There are GB series (national standard), JB series (mechanical department), HG series (chemical department), ASME B16.5 (American standard), BS4504 (British standard), DIN (German standard), JIS (Japanese standard).

Advantages:

The on-site installation is more convenient, and the process of welding seam rubbing can be omitted

Disadvantages:

The neck height of the flat welded flange with a neck is relatively low, which improves the stiffness and load-bearing capacity of the flange. Compared with butt welded flanges, the welding workload is large, the consumption of welding rods is high, and it cannot withstand high temperature and pressure, repeated bending, and temperature fluctuations.

The connection is not easily deformed, with good sealing effect, and is widely used. It is suitable for pipelines with significant temperature or pressure fluctuations, as well as pipelines with high, high, and low temperatures. It is also used for transporting expensive media, flammable and explosive media, and toxic gases