This document specifies the styles and parameters, types and dimensions, technical requirements, pressure test, inspection and acceptance, marking and labeling, and supply requirements of Class designated cast iron pipe flanges and blank flanges.
This document is applicable to cast iron pipe flanges and blank flanges of gray cast iron and ductile cast iron, nominal pressures Class 25 ~ Class 300, nominal dimensions DN 25 ~ DN 1200 (NPS 1 ~ NPS 48).
2 Normative references
The following documents contain provisions which, through reference in this text, constitute provisions of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 152.4 Fasteners - Counterbores for hexagonbolts and nuts
GB/T 1047 Pipework components—Definition and selection of nominal size
GB/T 1048 Pipework components - Definition and selection of nominal pressure
GB/T 1348 Spheroidal graphite iron castings
GB/T 9439 Grey iron castings
GB/T 12716 Pipe threads with the thread angle of 60 degrees where pressure-tight joints are made on threads
3 Terms and definitions
For the purposes of this document, the terms and definitions given in GB/T 1047 and GB/T 1048 apply.
4 Types and parameters
4.1 Nominal pressure
This document specifies the following 5 pressure classes identified by Class for nominal pressure:
Class 25 (gray cast iron), Class 125 (gray cast iron), Class 150 (ductile cast iron), Class 250 (gray cast iron), Class 300 (ductile cast iron).
4.2 Nominal dimensions
This document specifies the following 21 specifications identified by DN (NPS) for nominal dimensions:
The flange sealing face includes two types: flat face and raised face, in which the flat face code is FF and the raised face code is RF, as shown in Figure 1. The applicable range of flange sealing face is shown in Table 1.
4.4 Flange types, codes and their application scope
The type, code and scope of application of flange are shown in Table 2 and Table 3 respectively.
Contents Foreword i Introduction II 1 Scope 2 Normative references 3 Terms and definitions 4 Types and parameters 4.1 Nominal pressure 4.2 Nominal dimensions 4.3 Types and codes of sealing faces 4.4 Flange types, codes and their application scope 5 Type and dimension 5.1 Type and dimension of integral cast iron pipe flange 5.2 Type and dimension of hubbed screwed cast iron pipe flange 5.3 Type and dimension of cast iron pipe flange with weld-on collar 5.4 Type and dimension of cast iron pipe blank flange 6 Technical requirements 6.1 Flange material 6.2 Pressure-temperature rating 6.3 Dimensional tolerances 6.4 Roughness of flange sealing face 6.5 Fasteners 6.6 Washer 6.7 Machining and manufacturing 7 Pressure test 8 Inspection and acceptance 8.1 Inspection 8.2 Acceptance 9 Marking and labeling 9.1 Marking 9.2 Labeling 10 Ordering requirements and packaging Annex A (Informative) Method for determination of pressure-temperature ratings A.1 General A.2 Method for determination of pressure-temperature ratings Annex B (Informative) Reference value for hydraulic test pressure of the system
