1 Different weld foams: a round pipe with neck flat welding flange and flange weld foam are fillet welds, while neck butt weld flanges and pipe seam weld foam are ring welds;
2 Different materials: The material of the neck flat welding flange is processed from ordinary steel plates of the required thickness, but the material of the neck butt weld flange is mainly processed from forged steel parts;
3 The nominal pressure is different: the nominal pressure of the flat welding flange with the neck is 0.6-4.0MPa, and the nominal pressure of the butt flange is 1-25MPa.
Neck butt welding flanges and connecting pipes are B-type seams, neck flat welding flanges and connecting pipes are C-type seams, and the non-destructive testing after welding is different.
The neck flat welding flange and the neck flat welding flange are not easy to replace. From a manufacturing point of view, the slip-on flange (SO stands for SLIPON) has a larger inner diameter, so it is light in weight and low in cost. In addition, weld neck flanges (WN stands for “weld neck”) having a nominal diameter greater than 250 mm must be tested, eliminating the need to test SO flanges, and reducing costs.
4 Various forms of welding: flat welding cannot be inspected by X-ray photography, but butt welding can be inspected. The flange welding method of the pipe neck flat welding flange is fillet welding, and the welding method of the neck butt welding flange and the pipe is ring welding. Flat welds are two fillet girth welds. A butt weld is a butt weld. The difference between the flat welding flange with a neck and the flat welding flange without a neck is that the flat welding flange with a neck has one more pipe welding position than the flat welding flange without a neck. The neckless flat welding flange is also a flat flange, and the boss without a flange is also a flat fillet weld. The welding between the neck flat welding flange and the connecting pipe belongs to the B type seam, and the welding between the neck flat welding flange and the connecting pipe belongs to the C type seam, and the non-destructive test after welding is different.
5 Different nominal pressures: the nominal pressure of the neck flat welding flange is 0.6—4.0MPa, and the nominal pressure of the neck butt welding flange is 1-25MPa. Apparently, the neck is flat welded. The applicable pressure rating of the flange is lower.
6 Differences in connection methods: The biggest structural difference between the neck flat welding flange and the neck flat welding flange is the connection difference between the pipe and the flange. Slip-on neck flanges are usually pipe and flanges. Corner connection, neck butt welding flange Flange is a butt joint of flange and nozzle.
Flat welding flanges can usually only be connected to pipes, not directly to butt weld pipe joints. Weld neck flanges can generally be directly connected to all butt weld pipe joints (including elbows, tees, reducers, etc.). That includes plumbing, of course.
Neck weld neck flanges are stronger than butt weld flanges, and butt welds are stronger than butt welds and have less leakage.
Neck flat welding flanges and neck flat welding flanges cannot be easily replaced. From a manufacturing point of view, the inner diameter of the neck flat welding flange (that is, the flange) is relatively large, so it is light in weight and low in cost. In addition, butt weld flanges with a nominal diameter neck greater than 250mm (WN stands for “weld neck”) must be tested, while SO flanges are not required to be tested, so the cost is relatively low.