The valve body design of the fully welded ball valve has a cylindrical structure and a spherical structure. The cylindrical structure is a double-welded seam. The welding process has large heat input, complex residual stress, and large axial and radial deformation.
The spherical structure is a splice of four welds. Now due to technological progress, the left and right valve bodies are hot forged and formed, which can be welded and formed in the middle of the weld, reducing the input of linear energy and reducing the axial and radial deformation. The split structure is generally composed of a valve body and left-right connecting body.
The connection body and the valve body are connected by bolts. The thickness of the connection flange and the connection strength of the bolts should be designed analogously to the flange equivalent to the inner diameter of the valve body. The connection strength must prevent pipeline stress from slackening the connection and failing the seal.