Difference between necked butt welding flange and necked flat welding flange

The main differences between butt-welded flanges and flat-welded flanges are the different types of welds, different materials, different nominal pressures, and different connection methods, as follows.

1. The form of the weld is different: The weld of the flat weld cannot be inspected by radiation, but the weld of the butt weld can. The welding form of the pipe and flange with neck flat welding flange is fillet weld, and the welding form of the neck butt welding flange with pipe is girth welding; Butt welding is a butt weld. 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 in the pipeline welding part than the flat welded flange without a neck. The flat welding method without a neck Blue is also a flat flange, and the boss without flange is also a fillet weld. Welds with neck butt-welded flanges connected to the pipe are Class B seams, and welds with necked flat-welded flanges connected to the pipe are Class C seams. The non-destructive testing after welding is different.

2. Different materials: The material of the neck welded flange is machined from ordinary steel plates with a thickness that meets the requirements, while the material of the neck welded flange is mostly machined from forged steel.

3. Nominal pressure is different: The nominal pressure of the flat welding flange with neck is 0.6 --- 4.0MPa, while the nominal pressure of the butt welding flange with neck is: 1--25MPa, obviously, the flat welding flange with neck The adaptation stress level is lower.

4. Different connection methods: The biggest structural difference between a flat neck welding flange with a neck and a butt welding flange with a neck lies in the difference between the connection method of the pipe and the flange. Generally, the flat welding flange with a neck is an angle connection between the pipe and the flange. But the neck butt welding flange is the butt joint between the flange and the pipe.