The difference between weld neck flange and slip-on flange

What is Weld neck flange?

Weld neck flange is a device with complex structure.

First of all, it is suitable for high pressure or temperature fluctuations of the pipeline or high pressure, low temperature pipeline.

Secondly, it is generally used for PN greater than 2.5MPa pipe and valve connection.

Finally, it can also be used in the transport of expensive, flammable, explosive medium in the pipeline.

What is Slip on flange?

Slip on flange is a full name of steel pipe with neck flat welding flange. It is a kind of steel pipe and pipe fittings extension into a flange, the process is through fillet welding and equipment or pipe connection flange.

The difference between weld neck flange and slip-on flange

Different forms of their welds

The weld form of flange pipe and flange neck flat welding is fillet welding, while the weld form of flange pipe and flange neck butt welding is ring welding.

different materials

The weld neck flange is made by ordinary steel plate machine according to the required thickness, while the slip on flange is made by machine processing with forged steel parts.

different nominal pressure

The weld neck flange nominal pressure is 0.6 — 4.0MPa. Slip on flange nominal pressure is 1 — 25MPa.

Different connection

The connection between weld neck flange and pipeline belongs to Class B joints. The connection between slip on flange and pipeline belongs to class C joints, and the NDT after welding is different.

Different cost

In terms of manufacturing angle, the weld neck flange has a large inner diameter, small weight, and low cost. In addition, weld neck flanges with nominal diameters greater than 250mm need to be tested. SO flanges do not need to be tested, So the cost is relatively low.

Conclusion:

In conclusion, the big difference between the two products lies in the connection mode of pipe and flange. The flange of the former is generally connected through the flange angle. While the flange of the latter is the butt connection between the flange and the pipe.