Weld neck flange connection quality requirements

　　The selection of weld neck flanges must conform to the design requirements. When the design is not required, the appropriate form and specification of the weld neck flange should be selected according to the factors of the highest working pressure, the highest working temperature, the working medium, the material grade of the ASTM 304 RF Class 300 Stainless Steel Weld Neck Flange and so on. The weld neck flange must be inspected before installation. The surface should be smooth. There should be no defects to reduce the strength of the weld neck flange, such as grinding holes, cracks, spots, burrs and so on. There should be no perforative scratches on the sealing surface which affect the sealing performance.

　　When weld neck flange and pipe are assembled, weld neck flange vertical ruler is used to check the verticality of weld neck flange. When the parallel deviation dimension of weld neck flange connection is not specified, it should not be greater than 1.5% of the weld neck flange outer diameter, and not more than 2 mm. When the two weld neck flanges are not parallel and exceed the stipulated requirements, they must be withered and rectified, and multiple gaskets must not be used to correct them. When the weld neck flange is welded to the pipe, the two sides shall be welded according to the standard, and the height of the welding foot shall comply with the regulations.