Socket welding flange refers to the pipe end into the flange ring ladder, in the pipe end and outside welding flange. There are two kinds with and without neck. The flange with neck pipe has good rigidity, small welding deformation and good sealing, which can be used for pressure between 1.0 MPa and 10.0mpa. Container flange type b is also a socket welded flange, used for high sealing requirements. When designing, socket welding flange can be checked by integral flange.