inquiry checklist
When inquiring, state: pressure class, size, grade, facing, standard or drawing; non-standard parts can be made to drawing or sample.