Body Dimensions of Cast Steel Gate Valves
1.3.1 Flanged Ends
18.104.22.168 Body end flanges shall comply with the dimensional requirements of ASME B16.5. Unless otherwise
specified, raised face end flanges shall be provided.
22.214.171.124 Face-to-face dimensions shall be in accordance with ASME B16.10 or ISO 5752. Body end flanges and
bonnet flanges shall be cast or forged integral with the body. However, flanges may be attached by welding when
approved by the purchaser.
126.96.36.199.1 Welding a flange to a valve body shall be by full penetration butt-welding. Unless otherwise specified,
attachment weld shall conform to ASME B31.3 or ISO 15649 for normal fluid service, including weld quality
acceptance criteria and qualifications for the weld procedure and welder or welding operator. Heat treatment shall be
performed in accordance with Table 3.
188.8.131.52.2 Integral or other alignment rings (centering backing rings) used to facilitate welding shall be removed after
the weld is completed.
1.3.2 Butt-welding Ends
184.108.40.206 Butt-welding ends for valve sizes greater than NPS 2 shall conform to the requirements of ASME B16.25 for
the bore specified for use without backing rings. Conversion of a flanged end gate valve to a butt-welding valve is not
permitted except by agreement between the purchaser and manufacturer.
220.127.116.11 End-to-end dimensions for butt-welding end class designated valves shall be in accordance with ASME
B16.10, unless otherwise specified by the purchaser.
1.3.3 Body Seats
18.104.22.168 The inside diameter of the seat opening shall not be less than that specified in Annex A of ASME B16.34 for
the nominal pipe size and pressure class.
22.214.171.124 Integral body seats are permitted in austenitic stainless steel gate valves. When an austenitic stainless steel or a
hardfacing material is used for the body seat, this material may be weld-deposited directly on the valve body.
126.96.36.199 Where separate seat rings are provided, they shall be shoulder or bottom seated, and either threaded or
welded in place, except that for NPS < 2 (DN ≤ 50) rolled or pressed in seat rings may be used. Threaded seat rings
in ASME Class 600 or higher pressure class valves shall be seal welded.
188.8.131.52 Body seat rings shall have adequate seating area surface and shall have edges equipped with a radius or
chamfer as necessary, to prevent galling or any other damage to the disc when the valve is operated against pressure.
184.108.40.206 Sealing compounds or greases shall not be used when assembling seat rings; however, a light lubricant
having a viscosity no greater than kerosene may be used to prevent galling of mating threaded surfaces.