DIFFERENCE BETWEEN BUTT-WELDED FLANGES AND NECK-WELDED FLANGES

What are butt welding flanges and flat welding flanges with necks? What is the connection between them and what is the difference?

 

What is a butt welding flange

Butt welding flange is a kind of pipe fitting, which refers to a flange with a neck and a round pipe transition and connected to the pipe by butt welding. Butt welding flange is not easy to deform, has good sealing, and is widely used. It has corresponding rigidity and elasticity requirements and reasonable butt welding thinning transition. The distance between the welding port and the joint surface is large, and the joint surface is protected from welding temperature deformation. It is more complicated. The squeak shape structure is suitable for pipelines with high pressure or temperature fluctuations or high temperature, high pressure and low temperature pipelines. It is generally used for the connection of pipelines and valves with PN greater than 2.5MPa; it is also used for conveying expensive, flammable and explosive on the medium pipeline.

 

What is a flat welded flange with a neck

The flat welding flange with neck is the same as the flat welding flange.It also extends the steel pipe, pipe fittings, etc. into the flange and is connected to the equipment or pipeline through the fillet weld.The sealing surface of the flat welding flange with neck is: raised surface (RF) , Concave surface (FM), convex surface (M), tenon surface (T), groove surface (G), full plane (FF). The material of neck flange welding is carbon steel, Luomo steel, 304, 316, 304L, 316L, 321, 347, CF8C.

The flat welded flange with a neck is also a flat welded flange, because it has a short neck, which improves the strength of the flange and improves the bearing strength of the flange. So it can be used on higher pressure pipes. Compared with plate-type flat welding flanges, the cost is higher, and due to its shape, it is easier to bump during transportation.

 

Distinction between butt welding flange and flat welding flange with neck

1. The weld form is different: Flat welds cannot be radiographically detected, but butt welds can. The difference between a flat welded flange with a neck and a flat welded flange without a neck is that the flat welded flange with a neck is one more than the one without a flat welded flange in the pipeline. .

2. The nominal pressure is different: the nominal pressure of the neck-welded flange is: 0.6 --- 4.0MPa, while the nominal pressure of the neck-welded flange is: 1--25MPa, obviously, the neck-welded flange The adaptive pressure level is lower.

3. Different connection methods: the biggest difference in the structure of the neck welded flange and the neck butt welded flange is the difference in the connection method of the nozzle and the flange. The neck welded flange is generally a corner joint between the nozzle and the flange , But the neck butt welding flange is the flange butt joint.

 

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