A weld neck flange is a type of industrial flange designed to transfer stresses to the pipe to reduce high stress concentrations at the base of the flange. Compared with other types, weld neck flanges are known for their tapered hub and gentle transition from flange thickness to pipe wall thickness. They are deformation-resistant, and are normally used for high pressure, high or low temperature conditions.

Size
Weld neck flange: 3/8"～160"
DN10～DN4000

Pressure
American Series: CLASS 150, CLASS 300, CLASS 400, CLASS 600, CLASS 900, CLASS 1500, CLASS 2500
European Series: PN 2.5, PN 6, PN 10, PN 16, PN 25, PN 40, PN 63, PN 100, PN 160, PN 250, PN 320, PN 400

Flange Facing Types
American Series: Flat Face(FF), Raised Face(RF), Tongue(T), Groove(G), Female(F), Male(M), Ring Joints Face(RJ)
European Series: Type A(Flat Face), Type B(Raised Face), Type C(Tongue), Type D(Groove), Type E(Spigot), Type F(Recess), Type G(O-Ring Spigot), Type H (O-Ring Groove)

Materials
Carbon steel: A105
Alloy steel: A182 F 1-F 2-F 5-F 9-F 10-F 91-F 92-F 122-F 911-F 11-F 12-F 21-F 22
Stainless steel: A182 304-304H-304L-304N-304LN 316-316H-316L-316N-316LN 321-321H 347-347H
Low temperature steel: A522 A707 Grade L 1-L 2-L 3-L 4-L 5-L 6-L 7-L 8
High performance steel: A694 F 42-F 46-F 48-F 50-F 52-F 56-F 60-F 65-F 70

Standards
GB/T9112-2000
GB/T9115.1-2000 GB/T9115.2-2000 GB/T9115.3-2000 GB/T9115.4-2000
GB/T9124-2000
GB/T13402-1992
SH/T3406-1996
GD2000 GD87-1101
JB/T74-1994
JB/T75-1994
JB/T82.1-1994 JB/T82.2-1994 JB/T82.3-1994 JB/T82.4-1994
HG/T20592-2009 HG/T20614-2009
HG/T20615-2009 HG/T20623-2009 HG/T20635-2009
ASME B16.5-2009 ASME B16.47-2006
API605-1988
MSS SP 44-2006
CSA Z245.12-05-2005
EN1092-1-2007 EN1759-1-2004
DIN2630 DIN2631 DIN2632 DIN2633 DIN2634 DIN2635 DIN2636 DIN2637 DIN2638
BS1560-3.1-1989 BS4504-3.1-1989
AFNOR NF E29-200-1-2007
ISO7005-1-1992
AS2129-2000
JIS B2220-2004