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Let’s Learn about These Flanges

Sep. 15, 2020

Flanges refer to the inlet and outlet components used to connect pumps, valves, machines, and other mechanical equipment with pipelines, and are usually integrated with these pipelines as part of the equipment. I believe that many people are very curious about this kind of component, and the Needle Valve supplier will take everyone to learn about these flanges.

1. The threaded flange is a non-welded flange, in which the inner hole of the flange is processed into pipe threads and connected with the threaded pipe. Compared with welding flanges, it has the characteristics of convenient installation and maintenance. It can be used on some occasions where welding is not allowed on site. But when the temperature is higher than 260 degrees Celsius and lower than -45 degrees Celsius, it is recommended not to use threaded flanges to avoid leakage accidents.

2. Flat welding flange is also called a lap welding flange. The connection between the flat welding flange and the pipeline is to insert the pipeline into the inner hole of the flange to a suitable position, and then perform lap welding. Its advantage is that it is easy to align during welding and assembly, and the price is cheap, so it has been widely used. Calculated according to the internal pressure, the strength of the flat welding flange is about two-thirds of the corresponding butt welding flange. The fatigue life is about one-third of that of the butt-welded flange. Therefore, flat welding flanges are only suitable for piping systems with relatively low-pressure ratings and no serious pressure fluctuations, vibrations, and shocks.

Definition of flat welding: when the surface to be welded is in an approximately horizontal position. Weld from above the joint.

Horizontal welding and horizontal plate welding are generally called flat welding. The inclination angle of the weld is 0 ~ 5. The welding position where the weld angle is 0 ~ 10 is called the flat welding position, and the welding at the flat welding position is called flat welding. This welding position belongs to the easiest position among all welding positions.

Flat welding flange: A type of flange that is directly welded to equipment or pipelines through fillet welds. It has a simple structure and convenient processing.

Threaded Flange

Threaded Flange

When used on the container, it is divided into A-type flat welding flange and B-type flat welding flange. Type A flat welding flange is directly welded to the container, and the weld size is small or no bevel welding is required. It cannot guarantee that the flange and the container are stressed at the same time. A thick short section is attached to the B-type flat welding flange, and the welding quality between the flange and the short section is reliable, which can ensure that the flange and the container are stressed at the same time. Flat welding flanges are widely used to connect medium and low-pressure vessels and pipelines.

3. Plate welded flange: Because the flange is directly welded to the steel pipe, the flange plate is in a poor state of force during operation and is easily deformed. Suitable for low-pressure occasions.

4. Long Weldneck Flange: Due to the addition of a thicker flange neck, the rigidity of the flange is increased. Greatly reduce the deformation of the flange. Suitable for medium and low-pressure occasions.

5. Butt welding flange also called high neck flange, is different from other flanges in that there is a long and inclined high neck from the joint between the flange and the pipe to the flange plate. And the wall thickness of the high neck gradually transitions to the pipe wall thickness along the height direction, which improves the stress discontinuity, thereby increasing the strength of the flange. Butt welding flanges are mainly used in harsh working conditions, such as large stresses or repeated stress changes at the flange due to pipeline thermal expansion or other loads. Pipelines with large pressure and temperature fluctuations, high temperature, high pressure, and sub-zero temperature pipelines.