In high-pressure pipeline systems such as petrochemicals, electric power and energy, butt-welded flanges are very critical connectors. They have excellent sealing and structural strength. The design and application of butt-welded flanges are directly related to the safety and reliability of the entire pipeline system, and will also improve work efficiency and reduce maintenance costs.
What is a welding neck flange?
Also known as tapered hub flanges or high hub flanges, the role of the butt welding flange is to transfer stress to the pipe, thereby ensuring high stress concentration at the bottom of the flange.
There are two main designs of neck welding flanges: the first is used for the connection of pipelines and is suitable for fluid transportation. The second is a longer shape used for process equipment. The neck welding flange consists of a circular joint that extends beyond the circumferential edge. These flanges are usually made of forgings and are actually welded to the pipe.
The neck welding flange is made of forgings, and multiple holes are drilled on the outer rim of the flange in order to connect the flange to the bolted flange.
Core Standards
International standards:
American standard: ASME B16.5 (Class 150~2500)
European standard: EN 1092-1 (PN6~PN100)
Chinese standard:
GB/T 9119 (replaces HG/T 20592)
Welding neck flange type
Long Neck Weld Flange
Similar to Weld Flange, but with a longer neck design, usually used as a cylindrical or barrel nozzle. You can also choose from equal diameter LWN barrel flanges and LWN heavy barrel flanges, which have thick walls and unique shapes.
Reducing Weld Flange
Also known as reduced neck Weld Flange, it has a smaller neck diameter and can be welded to smaller diameter pipes.
NW Long Neck Weld Flange
This flange type is considered a high hub flange and is designed to transfer stress to the pipe and reduce stress concentration at the bottom of the flange.
WN Flange Material
Neck Weld Flange is available in a variety of materials. These materials must meet established standards. The material should also meet the quality requirements specified by ASTM or ASME standards. However, the thickness and inner diameter of the flange will depend on the size of the pipe for which the weld neck flange is manufactured.
Compared with other types
slip on flange vs weld neck
|
Comparison Items |
Slip On Flange |
welding neck flange |
|
Connection method |
The pipe is inserted into the inner hole of the flange and fixed with internal and external fillet welds |
Pipe and flange neck girth weld butt joint, full penetration welding |
|
Applicable pressure |
0.6~4.0MPa (medium and low pressure) |
1~25MPa (high pressure) |
|
Applicable temperature |
Normal or low temperature |
High temperature conditions (such as steam, oil and gas) |
|
cost |
Low (about 60% of WN) |
High (forged steel material + precision machining) |
