This standard specifies the types and dimensions of hubbed threaded gray cast iron, ductile cast iron and malleable cast iron pipe flanges whose nominal pressure, PN, is 1.0, 1.6, 2.0, 2.5, 4.0 or 5.0MPa.
2 Normative References
The following normative documents contain provisions which, through reference in this text, constitute provisions of this standard. At time of publication, the editions indicated were valid. All the standards will be modified, and all parties using this standard shall discuss the possibility of using the latest version.
GB/T 17241.3-1998 The following standards are cited：
