The sealing surface forms of the neck butt welding flange are:

Raised surface (RF), concave surface (FM), convex surface (M), tenon surface (T), groove surface (G), full surface (FF).

advantage:

The connection is not easy to deform, the sealing effect is good, and it is widely used. It is suitable for pipelines with large fluctuations in temperature or pressure or high temperature, high pressure and low temperature pipelines. It is also used for pipelines that transport expensive media, flammable and explosive media, and toxic gases.

shortcoming:

The necked butt welding flange is bulky, heavy, expensive, and difficult to install and locate. Therefore, it is easier to bump during transportation.