Some Knowledge Of Butt Welding Flange

Butt welding flange refers to the flange with neck, circular pipe transition, and butt welding with the pipe. The butt welding flange is not easy to deform and seal, so it is widely used in pipeline welding. Moreover, the butt welding flange is suitable for pipelines with large pressure or temperature fluctuations or high-temperature, high-pressure, and low-temperature pipelines, and is also suitable for pipelines that transport expensive, flammable, and explosive media.

The butt welding flange is suitable for the connection of steel pipes with a nominal pressure of less than 2.5MPa. It plays an important role and value in the pipe connection, but the nominal pressure needs to be kept within a certain range during use. There are three types of sealing surfaces for butt welding flanges: smooth, concave-convex, and tongue-and-groove. Smooth butt welding flanges are widely used and are mostly used in occasions with mild media conditions, such as low-pressure unpurified compressed air and low-pressure circulating water. It has the advantage of being relatively cheap. Butt welding flanges are suitable for pipelines with large pressure or temperature fluctuations, or high-temperature, high-pressure, low-temperature pipelines, and pipelines that transport expensive, flammable and explosive media.

1. The level and process of the butt welding flange must meet the corresponding requirements of JB4726-4728 to avoid quality problems.

2. Butt welding flanges are generally manufactured by the forging or forging process. If it is made of steel plate or section steel, it must meet the following requirements to be qualified.

1) Ultrasonic flaw detection is required for butt welding flanges. This step is to avoid delamination defects of flanges.

2) The ring butt weld should be heat treated after welding, and ray or ultrasonic flaw detection should be used to prevent the flange from being hidden. The flaw detection standard here needs to meet the national standard.

3) The butt welding flange cannot be directly processed into a neck butt welding flange with a steel plate. It needs to be cut into strips along the rolling direction of the steel, and then bent and welded into a ring, so that the surface of the steel forms a cylindrical surface of the ring. Butt welds require full penetration welds.

3. The technical parameters of butt welding flanges need to be strictly controlled during the production and welding process to ensure that they can fully play their role and value in production and use. Therefore, the lateral inclination of the neck of the butt welding flange should not exceed 7.

Butt welding flanges are mainly used for butt welding of flanges and pipes. Reasonable structure, high strength, and rigidity can withstand high temperature and high pressure, repeated bending and temperature fluctuation, and reliable sealing performance. The butt welding flange with a nominal pressure of 0.25~2.5MPa adopts a concave-convex sealing surface. It is widely used and promoted in butt welding flange pipe fittings, and it needs to be used in corresponding ways and methods.