First of all, the welding method is different: the welding method of the necked flange pipe is fillet weld, and the welding method of the necked butt welded flange and the pipe is the girth weld. Different materials: the data of the necked flat welded flange is required It is processed by thick general steel plate, and the flange material with neck butt welding is mainly made of forged steel parts.
The nominal pressure is different: the nominal pressure of the flat-neck welded flange is 0.6~4.0MPa, and the nominal pressure of the necked welded flange is 1~25 MPa. The welds of necked butt-welded flanges and pipes are classified as Class B welds, and the welds of necked flat-welded flanges and pipe joints are classified as Class C welds. The non-destructive testing after welding is different.
The difference between neck butt welding flanges and neck butt welding flanges. Neck butt welding flanges and neck butt welding flanges cannot be replaced at will. As far as the manufacturing angle is concerned, the neck flat welding flange (SLIPON for short SLIPON) is large and light ,low cost. In addition, butt welding flanges with a nominal diameter greater than 250 mm (WN is the abbreviation of WELDINGNECK) should also be tested, and the cost is low.
The shape of the weld is different: the flat weld seam cannot be inspected by radiography, but the weld seam is inspected by radiography. The welding method of the flange and the flange is fillet welding, and the welding method between the neck butt welding flange and the pipe fittings is the girth weld, the flat welding is the two-corner girth weld, and the butt welding is the butt weld girth weld. The difference between a flat-welded flange with a neck and a flat-welded flange without a neck is that, in the welding part of the pipeline, there are more flat-welded flanges with a neck than a welding flange without a neck.