Definition and Details of Weld Neck Flange 

Weld neck flange (also known as a high-hub flange and tapered hub flange) is a type of flange. There are two designs. The regular type is used with pipes. The long type is unsuitable for pipes and is used in process plant.A weld neck flange consists of a circular fitting with a protruding rim around the circumference. Generally machined from a forging, these flanges are typically butt welded to a pipe. The rim has a series of drilled holes that permit the flange to be affixed to another flange with bolts.

Advantages of Weld Neck Flange 

Such flanges are suitable for use in hostile environments that have extremes of temperature, pressure or other sources of stress.The resilience of this type of flange is achieved by sharing the environmental stress with the pipe with which it is welded.This type of flange has been used successfully at pressures up to 5,000 psi.

The welding neck flange derives its name from the neck portion of the flange that is welded to the end of a piping system. It is designed to transfer stress to the pipe, thereby reducing high stress concentrations at the base of the flange. Weldneck flanges are costlier due to their design and engineering, and increased material.

Uses of Weld Neck Flanges:

Weld Neck Flanges have a long tapered hub and are often used for high pressure applications. When ordering a weld neck flange, it is important to specify the schedule pipe is being used for. This is because the inside diameter of the flange will match the inside diameter of your pipe. The buttweld joint this flange has with the pipe along with the tapered hub, makes this flange very resistant to dishing and a very sturdy connection. These flanges are ideal for extreme fluctuations of temperature and in environments where there may be a lot of bending and handling of the flanges.

Weld Neck Flanges Size and Pressure 

Size : 1/8″ NB TO 48″NB.

Class : 150#, 300#,400 #,600#,900#, 1500# & 2500 #.

Weld Neck Flanges Standard 

ASME B16.5 Pipe Flanges and Flanged Fittings
ASME B16.47 Series A Steel Flanges NPS 26 Through NPS 60
API 605/ASME B16.47 Series B Steel Flanges NPS 26 Through NPS 60
BS EN 1759 Flanges and their joints. Circular flanges for pipes, valves, fittings and accessories, class-designated. Steel flanges
EN 1092 Circular flanges for pipes, valves, fittings

BS 3293 Carbon steel pipe flanges For the petroleum industry

BS 4504 Circular flanges for pipes,valves and fittings
JIS B2220 Steel pipe flanges
DIN 2628 PN250 Welding Neck

DIN 2629 PN320 Welding Neck
DIN 2630 PN2.5 Welding Neck Flange
DIN 2631 PN6 Welding Neck Flange
DIN 2632 PN10 Welding Neck Flange
DIN 2633 PN16 Welding Neck Flange
DIN 2634 PN25 Welding Neck Flange
DIN 2635 PN40 Welding Neck Flange
DIN 2636 PN64 Welding Neck Flange
DIN 2637 PN100 Welding Neck Flange
DIN 2638 PN160 Welding Neck Flange
GOST 12821 Steel Butt Welded/Weld Neck Flanges for Pnom from 0.1 to 20.0 MPa

Weld Neck Flange Materials:

Carbon Steel Blind Flange:
A105 GradeⅠ Carbon Steel Blind Flange
A105 GradeⅡ Carbon Steel Blind Flange
Alloy Steels Blind Flange:
A182 Grade F1 Alloy Steel Blind Flange
A182 Grade F5 Alloy Steel Blind Flange
A182 Grade F7 Alloy Steel Blind Flange
A182 Grade F9 Alloy Steel Blind Flange
A182 Grade F11 Alloy Steel Blind Flange
A182 Grade F12 Alloy Steel Blind Flange
A182 Grade F22 Alloy Steels Blind Flange
Low-Temperat Steel Blind Flange:
A350 Grade LF1 Low-Temperat Steel Blind Flange
A350 Grade LF3 Low-Temperat Steel Blind Flange
A350 Grade LF4 Low-Temperat Steel Blind Flange
A350 Grade LF6 Low-Temperat Steel Blind Flange
A350 Grade LF8 Low-Temperat Steel Blind Flange
Stainless Steel Blind Flange:
A182 Grade F304 Stainless Steel Blind Flange
A182 Grade F304H Stainless Steel Blind Flange
A182 Grade F304L Stainless Steel Blind Flange
A182 Grade F316 Stainless Steel Blind Flange
A182 Grade F316H Stainless Steel Blind Flange
A182 Grade F316L Stainless Steel Blind Flange
A182 Grade F321 Stainless Steel Blind Flange
A182 Grade F321H Stainless Steel Blind Flange
A182 Grade F347 Stainless Steel Blind Flange
A182 Grade F347H Stainless Steel Blind Flange