What is the difference between a neck butt weld flange and a neck weld flat flange?

1. The weld seams are different in form: the welded welds with the neck flat welded flanges and the flanges are in the form of fillet welds, and the welded welds with the neck butt welds and the pipes are in the form of girth welds;

    Different materials: the flat welding flange with neck is made of ordinary steel plate with the thickness meeting the requirements, and the material with neck butt welding is machined from forged steel.

    The nominal pressure is different: the nominal pressure of the neck flat welding flange is: 0.6---4.0 MPa, and the nominal pressure of the neck butt welding flange is: 1--25 MPa.

2. Another point is that the weld with the neck butt weld flange and the joint is a type B joint, and the weld with the neck flat weld flange and the joint is a type C joint, and the non-destructive testing after welding is different.

3. The neck flat welding flange and the neck butt welding flange can not be replaced casually. In terms of manufacturing angle, the neck flat welding flange (SO is SLIP ON abbreviation) has a large inner diameter, which means that the weight is small and the cost is low. The necked butt flange with a nominal diameter of more than 250 mm (WN is the abbreviation of WELDING NECK) is to be tested. The flange of the SO does not need to be tested, so the cost is low.

(1) Different weld forms: Flat welds cannot be radiographically flawed, but butt welds can be used. The welding seam of the pipe with the neck flat welded flange and the flange is in the form of fillet weld, and the welded weld of the neck butt weld flange and the pipe is in the form of a ring weld; the flat weld is a joint of two corner joints. Butt welding is a butt joint 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 than the welded portion of the welded joint with no neck, without neck welding. Lan is also a flat flange, and the flange without flange is also a fillet weld. The weld with the neck butt weld flange and the joint is a type B joint, and the weld with the neck flat weld flange and the joint is a type C joint, and the non-destructive testing after welding is different.

(2) The nominal pressure is different: 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 grade, obviously, the neck flat welding flange The adaptation pressure level is lower.

(3) The connection method is different: the biggest difference between the neck flat welding flange and the neck butt welding flange is that the connection between the nozzle and the flange is different. The neck flat welding flange is generally the joint between the neck and the flange. And the neck butt weld flange is the flange and the butt joint.

    Flat welding flanges can only be connected to pipes, but not directly to butt welded pipe fittings; butt welding flanges can be directly connected to all butt welded pipe fittings (including elbows, tees, reducers, etc.). Also includes pipes.

    The rigidity of the neck-welded flange is greater than that of the neck-welded flange, and the butt weld is stronger than the flat weld and does not leak easily.

    The neck-welded flange and the neck-welded flange cannot be replaced casually. In terms of manufacturing angle, the neck-welded flange (so flange) has a large internal diameter, which means that the weight is small and the cost is low. The nominal diameter is more than 250mm. The neck-welded flange (WN is the abbreviation of WELDING NECK) to be tested, the flange of the SO does not need to be tested, so the cost is relatively low.

    Neck-welded flat welding is used on imported petroleum equipment, similar to American standard S0, with neck butt welding flange for highly hazardous medium

    The butt weld flange is the same as the pipe to be welded at the interface end, and is welded like two pipes.

    The flat welding flange is a concave table whose inner hole is slightly larger than the outer diameter of the pipe, and the pipe is welded inside.

    Flat welding and butt welding refer to the welding method when the flange and the pipe are connected. When welding the flat welding flange, only one side welding is required, and the inner joint of the welded pipe and the flange connection is not required. The welding installation of the welding flange requires a double flange. Face welding. Therefore, the flat welding flange is generally used for low and medium pressure pipelines, and the butt welding flange is used for the connection of medium and high pressure pipelines. The butt welding flange is generally at least PN2.5 MPa. The butt welding is used to reduce stress concentration. The welding flange is mostly a neck flange, also called a high neck flange. Therefore, the installation cost of the welding flange, labor and auxiliary materials costs are high, because there is one more process.