The Welding neck flanges is normally referred to as the high hub flange. It is designed to transfer stresses to the pipe, thereby reducing high stress concentrations at the base of the flange. The welding neck flange is the best designed butt-welded flange of those currently available becuase of its inherent structural value. It is expensive because of the design.
Standards, Dimensions & Weight：
ASME/ANSI B16.5 Class 150 WN
ASME/ANSI B16.5 Class 300 WN
ASME/ANSI B16.5 Class 600 WN
ASME/ANSI B16.5 Class 900 WN
ASME/ANSI B16.5 Class 1500 WN
ASME/ANSI B16.5 Class 2500 WN
ASME B16.47 Series A/MSS SP-44 Class 150 WN
ASME B16.47 Series A/MSS SP-44 Class 300 WN
ASME B16.47 Series A/MSS SP-44 Class 600 WN
ASME B16.47 Series A/MSS SP-44 Class 900 WN
ASME B16.47 Series B/API 605 Class 75 WN
ASME B16.47 Series B/API 605 Class 150 WN
ASME B16.47 Series B/API 605 Class 300 WN
ASME B16.47 Series B/API 605 Class 600 WN
ASME B16.47 Series B/API 605 Class 900 WN
BS 3293 Class 150 WN
BS 3293 Class 300 WN
BS 3293 Class 600 WN
DIN 2631 PN 6
DIN 2632 PN 10
DIN 2633 PN 16
DIN 2634 PN 25
DIN 2635 PN40
GOST 12821-80 PN6
GOST 12821-80 PN10
GOST 12821-80 PN16
GOST 12821-80 PN25
Specifications:
Size: 1/2” to 60”, DN 12mm to DN 1500mm
Pressure class: Class 150 to Class 2,500, PN 2.5 to PN 250
Facing: RF / RTJ
Material: Cabon steel: A105, A350 LF2, C22.8, S355JR
Stainless steel: A182 F304/F304L/F316/F316L/F321
Alloy steel: F11, F12, F22
Packing: plywood case and plywood pallet
NW Long Weld Neck Flanges：
Tube OD sizes: 3/8 to 2 inches
Materials:
Flange: 304 or 316L stainless steel
O-rings: Viton, Buna, & silicone
Fasteners: Wingnut, SureSeal, bulkhead & EVAC clamps
Vacuum range：
Elastomer seal: >=1 x 10^-8 Torr – High vacuum
EVAC metal seal: >=1 x 10^-11 Torr – UHV
Temperature range：
Viton: -20°C to 200°C
Silicone: -50°C to 230°C
Buna: -30°C to 110°C
EVAC metal seal: -270°C to 150°C