A weld neck flange, also called a tapered hub flange or high-hub flange, is a kind of flange that can relocate stress to the pipes, ensuring a decrease in high-stress concentration at the bottom of the flange. There are two welding neck flanges designs – the first type is used with wipes while the second, longer type cannot be used with pipes but with a process plant. The weld neck flange comprises of a round fitting that extends beyond the rim of the circumference. These flanges, typically manufactured from forging, are actually welded to pipes.
The rim has numerous holes drilled into it that enables the flanged to be attached to a bolted flange. This design is far better because of the structural valve.
Types of Weld Neck Flange:
1. Long weld neck Flange
Long weld neck flange(LWN flange) is also call integral flange, it means a welding neck flange has a very long neck. Commonly, the welding neck flange has a tapered neck and a bevel end which is going to butt welding with the matching pipe. But the long weld neck flange, has a straight short pipe as the neck of a long weld neck flange.
2. Reducing Weld Neck Flange
Reducing WN Flange also called Reducing WN flange, because the flange neck has a reducing diameter that to weld to a smaller diameter pipe.
3. NW Long Weld Neck Flanges
The NW Long Weld Neck Flange 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 NW Long Weld 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.
Material: Carbon, Alloy and Stainless Steel
Sizes: 1/2'' to 24'', Customized up to 48''
Thickness: Schedule 10(S) to SCH 160
Class range: Class 150 to 2500(# or LB). PN 2.5 to PN 250
Face Type: RF, RTJ
ASTM A105 for carbon steel welding neck flanges.
ASTM A182 for alloy and stainless welding neck flange. (Alloy for F11, F22, stainless for F304/F304L, F316/F316L)
ASME B16.5
ASME B16.47
BS 3293
DIN 2630 PN 1 and PN 2.5, 2631 PN 6, 2632 PN 10, 2634 PN 16, 2634 PN 25, 2635 PN 40
Prior to ordering the weld neck flange, the companies shall need to confirm the material standard, outer diameter, pressure class, face type and thickness schedule.
A standard description for welding neck flange is: '' Flange, 10'' Weld Neck, Class 150, RF, Schedule 40, ASTM A105 ASME B 16.5.''
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